Micro-Para (Reviewer)

Question 1

1. Carlo has leukemia; unfortunately, he was exposed to HBsAg positive blood. The best immediate management which can be given to him is to give:
   a. recombinant Hep B
   b. Vaccine passive immunization
   c. anti-viral drugs
   d. vitamins

Answer 1

b. Vaccine passive immunization

Rationale: In cases of exposure to HBsAg positive blood, the best immediate management is to provide passive immunization with hepatitis B immune globulin (HBIG) to provide immediate protection.

Question 2

2. Mario, a 45-year-old executive is a sickly guy. He always complains of coughs and colds. He used to be a smoker but he had stopped since he was in his early thirties. His doctor said that he is often attacked by organisms which attack/attach to the mucous membranes of his respiratory tract. These organisms then do which of the following actions against its host:
   a. breakdown of IgA by producing proteases
   b. evasion of phagocytosis by means of their capsule
   c. excretion of hyaluronidase
   d. neutralization of lysozymes

Answer 2

a. breakdown of IgA by producing proteases

Rationale: Many pathogens that infect the respiratory tract produce IgA proteases to break down IgA antibodies, facilitating their ability to infect mucous membranes.

Question 3

3. A child who is breastfed is not usually prone to diarrhea, this is probably because of:
   a. the presence of hydrolytic enzymes in the saliva which kills most bacteria
   b. the acidity of the stomach
   c. presence of proteolytic enzymes and active macrophages in the small intestines
   d. all of the above

Answer 3

d. all of the above

Rationale: Breastfeeding provides various protective factors including hydrolytic enzymes, the acidity of the stomach, and the presence of proteolytic enzymes and active macrophages in the intestines, which collectively help prevent diarrhea.

Question 4

4. Luna was diagnosed to have a starting skin cancer, which somehow spontaneously resolved. Aside from a possible miracle, the doctor said it could be due to Luna’s natural killer cells. Which is NOT a characteristic of natural killer (NK) cells?
   a. morphologically related to T cells
   b. they can lyse malignant cells
   c. they resemble large granular lymphocytes
   d. all of the above

Answer 4

d. all of the above

Rationale: NK cells are morphologically related to T cells, can lyse malignant cells, and resemble large granular lymphocytes.

Question 5

5. Martin suffers from a runny nose, itchy eyes, and frequent sneezing especially during the months of March to May and November to January. He probably has:
   a. Type I hypersensitivity
   b. Type II hypersensitivity
   c. Type III hypersensitivity
   d. Type IV hypersensitivity

Answer 5

a. Type I hypersensitivity

Rationale: The symptoms of runny nose, itchy eyes, and frequent sneezing, especially during specific seasons, are indicative of Type I hypersensitivity, commonly associated with allergies like hay fever.

Question 6

6. Vivian was rushed to the hospital for shortness of breath. She gave a history of taking penicillin for her sore throat two days prior to admission. She gave no history of allergy to penicillin. Laboratory tests done on her blood showed the presence of antibodies which hemolyze her own RBCs. She is probably suffering from:
   a. Type I hypersensitivity
   b. Type II hypersensitivity
   c. Type III hypersensitivity
   d. Type IV hypersensitivity

Answer 6

b. Type II hypersensitivity

Rationale: The presence of antibodies that hemolyze RBCs after penicillin administration suggests a Type II hypersensitivity reaction, where antibodies target and destroy the body’s own cells.

Question 7

7. Athena was born December 2004. She has an older brother Bitoy who got sick with chickenpox when Athena was one month old. Ikay, another older sister of Athena, got sick with chickenpox while she did not. This is because of:
   a. Maternal IgA
   b. Athena’s IgA
   c. Maternal IgG
   d. Athena’s IgG

Answer 7

c. Maternal IgG

Rationale: Maternal IgG antibodies are transferred to the infant through the placenta and provide immunity to the baby in the first few months of life, protecting Athena from chickenpox.

Question 8

8. Isabel becomes a different person during the months of December. In these months, she is grouchy because of hay fever. Her doctor explained that she is allergic to pollen and the major culprit is the so-called IgE, which is a homocytotropic immunoglobulin that binds to all of the following cells below except:
   a. eosinophils
   b. mast cells
   c. basophils
   d. neutrophils

Answer 8

d. neutrophils

Rationale: IgE binds to eosinophils, mast cells, and basophils but not to neutrophils.

Question 9

9. Betty has colds almost every three months. But she is not bothered because she noticed that even without treatment she gets better. The self-limiting nature of her colds, which is often of viral etiology, is partly attributed to:
   a. Gamma interferon
   b. Alpha interferon
   c. Beta interferon
   d. All choices are correct except A

Answer 9

d. All choices are correct except A

Rationale: Alpha and beta interferons play roles in antiviral responses, helping to limit the duration and severity of viral infections such as the common cold.

Question 10

10. Mike was sick with pneumonia, for which he almost died. Before his discharge from the hospital, he asked the doctor to explain to him his illness and how he was able to recover. The doctor talked about the germs having slimy materials around them. That it was necessary for some substance to coat the germs so that the scavenger’s cells in the body can eat them up. The doctor was referring to opsonization. Which of the following substances is involved in opsonization?
    a. C3a
    b. C3b
    c. C2a
    d. C2b

Answer 10

b. C3b

Rationale: C3b is involved in opsonization, coating pathogens to enhance their recognition and ingestion by phagocytes.

Question 11

11. A 7-year-old girl was brought to the dermatology section of UPHR Medical Center for swollen, weeping earlobes with some signs of crusting. One earlobe has an almost embedded tiny earring. The doctor said the girl was probably allergic to the nickel component of the fancy earrings. This condition is also termed as:
    a. Contact hypersensitivity
    b. Tuberculin hypersensitivity
    c. Atopic hypersensitivity
    d. Immune complex hypersensitivity

Answer 11

a. Contact hypersensitivity
Rationale: Contact hypersensitivity, also known as contact dermatitis, is an allergic reaction caused by direct contact with an allergen such as nickel in earrings.

Question 12

12. Nonong was an OFW from Puerto Rico. He came home because he was diagnosed with syphilis. He consulted a local doctor for a second opinion. The doctor scrapped off the base of the ulcer found in his buccal mucosa. He explained to Nonong that he will add to the specimen a substance which he called antibody to which will be attached a certain dye which will emit light under a “dark microscope.” This immunologic diagnostic test is probably:
    a. Immunoblotting
    b. Immunofluorescence
    c. ELISA
    d. Radioimmunoassay

Answer 12

b. Immunofluorescence
Rationale: Immunofluorescence involves using antibodies tagged with a fluorescent dye to detect the presence of specific antigens under a microscope.

Question 13

13. Jake had typhoid fever. When seen by the doctor he has already been on the third week and had started to feel better. If you can enter Jake’s body which of the following items below would show that he had achieved an adaptive immune response against typhoid bacilli?
    a. physical barriers
    b. chemical barriers
    c. clonal expansion of effector cells
    d. phagocytosis

Answer 13

c. clonal expansion of effector cells
Rationale: Clonal expansion of effector cells indicates an adaptive immune response, where specific immune cells proliferate in response to an antigen.

Question 14

14. Doy was diagnosed to have an infectious disease of unknown etiology. Examination of his blood showed that the complement levels are normal. In infections, one defense against the agent is the activation of the complement. What then among the items below is the best trigger for the of complement activation?
    a. IgG
    b. Mannose-containing bacterial glycolipids
    c. Microbial surfaces
    d. IgM-antigen immune complexes

Answer 14

d. IgM-antigen immune complexes
Rationale: IgM-antigen immune complexes are potent activators of the complement system, initiating the classical pathway of complement activation.

Question 15

15. A 13-year-boy from Ilocos tested negative in the lepromin test. He presents with multiple, erythematous, anesthetic lesions all over the body. The skin test shows which type of hypersensitivity:
    a. Type I Hypersensitivity
    b. Type II hypersensitivity
    c. Type III hypersensitivity
    d. Type IV hypersensitivity

Answer 15

d. Type IV hypersensitivity
Rationale: The lepromin test and the presentation of multiple erythematous, anesthetic lesions indicate a Type IV hypersensitivity reaction, which is a delayed-type hypersensitivity.

Question 16

16. Roy was found to have antibodies to AIDS by the ELISA method. To confirm the diagnosis, antigens of the virus must be detected in his blood. Which of the following methods will identify the HIV antigen mix in a complex mixture of proteins:
    a. Western blotting
    b. Southern blotting
    c. Eastern blotting
    d. Northern blotting

Answer 16

a. Western blotting
Rationale: Western blotting is used to detect specific proteins, such as HIV antigens, in a complex mixture.

Question 17

17. The human vaccine for this viral infection is made of killed virus grown in human diploid fibroblasts or chicken fibroblasts:
    a. Rubella
    b. Rabies
    c. Jap B encephalitis

Answer 17

b. Rabies
Rationale: The human rabies vaccine is made from killed virus grown in human diploid fibroblasts or chicken fibroblasts.

Question 18

18. Luisa is an absent-minded medical intern. She was asked by the resident to get some influenza vaccines from the refrigerator in the call room and to bring them to the OPD for immunization of the old nurses in the section. Luisa followed the instructions. Unfortunately, she did not find the resident so she placed the vaccine on the table with a short note. After 2-4 hours, the resident came and found the vaccines. Influenza is a killed viral vaccine; all of the following are its disadvantages EXCEPT:
    a. high stability at room temperature
    b. shorter duration of immunity
    c. poor CMI produced
    d. no IgA produced

Answer 18

a. high stability at room temperature
Rationale: Killed viral vaccines like the influenza vaccine are less stable at room temperature compared to live vaccines, making high stability an incorrect disadvantage.

Question 19

19. Allan was bitten by his dog in the lower leg. The wound is not deep but it bled. In the decision to give postexposure prophylaxis the following are considered except which of the following:
    a. manner of attack
    b. nature of biting animal
    c. severity of the bite
    d. none of the choices

Answer 19

d. none of the choices

Rationale: When deciding whether to administer post-exposure prophylaxis (PEP) for rabies after a dog bite, several factors are considered, including:

• Manner of attack: This can indicate whether the dog was provoked or behaving aggressively without provocation, which may suggest a higher risk of rabies.
• Nature of biting animal: Understanding whether the animal is a domestic pet, stray, or wild animal helps assess the likelihood of rabies.
• Severity of the bite: The depth and extent of the bite wound can influence the risk of rabies transmission and the need for PEP.

Question 20

20. Laura was in her 2nd month of pregnancy when she tested positive for Rubella antibodies. Despite this, she decided to continue with the pregnancy. She delivered the baby 4 weeks earlier than the expected date. At a glance, the baby seemed normal. She asked her doctor what could be the possible effect if her baby got congenital rubella. Which of the following could explain any abnormality that may be later seen in Laura’s baby?
    a. infected cells in the baby have a reduced growth rate
    b. hypoplastic organs result in abnormalities in the embryonic cells which have a reduced growth rate
    c. structural anomalies due to hypoplastic organs
    d. all of the above

Answer 20

d. all of the above

Rationale: Congenital rubella syndrome (CRS) can result in various abnormalities and complications for the baby due to the teratogenic effects of the rubella virus on the developing fetus. The effects can include:

• Infected cells in the baby have a reduced growth rate: Rubella virus infection in utero can lead to reduced cell growth and proliferation, affecting overall fetal development.
• Hypoplastic organs result in abnormalities in the embryonic cells which have a reduced growth rate: The virus can cause hypoplasia (underdevelopment) of organs, leading to structural anomalies and reduced function.
• Structural anomalies due to hypoplastic organs: The developmental abnormalities can manifest as structural defects in the heart, eyes, ears, and other organs, which are typical manifestations of CRS.

Question 21

21. A baby born with congenital rubella was found to be deaf. Defects in rubella are grouped into broad categories, i.e., temporary, developmental, permanent. Deafness is under:
    a. temporary
    b. developmental
    c. permanent
    d. none of the choices

Answer 21

c. permanent
Rationale: Deafness resulting from congenital rubella is a permanent defect, as it causes lasting damage to the auditory system.

Question 22

22. Ana is getting married and thus was advised to get her Rubella vaccine shot. Which of the following is/are true of the rubella vaccine?
    a. it is a live attenuated vaccine
    b. it is given to prevent congenital rubella infection
    c. vaccinated children pose no threat to mothers who are susceptible and pregnant
    d. all of the above

Answer 22

d. all of the above
Rationale: The rubella vaccine is a live attenuated vaccine, it is given to prevent congenital rubella infection, and vaccinated children do not pose a threat to susceptible and pregnant mothers.

Question 23

23. Jay, a 9-month-old baby, is rushed to the ER for fever and persistent cough. On examination, rales are heard on his left chest and an infiltrate in the left lung is seen on the chest x-ray film. The diagnosis given is pneumonia. Which of the following viruses is the most likely cause?
    a. Rhinovirus
    b. Respiratory syncytial virus
    c. Adenovirus

Answer 23

b. Respiratory syncytial virus
Rationale: Respiratory syncytial virus (RSV) is a common cause of pneumonia in infants and young children.

Question 24

24. In this viral infection, humans are dead-end hosts, thus virus shedding does not occur.
    a. measles
    b. Rabies
    c. influenza
    d. chickenpox

Answer 24

b. Rabies
Rationale: In rabies, humans are dead-end hosts, meaning the virus is not shed from an infected person and cannot be transmitted to others.

Question 25

25. A ten-year-old girl complained of difficulty and pain in swallowing. It was accompanied by a runny nose and fever. Upon examination, rales are heard on his left chest and an infiltrate in the left lung is seen on the chest x-ray film. The diagnosis given is upper respiratory infection. The most likely etiologic agent for this case is: a. adenovirus b. Respiratory syncytial virus c. Rhinovirus d. Coronavirus

Answer 25

**a. adenovirus** **Rationale:** Adenovirus is a common cause of respiratory infections in children and can present with a variety of symptoms including fever, sore throat (pharyngitis), runny nose, and lower respiratory tract involvement (pneumonia), which can be seen as infiltrates on a chest x-ray. Adenoviruses can also cause more severe respiratory infections, especially in children, leading to symptoms that align well with the given case. **Clue words:** "difficulty and pain in swallowing," "runny nose," "fever," "rales," "infiltrate in the left lung," "upper respiratory infection," "adenovirus"

Question 26

26. Ramon, a 4-year-old boy, was seen by a pediatrician for complaints of low-grade fever, cold, and rash on the face which showed a typical "slapped cheek" appearance. Complaints of flu-like symptoms such as malaise and myalgias were also noted. The pediatrician gave a diagnosis of erythema infectiosum of the fifth disease which is caused by which of the following viruses: a. Hanta virus b. B19 parvovirus c. Herpes simplex d. Coxsackie viruses

Answer 26

b. B19 parvovirus Rationale: Erythema infectiosum, or fifth disease, is caused by B19 parvovirus and is characterized by a "slapped cheek" appearance and flu-like symptoms.

Question 27

27. Last summer, a community hospital in Laguna, recorded 25 cases of pharyngoconjunctivitis among the grade five students from a private school in the nearby municipality. It was learned that all of them attended a summer camp, which lasted for 2 weeks. Which of the following adenovirus serotypes are most likely involved? a. types 3 and 7 b. types 1 and 70 c. types 40 and 45 d. types 8 and 10

Answer 27

a. types 3 and 7 Rationale: Adenovirus types 3 and 7 are commonly associated with pharyngoconjunctivitis outbreaks.

Question 28

28. A 2 ½-year-old boy was noticed by his mother to have less appetite for solid food, but when given ice cream and soft drinks he was quite happy. This was unusual because he likes to eat and play with solid foods. The mother examined him and found that he has some swollen nodules in his neck. Suspecting something in the mouth, she examined the mouth and found vesicular lesions in the buccal mucosa. This is probably caused by: a. Candida albicans b. Streptococcus pyogenes c. Measles virus d. Herpes simplex virus

Answer 28

d. Herpes simplex virus Rationale: Herpes simplex virus can cause vesicular lesions in the buccal mucosa, leading to reduced appetite for solid foods.

Question 29

29. Yoyong, a 15-year-old boy acquired chickenpox. When vesicular lesions became evident, he was "isolated" by his mother from the rest of the family by confining him to his room. After a week, his pocks subsided with some lesions already developing scabs. It was at this time that two other siblings started showing the same signs and symptoms he had. Which of the following items below best describes the disease/etiologic agent involved in Yoyong's case? a. the virus infects only humans b. the disease is highly contagious c. both are correct d. neither one is correct

Answer 29

c. both are correct Rationale: Chickenpox (varicella) virus infects only humans and the disease is highly contagious, explaining the spread to Yoyong's siblings.

Question 30

30. Idang is due two deliver in two weeks’ time. Unfortunately, she had premature labor and delivered a stillborn baby boy. The baby was autopsied and the one finding was the presence of cells that look like “owls eye," i.e. cells with large intranuclear inclusion bodies. The most probable diagnosis is: a. Congenital measles b. Congenital rubella c. Congenital chickenpox d. congenital cytomegalovirus infection

Answer 30

d. congenital cytomegalovirus infection Rationale: The presence of cells with "owl's eye" inclusions is characteristic of congenital cytomegalovirus infection.

Question 31

31. JR, a macho dancer from the red district, did not report for work for almost three days. RJ, his friend, became worried and went to his place. He found JR with fever, headache, and feels weak and tired. They went to the clinic and was found to have enlarged lymph nodes and spleen and slightly icteric conjunctiva. Blood exam showed large, atypical lymphocytes. The most probable diagnosis is: a. Cytomegalovirus infectious mononucleosis b. Infectious mononucleosis c. Herpes simplex infection d. Mumps

Answer 31

b. Infectious mononucleosis Rationale: Infectious mononucleosis, commonly caused by the Epstein-Barr virus (EBV), is characterized by fever, headache, fatigue, enlarged lymph nodes, spleen, icteric conjunctiva, and atypical lymphocytes.

Question 32

32. A 28-year-old woman has recurrent genital herpes. Which of the following about genital herpes infection is true? a. cannot be transmitted in the absence of apparent lesions b. reactivation of latent virus during pregnancy poses no threat to the newborn c. can be caused by either herpes simplex type 1 or type 2 d. recurrent episodes are more severe than the primary infection

Answer 32

c. can be caused by either herpes simplex type 1 or type 2 Rationale: Genital herpes can be caused by either herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2).

Question 33

33. MR consulted a dermatologist for the small, pink, wart-like lesions on her face, arms, back, and buttocks. The diagnosis given was molluscum contagiosum infection. Which of the following about this is NOT true? a. virus has a wide range of host b. transmission is by direct and indirect contact c. it is considered a sexually transmitted disease d. the virus has a DNA genome

Answer 33

a. virus has a wide range of host Rationale: Molluscum contagiosum virus is specific to humans, hence it does not have a wide range of hosts.

Question 34

34. Motong is a leukemia patient. He was admitted for post-transfusion hepatitis. Test showed the etiologic agent to be flavivirus. This virus is: a. Hepatitis A b. Hepatitis B c. Hepatitis C d. Hepatitis E

Answer 34

c. Hepatitis C Rationale: Hepatitis C virus (HCV), a flavivirus, is commonly associated with post-transfusion hepatitis.

Question 35

35. Ferdie was diagnosed as a carrier of Hepatitis B. In one of his follow-ups in the clinic, anti-HBe antibodies were detected in his serum. This means that: a. he is now developing resistance b. his HB virus titer is now low c. it has no meaning d. a mistake was committed because HBs Ag and anti-HBe do not exist together in the blood

Answer 35

b. his HB virus titer is now low Rationale: The presence of anti-HBe antibodies suggests a lower viral replication and a decrease in the infectiousness of Hepatitis B.

Question 36

36. Lola, a middle-aged woman, complained of acute onset fever, and nausea. Her eyes were "yellow" and she was surprised to see her urine to be dark colored. She consulted a private clinic and the laboratory test done on her blood was positive for HAV IgM antibody. What will you tell Lola if you are the physician? a. That she acquired the disease through sexual contact b. that probably it was transmitted to her when she had a blood transfusion c. to be very careful, because she can transmit the infection to other members of her family by person-to-person spread d. that she might develop liver carcinoma in the future

Answer 36

c. to be very careful, because she can transmit the infection to other members of her family by person-to-person spread Rationale: Hepatitis A virus (HAV) is typically transmitted via the fecal-oral route, making person-to-person spread within a household common.

Question 37

37. A young executive from Makati was hospitalized for myopericarditis with mild congestive heart failure that increases over several weeks. The attending physician gave a diagnosis of Coxsackie B5 infection. Other than his conditions what other syndrome/s is/are associated with this virus? a. herpangina b. aseptic meningitis c. acute hemorrhagic conjunctivitis d. all of the above

Answer 37

d. all of the above Rationale: Coxsackie B virus can cause herpangina, aseptic meningitis, and acute hemorrhagic conjunctivitis, in addition to myopericarditis.

Question 38

38. After getting his first salary, Bitoy went to the seaside restaurant and feasted on seafood, particularly raw oyster with his favorite beer. After 24 hours, he became ill with sudden onset of vomiting, diarrhea and headache. He consulted a private clinic and the physician, after a thorough examination, ruled out a bacterial etiology. To him, the most probable viral etiologic agent is: a. Astrovirus b. Norwalk virus c. Rotavirus d. Hepatitis A virus

Answer 38

b. Norwalk virus Rationale: Norwalk virus (norovirus) is a common cause of gastroenteritis associated with the consumption of contaminated seafood, leading to symptoms like vomiting, diarrhea, and headache.

Question 39

39. A 45-year-old woman from a ranch in Mindanao, complained of fever, malaise, and sore throat, followed by nausea, vomiting and then sudden stupor. She was diagnosed to be suffering from eastern equine encephalitis. The control of this disease in humans could be accomplished by eradication/control of: a. ticks b. birds c. mosquitoes d. sandflies

Answer 39

c. mosquitoes Rationale: Eastern equine encephalitis virus is transmitted by mosquitoes, so controlling mosquito populations can help prevent the disease.

Question 40

40. DJ went to Boracay last summer. He had a good tan except on some portion of his neck down to his upper back which showed minimal scaling. After a week, the tan portion of his skin started to peel. To his surprise, the "untanned" portion of his skin seemed to have become bigger. His skin started to return to its normal color but the "untanned" portion seemed to stand out this time looking more whitish than his normal light brown skin. The most likely diagnosis is: a. Leprosy b. superficial mycoses c. avitaminosis

Answer 40

b. superficial mycoses Rationale: The description suggests a superficial fungal infection, such as tinea versicolor, which can cause hypopigmented patches on the skin.

Question 41

DJ consulted a dermatologist for the whitish discoloration which showed after his Boracay escapade. The doctor made a KOH mount of the skin scrapings and found, short, stout, angular hyphal elements. The skin lesions also fluoresce under the Wood's lamp. The most likely etiologic agent is: a. Tinea corporis b. Pityriasis versicolor c. White piedra d. candidiasis

Answer 41

b. Pityriasis versicolor Rationale: Pityriasis versicolor, caused by Malassezia species, presents with short, stout, angular hyphal elements and fluoresces under Wood's lamp. Clue words: "whitish discoloration," "KOH mount," "short, stout, angular hyphal elements," "fluoresce under the Wood's lamp"

Question 42

Melanie is a cook in a small restaurant responsible for the barbecue stand. Later, because of arthritis, she was reassigned to the counter as the one taking the orders. She noticed that her left hand still showed the blackish discoloration caused by handling charcoal. She had not noticed it before because after cooking, she does not wash her hand often because of fear of "pasma". This time she used alcohol to clean the discoloration, but to her surprise, it had no effect on the "dirt". After trying to remove it to no avail for a week, she decided to consult a doctor. The diagnosis given was tinea nigra. The etiologic agent of this is: a. Hortaea werneckii b. Cladosporium spp. c. Trichophyton spp. d. Exophiala hortai

Answer 42

a. Hortaea werneckii Rationale: Tinea nigra is caused by Hortaea werneckii, leading to blackish discoloration on the skin that cannot be removed by washing or alcohol. Clue words: "blackish discoloration," "tinea nigra," "Hortaea werneckii"

Question 43

A group of "street oldies" was taken to the DSWD. They were given a bath, fresh clothes, and something to eat. A medical team was also present who did some quickie check-ups on them. One man became the center of attraction of the doctors and interns because of the presence of soft, yellowish nodules on the hair of his axilla and beard. The interns thought of them as the eggs and nits of lice. They were, however, proven wrong after they had squeezed some of it. The most likely diagnosis for this is: a. Black piedra b. Trichophyton hair infection c. White piedra d. Excess soap suds

Answer 43

c. White piedra Rationale: White piedra, caused by Trichosporon species, presents with soft, yellowish nodules on hair. Clue words: "soft, yellowish nodules," "hair of his axilla and beard," "eggs and nits of lice"

Question 44

Vic plays basketball almost every day after school for the last 6 weeks until the vesicular lesions in his both feet, particularly in the toe webs, became ulcerative and painful. Also, he gets embarrassed in the shower room because his feet smell. The obvious diagnosis is athlete's foot. Three of the following dermatophytes below are common etiologic agents of athlete's foot except: a. T.mentagrophytes b. T. rubrum c. E. flocossum d. M. canis

Answer 44

d. M. canis Rationale: M. canis typically causes infections in animals and is less common in athlete's foot, which is usually caused by T. rubrum, T. mentagrophytes, and E. floccosum. Clue words: "vesicular lesions," "toe webs," "athlete's foot"

Question 45

RC, a 40-year-old farmer consulted a dermatologist for the multiple sinuses in his left arm that seem to follow a line. According to him, it started as small wounds caused by rose thorns when he was pruning the ground roses. The discharge from the sinuses showed oval budding cells that are variable in shape but often fusiform. The discharge was cultured in SAB. Growth in SAB yielded septate hyphae with small conidia clustered at the tip of conidiophores, appearing like daisies with a stem. The most likely identification of this organism is: a. Trichophyton mentagrophytes b. Phialophora species c. Sporothrix schenckii d. Cladosporium carrionii

Answer 45

c. Sporothrix schenckii Rationale: Sporothrix schenckii causes sporotrichosis, presenting with linear lesions and characteristic conidia growth that resembles daisies. Clue words: "multiple sinuses," "rose thorns," "septate hyphae," "daisies with a stem"

Question 46

A farmer from Laguna consulted the district hospital for his "big foot" with draining sinuses. He has been with it for almost three years now. He was forced to see a doctor because he could no longer do his job in the farm. The doctor noted that black granules are coming out of the sinuses. The most probable diagnosis is: a. sporotrichosis b. mycetoma c. elephantiasis d. chromoblastomycosis

Answer 46

b. mycetoma Rationale: Mycetoma is characterized by chronic infection with draining sinuses that produce black granules. Clue words: "big foot," "draining sinuses," "black granules"

Question 47

The black granules coming out of the sinuses in the "big foot" of a farmer are hard and showed intertwined septate hyphae. Which of the following is the most likely etiologic agent? a. Madurella grisea b. Actinomyces c. Nocardia spp. d. Trichophyton rubrum

Answer 47

a. Madurella grisea Rationale: Madurella grisea is a common cause of mycetoma, characterized by hard black granules and septate hyphae. Clue words: "black granules," "intertwined septate hyphae," "big foot"

Question 48

Jojo, a Filipino migrant in California, came home for a two-month vacation. He thought he could relax, but on his second week in the Philippines, he had no choice but to seek medical help for a small draining sinus on his left chest at the level of the axilla. Other symptoms were cough and fever. Examination of the discharge using 10% KOH showed sac-like structures with spore-like structures inside. The most likely diagnosis is: a. Histoplasmosis b. Coccidioidomycosis c. Blastomycosis d. Tuberculosis

Answer 48

b. Coccidioidomycosis Rationale: Coccidioidomycosis (Valley Fever) can present with draining sinuses and is identified by sac-like structures with endospores in tissue samples. Clue words: "small draining sinus," "sac-like structures with spore-like structures," "cough and fever"

Question 49

An elderly woman with pneumonia developed bloody diarrhea on the 7th hospital day, accompanied by abdominal cramps and fever. The doctors got worried because her fever caused by pneumonia had lysed as early as her 3rd hospital day. She was immediately placed in the ICU, and all antibiotics were stopped. She has been on ampicillin for 5 days prior to admission and on admission was started with clindamycin and augmentin. Her condition is probably caused by: a. Enterohemorrhagic Escherichia coli b. Shigella dysenteriae c. Clostridium difficile d. Vibrio parahemolyticus

Answer 49

c. Clostridium difficile Rationale: Clostridium difficile infection is commonly associated with antibiotic use and presents with bloody diarrhea, abdominal cramps, and fever. Clue words: "bloody diarrhea," "antibiotics," "pneumonia"

Question 50

Severino had an accident that resulted in the amputation of his right leg, two inches above the knee. About five days post-op, signs of wound infection were evident. Local wound care was given, and the exudate was sent to the lab. The doctors were willing to wait for the lab results before changing antibiotics. After two days, the culture came with no organism isolated from the specimen as reported. They suspected anaerobic infection. Anaerobic infection is usually suspected when: a. there is the presence of a foul smell b. the site of infection is near a mucosal surface c. there is gas in tissues d. all of the above

Answer 50

d. all of the above Rationale: Anaerobic infections are characterized by a foul smell, proximity to mucosal surfaces, and the presence of gas in tissues. Clue words: "wound infection," "no organism isolated," "anaerobic infection"

Question 51

George was rushed to the hospital for fever and pain in the right lower abdomen. Rectal exam was compatible with the diagnosis of appendicitis. He was again rushed to the operating table because of unstable vital signs. On opening up, he was found to have a ruptured appendicitis with abscess formation around it. The exudates later yielded Bacteroides fragilis. Which of the following factors promotes abscess formation by B. fragilis? a. capsule b. lipopolysaccharide c. pili d. superoxide dismutase

Answer 51

a. capsule Rationale: The capsule of Bacteroides fragilis is a significant virulence factor that promotes abscess formation by evading the immune response and facilitating adherence. Clue words: "ruptured appendicitis," "abscess formation," "Bacteroides fragilis"

Question 52

GC, a 20-year-old girl working in the call center, consulted a gynecologist because of whitish-gray vaginal discharge with a bad odor of about a week duration. Previous to it, she had several sexual relationships with her boyfriend of two months. With her condition, she felt guilty and decided to lead a clean life as soon as she gets well. The doctor got some fluid from the vaginal canal, placed some on the slide, and some she tested for pH which was 5.5 against the normal value of 4.5. Wet mount showed many epithelial cells which appear granular. No PMN was noted. Which of the following is the most likely diagnosis? a. Trichomonas vaginalis b. Yeast vaginitis c. Gonorrhea d. Bacterial vaginosis

Answer 52

d. Bacterial vaginosis Rationale: Bacterial vaginosis presents with a whitish-gray discharge, a higher pH, and clue cells (granular epithelial cells) without PMNs. Clue words: "whitish-gray vaginal discharge," "pH 5.5," "granular epithelial cells"

Question 53

A 67-year-old man was taken to the ER for difficulty in breathing. He has been feeling weak since 4 days ago. He has a chronic cigarette cough since he was in his 40s but did not bother to see a doctor for his complaints until his son noticed that he looked worst. On physical examination, inspiratory and expiratory wheezes and rales were noted over the right lower lung. His chest x-ray further revealed patchy lower right lung infiltrates. The differential diagnosis for this patient is: a. Streptococcus pneumoniae b. Legionella pneumophila c. Mycoplasma pneumoniae d. all of the above

Answer 53

d. all of the above Rationale: The differential diagnosis for pneumonia in a chronic smoker with these symptoms includes Streptococcus pneumoniae, Legionella pneumophila, and Mycoplasma pneumoniae. Clue words: "difficulty in breathing," "chronic cigarette cough," "patchy lower right lung infiltrates"

Question 54

Joe was diagnosed with lung cancer and in his bronchial washing acid-fast bacilli were seen mixed with the cancer cells. Joe had been given the full short course of the TB regimen before and so the doctor suspected a drug-resistant strain. The bronchial washing was cultured, and it grew orange-colored colonies when exposed to light. The most probable etiologic agent is: a. Mycobacterium tuberculosis b. Mycobacterium smegmatis c. Mycobacterium kansasii d. Mycobacterium avium complex

Answer 54

c. Mycobacterium kansasii Rationale: Mycobacterium kansasii produces orange colonies when exposed to light and can cause pulmonary infections. Clue words: "lung cancer," "acid-fast bacilli," "orange-colored colonies"

Question 55

55. You are giving lectures to TB patients about the characteristics of Mycobacterium tuberculosis. This is to convince them that they should cover their mouths when coughing and avoid spitting in the environment. Which of the following characteristics should NOT be emphasized to them? a. The organism is grown in complex media b. The organism is resistant to drying and survives for long periods in dried sputum c. The organism is resistant to acid and alkali d. The organism is found in the droplet nuclei discharged by the infected person.

Answer 55

a. The organism is grown in complex media Rationale: Mycobacterium tuberculosis is grown in specialized media, not complex media, and this is less relevant to patient behavior compared to the other characteristics. Clue words: "lectures to TB patients," "Mycobacterium tuberculosis"

Question 56

56. A visiting media team conducted the "search for the child with primary complex" in an elementary school in Tanay. After a thorough physical examination, the children in two grade one sections were skin tested using tuberculin at a dose of 5TU. Which of the following statements on PPD is correct? a. The tuberculin skin test becomes positive within 4-6 weeks after primary infection. b. Immunization with BCG will result in a positive PPD that may last for 3-7 years. c. Persons who had been PPD positives before but are healthy may fail to give a positive PPD test when tested again. d. All of the above are correct.

Answer 56

d. All of the above are correct. Rationale: All the listed statements about the PPD (tuberculin skin test) are correct: it becomes positive within 4-6 weeks after infection, BCG immunization can cause a positive PPD, and previous positives may not always test positive again. Clue words: "tuberculin skin test," "PPD"

Question 57

57. About fifty percent of the grade one students from Barrio Tubibi were found to have primary tuberculosis. Which of the following features of tuberculosis is most correct? a. Characterized by acute exudative lesions that rapidly spread to the lymphatics and regional lymph nodes b. All organisms are killed by the immune response that develops during primary infection c. It is often accompanied by severe pulmonary edema d. Caseous materials streaked with blood are often seen in expectorated sputum

Answer 57

a. Characterized by acute exudative lesions that rapidly spread to the lymphatics and regional lymph nodes Rationale: Primary tuberculosis is characterized by acute exudative lesions and spread to lymph nodes. Clue words: "primary tuberculosis," "acute exudative lesions"

Question 58

58. Paul, a 33-year-old lawyer from Ilocos, was seen in the OPD with a maculopapular rash over his trunk but not in his mouth or on his palms. He is a bachelor and travels around the Philippines a lot. The attending doctor’s impression was secondary syphilis. He ordered an RPR test to be done, which turned out to be reactive. Paul was advised to send his serum to a diagnostic test for TPHA or FTA-ABS test, which later turned out to be positive. Which of the following diseases can be ruled out? a. Atypical measles b. Secondary syphilis c. Coxsackie virus infection d. German measles

Answer 58

b. Secondary syphilis Rationale: The positive RPR and TPHA/FTA-ABS tests confirm secondary syphilis, ruling out other conditions. Clue words: "maculopapular rash," "RPR test," "TPHA or FTA-ABS"

Question 59

59. You Ming, a 14-year-old exchange student from China, joined the annual Boy Scout camping. They stayed in the province for two weeks. On their second week, You Ming, together with some boys, went to the forest and came back with many insect bites. You was so afraid because they even extracted a fat-bellied tick from his right leg. At the end of the two weeks, he noticed the tick bite to be reddish but flat. It grew bigger every day, with clearing of the central area. With the expansion of the lesion came fever, chills, myalgias, and headache. At this point, his guardian brought him to the hospital. The most likely diagnosis is: a. Leptospirosis b. Lyme disease c. Scrub typhus d. Rat-bite fever

Answer 59

b. Lyme disease Rationale: The description of the expanding rash with central clearing (erythema migrans) and systemic symptoms is characteristic of Lyme disease, caused by tick bites. Clue words: "tick bite," "reddish but flat," "clearing of the central area," "fever, chills, myalgias"

Question 60

60. An MMDA traffic enforcer was admitted to the hospital for the sudden onset of high fever (39C), headache, and pain in his calf muscles. On admission, his blood tests showed increased PMN, abnormal liver and renal function tests. On physical examination, he also had subconjunctival hemorrhage. He also had a history of wading in the floodwaters of Tondo, about 10 days prior to the illness. The diagnosis of the attending medical intern was leptospirosis. Which of the following would be most likely to confirm the diagnosis? a. Test acute and convalescent sera using the RPR b. Culture the blood on Thayer Martin agar c. Test acute and convalescent serum for antileptospiral antibodies d. Do a dark-field examination of serum and urine for leptospires

Answer 60

c. Test acute and convalescent serum for antileptospiral antibodies Rationale: Confirming leptospirosis involves testing for antileptospiral antibodies in acute and convalescent serum samples. Clue words: "sudden onset of high fever," "pain in his calf muscles," "subconjunctival hemorrhage," "wading in the floodwaters"

Question 61

61. A 31-year-old female from Southern Mindanao is brought in for chronic diarrhea of two months' duration. Stool examination reveals larvae with a prominent genital primordium. What is your probable diagnosis? a. Capillariasis b. Hookworm infection c. Strongyloidiasis d. Ascariasis

Answer 61

c. Strongyloidiasis Rationale: The presence of larvae with a prominent genital primordium is characteristic of Strongyloides stercoralis, which causes strongyloidiasis. Clue words: "chronic diarrhea," "larvae," "prominent genital primordium"

Question 62

62. A 10-year-old girl with perianal pruritus was brought by her mother to her pediatrician. What is your most probable diagnosis? a. Ascariasis b. Trichuriasis c. Enterobiasis d. Hookworm infection

Answer 62

c. Enterobiasis Rationale: Enterobiasis (pinworm infection) is the most common cause of perianal pruritus in children. Clue words: "perianal pruritus," "10-year-old girl"

Question 63

63. A 10-year-old girl with perianal pruritus was brought by her mother to her pediatrician. Based on your probable diagnosis, what diagnostic procedure will you request to support your diagnosis? a. Stool concentration technique b. Direct fecal smear c. Harada-Mori stool culture d. Cellulose tape swab

Answer 63

d. Cellulose tape swab Rationale: The cellulose tape swab (scotch tape test) is used to diagnose Enterobiasis by capturing the eggs of Enterobius vermicularis. Clue words: "perianal pruritus," "diagnostic procedure"

Question 64

64. A 15-year-old boy from Davao del Norte is noted to have pallor and malnutrition. Stool examination reveals an ovum with a thin colorless cell wall. What is your diagnosis? a. Ascariasis b. Trichuriasis c. Enterobiasis d. Hookworm infection

Answer 64

d. Hookworm infection Rationale: Hookworm infection leads to iron deficiency anemia (pallor) and malnutrition. The ova of hookworms have a thin, colorless cell wall. Clue words: "pallor," "malnutrition," "ovum with a thin colorless cell wall"

Question 65

65. A 15-year-old boy from Davao del Norte is noted to have pallor and malnutrition. Stool examination reveals an ovum with a thin colorless cell wall. The probable diagnosis is hookworm infection. Name the portal of entry of this worm. a. Oral ingestion b. Inhalation c. Skin penetration d. Mosquito bite

Answer 65

c. Skin penetration Rationale: Hookworm larvae penetrate the skin to enter the human body. Clue words: "hookworm infection," "portal of entry"

Question 66

66. Ova with flat bi-polar plugs were seen in the stool specimen of a 16-year-old female with chronic diarrhea from Compostela Valley province. What is your diagnosis? a. Capillariasis b. Hookworm infection c. Strongyloidiasis d. Ascariasis

Answer 66

a. Capillariasis Rationale: Capillariasis is characterized by the presence of ova with bipolar plugs. Clue words: "ova with flat bi-polar plugs," "chronic diarrhea"

Question 67

67. Ova with flat bi-polar plugs were seen in the stool specimen of a 16-year-old female with chronic diarrhea from Compostela Valley province. If your diagnosis is correct, how did this patient acquire the infection? a. Eating of salad b. Eating raw infected snail c. Eating raw infected freshwater fish d. Eating raw or improperly cooked meat

Answer 67

c. Eating raw infected freshwater fish Rationale: Capillariasis is often acquired by eating raw or undercooked freshwater fish containing the infectious larvae. Clue words: "ova with flat bi-polar plugs," "chronic diarrhea," "eating raw infected freshwater fish"

Question 68

68. A 24-year-old abaca farmer from Sorsogon with fever associated with signs and symptoms of inflammation of the lymph glands was brought to the Outpatient Department of the Philippine General Hospital. What parasitic diagnostic procedure will you request in the laboratory? a. Stool examination b. Sputum examination c. Thick blood film d. Urine examination

Answer 68

c. Thick blood film Rationale: A thick blood film is used to diagnose parasitic infections such as malaria and filariasis that cause lymphadenitis. Clue words: "fever," "inflammation of the lymph glands," "diagnostic procedure"

Question 69

69. A 24-year-old abaca farmer from Sorsogon with fever associated with signs and symptoms of inflammation of the lymph glands was brought to the Outpatient Department of the Philippine General Hospital. Microscopic finding in the blood taken at 10:00 pm revealed the presence of larvae. What is your diagnosis? a. Malaria b. Toxoplasmosis c. Filariasis d. Angiostrongyliasis

Answer 69

c. Filariasis Rationale: The presence of larvae (microfilariae) in a blood sample taken at night is characteristic of filariasis. Clue words: "fever," "inflammation of the lymph glands," "presence of larvae"

Question 70

70. A 24-year-old abaca farmer from Sorsogon with fever associated with signs and symptoms of inflammation of the lymph glands was brought to the Outpatient Department of the Philippine General Hospital. Microscopic finding in the blood taken at 10:00 pm revealed the presence of microfilariae. What drug can you prescribe to this patient? a. Mebendazole b. Metronidazole c. Diethylcarbamazine d. Praziquantel

Answer 70

c. Diethylcarbamazine Rationale: Diethylcarbamazine (DEC) is the drug of choice for treating filariasis. Clue words: "presence of microfilariae," "drug to prescribe"

Question 71

A 40-year-old male overseas worker complaining of muscle pains seeks medical attention upon his arrival in the Philippines. Biochemical tests showed elevated creatinine, phosphokinase, lactate dehydrogenase, and myokinase levels. Results of a complete blood count showed high blood eosinophilia. What is your most probable diagnosis? a. Taeniasis b. Capillariasis c. Trichinosis d. Filariasis

Answer 71

c. Trichinosis Rationale: Trichinosis, caused by Trichinella spiralis, presents with muscle pain, elevated muscle enzymes, and high blood eosinophilia. Clue words: "muscle pains," "elevated creatinine, phosphokinase, lactate dehydrogenase, and myokinase," "high blood eosinophilia"

Question 72

A 40-year-old male overseas worker complaining of muscle pains seeks medical attention upon his arrival in the Philippines. Biochemical tests showed elevated creatinine, phosphokinase, lactate dehydrogenase, and myokinase levels. Results of a complete blood count showed high blood eosinophilia. What other laboratory test would you recommend to confirm your probable diagnosis? a. Bentonite flocculation test b. Montenegro test c. Sabin Feldman test d. Knott’s blood concentration test

Answer 72

a. Bentonite flocculation test Rationale: The Bentonite flocculation test is used to diagnose trichinosis by detecting antibodies against Trichinella spiralis. Clue words: "muscle pains," "elevated muscle enzymes," "high blood eosinophilia," "confirm your probable diagnosis"

Question 73

A 40-year-old male overseas worker complaining of muscle pains seeks medical attention upon his arrival in the Philippines. Biochemical tests showed elevated creatinine, phosphokinase, lactate dehydrogenase, and myokinase levels. Results of a complete blood count showed high blood eosinophilia. Serological tests may confirm your diagnosis, but since there is no available serological test, what would you request to confirm your diagnosis? a. Skin test b. Muscle biopsy c. Rectal biopsy d. Skin scraping

Answer 73

b. Muscle biopsy Rationale: A muscle biopsy can confirm trichinosis by demonstrating the presence of Trichinella larvae in the muscle tissue. Clue words: "muscle pains," "elevated muscle enzymes," "high blood eosinophilia," "confirm your diagnosis"

Question 74

A flat whitish worm, measuring 1.5 cm long, was submitted to the Diagnostic Parasitology Laboratory for identification. It was found in the underwear of a 7-year-old girl complaining of abdominal discomfort and occasional itchiness of the perianal area. What parasitic infection would you consider? a. Enterobiasis b. Taeniasis c. Strongyloidiasis d. Heterophydiasis

Answer 74

b. Taeniasis Clue words: "flat whitish worm," "abdominal discomfort," "perianal area"

Question 75

75. A flat whitish worm, measuring 1.5 cm long, was submitted to the Diagnostic Parasitology Laboratory for identification. It was found in the underwear of a 7-year-old girl complaining of abdominal discomfort and occasional itchiness of the perianal area. Laboratory results identified the worm as a segment of a Taenia saginata. How did this patient acquire the infection? a. Eating of infected pork salad b. Eating raw infected snail c. Eating raw infected freshwater fish d. Eating raw infected beef

Answer 75

d. Eating raw infected beef Rationale: Taenia saginata is acquired by eating raw or undercooked beef containing the larvae. Clue words: "Taenia saginata," "raw infected beef"

Question 76

76. A flat whitish worm, measuring 1.5 cm long, was submitted to the Diagnostic Parasitology Laboratory for identification. It was found in the underwear of a 7-year-old girl complaining of abdominal discomfort and occasional itchiness of the perianal area. Laboratory results identified the worm as a segment of a Taenia saginata. What is the drug of choice for this parasitic infection? a. Mebendazole b. Albendazole c. Praziquantel d. Piperazine

Answer 76

c. Praziquantel Rationale: Praziquantel is the drug of choice for treating Taenia saginata infection. Clue words: "Taenia saginata," "drug of choice"

Question 77

77. An adult roundworm, measuring 27 cm in length, was seen in the colon of a 10-year-old boy who died of pneumonia. Manifestations such as lung infiltration, asthmatic attacks, and edema of the lips were documented before the patient died. What is the most probable parasitic infection you can identify in this case? a. Trichuriasis b. Ascariasis c. Capillariasis d. Hookworm infection

Answer 77

b. Ascariasis Rationale: Ascariasis, caused by Ascaris lumbricoides, is characterized by large roundworms and respiratory symptoms. Clue words: "adult roundworm," "lung infiltration," "10-year-old boy"

Question 78

78. A fisherman from Davao Oriental was rushed to a nearby hospital with chest pain, persistent cough, and hemoptysis as his main complaints. Patient interview revealed excessive drinking of native alcohol together with raw mountain crabs as their “pulutan.” What is the Diagnostic work-up you should include for this patient? a. Chest x-ray b. Sputum examination c. Stool examination d. All of the above

Answer 78

b. Sputum examination

Question 79

79. A fisherman from Davao Oriental was rushed to a nearby hospital with chest pain, persistent cough, and hemoptysis as his main complaints. Patient interview revealed excessive drinking of native alcohol together with raw mountain crabs as their “pulutan.” Chest x-ray demonstrated patchy, cloudy infiltration of the lungs with nodular shadows and calcified spots. What parasitic infection can you consider? a. Pulmonary tuberculosis b. Paragonimiasis c. Ascariasis d. Strongyloidiasis

Answer 79

b. Paragonimiasis Rationale: Paragonimiasis, caused by the lung fluke Paragonimus, can present with chest symptoms and characteristic lung findings on x-ray. Clue words: "chest x-ray," "patchy, cloudy infiltration," "nodular shadows," "calcified spots"

Question 80

80. A fisherman from Davao Oriental was rushed to a nearby hospital with chest pain, persistent cough, and hemoptysis as his main complaints. Patient interview revealed excessive drinking of native alcohol together with raw mountain crabs as their “pulutan.” Chest x-ray demonstrated patchy, cloudy infiltration of the lungs with nodular shadows and calcified spots. Paragonimiasis is the parasitic infection you are considering? What social factor strongly contributes to your diagnosis? a. Drinking habits b. Occupation c. Eating habits d. Gender

Answer 80

c. Eating habits Rationale: The consumption of raw or undercooked freshwater crabs, a known source of Paragonimus infection, is a key social factor contributing to the diagnosis. Clue words: "raw mountain crabs," "eating habits"

Question 81

81. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia. Based on clinical and laboratory results, what parasitic disease can you suggest? a. Schistosomiasis b. Paragonimiasis c. Leishmaniasis d. Heterophydiasis

Answer 81

a. Schistosomiasis Rationale: Schistosomiasis is characterized by the presence of eggs with miracidia in tissue biopsies and is associated with hepatomegaly and eosinophilia. Clue words: "eggs with miracidia," "hepatomegaly," "eosinophilia," "abdominal pain," "frequent loose stools"

Question 82

82. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia. What factor should you consider to make your specific diagnosis? a. Clinical signs and symptoms b. Recovery of characteristic eggs c. Increase in eosinophilia d. Evidence of exposure to an endemic area

Answer 82

b. Recovery of characteristic eggs Rationale: The presence of characteristic eggs with miracidia in the rectal biopsy is definitive for diagnosing schistosomiasis. Clue words: "eggs with miracidia," "rectal biopsy," "specific diagnosis"

Question 83

83. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia. What is/are the possible reason for the false-negative result of stool examination? a. Early infection b. All-male infection c. All-female infection d. All of the above

Answer 83

d. All of the above Rationale: False-negative stool examinations in schistosomiasis can occur due to early infection, all-male infection, or all-female infection. Clue words: "false-negative result," "stool examination," "schistosomiasis"

Question 84

84. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia, which lead you to diagnose schistosomiasis. This parasitic infection is also known as: a. Bilharziasis b. Katayama fever c. Snail fever d. All of the above

Answer 84

d. All of the above Rationale: Schistosomiasis is also known as Bilharziasis, Katayama fever, and Snail fever. Clue words: "schistosomiasis," "also known as"

Question 85

85. A 62-year-old farmer from Sorsogon was diagnosed with schistosomiasis japonicum. Its main pathology and disease manifestation are due to host granulomatous reaction. The underlying mechanism for its granuloma formation is due to: a. Acute inflammatory reaction b. Chronic vascular obstruction c. Immediate allergic reaction d. Delayed hypersensitivity

Answer 85

d. Delayed hypersensitivity Rationale: Granuloma formation in schistosomiasis is due to delayed hypersensitivity reaction to the eggs. Clue words: "granulomatous reaction," "schistosomiasis japonicum," "delayed hypersensitivity"

Question 86

86. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia, which lead you to diagnose schistosomiasis. What is the drug of choice for this parasitic infection? a. Mebendazole b. Albendazole c. Praziquantel d. Piperazine

Answer 86

c. Praziquantel Rationale: Praziquantel is the drug of choice for treating schistosomiasis. Clue words: "schistosomiasis," "drug of choice"

Question 87

87. A 51-year-old farmer from Surigao, Mindanao, was brought to a hospital with abdominal pain and frequent loose stools. Further examination revealed hepatomegaly with tenderness in the upper right quadrant of the abdomen. Laboratory results showed an increase in eosinophilia. Direct fecal smear showed no ova or parasites seen, while rectal biopsy demonstrated eggs with miracidia, which lead you to diagnose schistosomiasis. Serious complications of this parasitic disease include: a. Renal failure b. Intestinal lesions c. Bone metastases d. Cerebral involvement

Answer 87

d. Cerebral involvement Rationale: Cerebral involvement is a serious complication of schistosomiasis, particularly with Schistosoma japonicum. Clue words: "schistosomiasis," "serious complications"

Question 88

88. A sexually active 26-year-old woman consulted a VD control clinic for vaginal itching and purulent discharge. Your tentative diagnosis should include the following: a. Gonorrhea b. Trichomoniasis c. Candidiasis d. All of the above

Answer 88

d. All of the above Rationale: Vaginal itching and purulent discharge can be caused by gonorrhea, trichomoniasis, and candidiasis. Clue words: "vaginal itching," "purulent discharge," "tentative diagnosis"

Question 89

89. A sexually active 26-year-old woman consulted a VD control clinic for vaginal itching and purulent discharge. Trichomoniasis is your tentative diagnosis. What parasitologic examination should you include in your work-up? a. Stool culture b. Wet mount of vaginal fluid c. pH test of a blood sample d. Ova and parasite fecal smear

Answer 89

b. Wet mount of vaginal fluid Rationale: A wet mount of vaginal fluid is used to diagnose trichomoniasis by visualizing the motile trichomonads. Clue words: "trichomoniasis," "parasitologic examination"

Question 90

90. A sexually active 26-year-old woman consulted a VD control clinic for vaginal itching and purulent discharge. Trichomoniasis is your tentative diagnosis, which is best treated with: a. Albendazole b. Mebendazole c. Metronidazole d. Praziquantel

Answer 90

c. Metronidazole Rationale: Metronidazole is the drug of choice for treating trichomoniasis. Clue words: "trichomoniasis," "best treated with"

Question 91

91. A sexually active 26-year-old woman consulted a VD control clinic for vaginal itching and purulent discharge. Trichomoniasis is your tentative diagnosis, which is contracted almost exclusively through sexual intercourse. Control and prevention require a. Prompt treatment of the patient b. Prompt treatment of sexual partner c. Treatment of both d. Require no treatment, since it is self-limiting

Answer 91

c. Treatment of both Rationale: Effective control and prevention of trichomoniasis require treating both the infected individual and their sexual partner to prevent reinfection. Clue words: "vaginal itching," "purulent discharge," "Trichomoniasis," "control and prevention"

Question 92

92. A 30-year-old woman, a native of Bulacan, traveled to Palawan for a vacation. After 2 weeks, she consulted her doctor with chills and fever as her main complaints. What parasitologic test would you request to establish your diagnosis? a. Sputum examination b. Stool examination c. Thick blood smear d. Thick and thin blood smear

Answer 92

d. Thick and thin blood smear Rationale: Thick and thin blood smears are used to diagnose malaria by detecting Plasmodium parasites in the blood. Clue words: "chills and fever," "parasitologic test"

Question 93

93. A 30-year-old woman, a native of Bulacan, traveled to Palawan for a vacation. After 2 weeks, she consulted her doctor with chills and fever as her main complaints. Microscopic examination of thick and thin blood smear showed infected RBC with double chromatin dot. What is your most probable diagnosis? a. Not malaria b. Plasmodium falciparum c. Plasmodium vivax d. Plasmodium malariae

Answer 93

b. Plasmodium falciparum Rationale: The presence of double chromatin dots in infected RBCs is characteristic of Plasmodium falciparum. Clue words: "infected RBC with double chromatin dot," "chills and fever"

Question 94

94. A 6-month-old baby was brought in for a fever of one-day duration. She is found to have a temperature of 38.5°C and with hepatomegaly (3 cm) and splenomegaly (3 cm). Microscopic examination revealed infected RBC with the presence of band form stages. What is your most probable diagnosis? a. Not malaria b. Plasmodium falciparum c. Plasmodium vivax d. Plasmodium malariae

Answer 94

**d. Plasmodium malariae** **Rationale:** - **Fever, hepatomegaly, and splenomegaly:** These symptoms are indicative of a systemic infection often associated with malaria. - **Infected RBCs with band form stages:** The presence of band forms in infected red blood cells is a distinguishing feature of Plasmodium malariae. This parasite typically shows band-shaped trophozoites across the width of the red blood cell. **Clue words:** - "fever of one-day duration" - "hepatomegaly (3 cm)" - "splenomegaly (3 cm)" - "infected RBC with the presence of band form stages"

Question 95

95. A 49-year-old man from Manila received 4 units of packed red blood cells (PRBCs) on January 15 while undergoing hip replacement surgery. He was again hospitalized on February 1 with fever, hypotension, and renal failure. Peripheral blood smears confirmed malarial infection. The patient has never traveled outside Manila for 20 years. How did this patient acquire the infection? a. Bite of mosquito b. Blood transfusion c. Relapse d. Infected syringe

Answer 95

b. Blood transfusion Rationale: Malaria can be transmitted through blood transfusion if the donor blood is infected with Plasmodium parasites. Clue words: "PRBCs," "fever, hypotension, and renal failure," "never traveled outside Manila"

Question 96

96. A company plans to send a large number of employees to work in Afghanistan, for variable periods. Medical examination by their employees’ health service accidentally found this banana-shaped organism while doing routine CBC. Will there be a malaria risk in Afghanistan? a. No risk b. Risk in all areas c. Risk in areas where mosquito vectors are present d. Risk in all areas, during the rainy season only

Answer 96

c. Risk in areas where mosquito vectors are present Rationale: Malaria risk is present in areas where the Anopheles mosquito vector is present. Clue words: "banana-shaped organism," "malaria risk," "Afghanistan"

Question 97

97. A 6-month-old baby was brought in for a fever of one-day duration. She is found to have a temperature of 38.5°C and with hepatomegaly (3 cm) and splenomegaly (3 cm). Microscopic examination revealed infected RBC with the presence of a ring form stage only. What is your most probable diagnosis? a. Not malaria b. Plasmodium falciparum c. Plasmodium vivax d. Plasmodium ovale

Answer 97

b. Plasmodium falciparum Rationale: The presence of only ring forms in infected RBCs is typical of Plasmodium falciparum. Clue words: "infected RBC with a ring form stage only," "fever," "hepatomegaly," "splenomegaly"

Question 98

98. A 40-year-old man, a resident of Manila, presents to an emergency room with a 5-day history of fever, chills, nausea, vomiting, and myalgias. He returned 2 weeks ago from a 2-year job contract from Zambia. Microscopic examination revealed oval-shaped infected RBC. What is your most probable diagnosis? a. Plasmodium falciparum b. Plasmodium vivax c. Plasmodium ovale d. Plasmodium malariae

Answer 98

c. Plasmodium ovale Rationale: Oval-shaped infected RBCs are characteristic of Plasmodium ovale. Clue words: "oval-shaped infected RBC," "fever, chills, nausea, vomiting, and myalgias," "returned from Zambia

Question 99

99. An overseas worker with a febrile illness that began in December 2003, approximately 3 months and 14 months, respectively, after leaving Africa, consulted the hospital. During the course of his illness, the patient experienced fluctuating temperatures and lost 13 pounds of bodyweight. Light-microscopic examinations or cultures of bone marrow and liver-biopsy specimens noted a group of intracellular small rounded organisms. Laboratory results identify it as the amastigote stage. What is the most likely parasitic infection present in this patient? a. Malaria b. Leishmaniasis c. Toxoplasmosis d. Trypanosomiasis

Answer 99

b. Leishmaniasis Rationale: The presence of intracellular amastigotes in bone marrow or liver biopsy is indicative of Leishmaniasis. Clue words: "amastigote stage," "fluctuating temperatures," "lost 13 pounds," "leaving Africa"

Question 100

100. An overseas worker coming home from Uganda was rushed to a nearby hospital for a seizure attack. His relatives informed the medical officer on duty that the patient is experiencing progressive confusion and personality changes. Laboratory examination of the CSF revealed the presence of polymorphic with undulating membrane. What is the most likely parasitic infection present in this patient? a. Malaria b. Leishmaniasis c. Toxoplasmosis d. Trypanosomiasis

Answer 100

d. Trypanosomiasis - Rationale: The presence of polymorphic organisms with undulating membranes in the CSF is characteristic of Trypanosomiasis (African sleeping sickness). - Clue words: "seizure attack," "progressive confusion and personality changes," "polymorphic with undulating membrane," "Uganda"

Question 101

1. Which is true about the bacterial cell? A. Prokaryotic, unicellular B. Gram-positive bacteria have an outer membrane C. Gram-negative bacteria have a thicker cell wall than gram-positive bacteria D. Eukaryotic, multicellular

Answer 101

A. Prokaryotic, unicellular Rationale: Bacterial cells are prokaryotic and unicellular. Gram-positive bacteria do not have an outer membrane, and gram-negative bacteria have a thinner cell wall than gram-positive bacteria. Clue words: "Prokaryotic," "unicellular"

Question 102

2. Which structure is found in gram-negative bacteria but not in gram-positive bacteria? A. Outer membrane B. Peptidoglycan C. Nucleoid D. Plasma membrane

Answer 102

A. Outer membrane Rationale: Gram-negative bacteria have an outer membrane, which is absent in gram-positive bacteria. Both types have peptidoglycan, nucleoid, and plasma membrane. Clue words: "gram-negative bacteria," "outer membrane"

Question 103

3. True about the transfer of genes from one bacterium to another. A. Gram-negative bacteria that have sex pili transfer plasmids by conjugation B. Free DNA fragments are transferred by transformation C. Bacteriophages are involved in transduction D. Involves participation of flagella

Answer 103

A. Gram-negative bacteria that have sex pili transfer plasmids by conjugation Rationale: Conjugation involves sex pili, transformation involves free DNA fragments, and transduction involves bacteriophages. Flagella are not involved in gene transfer. Clue words: "conjugation," "transformation," "transduction"

Question 104

4. Which of the following bacteria is gram-negative? A. Staphylococcus B. Vibrio C. Corynebacterium D. Lactobacillus

Answer 104

B. Vibrio Rationale: Vibrio is a gram-negative bacterium, while Staphylococcus, Corynebacterium, and Lactobacillus are gram-positive. Clue words: "gram-negative," "Vibrio"

Question 105

5. True about obligate anaerobes A. Use sugars by oxidative pathway B. Infections are limited to muscle tissues C. Lack superoxide dismutase D. Can use oxygen in small amounts

Answer 105

C. Lack superoxide dismutase Rationale: Obligate anaerobes lack superoxide dismutase, which is necessary for detoxifying oxygen radicals, and thus cannot survive in the presence of oxygen. Clue words: "obligate anaerobes," "lack superoxide dismutase"

Question 106

6. Which structure is associated with the virulence of a bacterium A. Cell wall B. Lipopolysaccharide C. Flagella D. Endospores

Answer 106

B. Lipopolysaccharide Rationale: Lipopolysaccharides (LPS) in the outer membrane of gram-negative bacteria are associated with virulence. Clue words: "virulence," "Lipopolysaccharide"

Question 107

7. This mechanism of gene transfer is characterized by the requirement for cell-to-cell contact A. Conjugation B. Transduction C. Transformation D. Transfection

Answer 107

A. Conjugation Rationale: Conjugation requires direct cell-to-cell contact for the transfer of genetic material. Clue words: "cell-to-cell contact," "Conjugation"

Question 108

8. Action of lysozyme A. Involved in the formation of peptide bond between two peptidoglycan subunits B. Hydrolyzes peptidoglycan by cleaving the glycosyl bonds between N-acetylmuramic acid and N-acetylglucosamine C. An enzyme that dissolves the peptidoglycan layer D. Located in the periplasmic space and is involved in the hydrolysis of foreign DNA

Answer 108

B. Hydrolyzes peptidoglycan by cleaving the glycosyl bonds between N-acetylmuramic acid and N-acetylglucosamine Rationale: Lysozyme cleaves the glycosyl bonds between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan. Clue words: "lysozyme," "hydrolyzes peptidoglycan"

Question 109

9. True about gram-negative bacteria A. Have simpler but thicker cell wall than gram-positive bacteria B. Has an outer membrane located outside the peptidoglycan layer C. Contains teichoic acid polymers dispersed throughout the peptidoglycan D. Removal of the cell wall results in the formation of protoplasts

Answer 109

B. Has an outer membrane located outside the peptidoglycan layer Rationale: Gram-negative bacteria have an outer membrane outside the peptidoglycan layer, which distinguishes them from gram-positive bacteria. Clue words: "gram-negative bacteria," "outer membrane"

Question 110

10. This type of antibiotic should be used with caution because of renal and ototoxicity. A. Penicillins B. Macrolides C. Aminoglycosides D. Tetracyclines

Answer 110

C. Aminoglycosides Rationale: Aminoglycosides can cause renal and ototoxicity and should be used with caution. Clue words: "renal and ototoxicity," "Aminoglycosides"

Question 111

Lack/s the ability to develop catalase and superoxide dismutase: A. Obligate aerobes B. Obligate anaerobes C. Facultative anaerobes D. Aerotolerant anaerobes

Answer 111

B. Obligate anaerobes Rationale: Obligate anaerobes lack the enzymes catalase and superoxide dismutase, which are necessary for detoxifying oxygen radicals. Clue words: "lack/s the ability," "catalase and superoxide dismutase"

Question 112

Which bacterial structure is not essential for growth but may confer a survival advantage under certain conditions? A. Cell wall B. Outer membrane C. Endospore D. Flagella

Answer 112

D. Flagella Rationale: * Flagella (D): While flagella are not essential for the growth of bacteria, they provide motility, which can confer a survival advantage in certain environments by allowing bacteria to move toward favorable conditions and away from harmful ones. This motility can be crucial for finding nutrients, escaping predators, or colonizing new environments. Other Options: * Cell wall (A): Essential for the structural integrity and protection of bacteria. * Outer membrane (B): Essential for Gram-negative bacteria, contributing to structural integrity and selective permeability. * Endospore (C): Not necessary for the bacteria’s growth under normal conditions but provides a significant survival advantage in harsh environments. Clue words: * “not essential for growth” * “survival advantage” * “under certain conditions”

Question 113

Serves as an anchor to bind and pull apart daughter chromosomes during cell division A. Pili B. Mesosome C. Flagella D. Outer membrane

Answer 113

B. Mesosome Rationale: Mesosomes in bacteria are thought to play a role in cell division by helping to segregate chromosomes. Clue words: "anchor," "bind and pull apart daughter chromosomes," "cell division"

Question 114

Responsible for the endotoxin activity of lipopolysaccharide A. Somatic O polysaccharide B. Core polysaccharide C. Lipid A D. Protein A

Answer 114

C. Lipid A Rationale: Lipid A is the component of lipopolysaccharide (LPS) responsible for its endotoxin activity. Clue words: "endotoxin activity," "lipopolysaccharide"

Question 115

Use organic compounds as a carbon source and chemical reactions as an energy source A. Chemolithotrophs B. Chemoorganotrophs C. Photoorganotrophs D. Photolithotrophs

Answer 115

B. Chemoorganotrophs Rationale: Chemoorganotrophs use organic compounds for both carbon and energy sources. Clue words: "organic compounds," "carbon source," "energy source"

Question 116

A mutant bacterium lacks the ability to produce the amino acid leucine and grows only in a culture medium containing leucine. This bacterium was exposed to a preparation of DNA from Pseudomonas aeruginosa and was able to grow in a medium without leucine. What mechanism or event may have taken place? A. Transduction B. Transformation C. Conjugation D. Chromosomal mutation

Answer 116

B. Transformation Rationale: Transformation involves the uptake of free DNA from the environment, which can confer new genetic traits such as leucine synthesis. Clue words: "exposed to a preparation of DNA," "grow in a medium without leucine"

Question 117

Normally sterile site in the body A. Mouth B. Anus C. Vagina D. CSF

Answer 117

D. CSF Rationale: Cerebrospinal fluid (CSF) is normally a sterile site in the body, while the mouth, anus, and vagina contain normal microbiota. Clue words: "normally sterile site"

Question 118

A strain of Streptococcus pyogenes is able to produce pyrogenic exotoxin encoded by a prophage is an example of: A. Transposition B. Lysogeny C. Conjugation D. Chromosomal mutation

Answer 118

B. Lysogeny Rationale: Lysogeny involves the integration of a prophage into the bacterial genome, which can encode virulence factors such as pyrogenic exotoxin. Clue words: "prophage," "produce pyrogenic exotoxin"

Question 119

Calcium dipicolinate is found in: A. Aspergillus B. Bacillus C. Escherichia D. Mycobacteria

Answer 119

B. Bacillus Rationale: Calcium dipicolinate is found in the endospores of Bacillus species and helps in spore resistance and stability. Clue words: "Calcium dipicolinate," "endospores"

Question 120

Antimicrobial which exerts its action through inhibition of cell wall synthesis. A. Aminoglycoside B. Tetracycline C. Penicillin D. Rifampicin

Answer 120

C. Penicillin Rationale: Penicillin inhibits bacterial cell wall synthesis, leading to cell lysis and death. Clue words: "inhibition of cell wall synthesis"

Question 121

The diagnosis of a primary infection requires that a 4-fold increase in titer of this antibody be demonstrated: A. IgG B. IgM C. IgD D. IgA

Answer 121

A. IgG Rationale: A 4-fold increase in IgG titer is used to diagnose a primary infection as it indicates a significant rise in the immune response. Clue words: "4-fold increase," "titer," "primary infection"

Question 122

The presence of granules in discharge from draining sinus tracts is indicative of: A. Chromomycosis B. Mycetoma C. Lobomycosis D. Sporotrichosis

Answer 122

B. Mycetoma Rationale: Mycetoma is characterized by the presence of granules in discharge from draining sinus tracts. Clue words: "granules," "draining sinus tracts"

Question 123

A diver in deep stagnant water develops polypoid masses in his nostrils. He is likely to have acquired: A. Chromomycosis B. Rhinosporidiosis C. Lobomycosis D. Sporotrichosis

Answer 123

B. Rhinosporidiosis Rationale: Rhinosporidiosis is associated with polypoid masses in the nostrils and is acquired from stagnant water. Clue words: "diver," "deep stagnant water," "polypoid masses in nostrils"

Question 123

Cave explorers who develop pneumonia following such explorations are likely to have acquired: A. Blastomycosis B. Candidiasis C. Histoplasmosis D. Cryptococcosis

Answer 123

C. Histoplasmosis Rationale: Histoplasmosis is commonly acquired from bat or bird droppings in caves and can cause pneumonia. Clue words: "cave explorers," "pneumonia," "explorations"

Question 124

A farmer developed verrucous and warty lesions on his legs. Upon examination of a sample of skin crusting by KOH preparation, dark-colored sclerotic bodies were seen. The most likely diagnosis is: A. Chromomycosis B. Mycetoma C. Lobomycosis D. Sporotrichosis

Answer 124

A. Chromomycosis Rationale: Chromomycosis is characterized by verrucous and warty lesions with dark-colored sclerotic bodies on KOH preparation. Clue words: "verrucous and warty lesions," "dark-colored sclerotic bodies"

Question 125

A gardener developed multiple subcutaneous nodules on his forearm. A biopsy material did not show any fungus on direct microscopic examination. However, in culture, white, pasty, and moist colonies were seen. Wet mount using lactophenol cotton blue of the culture showed the presence of very fine hyphae and tear-drop-shaped conidia. A. The probable organism will form yeast cells when grown in brain heart infusion blood agar at 37°C B. The culture above showed the tissue form of the fungus C. The infection was most likely acquired from diving in deep stagnant water D. The causative fungus easily disseminates to other tissues

Answer 125

A. The probable organism will form yeast cells when grown in brain heart infusion blood agar at 37°C Rationale: The description is suggestive of Sporothrix schenckii, which forms yeast cells at 37°C. Clue words: "subcutaneous nodules," "white, pasty, and moist colonies," "very fine hyphae," "tear-drop-shaped conidia"

Question 126

The presence of multiple budding cells in a chain in a biopsy specimen obtained from subcutaneous nodules in the legs is suggestive of: A. Paracoccidioidomycosis B. Blastomycosis C. Lobomycosis D. Sporotrichosis

Answer 126

C. lobomycosis

Question 127

The tissue form of Histoplasma capsulatum is seen as: A. Intracellular yeast in macrophages B. Spherules C. Multiple budding cells D. Encapsulated yeast

Answer 127

A. Intracellular yeast in macrophages Rationale: Histoplasma capsulatum in tissue appears as intracellular yeast in macrophages. Clue words: "Histoplasma capsulatum," "intracellular yeast," "macrophages"

Question 128

The infection caused by this fungus is initiated by inhalation of arthroconidia, which are found in semi-arid regions: A. Coccidioides immitis B. Blastomyces dermatitidis C. Histoplasma capsulatum D. Cryptococcus neoformans

Answer 128

A. Coccidioides immitis Rationale: Coccidioides immitis infection is initiated by inhalation of arthroconidia, commonly found in semi-arid regions. Clue words: "inhalation of arthroconidia," "semi-arid regions"

Question 129

In histoplasmosis, the causative organism identified based on the presence of: A. Tuberculate macroconidia in culture at room temperature B. Encapsulated yeast by India ink preparation C. Mucoid colonies on Sabouraud’s agar D. Single budding yeast cells in infected tissue

Answer 129

A. Tuberculate macroconidia in culture at room temperature Rationale: Histoplasma capsulatum can be identified by the presence of tuberculate macroconidia in culture. Clue words: "histoplasmosis," "tuberculate macroconidia," "culture at room temperature"`

Question 130

Which of the following is true about the members of the family Enterobacteriaceae? A. Salmonella serotype typhi is transmitted by human carriers as well as by animals B. Shigella dysenteriae toxin kills cells by activating adenyl cyclase C. Escherichia coli usually produces intestinal disease only when it carries a plasmid or a phage that code for virulence factors D. Proteus mirabilis is an important cause of gastroenteritis

Answer 130

C. Escherichia coli usually produces intestinal disease only when it carries a plasmid or a phage that code for virulence factors Rationale: E. coli can cause intestinal diseases when it has acquired virulence factors through plasmids or phages. Clue words: "Escherichia coli," "intestinal disease," "plasmid," "phage," "virulence factors"

Question 131

True about opportunistic members of the family Enterobacteriaceae A. They are nonpathogenic in the intestinal tract B. Infections are produced in and out of the intestines C. They are the most abundant flora of the colon D. They are not known to cause septicemia

Answer 131

A. They are nonpathogenic in the intestinal tract

Question 132

Which of the following is true about Rickettsiae A. All are transmitted by arthropods B. All infections are characterized by skin rashes C. All are obligate intracellular parasites D. All survive the environment by producing endospores

Answer 132

C. All are obligate intracellular parasites Rationale: Rickettsiae are obligate intracellular parasites, meaning they must live within host cells to survive. Clue words: "Rickettsiae," "obligate intracellular parasites"

Question 133

A 16-year-old salesgirl presents to the physician with the chief complaints of headache, vomiting, neck stiffness, high-grade fever, photophobia, and petechial rashes. P.E. reveals an ill-appearing child unable to flex his neck without eliciting pain and diffuse petechial rashes in his extremities. Kernig and Brudzinski signs are positive. CSF analysis reveals increased neutrophils, increased protein, and low glucose. What is the most probable causative agent? A. Listeria monocytogenes B. Escherichia coli C. Neisseria meningitidis D. Reovirus

Answer 133

C. Neisseria meningitidis Rationale: The symptoms and CSF findings are consistent with bacterial meningitis caused by Neisseria meningitidis. Clue words: "neck stiffness," "high-grade fever," "petechial rashes," "Kernig and Brudzinski signs," "increased neutrophils," "low glucose"

Question 134

Which is the best method of diagnosis of typhoid fever? A. Widal test B. Typhi dot C. Blood culture D. Stool culture

Answer 134

C. blood culture Rationale: Blood culture is the gold standard for diagnosing typhoid fever, especially in the early stages of the disease. Clue words: "diagnosis of typhoid fever," "blood culture"

Question 135

Which is the most common cause of non-gonococcal urethritis? A. C. trachomatis B. M. pneumoniae C. U. urealyticum D. S. aureus

Answer 135

A. C. trachomatis Rationale: Chlamydia trachomatis is the most common cause of non-gonococcal urethritis. Clue words: "non-gonococcal urethritis," "C. trachomatis"

Question 136

Resistance to tuberculosis is mediated by A. Cell-mediated immunity B. Humoral immunity C. Interferon D. NK cells

Answer 136

A. Cell-mediated immunity Rationale: Cell-mediated immunity, particularly involving T cells, plays a crucial role in resistance to tuberculosis. Clue words: "resistance to tuberculosis," "cell-mediated immunity"

Question 137

Which of the following is LEAST likely about Escherichia coli? A. Pathogenicity in the GIT is associated with the presence of a plasmid B. Strains producing K1 antigen are associated with neonatal meningitis C. Enterotoxigenic strains produce diarrhea by invasion of the intestinal mucosa D. Serotype O157 is associated with hemolytic uremic syndrome

Answer 137

C. Enterotoxigenic strains produce diarrhea by invasion of the intestinal mucosa Rationale: Enterotoxigenic E. coli (ETEC) causes diarrhea through toxin production rather than invasion of the intestinal mucosa. Clue words: "LEAST likely," "Escherichia coli," "enterotoxigenic strains," "diarrhea," "invasion"

Question 138

Which of the following characterizes Salmonella typhi? A. Infects man and animals B. Non-invasive C. The organism is a non-lactose fermenting, nonmotile bacillus D. Chronic carriers harbor the organism in the gallbladder

Answer 138

D. Chronic carriers harbor the organism in the gallbladder Rationale: Chronic carriers of Salmonella typhi often harbor the bacteria in the gallbladder. Clue words: "Salmonella typhi," "chronic carriers," "gallbladder"

Question 139

One of the following produces a toxin that inhibits protein synthesis by ADP-ribosylation of EF-2 A. S. dysenteriae B. S. pyogenes C. C. diphtheriae D. M. tuberculosis

Answer 139

C. C. diphtheriae Rationale: Corynebacterium diphtheriae produces diphtheria toxin, which inhibits protein synthesis by ADP-ribosylation of elongation factor 2 (EF-2). Clue words: "toxin," "inhibits protein synthesis," "ADP-ribosylation," "EF-2"

Question 140

41. Which of the following produces a mononucleosis-like disease? A. Orientia tsutsugamushi B. Rickettsia prowazeki C. Ehrlichia chafeensis D. Coxiella burnetii

Answer 140

C. Ehrlichia chaffeensis Rationale: Ehrlichia chaffeensis can cause human monocytic ehrlichiosis, which presents with symptoms similar to mononucleosis. Clue words: "mononucleosis-like disease"

Question 141

42. A 63-year-old man has been hospitalized for the previous 21 days for the management of newly diagnosed leukemia. During the period of hospitalization, the patient developed a urinary tract infection with Escherichia coli and was treated for 14 days with broad-spectrum antibiotics. On the 21st hospital day, the patient developed fever and shaking chills. Within 24 hours, the patient became hypotensive, and ecthymic skin lesions appeared. Despite aggressive therapy with antibiotics, the patient expired. Multiple blood cultures were positive for gram-negative bacilli that showed negative results in most biochemical tests and failed to ferment sugars. Which of the following is the MOST likely causative agent? A. E. coli B. K. pneumoniae C. L. pneumophila D. P. aeruginosa

Answer 141

D. Pseudomonas aeruginosa Rationale: Pseudomonas aeruginosa is a common nosocomial pathogen that is resistant to many antibiotics and can cause severe infections in immunocompromised patients. It is a non-fermenter of sugars and can lead to ecthyma gangrenosum. Clue words: "gram-negative bacilli," "failed to ferment sugars," "nosocomial pathogen"

Question 142

43. A 20-year-old woman presents with sudden onset of fever of 40°C, severe headache, and a generalized petechial rash. Physical examination reveals nuchal rigidity. Meningococcemia is suspected and is confirmed by a culture CSF. She has a history of several serious infections with the causative organism. Which one of the following is the MOST likely predisposing factor? A. She is HIV antibody-positive B. She is deficient in CD8-positive cells C. She is deficient in one of the late-acting complement components D. She is deficient in antigen-presenting cells

Answer 142

C. She is deficient in one of the late-acting complement components Rationale: Deficiency in late-acting complement components (C5-C9) predisposes individuals to recurrent Neisseria meningitidis infections. Clue words: "recurrent infections," "Neisseria meningitidis," "complement deficiency"

Question 143

44. This test will differentiate Staphylococcus from Streptococcus. A. Coagulase B. Catalase C. Oxidase D. Sugar fermentation

Answer 143

B. Catalase Rationale: The catalase test differentiates Staphylococcus (catalase-positive) from Streptococcus (catalase-negative). Clue words: "differentiate Staphylococcus from Streptococcus," "catalase"

Question 144

45. Laboratory procedure of choice for primary syphilis. A. Darkfield microscopy B. RPR C. MHA TP D. VDRL

Answer 144

A. Darkfield microscopy Rationale: Darkfield microscopy is used to directly visualize Treponema pallidum in primary syphilis. Clue words: "primary syphilis," "darkfield microscopy"

Question 145

46. Infective particle of Chlamydia. A. Elementary body B. Reticulate body C. Endospore D. Fission body

Answer 145

A. Elementary body Rationale: The elementary body is the infectious form of Chlamydia. Clue words: "infective particle," "Chlamydia"

Question 146

47. The toxin of V. cholerae is antigenically similar to A. Shiga toxin B. LT of E. coli C. ST of E. coli D. Enterotoxin of Shigella

Answer 146

B. LT of E. coli Rationale: The cholera toxin of Vibrio cholerae is antigenically similar to the heat-labile toxin (LT) of enterotoxigenic Escherichia coli. Clue words: "antigenically similar," "cholera toxin," "LT of E. coli"

Question 147

48. Responsible for the virulence of M. tuberculosis A. Exotoxin B. Trehalose 6,6 dimycolate C. Mycolic acid D. Endotoxin

Answer 147

B. Trehalose 6,6 dimycolate Rationale: Trehalose 6,6 dimycolate (cord factor) is a major virulence factor in Mycobacterium tuberculosis. Clue words: "virulence," "M. tuberculosis," "Trehalose 6,6 dimycolate"

Question 148

49. A 5-year-old girl was brought by her mother to the E.R. due to high-grade fever. The patient also complained of dysphagia and sore throat. On physical exam, the throat was erythematous with a white, leathery membrane on both tonsillar pillars. Culture and sensitivity were done, and Corynebacterium diphtheriae was isolated. This organism produces diphtheria toxin. This toxin A. Is a neurotoxin B. Induces cAMP production C. Inhibits protein synthesis D. Is heat-stable

Answer 148

C. Inhibits protein synthesis Rationale: Diphtheria toxin inhibits protein synthesis by ADP-ribosylation of elongation factor 2 (EF-2). Clue words: "Corynebacterium diphtheriae," "diphtheria toxin," "inhibits protein synthesis"

Question 149

50. Purpose/s of giving Penicillin in cases of tetanus infection is/are: A. Inhibit the growth of C. tetani B. Neutralize unbound toxin C. Relax the muscle D. To sterilize the necrotic tissue

Answer 149

A. Inhibit the growth of C. tetani Rationale: Penicillin is given to inhibit the growth of Clostridium tetani in tetanus infection. Clue words: "tetanus infection," "Penicillin," "inhibit the growth"

Question 150

51. A high titer of this in the serum indicates acute or recent infection A. IgG B. IgM C. IgD D. IgA

Answer 150

B. IgM Rationale: IgM is the first antibody produced in response to an infection and indicates a recent or acute infection. Clue words: "acute or recent infection," "IgM"

Question 151

52. A patient had a viral infection that started to manifest 7 days ago. Laboratory test showed that the patient’s antibodies against this virus have a high ratio of IgM to IgG. What is your conclusion? A. It’s likely that the patient has been exposed to the virus for the first time B. It’s likely that the patient has an autoimmune disease C. The patient is predisposed to type 1 hypersensitivity reactions D. The patient developed an anamnestic response to the virus

Answer 151

A. It’s likely that the patient has been exposed to the virus for the first time Rationale: A high ratio of IgM to IgG suggests a primary immune response, indicating a first-time exposure to the virus. Clue words: "high ratio of IgM to IgG," "first time"

Question 152

53. A patient is suspected of having diphtheria. The bacterium was isolated, but you want to test if it produces an exotoxin. An agar plate, in which a filter paper containing specific antitoxin is embedded, was streaked with the bacterial isolate perpendicular to the filter paper. A precipitin line was formed between the antitoxin and the isolate. Which technique was used? A. Double immunodiffusion B. Immunoelectrophoresis C. Single radial immunodiffusion D. Immunoblot

Answer 152

A. Double immunodiffusion Rationale: The formation of a precipitin line in a setup with antitoxin and bacterial isolate indicates the use of double immunodiffusion. Clue words: "precipitin line," "antitoxin," "double immunodiffusion"

Question 153

54. You want to determine whether your patient is infected with a deadly virus, HIV. Which is the most sensitive technique that you will request in the laboratory? A. Complement fixation B. ELISA C. Countercurrent immunoelectrophoresis D. Indirect immunofluorescence

Answer 153

B. ELISA Rationale: ELISA is a highly sensitive and commonly used technique to detect antibodies against HIV. Clue words: "most sensitive technique," "HIV," "ELISA"

Question 154

55. The biologic properties of Ig are a function of A. Fc fragment B. Fab fragment C. Hinge region D. Disulfide bonds

Answer 154

A. Fc fragment Rationale: The Fc fragment of an immunoglobulin is responsible for its biological functions, including interaction with cell receptors and complement activation. Clue words: "biologic properties," "Fc fragment"

Question 155

56. High levels in the fetus with intrauterine infection: A. IgG B. IgM C. IgE D. IgD

Answer 155

B. IgM Rationale: Elevated IgM levels in the fetus indicate intrauterine infection, as IgM does not cross the placenta. Clue words: "intrauterine infection," "IgM"

Question 156

57. Predominant antibody in tears A. IgG B. IgM C. IgA D. IgE

Answer 156

C. IgA Rationale: IgA is the predominant antibody found in mucosal secretions, including tears. Clue words: "tears," "IgA"

Question 157

58. Predominant antibody in the secondary immune response A. IgG B. IgM C. IgA D. IgE

Answer 157

A. IgG Rationale: IgG is the predominant antibody produced during the secondary immune response. Clue words: "secondary immune response," "IgG"

Question 158

59. The coating of bacteria by antibody leading to engulfment by phagocytes is known as A. ADCC B. Opsonization C. Anamnestic response D. Hybridization

Answer 158

B. Opsonization Rationale: Opsonization is the process by which antibodies coat bacteria, enhancing their recognition and engulfment by phagocytes. Clue words: "coating of bacteria," "engulfment by phagocytes," "opsonization"

Question 159

60. This function of the T cells plays a central role in both humoral and CMI. A. Effector function B. Anaphylaxis C. Regulatory function D. Atopy

Answer 159

C. Regulatory function Rationale: The regulatory function of T cells is crucial for coordinating both humoral and cell-mediated immunity. Clue words: "central role," "humoral and CMI," "regulatory function"

Question 160

61. Which is true about the complement? A. All of the complement components are produced by the liver B. Always in an active state under normal conditions. C. Activated via a cascade mechanism. D. Alternative pathway is part of the Adaptive Immunity

Answer 160

C. Activated via a cascade mechanism Rationale: Complement components are activated in a sequential cascade, which is essential for the immune response. Clue words: "complement," "cascade mechanism"

Question 161

62. Dengue hemorrhagic fever is an example of: A. Anaphylactic B. Cytotoxic C. Immune complex D. Delayed

Answer 161

C. Immune complex Rationale: Dengue hemorrhagic fever involves the formation of immune complexes that contribute to the severe symptoms. Clue words: "Dengue hemorrhagic fever," "immune complex"

Question 162

63. What method will you use to detect antigen directly in tissue? A. ELISA B. Immunoelectrophoresis C. Immunofluorescence D. Hemagglutination

Answer 162

C. Immunofluorescence Rationale: Immunofluorescence is used to detect antigens directly in tissue samples by using fluorescently labeled antibodies. Clue words: "detect antigen," "tissue," "immunofluorescence"

Question 163

64. Protective antibody in viral infections localized in the respiratory tract A. IgG B. IgM C. IgA D. IgE

Answer 163

C. IgA Rationale: IgA is the predominant antibody in mucosal secretions, providing protection in the respiratory tract. Clue words: "respiratory tract," "IgA"

Question 164

65. Which is the most potent anaphylatoxin: A. C5a B. C5b C. C4a D. C3a

Answer 164

A. C5a Rationale: C5a is the most potent anaphylatoxin, causing strong inflammatory responses and attracting immune cells. Clue words: "most potent anaphylatoxin," "C5a"

Question 165

66. The Fc region of an immunoglobulin is involved in A. Binding with antigen B. Binding with complement C. Interaction with class I MHC of T cells D. All of the above

Answer 165

B. Binding with complement Rationale: The Fc region of an antibody binds to complement and cell receptors, mediating immune responses. Clue words: "Fc region," "binding with complement"

Question 166

67. A 3-year-old boy is having recurrent infections particularly by encapsulated bacteria. You suspect that he is immunodeficient, particularly with a low level of IgA. The most appropriate test to determine this is A. Single radial immunodiffusion B. ELISA C. Immunofluorescence D. Complement fixation test

Answer 166

A. Single radial immunodiffusion Rationale: Single radial immunodiffusion is commonly used to quantify immunoglobulin levels, such as IgA, in the serum. Clue words: "low level of IgA," "determine," "single radial immunodiffusion"

Question 167

68. The most common cause of bronchiolitis and pneumonitis in infants A. Adenovirus B. Parainfluenza virus C. RSV (Respiratory Syncytial Virus) D. Measles virus

Answer 167

C. RSV (Respiratory Syncytial Virus) Rationale: RSV is the leading cause of bronchiolitis and pneumonia in infants. Clue words: "bronchiolitis and pneumonitis in infants," "RSV"

Question 168

69. Which is pathognomonic of Rabies? A. Viral culture B. Negri bodies C. Fluorescent antibody test D. None

Answer 168

B. Negri bodies Rationale: Negri bodies are characteristic cytoplasmic inclusions found in neurons infected with rabies virus. Clue words: "Rabies," "pathognomonic," "Negri bodies"

Question 169

70. A patient who partially recovers from paralytic poliomyelitis experiences a new onset of muscular weakness, pain, and muscular atrophy, 25-35 years after the acute illness. Which condition is described? A. Aseptic Poliomyelitis B. Post-poliomyelitis Syndrome C. Paralytic Polio D. Non-paralytic Polio

Answer 169

B. Post-poliomyelitis Syndrome Rationale: Post-poliomyelitis syndrome is characterized by new muscle weakness and other symptoms occurring years after recovery from polio. Clue words: "paralytic poliomyelitis," "new onset of muscular weakness," "25-35 years," "Post-poliomyelitis Syndrome"

Question 170

71. The most antigenically unstable influenza type A. Type A B. Type B C. Type C D. All

Answer 170

A. Type A Rationale: Influenza Type A is known for its antigenic variability, undergoing frequent changes through antigenic drift and shift. Clue words: "antigenically unstable," "Type A"

Question 171

72. Which denotes infectivity and HBV replication A. Hbe Ag B. HBs Ag C. Anti HBe D. Anti HBs

Answer 171

A. HBe Ag Rationale: The presence of HBeAg indicates active replication of HBV and high infectivity. Clue words: "HBV replication," "infectivity," "HBe Ag"

Question 172

73. Which is NOT a member of the family Herpesviridae A. Herpes simplex virus B. Cytomegalovirus C. Chickenpox virus D. Variola virus

Answer 172

D. Variola virus Rationale: Variola virus, which causes smallpox, belongs to the Poxviridae family, not Herpesviridae. Clue words: "NOT a member," "Herpesviridae," "Variola virus"

Question 173

74. Which is true about Hepadnaviridae? A. Has RNA genome B. Carries reverse transcriptase C. Has an infectious genome D. Dependent on delta hepatitis virus for replication

Answer 173

B. **Carries reverse transcriptase** ### Rationale: 1. **Has RNA genome**: - **Explanation**: This is incorrect. Hepadnaviridae, which includes the Hepatitis B virus (HBV), has a partially double-stranded DNA genome. 2. **Carries reverse transcriptase**: - **Explanation**: This is correct. Hepadnaviridae viruses carry a reverse transcriptase enzyme that allows them to replicate their DNA genome through an RNA intermediate. This is a unique feature of Hepatitis B virus among DNA viruses. 3. **Has an infectious genome**: - **Explanation**: This is incorrect. The genome of Hepadnaviridae (Hepatitis B virus) is not directly infectious. It requires reverse transcription and other processes inside the host cell to produce infectious virions. 4. **Dependent on delta hepatitis virus for replication**: - **Explanation**: This is incorrect. While the Hepatitis D virus (HDV) depends on HBV for its replication and transmission (it uses HBV's surface antigen), HBV does not depend on HDV for replication. ### Summary: The correct statement about Hepadnaviridae (specifically Hepatitis B virus) is that it **carries reverse transcriptase** (option B), which is essential for its replication cycle involving an RNA intermediate.

Question 174

75. Neutralization test was done in a patient suspected of suffering from a viral infection characterized by fever, malaise, and respiratory symptoms. Using anti-echovirus antibody, no CPE was observed. Which statement is true regarding this infection? A. The patient is infected with enterovirus B. The patient is infected with echovirus C. The patient is unlikely to produce antibodies against enterovirus D. The result is inconclusive; other tests must be done

Answer 174

B. The patient is infected with echovirus Rationale: * Neutralization test: This test is used to detect the presence of neutralizing antibodies against specific viruses. If no cytopathic effect (CPE) is observed in the presence of anti-echovirus antibodies, it indicates that the antibodies have successfully neutralized the virus, suggesting the presence of echovirus infection. * Fever, malaise, and respiratory symptoms: These are common symptoms associated with viral infections, including echovirus. * Anti-echovirus antibody: The use of specific antibodies in the test that neutralizes the virus and prevents CPE confirms that the virus present is echovirus. Clue words: * “neutralization test” * “no CPE observed” * “anti-echovirus antibody” * “fever, malaise, and respiratory symptoms”

Question 175

76. Viruses are cultivated in the following EXCEPT A. Cell culture B. Chick embryo C. Animals D. Enriched agar medium

Answer 175

D. Enriched agar medium Rationale: Viruses cannot be cultivated in enriched agar medium as they require living cells to replicate. Clue words: "cultivated," "EXCEPT," "enriched agar medium"

Question 176

77. Which of the following identifies a virus using a labeled specific antibody? A. Immunofluorescence B. PCR C. Electron microscopy D. Virus isolation

Answer 176

A. Immunofluorescence Rationale: Immunofluorescence uses labeled specific antibodies to detect and identify viruses. Clue words: "identifies a virus," "labeled specific antibody," "Immunofluorescence"

Question 177

78. Hemagglutination inhibition test is NOT applicable to which virus? A. Influenza virus B. Mumps virus C. RSV (Respiratory Syncytial Virus) D. Parainfluenza virus

Answer 177

C. RSV (Respiratory Syncytial Virus) Rationale: RSV does not cause hemagglutination, so the hemagglutination inhibition test is not applicable. Clue words: "Hemagglutination inhibition test," "NOT applicable," "RSV"

Question 178

79. A 2-month pregnant mother suspected of having acquired rubella because of exposure to a friend who has the illness was tested for antibodies using HAI test. The result showed that the mother was positive for IgG but not IgM. Which is the best statement that describes this case? A. The mother has been infected with the virus in the past before pregnancy B. The mother is incubating and would manifest the infection later C. The fetus will most likely be infected transplacentally D. The mother has no immunity

Answer 178

A. The mother has been infected with the virus in the past before pregnancy Rationale: The presence of IgG without IgM suggests past infection and immunity to rubella, indicating she was infected before pregnancy. Clue words: "positive for IgG," "not IgM," "past infection"

Question 179

80. A hemagglutination inhibition test was done on the serum of a 6-month-old boy suffering from severe respiratory distress. The results showed that hemagglutination occurred when parainfluenza virus type 1 Ag was reacted with the serum; no hemagglutination with parainfluenza virus type 2; hemagglutination with RSV. Which is the infecting agent? A. Parainfluenza type 1 B. Parainfluenza type 2 C. RSV (Respiratory Syncytial Virus) D. The result is inconclusive

Answer 179

A. Parainfluenza type 1 Rationale: • The results show that the patient’s serum inhibited hemagglutination with parainfluenza virus type 2 antigen but not with parainfluenza virus type 1 or RSV antigens. • The presence of antibodies that inhibit hemagglutination indicates previous exposure or current infection. • Given the severe respiratory distress and the fact that hemagglutination was not inhibited by the patient’s serum with parainfluenza virus type 1 antigen, it suggests that the patient has a current infection with parainfluenza virus type 1. Summary: The hemagglutination inhibition test results indicate that the infecting agent is parainfluenza virus type 1 (option A).

Question 180

81. Genetic reassortment occurs when segmented genomes of duck strains of influenza A virus are enclosed together with those of human strains in a capsid. Which of the following is the most likely to occur? A. Point mutation B. A new strain of virus will appear C. The human population is protected because of previous infection with the human strain D. Antigenic drift

Answer 180

B. A new strain of virus will appear Rationale: Genetic reassortment can result in the creation of a new strain of the virus with different antigenic properties. Clue words: "Genetic reassortment," "segmented genomes," "new strain"

Question 181

82. Which is associated with congenital abnormalities? A. Mumps B. German measles C. Rubeola D. All of the above

Answer 181

B. German measles Rationale: German measles (Rubella) is known to cause congenital abnormalities if a woman contracts it during pregnancy. Clue words: "congenital abnormalities," "German measles"

Question 182

83. Which is true about poliovirus infection? A. CNS involvement is NOT common B. Most infections have transient viremia C. The virus multiplies in the muscles D. There is no effective preventive measure

Answer 182

B. Most infections have transient viremia Rationale: Poliovirus infections commonly result in transient viremia, and CNS involvement is relatively rare. Clue words: "poliovirus infection," "transient viremia"

Question 183

84. Herpangina, which is characterized by the formation of vesicular lesions in the pharynx, is most commonly associated with A. Poliovirus B. Hepatitis A virus C. Coxsackie A virus D. Coxsackie B virus

Answer 183

C. Coxsackie A virus Rationale: Herpangina is typically caused by Coxsackie A virus and is characterized by vesicular lesions in the pharynx. Clue words: "Herpangina," "vesicular lesions," "Coxsackie A virus"

Question 184

85. An astray dog bit your neighbor. The wound was bleeding and was cleaned with soap and water. Your advice will be A. Kill the dog and submit the head for examination for Negri bodies B. Give rabies immunoglobulin and vaccine C. Observe the dog D. Observe the patient

Answer 184

B. Give rabies immunoglobulin and vaccine Rationale: Post-exposure prophylaxis with rabies immunoglobulin and vaccine is crucial after a potential rabies exposure. Clue words: "bit by a dog," "rabies immunoglobulin and vaccine"

Question 185

86. Latency occurs in the trigeminal ganglion A. HSV-1 B. HSV-2 C. HSV-6 D. HSV-8

Answer 185

A. HSV-1 Rationale: HSV-1 commonly establishes latency in the trigeminal ganglion. Clue words: "latency," "trigeminal ganglion," "HSV-1"

Question 186

87. Latency occurs in the mononuclear cells and kidneys. A. HSV-1 B. HSV-3 C. CMV D. Variola

Answer 186

C. CMV Rationale: Cytomegalovirus (CMV) establishes latency in mononuclear cells and kidneys. Clue words: "latency," "mononuclear cells," "kidneys," "CMV"

Question 187

88. The difference between Dengue fever and Dengue Hemorrhagic fever is that A. There is a presence of bleeding in DHF B. Hematocrit is elevated in DHF C. PPT is prolonged in DHF D. There is an absence of AbV in the former formation

Answer 187

B. Hematocrit is elevated in DHF

Question 188

89. A 4-year-old girl is brought to the physician’s office because she developed red cheeks that appear as if someone has slapped her, and a lacy rash on her upper extremities and trunk. What is the MOST probable causative agent? A. Adenovirus B. Parvovirus C. Marburg virus D. Rotavirus

Answer 188

B. Parvovirus Rationale: Parvovirus B19 causes erythema infectiosum (fifth disease), characterized by a "slapped cheek" appearance and lacy rash. Clue words: "red cheeks," "slapped," "lacy rash," "Parvovirus"

Question 189

90. A defective virus that causes infection only in the presence of HBV A. HAV B. HBV C. HCV D. HDV

Answer 189

D. HDV Rationale: Hepatitis D virus (HDV) is a defective virus that requires hepatitis B virus (HBV) for its replication. Clue words: "defective virus," "presence of HBV," "HDV"

Question 190

91. Very important serologic marker for HBV during the window phase A. Anti HBs B. HBs Ag C. Anti HBc D. HBe Ag

Answer 190

C. Anti HBc Rationale: During the window phase of HBV infection, HBsAg has disappeared and Anti-HBs is not yet detectable. Anti-HBc is the only marker present. Clue words: "window phase," "HBV," "Anti HBc"

Question 191

92. A modified cellular protein that is capable of auto-catalytically making several copies of itself A. viroid B. virusoid C. prion D. satellite RNA

Answer 191

C. prion Rationale: Prions are infectious agents composed of protein that can induce abnormal folding of specific normal cellular proteins. Clue words: "modified cellular protein," "auto-catalytically," "prion"

Question 192

93. Responsible for attachment of influenza virus on specific host cell receptor A. H glycoprotein B. N glycoprotein C. matrix protein D. capsid protein

Answer 192

A. H glycoprotein Rationale: Hemagglutinin (H glycoprotein) is responsible for the attachment of the influenza virus to host cell receptors. Clue words: "attachment," "influenza virus," "H glycoprotein"

Question 193

94. Measles is most infectious during the appearance of A. Koplik spots B. Fever, cough, coryza, and conjunctivitis C. Macupapular rash

Answer 193

B. Fever, cough, coryza, and conjunctivitis Rationale: Measles is most infectious during the prodromal phase, which includes fever, cough, coryza, and conjunctivitis. Clue words: "most infectious," "measles," "fever, cough, coryza, conjunctivitis"

Question 194

95. Oseltamivir is an antiviral drug used against A. parainfluenza B. influenza C. measles D. RSV

Answer 194

B. influenza Rationale: Oseltamivir is a neuraminidase inhibitor used to treat and prevent influenza. Clue words: "Oseltamivir," "antiviral," "influenza"

Question 195

96. Which is associated with extrahepatic manifestations A. HAV B. HCV C. HBV D. HEV

Answer 195

C. HBV

Question 196

97. A woman appears in a hospital ER with vesicular lesions on her vulva. These lesions clinically resemble those caused by herpes simplex virus. From which of the following clinical specimens would the virus most likely be isolated? A. urine B. Blood C. Throat secretions D. Vesicular fluid

Answer 196

D. Vesicular fluid Rationale: Herpes simplex virus is best isolated from vesicular fluid from the lesions. Clue words: "vesicular lesions," "herpes simplex virus," "vesicular fluid"

Question 197

98. A 5-year-old child presents fever for 8 days, lymphadenopathy, splenomegaly, and numerous reactive or atypical lymphocytes on peripheral blood smear. The monospot test is negative. A likely cause of the clinical picture is infection with A. respiratory syncytial virus B. Cytomegalovirus C. Adenovirus D. herpes virus

Answer 197

B. Cytomegalovirus Rationale: Cytomegalovirus (CMV) can cause a mononucleosis-like syndrome with negative monospot test. Clue words: "fever, lymphadenopathy, splenomegaly," "atypical lymphocytes," "negative monospot," "CMV"

Question 198

99. A 30-year-old school teacher presents with a cough of 1-month duration, fever, night sweats, and weight loss. PE is normal. How many sputum smears are recommended by the council on Tuberculosis to establish a diagnosis of TB? A. Four B. Three C. Two D. One

Answer 198

B. Three Rationale: The World Health Organization recommends three sputum samples for the diagnosis of tuberculosis. Clue words: "cough, fever, night sweats," "sputum smears," "TB diagnosis," "three"

Question 199

100. A woman develops fever, rash, and polyarthralgia during menstruation. Gram stain of the synovial fluid of her right knee reveals gram-negative diplococci. Which of the following organisms is MOST likely to be responsible? A. Haemophilus influenzae B. Staphylococcus epidermidis C. Neisseria gonorrhoeae D. Pseudomonas aeruginosa

Answer 199

C. Neisseria gonorrhoeae - Rationale: Neisseria gonorrhoeae is a gram-negative diplococcus that can cause disseminated gonococcal infection, presenting with arthritis, fever, and rash. - Clue words: "fever, rash, polyarthralgia," "gram-negative diplococci," "Neisseria gonorrhoeae"