Assessment PARA Flashcards by Karl Dashley Atinen

ECOFRIENDLY fecal fixative:

Formalin
Schaudinn’s
Polyvinyl alcohol
Merthiolate-iodine-formalin

Polyvinyl alcohol

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The formalin–ether (ethyl acetate) concentration procedure for feces is used to demonstrate:

Motility of helminth larvae
Protozoan cysts and helminth eggs
Formation of amoebic pseudopods
Trophozoites

Protozoan cysts and helminth eggs

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Layers obtained in the formalin ether sedimentation technique (top to
bottom):

Sediment > formalin > debris > ether
Sediment > debris > formalin > ether
Ether > formalin > debris > sediment
Ether > debris > formalin > sediment

Ether > debris > formalin > sediment

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“Cultures of parasites are different from bacterial cultures; no quality control is needed.” This statement is:

True, if two tubes of media are set up for each patient
True, if the media are checked every 24 hours
False, unless two different types of media are used
False, and organism and media controls need to be set up

False, and organism and media controls need to be set up

Duplicate cultures should be set up, and specific American Type Culture Collection (ATCC)
strains should be cultured along with the patient specimens to confirm that the culture
system is operating properly. This approach is somewhat different from that used in
diagnostic bacteriology and mycology

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Charcot–Leyden crystals in stool may be associated with an immune
response and are thought to be formed from the breakdown products of:

Neutrophils
Eosinophils
Lymphocytes
Monocytes

Eosinophils

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A mother states that she has observed her 4-year-old son scratching his
anal area frequently. The most likely cause of this condition is:

Trichomonas vaginalis
Enterobius vermicularis
Ascaris lumbricoides
Necator americanus
Entamoeba histolytica

Enterobius vermicularis

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The term internal autoinfection can be associated with the following parasites:

Cryptosporidium spp. and Giardia lamblia
Cystoisospora belli and Strongyloides stercoralis
Cryptosporidium spp. and Strongyloides stercoralis
Giardia lamblia and Cystoisospora belli

Cryptosporidium spp. and Strongyloides stercoralis

Both Cryptosporidium and S. stercoralis have an internal autoinfection capability in their
life cycles. This means that the cycle and infection can continue even after the patient has
left the endemic area. In the case of Cryptosporidium, the cycle continues in patients who
are immunocompromised and unable to self-cure.

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Larva with heart to lung migration, except:

Ascaris lumbricoides
Hookworms
Strongyloides stercoralis
Trichuris trichiura

Trichuris trichiura

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Triad of infection or unholy 3, except:

Ascaris lumbricoides
Hookworms
Strongyloides stercoralis
Trichuris trichiura

Strongyloides stercoralis

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Visceral larva migrans is associated with which of the following organisms?

Toxocara—serology
Onchocerca—skin snips
Dracunculus—skin biopsy
Angiostrongylus—CSF examination

Toxocara—serology

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Ingestion of which of the following eggs will result in infection?

Strongyloides stercoralis
Opisthorchis sinensis
Toxocara canis
Schistosoma japonicum

Toxocara canis

The eggs of T. canis are infectious for humans and cause visceral larva migrans. These ascarid eggs of the dog can infect humans; the eggs hatch and the larvae wander through the deep tissues, occasionally the eye. In this case, the human becomes the accidental
intermediate host.

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A helminth egg is described as having terminal polar plugs. The most likely helminth is:

Hookworm
Trichuris trichiura
Fasciola hepatica
Diphyllobothrium latum

Trichuris trichiura

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You are working in a rural medical clinic in China and a 3-year- old girl is
brought in by her mother. The child appears emaciated and, upon testing,
is found to have a hemoglobin level of 5 g/dL. Her feet and ankles are
swollen, and there is an extensive rash on her feet, ankles, and knees. The
most likely parasitic infection that causes the child’s condition is:

Schistosomiasis
Cercarial dermatitis
Hookworm infection
Ascariasis

Hookworm infection

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May be associated with vertical transmission and congenital infections:

Ascaris lumbricoides
Ancylostoma duodenale
Necator americanus
Enterobius vermicularis

Ancylostoma duodenale

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The parasites penetrate the skin and cause cutaneous larva migrans (CLM), also referred to as creeping eruption:

Ancylostoma duodenale and Necator americanus
Ancylostoma braziliense and Ancylostoma caninum
Toxocara cati and Toxocara canis
Brugia malayi and Loa loa

Ancylostoma braziliense and Ancylostoma caninum

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An immunosuppressed man has several episodes of pneumonia, intestinal pain, sepsis with gram-negative rods, and a history of military
service in Southeast Asia 20 years earlier. The most likely cause is infection with:

Trypanosoma cruzi
Strongyloides stercoralis
Paragonimus westermani
Naegleria fowleri

Strongyloides stercoralis

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Characteristics of the rhabditiform (noninfective) larvae of Strongyloides stercoralis include a:

Short buccal capsule and large genital primordial
Long buccal capsule and pointed tail
Short buccal capsule and small genital primordium
Small genital primordium and notch in tail

Short buccal capsule and large genital primordial

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When the undercooked meat is digested in the stomach, the larvae are resistant to the gastric pH and pass to the intestine, where they invade
the mucosa:

Ascaris
Enterobius
Trichuris
Trichinella

Trichinella

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A 45-year-old hunter developed fever, myalgia, and periorbital edema. He has a history of bear meat consumption. The most likely causative agent is:

Toxoplasma gondii
Taenia solium
Hymenolepis nana
Trichinella spiralis

Trichinella spiralis

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After returning from a 2-year stay in India, a patient has eosinophilia, an
enlarged left spermatic cord, and bilateral inguinal lymphadenopathy. The most likely clinical specimen and organism match is:

Thin blood films—Leishmania
Urine—concentration for Trichomonas vaginalis
Thick blood films—microfilariae
Thin blood films—Babesia

Thick blood films—microfilariae

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The most common identified species of filarial worms that infect
humans:

Brugia malayi
Loa loa
Onchocerca volvulus
Wuchereria bancrofti

Wuchereria bancrofti

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Which microfilariae are usually not found circulating in the peripheral blood?

Brugia malayi
Wuchereria bancrofti
Onchocerca volvulus
Loa loa

Onchocerca volvulus

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Which of the following statements is true regarding onchocerciasis?

The adult worm is present in the blood
The microfilariae are in the blood during the lateevening hours
The diagnostic test of choice is the skin snip
The parasite resides in the deep lymphatics

The diagnostic test of choice is the skin snip

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The tail is often referred to as a “shepherd’s crook.”

Brugia malayi
Mansonella perstans
Mansonella streptocerca
Onchocerca volvulus

Mansonella streptocerca

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The worm has a characteristic, thick cuticle and a large uterus that fills the body cavity and contains rhabditoid larvae. Ancylostoma caninum Dracunculus medinensis Strongyloides stercoralis Trichinella spiralis

Dracunculus medinensis

The worms are incapable of maturation within the human host and migrate aimlessly, causing tissue damage and inflammation. Brugia malayi Dracunculus medinensis Gnathostoma spinigerum Trichinella spiralis

Gnathostoma spinigerum

Which parasite causes eosinophilic meningoencephalitis, a form of larva migrans causing fever, headache, stiff neck, and increased cells in the spinal fluid? Necator americanus Angiostrongylus cantonensis Strongyloides stercoralis Ancylostoma braziliense

Angiostrongylus cantonensis

The examination of sputum may be necessary to diagnose infection with: Paragonimus westermani Trichinella spiralis Wuchereria bancrofti Fasciola hepatica

Paragonimus westermani

Largest of the INTESTINAL trematodes, and infection is acquired by ingestion of raw water chestnuts or caltrop: Fasciolopsis buski Fasciola gigantica Heterophyes heterophyes Metagonimus yokogawai

Fasciolopsis buski

Eggs are operculated with slight opercular shoulders, yellow-brown, embryonated: Fasciola hepatica Heterophyes heterophyes Paragonimus westermani Schistosma japonicum

Heterophyes heterophyes

Severe infections may cause obstruction of the biliary ducts, resulting in enlargement and tenderness of the liver, cirrhosis, cholecystitis (inflammation of the gallbladder), and cholangiocarcinoma (cancerous growth in bile duct epithelium). C. sinensis and O. viverrini H. heterophyes and M. yokogawai P. westermani and P, mexicanus S. japonicum and S. mansoni

C. sinensis and O. viverrini

A 32-year-old male tourist traveled to Senegal for 1 month. During the trip, he swam in the Gambia river. Two months after his return, he began complaining of intermittent lower abdominal pain with dysuria. Laboratory results of ova and parasites revealed eggs with a terminal spine. Which of the following parasites is the cause of the patient’s symptoms? Schistosoma mansoni Schistosoma haematobium Ascaris lumbricoides Taenia solium

Schistosoma haematobium

Resembles egg of S. haematobium, but acid-fast positive: S. japonicum S. intercalatum S. mansoni S. mekongi

S. intercalatum

Schistosoma intercalatum eggs are found in: Stool Urine Both of these None of these

Stool ## Footnote S. intercalatum eggs are only found in feces, not in urine specimens

Examination of 24-hour unpreserved urine specimen is sometimes helpful in the recovery of: Trichomonas vaginalis trophozoites Schistosoma haematobium eggs Strongyloides stercoralis larvae Enterobius vermicularis eggs

Schistosoma haematobium eggs

The miracidial hatching test helps to demonstrate the viability of eggs of: Taenia species Schistosoma species Hookworm species Opisthorchis species

Schistosoma species

Two helminth eggs that may resemble one another are: Diphyllobothrium latum and Paragonimus westermani Opisthorchis sinensis and Fasciolopsis buski Taenia saginata and Hymenolepis nana Ascaris lumbricoides and Trichostrongylus

Diphyllobothrium latum and Paragonimus westermani

Eating poorly cooked pork can lead to an infection with: Taenia solium and Trichinella spiralis Taenia saginata and Hymenolepis nana Trichuris trichiura and Hymenolepis diminuta Diphyllobothrium latum and Ascaris lumbricoides

Taenia solium and Trichinella spiralis

Several Papua New Guinea villagers known to eat pork during celebrations were reported to be suffering from an outbreak of epileptiform seizures. One of the first things you should investigate is: The prevalence of Ascaris infections in the population The prevalence of schistosomiasis in the population The presence of Trypanosoma brucei gambiense in the villagers The presence of Giardia cysts in the drinking water The presence of Taenia solium in the pigs

The presence of Taenia solium in the pigs

An operculated cestode egg that can be recovered from human feces is: Clonorchis sinensis Diphyllobothrium latum Paragonimus westermani Dipylidium caninum

Diphyllobothrium latum ## Footnote D. latum is the only operculated cestode egg that is found in humans; the infection is acquired from the ingestion of raw freshwater fish.

Humans acquire infections with Diphyllobothrium latum adult worms by: Ingestion of freshwater crabs Skin penetration of cercariae Ingestion of water chestnuts Ingestion of raw freshwater fish

Ingestion of raw freshwater fish

In infections with Taenia solium, humans can serve as the: Definitive host Intermediate host Either the definitive or the intermediate host None of these options

Either the definitive or the intermediate host ## Footnote If humans ingest T. solium cysticerci in uncooked or rare pork, the adult tapeworm will mature within the intestine (human will serve as definitive host); if eggs from the adult tapeworm are ingested, then the cysticerci will develop in human tissues (accidental intermediate host), causing cysticercosis.

In a condition resulting from the accidental ingestion of eggs, the human becomes the intermediate rather than the definitive host. The correct answer is: Trichinosis Strongyloidiasis Ascariasis Cysticercosis

Cysticercosis

Humans can serve as both the intermediate and definitive host in infections caused by: Enterobius vermicularis Hymenolepis nana Schistosoma japonicum Ascaris lumbricoides

Hymenolepis nana

Infection is more frequent in populations living in conditions of poverty or poor hygiene, in day care centers, and in persons living in institutional settings or prisons. D. latum D. caninum H. nana T. saginata

H. nana

The eggs (70 to 85 μm by 60 to 80 μm) are large, ovoid, yellowish, and moderately thick-shelled. The eggs contain a six-hooked oncosphere with the absence of polar filaments in the space between the oncosphere and the eggshell. H. diminuta H. nana Both of these None of these

H. diminuta

Eggs are small and have polar filaments present in the space between the oncospheres and the eggshell. H. diminuta H. nana Both of these None of these

H. nana

The adult tapeworm of Echinococcus granulosus is found in the intestine of: Dogs Sheep Humans Cattle

Dogs ## Footnote Although the hydatid cysts are found in sheep or in humans (accidental intermediate host), the adult tapeworms of E. granulosus are found in the intestine of the dog.

Surgery is the most common form of treatment for hydatid disease. The procedure involves surgical removal of cysts or inactivation of hydatid sand by injecting the cyst with __________ and then removing it. 10% formalin Hydrogen peroxide Methanol Acetone

10% formalin ## Footnote Surgery is the most common form of treatment for hydatid disease. The procedure involves surgical removal of cysts or INACTIVATION OF HYDATID SAND by injecting the cyst with 10% FORMALIN and then removing it. If surgical removal is not feasible: PAIR (PUNCTURE, ASPIRATION, INFECTION, AND REINJECTION) Used for the inactivation of hydatid sand by injecting the cyst with a CYSTICIDAL AGENT ***HYPERTONIC 30% SALINE*** ****0.5% CETRIMIDE*** ****70 TO 95% ETHANOL***

Most lethal of all helminthic diseases: Taenia saginata Taenia solium Echinococcus granulosus Echinococcus multilocularis

Echinococcus multilocularis

Tapeworm that causes coenurosis in humans: Echinococcus multilocularis Spirometra mansonoides Taenia multiceps Taenia solium

Taenia multiceps

An Entamoeba histolytica trophozoite has the following characteristics: -Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia -Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane -Ingested RBCs, clear pseudopodia, and large glycogen vacuoles in cytoplasm -Large, blotlike karyosome, ingested white blood cells (WBCs), and granular pseudopods

Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia

A patient has been diagnosed as having amebiasis but continues to be asymptomatic. The physician has asked for an explanation and recommendations regarding follow-up. Suggestions should include: Consideration of Entamoeba histolytica versus Entamoeba dispar A request for an additional three stools for culture Initiating therapy, regardless of the patient’s asymptomatic status Performance of barium x-ray studies

Consideration of Entamoeba histolytica versus Entamoeba dispar

A Gram stain from a gum lesion showed what appeared to be amoebae. A trichrome smear showed amoebae with a single nucleus and partially digested PMNs. The correct identification is: Trichomonas tenax Entamoeba histolytica/E. dispar Entamoeba polecki Entamoeba gingivalis

Entamoeba gingivalis

If the granules are on one side, the nucleus may appear to have a “basket nucleus” arrangement of chromatin, more commonly seen in the cyst stage. D. fragilis E. gingivalis E. nana I. butschlii

I. butschlii

Cysts of Iodamoeba bütschlii typically have: Chromatoidal bars with rounded ends A heavily vacuolated cytoplasm A large glycogen vacuole Many ingested bacteria and yeast cells

A large glycogen vacuole

A 12-year-old girl is brought to the emergency department with meningitis and a history of swimming in a warm-water spring. Motile amoebae that measure 10 μ in size are seen in the CSF and are most likely: Iodamoeba bütschlii trophozoites Dientamoeba fragilis trophozoites Naegleria fowleri trophozoites Endolimax nana trophozoites

Naegleria fowleri trophozoites

Which of the following causes granulomatous amebic encephalitis (GAE), primarily in immunosuppressed, chronically ill, or otherwise debilitated individuals? Acanthamoeba Dientamoeba Iodamoeba Naegleria

Acanthamoeba

Eye infections with Acanthamoeba spp. have most commonly been traced to: Use of soft contact lenses Use of hard contact lenses Use of contaminated lens care solutions Failure to remove lenses while swimming

Use of contaminated lens care solutions

Select the most sensitive recovery method for Acanthamoeba spp. from lens care solutions or corneal biopsies. The trichrome staining method The use of monoclonal reagents for the detection of antibody The use of non-nutrient agar cultures seeded with Escherichia coli The Giemsa’s stain method

The use of non-nutrient agar cultures seeded with Escherichia coli

Which of the following is the best technique to identify Dientamoeba fragilis in stool? Formalin concentrate Trichrome-stained smear Modified acid-fast–stained smear Giemsa’s stain

Trichrome-stained smear

Trophozoites are teardrop shaped and have been described as “someone looking at you" C. mesnili D. fragilis G. lamblia T. vaginalis

G. lamblia

The organism is found most commonly in the CRYPTS IN THE DUODENUM: Cryptosporidium Isospora spp. Giardia lamblia Entamoeba histolytica

Giardia lamblia

Infection mimics acute viral enteritis, bacillary dysentery, bacterial or other food poisonings, acute intestinal amebiasis, or “traveler’s diarrhea” C. mesnili D. fragilis E. hartmanni G. lamblia

G. lamblia

One of the following protozoan organisms has been implicated in waterborne and foodborne outbreaks. The suspect organism is: Pentatrichomonas hominis Giardia lamblia Balantidium coli Dientamoeba fragilis

Giardia lamblia

Organisms that should be considered in a waterborne outbreak of diarrheal disease include: Giardia lamblia and Cryptosporidium spp. Endolimax nana and Entamoeba histolytica Blastocystis hominis and Trichomonas vaginalis Toxoplasma gondii and Schistosoma mansoni

Giardia lamblia and Cryptosporidium spp.

Organisms that should be considered in a nursery school outbreak of diarrhea include: -Endolimax nana, Giardia lamblia, and Entamoeba coli -Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp. -Cryptosporidium spp., Trichomonas vaginalis, and Entamoeba coli -Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana

Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp. ## Footnote G. lamblia, D. fragilis, and Cryptosporidium have been implicated in nursery school outbreaks. Among the many protozoa and coccidia found in the human, these three organisms have become the most likely parasites in this type of setting.

Fecal immunoassays have become more commonly used to diagnose infections with: -Endolimax nana and Blastocystis hominis -Giardia lamblia and Cryptosporidium spp. -Ascaris lumbricoides and Trichuris trichiura -Strongyloides stercoralis and Trichomonas vaginalis

Giardia lamblia and Cryptosporidium spp. ## Footnote Rapid fecal immunoassays have become more widely used for the diagnosis of infections with G. lamblia and Cryptosporidium. For these two organisms, the fecal immunoassays are more sensitive than the routine O&P examination.

Cysts have a single nucleus and a typical curved cytostomal fibril, called the shepherd’s crook: C. mesnili D. fragilis G. lamblia I. butschlii

C. mesnili

The life cycle and mode of transmission of this protozoan are not known, although transmission in helminth eggs (e.g., Ascaris and Enterobius spp.) has been postulated: C. mesnili D. fragilis G. lamblia I. butschlii

D. fragilis

Parasitic organisms that are most often transmitted sexually include: Entamoeba gingivalis Dientamoeba fragilis Trichomonas vaginalis Diphyllobothrium latum

Trichomonas vaginalis

Which specimen is the LEAST likely to provide recovery of Trichomonas vaginalis? Urine Urethral discharge Vaginal discharge Feces

Feces

A sexually active 24-year-old woman complains of vaginal itching and vaginal discharge. To verify your tentative diagnosis of trichomoniasis, you should include which of the following in your workup? Specific serologic test Ova and parasite fecal smear Wet mount of vaginal fluid Enzyme-linked immunoassay (ELISA) test of serum Stool culture

Wet mount of vaginal fluid

A 60-year-old Brazilian patient with cardiac irregularities and congestive heart failure suddenly dies. Examination of the myocardium revealed numerous amastigotes, an indication that the cause of death was most likely: Leishmaniasis with Leishmania donovani Leishmaniasis with Leishmania braziliense Trypanosomiasis with Trypanosoma gambiense Trypanosomiasis with Trypanosoma cruzi

Trypanosomiasis with Trypanosoma cruzi ## Footnote T. cruzi, the cause of Chagas disease, has two forms within the human: the trypomastigote in the blood and the amastigote in the striated muscle (usually cardiac muscle and intestinal tract muscle).

When malaria smears are requested, what patient information should be obtained? Diet, age, sex Age, antimalarial medication, sex Travel history, antimalarial medication, date of return to United States Fever patterns, travel history, diet

Travel history, antimalarial medication, date of return to United States

Massive hemolysis, blackwater fever, and central nervous system involvement are most common with: Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium ovale

Plasmodium falciparum

An apparently fatigued but alert 38-year-old woman has spent 6 months as a teacher in a rural Thailand village school. Her chief complaints include frequent headaches, occasional nausea and vomiting, andperiodic fever. You suspect malaria and indeed find parasites in red blood cells in a thin blood smear. To rule out the dangerous falciparum form of malaria, which one of the following choices is NOT consistent with a diagnosis of Plasmodium falciparum malaria based on a microscopic examination of the blood smear? Red blood cells containing trophozoites with Schuffner’s dots Red blood cells containing >1 parasite per RBC Banana-shaped or crescent-shaped gametocytes Parasites within normal-sized red blood cells Parasites with double nuclei

Red blood cells containing trophozoites with Schuffner’s dots

Plasmodium vivax and Plasmodium ovale are similar because they: Exhibit Schüffner’s dots and have a true relapse in the life cycle Commonly have appliqué forms in the red cells Have true stippling, do not have a relapse stage, and infect old red cells Have no malarial pigment and multiple rings

Exhibit Schüffner’s dots and have a true relapse in the life cycle

Key characteristics of infection with Plasmodium knowlesi include: Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease Erythrocytic cycle limited to young RBCs and causes a relatively benign disease The possibility of a true relapse from the liver, infection in older RBCs, and causes serious disease Extended life cycle (72 hr), will infect all ages of RBCs, and disease is similar to that caused by P. ovale

Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease ## Footnote Key characteristics of an infection with Plasmodium knowlesi include a rapid life cycle (24 hr), the potential to infect all ages of RBCs, and the possibility of serious symptoms similar to those seen with P. falciparum infections. There is no relapse from the liver with this species

Early ring stages of the fifth human malaria, Plasmodium knowlesi, resemble those of: Plasmodium malariae Plasmodium ovale Plasmodium falciparum Plasmodium vivax

Plasmodium falciparum

Older developing stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowlesi, resemble those of: Plasmodium malariae Plasmodium ovale Plasmodium falciparum Plasmodium vivax

Plasmodium malariae

A patient is being seen in the emergency department for a low-grade fever, headache, and general malaise after returning from Africa on a photographic safari. The physician has requested blood for malaria; the laboratory would like to have patient information regarding: Specific travel history and body temperature every 4 hours Liver function tests and prophylactic medication history Transfusion history and body temperature every 4 hours Prophylactic medication history and specific travel history

Prophylactic medication history and specific travel history ## Footnote If the patient has malaria and has been taking prophylaxis (often sporadically), the number of parasites on the blood smear will be reduced and examination of routine thick and thin blood films should be more exhaustive. Also specific geographic travel history may help to determine whether chloroquine-resistant Plasmodium falciparum may be a factor.

Recommended stain for all parasitic blood works: Giemsa Wright Modified acid fast stain Modified trichrome stain

Giemsa

There are few procedures considered STAT in parasitology. The most obvious situation would be: Ova and parasite examination for giardiasis Baermann’s concentration for strongyloidiasis Culture of amoebic keratitis Blood films for malaria

Blood films for malaria

Babesia has been implicated in disease from both splenectomized and nonsplenectomized patients. Morphologically, the parasites resemble: Plasmodium falciparum rings Leishmania donovani amastigotes Microsporidial spores Trypanosoma cruzi trypomastigotes

Plasmodium falciparum rings

Oocysts survive in the environment for several months to more than 1 year and are resistant to disinfectants, freezing, and drying. However, they are killed by heating to 70°C for 10 minutes. Balamuthia mandrillaris Pentatrichomonas hominis Isospora belli Toxoplasma gondii

Toxoplasma gondii

When staining Cystoisospora belli oocysts with modified acid-fast stains, the important difference between these methods and the acid-fast stains used for acid-fast bacilli (AFB) is: The staining time is much longer with regular AFB acid-fast stains The decolorizer is weaker than acid alcohol used for AFB decolorizing A counterstain must be used for the modified methods The stain is more concentrated when staining for AFB

The decolorizer is weaker than acid alcohol used for AFB decolorizing

Patients with severe diarrhea should use “enteric precautions” to prevent nosocomial infections with: Giardia lamblia Ascaris lumbricoides Cystoisospora belli Cryptosporidium spp.

Cryptosporidium spp. ## Footnote Cryptosporidium oocysts (unlike those of C. belli) are immediately infective when passed in stool, and nosocomial infections have been well documented with this coccidian.

Parasite stages that are immediately infective for humans on passage from the gastrointestinal tract include: Schistosoma spp. eggs Toxoplasma gondii bradyzoites Giardia lamblia trophozoites Cryptosporidium spp. oocysts

Cryptosporidium spp. oocysts ## Footnote Cryptosporidium spp. oocysts are immediately infectious when passed in the stool, regardless of the stool consistency (formed—liquid).

In an outbreak of diarrheal disease traced to a municipal water supply, the most likely causative agent is: Cryptosporidium spp. Cystoisospora belli Entamoeba histolytica Dientamoeba fragilis

Cryptosporidium spp. ## Footnote Cryptosporidium oocysts have been transmitted through contaminated municipal water supplies. Such outbreaks have been well documented.

Oocysts of Cryptosporidium spp. can be detected in stool specimens using: Modified Ziehl–Neelsen acid-fast stain Gram stain Methenamine silver stain Trichrome stain

Modified Ziehl–Neelsen acid-fast stain

Sporadic mini-outbreaks of diarrheal disease have been associated with the ingestion of strawberries, raspberries, fresh basil, mesclun (baby lettuce leaves), and snow peas. The most likely causative agent is: Dientamoeba fragilis Cystoisospora belli Cyclospora cayetanensis Schistosoma mansoni

Cyclospora cayetanensis

Examination of a modified acid-fast stained fecal smear reveals round structures measuring approximately 8–10 μm, some of which are stained and some of which are not. They do not appear to show any internal morphology. The patient is symptomatic with diarrhea, and the cause may be: Blastocystis hominis Polymorphonuclear leukocytes Large yeast cells Cyclospora cayetanensis

Cyclospora cayetanensis ## Footnote One of the newer coccidian parasites, C. cayetanensis, has been implicated in cases of human diarrhea. The recommended stains are modified acid-fast stains, and the organisms are quite variable in their staining characteristics. The oocysts are immature when passed (no internal morphology) and they measure about 8–10 μm.

Autofluorescence requires no stain and is recommended for the identification of: Entamoeba histolytica cysts Toxoplasma gondii tachyzoites Dientamoeba fragilis trophozoites Cyclospora cayetanensis oocysts

Cyclospora cayetanensis oocysts

Primary infections with the microsporidia may originate in: The lung The nervous system The gastrointestinal tract Mucocutaneous lesions

The gastrointestinal tract

The microsporidia are protozoans (now classified with the fungi) that have been implicated in human disease primarily in Immunocompromised patients Pediatric patients under the age of 5 years Adult patients with congenital immunodeficiencies Patients who have been traveling in the tropics

Immunocompromised patients

A transplant patient on immunosuppressive drugs developed increasing diarrhea. The most likely combination of disease and diagnostic procedure is: Trichinosis and trichrome stain Microsporidiosis and modified trichrome stain Paragonimiasis and wet preparation Toxoplasmosis and Gram stain

Microsporidiosis and modified trichrome stain

Microsporidia have been identified as causing severe diarrhea, disseminated disease in other body sites, and ocular infections. Routes of infection have been identified as: Ingestion Inhalation Direct contamination from the environment Ingestion, inhalation, and direct contamination

Ingestion, inhalation, and direct contamination

Confirmation of an infection with microsporidia can be achieved by seeing: The oocyst wall Sporozoites within the spore Evidence of the polar tubule Organisms stained with modified acid-fast stains

Evidence of the polar tubule ## Footnote Confirmation of an infection with microsporidial spores can be achieved by seeing evidence of the polar tubule within the spores (horizontal or diagonal line across/within the spore).

Microsporidial infections can be confirmed using: Light microscopy and modified trichrome stains Phase contrast microscopy and routine trichrome stains Electron microscopy and modified acid-fast stains Fluorescence microscopy and hematoxylin stains

Light microscopy and modified trichrome stains ## Footnote An infection with microsporidia can be confirmed using modified trichrome stains (10X the normal dye content found in routine trichrome stains) and light microscopy. The internal polar tubule will be visible within some of the spores; this will serve as confirmation of the infection.

All of the following are sexually transmitted protozoans except: Trichomonas vaginalis Entamoeba histolytica Giardia lamblia Cryptosporidium spp. Balantidium coli

Balantidium coli ## Footnote The World Health Organization has ranked trichomoniasis as the most prevalent, nonviral, sexually transmitted disease in the world with an estimated 172 million new cases a year. The intestinal protozoa Giardia lamblia, Entamoeba histolytica, and Cryptosporidium spp. are significant causes of STDs, especially among homosexual populations

Which of the following is associated with LOEFFLER’S SYNDROME: Ascaris lumbricoides Enterobius vermicularis Trichuris trichiura Wuchereria bancrofti

Ascaris lumbricoides ## Footnote LOEFFLER’S SYNDROME: transient pulmonary infiltration; day-to-day clearing in 3 to 14 days; associated with marked peripheral eosinophilia

VISCERAL LARVA MIGRANS (VLM) and OCULAR LARVA MIGRANS (OLM) are caused by accidental ingestion of eggs of: Ancylostoma braziliense, Ancylostoma caninum Toxocara cati, Tocara canis

Toxocara cati, Tocara canis ## Footnote A serum titer of 1: 8 is considered significant for OLM; 1: 32 is significant for VLM.

CREEPING ERUPTION or CUTANEOUS LARVA MIGRANS (CLM) is caused by skin penetration of infective larvae of: Ancylostoma braziliense, Ancylostoma caninum Toxocara cati, Tocara canis

Ancylostoma braziliense, Ancylostoma caninum

A patient presents with vague abdominal pains and a MICROCYTIC HYPOCHROMIC anemia. A possible causative parasite is: Enterobius vermicularis Ancylostoma duodenale Brugia malayi Trichinella spiralis

Ancylostoma duodenale

Infective stage is the SHEATHED FILARIFORM LARVA: Strongyloides stercoralis Ancylostoma duodenale, Necator americanus

Ancylostoma duodenale, Necator americanus

Infective stage is the UNSHEATHED FILARIFORM LARVA: Strongyloides stercoralis Ancylostoma duodenale, Necator americanus

Strongyloides stercoralis

Which of the following roundworms is capable of AUTOINFECTION, HYPERINFECTION, and a HEAVY WORM BURDEN with characteristic larval migration required in the life cycle? Ancylostoma duodenale Enterobius vermicularis Strongyloides stercoralis Ascaris lumbricoides

Strongyloides stercoralis

Parasite recovery from stool may be enhanced by the BAERMANN FUNNEL TECHNIQUE: Ascaris lumbricoides Enterobius vermicularis Strongyloides stercoaralis Ancylostoma duodenale

Strongyloides stercoaralis ## Footnote The basic method is to wrap the sample in a PAPER TISSUE OR CLOTH AND SUBMERGE IT IN A FUNNEL FILLED WITH WATER. The nematodes will clump and sink to the bottom of the funnel where they can be recovered.

A primate parasite, has been isolated from humans in Africa and causes a severe life-threatening condition called “SWOLLEN BELLY SYNDROME.” Toxocara cati Toxocara canis Ancylostoma caninum Strongyloides fuelleborni

Strongyloides fuelleborni

The intestinal nematode considered capable of VERTICAL TRANSMISSION and the potential cause for CONGENITAL INFECTIONS is: Ascaris lumbricoides Enterobius vermicularis Trichuris trichiura Ancylostoma duodenale

Ancylostoma duodenale

The filariform larva is the infective stage for: Ascaris lumbricoides, Trichostrongylus spp. Ascaris lumbricoides, Strongyloides stercoralis Ancylostoma duodenale, Strongyloides stercoralis Trichuris trichiura, Necator americanus

Ancylostoma duodenale, Strongyloides stercoralis

The examination of blood film should be performed at _____ to DETECT MICROFILARIAE. LPO HPO OIO

LPO ## Footnote MICROFILARIA: LPO PLASMODIA, TRYPANOSOMES: OIO

MOST COMMON identified species of filarial worms that infect humans: Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Wuchereria bancrofti

Lymphatic vessel involvement within the RETROPERITONEAL REGION is associated with: Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Wuchereria bancrofti

The nematode Loa loa is transmitted to humans by: Culex spp. Simulium spp. Mansonia spp. Chrysops spp.

Chrysops spp.

The parasite is transmitted by the black fly, Simulium spp. Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Onchocerca volvulus

Sheathed microfilaria, nuclei extend to the tail in an irregularly arranged fashion: Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Loa loa ## Footnote W. bancrofti: Sheathed, tail free of nuclei B. malayi: Sheathed, tail with 2 separate nuclei L. loa: Sheathed, nuclei up to the tip of the tail O. volvulus: Unsheathed, tail is free of nuclei M. perstans: Unsheathed, nuclei up to the tip of the tail M. ozzardi: Unsheathed, tail is free of nuclei M. streptocerca: Shepherd’s crook

Microfilariae are sheathed and contain 4 to 5 subterminal and 2 TERMINAL NUCLEI in the tail: Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Brugia malayi ## Footnote W. bancrofti: Sheathed, tail free of nuclei B. malayi: Sheathed, tail with 2 separate nuclei L. loa: Sheathed, nuclei up to the tip of the tail O. volvulus: Unsheathed, tail is free of nuclei M. perstans: Unsheathed, nuclei up to the tip of the tail M. ozzardi: Unsheathed, tail is free of nuclei M. streptocerca: Shepherd’s crook

Unsheathed microfilaria, tail is free of nuclei: Brugia malayi Loa loa Onchocerca volvulus Wuchereria bancrofti

Onchocerca volvulus ## Footnote W. bancrofti: Sheathed, tail free of nuclei B. malayi: Sheathed, tail with 2 separate nuclei L. loa: Sheathed, nuclei up to the tip of the tail O. volvulus: Unsheathed, tail is free of nuclei M. perstans: Unsheathed, nuclei up to the tip of the tail M. ozzardi: Unsheathed, tail is free of nuclei M. streptocerca: Shepherd’s crook

The tail of this microfilaria is often referred to as a “shepherd’s crook”: Mansonella perstans Mansonella ozzardi Mansonella streptocerca Wucheriria bancrofti

Mansonella streptocerca

The endosymbiont Wolbachia sp. is required for parasite reproduction in all of the following except: Onchocerca volvulus Brugia timori Loa loa Wuchereria bancrofti

Loa loa ## Footnote W. bancrofti, Brugia spp., and Onchocerca volvulus harbor an endosymbiotic alpha-proteobacterium, Wolbachia sp. Wolbachia is an obligate intracellular organism.

The worm has a characteristic, thick cuticle and a large uterus that fills the body cavity and contains rhabditoid larvae: Ascaris lumbricoides Enterobius vermicularis Ancylostoma duodenale Dracunculus medinensis

Dracunculus medinensis

Removal and gradual retraction of the adult gravid female worm is recommended in infections with: Ancylostoma braziliense Dracunculus medinensis Trichinella spiralis Toxocara cati

Dracunculus medinensis

The following infection may RESEMBLE ACUTE APPENDICITIS: Parastrongylus costaricensis Gnathostoma sp. Toxocara cati Parastrongylus caninum

Parastrongylus costaricensis

Infection with Clonorchis or Opisthorchis may result from eating raw or undercooked: Aquatic vegetation Crabs Crayfish Freshwater fish

Freshwater fish

Which of the following can be acquired by ingestion of crab or crayfish bearing the metacercaria: Fasciola hepatica Fasciolopsis buski Clonorchis sinensis Paragonimus westermani

Paragonimus westermani

The eggs are small, yellow-brown, EMBRYONATED, and operculated and may have MINIMAL OPERCULAR SHOULDERS: Fasciola hepatica Fasciolopsis buski Heterophyes heterophyes Paragonimus westermani

Heterophyes heterophyes ## Footnote EMBRYONATED (MATURE) EGGS “CHOS/SHOC” OPERCULATED: Clonorchis, Heterophyes, Opistorchis MATURE, NONOPERCULATED: Schistosoma UNEMBROYONATED (IMMATURE) EGGS, OPERCULATED Fasciola, Fasciolopsis, Echinostoma UNEMBRYONATED, WITH OPERCULUM AND ABORPERCULUM: Paragonimus

The infective life cycle stage of a fluke (except blood fluke) is the: Miracidium Cercariae Metacercariae Pleurocercariae

Metacercariae

The fluke acquired by eating contaminated vegetation is: Clonorchis sinensis Fasciolopsis buski Heterophyes heterophyes Paragonimus westermani

Fasciolopsis buski

Fish carrying metacercariae may transmit: Clonorchis sinensis Fasciolopsis buski Paragonimus westermani Schistosoma haematobium

Clonorchis sinensis

Paragonimus westermani infection is acquired by: Drinking contaminated water Eating infected crustacea Eating infected fish Eating infected water chestnuts

Eating infected crustacea

The mode of transmission of schistosomal infection is by: Ingestion of contaminated aquatic vegetation Direct penetration of the skin by cercariae Ingestion of raw fish Mosquito bite

Direct penetration of the skin by cercariae

The drug of choice for treatment of schistosome infections is: Metrifonate Praziquantel Bilarcil Niclosamide

Praziquantel ## Footnote Infection with S. mansoni may require a larger dose than that for the other species.

A diagnostic characteristic of the egg of Schistosoma mansoni is: A large lateral spine No spine A pointed terminal spine A small lateral spine

A large lateral spine

To optimize recovery of S. haematobium in urine, the specimen should be collected: Early morning Between noon and 2 pm Between 2 pm and 4 pm Between 10 pm and 2 am

Between noon and 2 pm

Infection with S. haematobium may present with which of the following? Nausea Basophilia Hematuria Jaundice

Hematuria

A patient from the Great Lakes area presents with vague abdominal symptoms and a MACROCYTIC ANEMIA. Which cestode would be the probable cause? Diphyllobothrium latum Echinococcus granulosus Taenia saginata Hymenolepis nana

Diphyllobothrium latum

In the Diphyllobothrium latum life cycle, the infective stage for humans is: Cysticercus Cysticercoid Procercoid Plerocercoid

Plerocercoid

Only cestode to have an aquatic life cycle: Diphyllobothrium latum Dipylidium caninum Hymenolepis diminuta Hymenolepis nana

Diphyllobothrium latum ## Footnote 1st intermediate host: COPEPOD 2nd intermediate host, reservoir host: FISH Definitive host: MAN

Lifespan of D. latum, T. saginata and T. solium: Usually less than 1 year 1 to 5 years 10 to 15 years Up to 25 years

Up to 25 years ## Footnote H. nana: Perhaps many years as a result of autoinfection H. diminuta: Usually less than 1 year D. caninum: Usually less than 1 year D. latum, Taenia: Up to 25 years

Thick-walled POLLEN GRAINS resemble the eggs of: Ascaris lumbricoides Dipylidium caninum Hymenolepis nana Taenia species

Taenia species

Which of the following can bypass the need for an intermediate host? Diphyllobothrium latum Dipylidium caninum Hymenolepis diminuta Hymenolepis nana

Hymenolepis nana

Which tapeworm infects CATTLE as an INTERMEDIATE HOST? Taenia saginata Dipylidium caninum Hymenolepis diminuta Hymenolepis nana

Taenia saginata

Definitive host of Taenia saginata: Cow Pig Insect Human

Human ## Footnote Human serves as the definitive host for beef (Taenia saginata) and pork (Taenia solium) tapeworms; cows/ camels and pigs serve as intermediate hosts, respectively. Humans also serve as the intermediate host for T. solium (cysticercosis).

Which tapeworm cannot be identified to the species level based on its egg morphology; instead, proglottids must be examined? Diphyllobothrium Dipylidium Hymenolepis Taenia

Taenia ## Footnote Uterine branches visualized by staining the proglottids with INDIA INK T. SAGINATA: 15 to 20 branches, dichotomous or tree-like T. SOLIUM: 7 to 13 lateral branches, dendritic or fingerlike

Gravid proglottids resemble rice grains(dry) or cucumber seeds (moist): Diphyllobothrium latum Dipylidium caninum Taenia spp. Hymenolepis nana

Dipylidium caninum

Eggs HAVE POLAR FILAMENTS present in the space between the oncospheres and the eggshell: Hymenolepis diminuta Hymenolepis nana

Hymenolepis nana

The eggs contain a six-hooked oncosphere with the ABSENCE OF POLAR FILAMENTS in the space between the oncosphere and the eggshell: Hymenolepis diminuta Hymenolepis nana

Hymenolepis diminuta

Protozoan with large karyosome, may be surrounded by refractile granules that are difficult to see (“BASKET NUCLEUS”): Endolimax nana Entamoeba coli Entamoeba histolytica Iodamoeba butschlii

Iodamoeba butschlii

Which operculated ovum contain a miracidium and can appear in sputum, often accompanied by blood and Charcot-Leyden crystals? Fasciola hepatica Paragonimus westermani Schistosoma mansoni Dipylidium caninum

Paragonimus westermani

Which of the following is the first intermediate host of the flukes? Snail Water plant Fish Crab

Snail

What is a schistosomule? Cercaria Cercaria minus tail Free-swimming cercaria Metacercaria

Cercaria minus tail

Which tapeworm proglottid makes its way across the fecal specimen by doubling movements, and is seen under the microscope to have numerous regular uterine branches (more than 15) resembling those of a tree? Taenia saginata Taenia solium Diphyllobothrium lactum Dipylidium caninum

Taenia saginata

Which species of Taenia has 7 to 12 uterine branches? Taenia solium Taenia saginata Echinococcus granulosus None of the above

Taenia solium

The eggs of Echinococcus granulosus are found in the feces of: Cats Fish Dog Cattle

Dog

Which of the following is found in the intermediate host of Echinococcus granulosus? Adult worm Egg Hydatid cyst Pseudocyst

Hydatid cyst

The first intermediate host of Diphyllobothrium latum: Copepod Snail Fish Crab

Copepod

The second intermediate host of Diphyllobothrium latum Cattle Waterplants Crayfish Freshwater fish

Freshwater fish

What is the infective stage of the broad fish tapeworms to human? Plerocercoid Coracidium Hydatid cyst Cysticerus

Plerocercoid

In some individuals, particularly those of Scandinavian extraction, this worm can case a megaloblastic anemia: Diphyllobothrium latum Dipylidium caninum Taenia solium Necator americanus

Diphyllobothrium latum

Which of the following worms have separate sexes? Intestinal flukes Liver flukes Tapeworms Blood flukes

Blood flukes

The male roundworm is differentiated from the female roundworm by its: Dorsally curved posterior Pointed posterior Square posterior Rounded posterior

Dorsally curved posterior

Which stage of Trichuris trichiura is infective to humans? Rhabditiform larva Filariform larva Cyst Embryonated egg

Embryonated egg

Trichuris trichiura, hookworm, and _______ ”unholy three” of roundworm. Enterobius vermicularis Ascaris lumbricoides Taenia saginata Hymenolepsis nana

Ascaris lumbricoides

The helminth that induces a hypochromic microcytic anemia in its host is the: Hookworm Whipworm Pinworm Threadworm

Hookworm

The rhabditiform larva of the hookworm has a: Long buccal cavity equal to the width of the body Short buccal cavity equal to ½ the width of the body Medium length buccal cavity Has no buccal cavity

Long buccal cavity equal to the width of the body

Which of the following larval worms enters the host by penetration of the skin? Strongloides stercoralis Ancylostoma duodenale Both of these None of these

Both of these

A roundworm that inhabits the small intestine and usually is demonstrated as rhabditiform larvae in the fecal specimen is the: Hookworm Large roundworm Whipworm Threadworm

Threadworm

Adults of filarial worms live in: Blood and feces Urine and lymphatics Subcutaneous tissues Lymphatics and subcutaneous tissues

Lymphatics and subcutaneous tissues

Dirofilaria immitis: Dog heartworm Dog hookworm Rat lungworm Cercarial dermatitis

Dog heartworm

Cutaneous larva migrans or creeping eruptions is caused by: Larvae of pinworm Microfilariae Filariform larvae of the dog hookworm Metacercariae

Filariform larvae of the dog hookworm

Specific gravity of zinc sulfate solution for the flotation method: 1.01 1.04 1.18 1.48

1.18

The ideal temperature at which to hold a fecal specimen for more than 1 hour is: Freezer temperature Refrigerator temperature Room temperature Incubator temperature

Refrigerator temperature

Most tapeworms are intestinal parasites of humans. Humans can be both the intermediate and the definitive host of: Taenia saginata Taenia solium Echinococcus granulosus Diphyllobothrium latum

Taenia solium

Charcot-Leyden crystals in stool may be associated with an immune response and are thought to be the breakdown products of: Neutrophils Eosinophils Monocytes Lymphocytes

Eosinophils

Characteristics of the rhabditiform (noninfective) larvae of Strongyloides stercoralis include a: Short buccal capsule and large genital primordium Long buccal capsule and pointed tail Short buccal capsule and small genital primordium Small genital primordium and notch in tail

Short buccal capsule and large genital primordium

A mother brings two male children; ages 3 and 4, to the clinic because they are restless, haven't been sleeping well, and frequently are scratching their bottoms. Examination is consistent with perianal pruritus. What is the most likely etiologic agent involved in this infection? Enterobius vermicularis Stronyloides stercoralis Acanthamoeba duodenale Necator americanus

Enterobius vermicularis

A 33-year-old dog owner presents with abdominal pain and signs of internal hemorrhaging. Blood tests show eosinophilia, but parasite eggs are NOT found in fecal smears. An ELISA test confirms a diagnosis of visceral larva migrans. What is the most likely etiologic agent involved in this infection? Schistosoma mansoni Taenia saginata Toxocara canis Dipylidium caninum

Toxocara canis

All of the following larva migrate through the lungs except one: Ascaris Hookworm Pinworm Stronyloides

Pinworm

Habitat of the adult Trichinella spiralis: Small intestines Skeletal muscles Blood CSF

Small intestines ## Footnote T. SPIRALIS ADULT - SMALL INTESTINES T. SPIRALIS LARVA - MUSCLES

Malabsorption syndrome is associated with this parasite: Enterobius vermicularis Necator americanus Trichuris trichiura Capillaria philippinensis

Capillaria philippinensis

The mouth of Necator americanus is characterized by the presence of: Teeth Cutting plates Both of these None of these

Cutting plates

Which of the following microfilariae is unsheathed? Wuchereria bancrofti Onchocerca volvulus Loa loa Brugia malayi

Onchocerca volvulus

Eye worm producing fugitive swelling or Calabar swelling: Loa loa Onchocerca volvulus Dipetalonema perstans Mansonella ozzardi

Loa loa

Infective stage of the Schistosomes to their final host: Miracidium Sporocyst Cercaria Metacercaria

Cercaria

Eggs of this fluke are small and shaped like an old-fashioned electric light bulb: Clonorchis sinensis Fasciola lanceolata Fasciolopsis buski Echinostoma ilocanum

Clonorchis sinensis

Infection with this fluke is acquired by eating the tissues of fresh water crabs: Heterophyes heterophyes Paragonimus westermani Clonorchis sinensis Fasciolopsis buski

Paragonimus westermani

Schistosoma cercaria enter the human body: By eating raw snail By eating contaminated vegetables and fish By blood transfusion By skin penetration

By skin penetration

Human tapeworm that does not require an intermediate host to complete its natural life cycle: Hymenolepis nana Hymenolepis diminuta Taenia saginata Dipylidium caninum

Hymenolepis nana

Microfilaria is sheathed, the body nuclei extend almost to the tip of the tail Wuchereria bancrofti Brugia malayi Loa loa Onchocerca volvulus

Loa loa

The term “internal autoinfection” is generally used in referring to infections with: Ascaris lumbricoides Necator americanus Trichuris trichiura Strongyloides stercoralis

Strongyloides stercoralis

A fibrous skin nodule is removed from the back of a patient from Central America. A microfilaria seen upon microscopic exam of the nodule is: Wuchereria bancrofti Brugia malayi Onchocerca volvulus Loa loa

Onchocerca volvulus

Cysticercosis is caused by the disseminated larva of: Hymenolepis nana Hymenolepis diminuta Taenia saginata Taenia solium

Taenia solium

A tapeworm with almond-shaped or spoon-shaped scolex is: Taenia saginata Taenia solium Dipylidium caninum Diphyllobothrium latum

Diphyllobothrium latum

An operculated CESTODE egg that can be recovered in human feces is: Clonorchis sinensis Paragonimus westermani Dipylidium caninum Diphyllobothrium latum

Diphyllobothrium latum ## Footnote Clonorchis and Paragonimus - TREMATODES, operculated egg D. caninum - CESTODE, CYLOPHYLLIDEAN, non-operculated egg D. latum - CESTODE, PSEUDOPHYLLIDEAN, operculated egg

Migrating larva of this parasite can be found in sputum: Ascaris lumbricoides Paragonimus westermani Both of these None of these

Ascaris lumbricoides ## Footnote LARVA IN SPUTUM - ASCARIS, STRONGYLOIDES, HOOKWORM EGG (OVUM) IN SPUTUM - PARAGONIMUS

Egg of this parasite can be found in sputum: Ascaris lumbricoides Paragonimus westermani Both of these None of these

Paragonimus westerman ## Footnote LARVA IN SPUTUM - ASCARIS, STRONGYLOIDES, HOOKWORM EGG (OVUM) IN SPUTUM - PARAGONIMUS

Serve as DEFINITIVE HOST for the beef tapeworm: Cows, camels Pigs Humans Dogs, cats

Humans ## Footnote TAENIA SAGINATA Humans serve as the definitive host for the beef tapeworm, whereas cows/camels serve as intermediate hosts.

INTERMEDIATE HOSTS of Taenia saginata: Cows, camels Pigs Humans Dogs, cats

Cows, camels ## Footnote TAENIA SAGINATA Humans serve as the definitive host for the beef tapeworm, whereas cows/camels serve as intermediate hosts.

Eggs can be confused with POLLEN GRAINS: Enterobius Trichuris Taenia Dipylidium

Taenia ## Footnote BAILEY & SCOTT'S: TAENIA EGGS Eggs can be confused with pollen grains (handle all proglottids with extreme care)

Gravid proglottids resemble rice grains (dry) or cucumber seeds (moist): Diphyllobothrium latum Dipylidium caninum Hymenolepis nana Hymenolepis diminuta

Dipylidium caninum ## Footnote BAILEY & SCOTT'S: DIPYLIDIUM CANINUM Gravid proglottids resemble rice grains (dry) or cucumber seeds (moist).

Parasite recovery from stool may be enhanced by the Baermann funnel technique: Ascaris lumbricoides Enterobius vermicularis Strongyloides stercoralis Trichinella spiralis

Strongyloides stercoralis

Consumption of the infective larval stage encysted on aquatic plants that have not been cooked results in infection with: Clonorchis sinensis Fasciola hepatica Heterophyes heterophyes Paragonimus westermani

Fasciola hepatica

A schistosoma egg with a terminal spine would be most likely found in which of the following? Feces Bile Sputum Urine

Urine ## Footnote S. HAEMATOBIUM - URINE

The motile, reproducing, feeding stage of the protozoans is which of the following? Cyst Trophozoite Ova (egg) Adult worm

Trophozoite

Which of the following organs of the body is most often involved in extraintestinal amoebiasis? Lungs Kidneys Pancreas Liver

Liver

Amoeba that inhibit the gastrointestinal tract of man are non-motile, nonfeeding, and infective during which stage? Pseudopod Cyst Trophozoite Cryptozoite

Cyst

Which of these trophozoites, when acting as a pathogen, is likely to ingest red blood cells of the host? Entamoeba coli Entamoeba hartmanni Entamoeba histolytica Endolimax nana

Entamoeba histolytica

The point of differentiation between Entamoeba histolytica and Entamoeba hartmanni is: Presence of peripheral chromatin Presence of chromatoid bodies Only one possesses a cyst form Size

Size

Failure to find bacteria in purulent spinal fluid should alert one to the possibility of an infection with: Viruses Amoeba Flagellates Worms

Amoeba

Which of the following would have a double-walled, wrinkled cyst form? Naegleria fowleri Entamoeba hartmanni Acanthamoeba castellanii Dientamoeba fragilis

Acanthamoeba castellanii

A cyst that possesses a single nucleus and a large glycogen vacuole that stains deeply with iodine belong to: Endolimax nana Iodamoeba butschlii Dientamoeba fragilis Entamoeba coli

Iodamoeba butschlii

Amoeba inhabiting the central nervous system enter the body through the: Mouth Nasal mucosa Urine Joint fluid

Nasal mucosa

In which specimen are Acanthamoeba and Naegleria usually found? Blood Cerebrospinal fluid Urine Joint fluid

Cerebrospinal fluid

Which of the following are often mistaken for cysts of amoeba? Blastocystis hominis Calcium carbonate crystals Ammonium magnesium phosphate crystal Epithelial cells

Blastocystis hominis

Which of the following is pathognomonic for Giardia lamblia and the stage it is found in? Spiral groove/trophozoite Undulating membrane/cyst Cytostome/trophozoite Ventral sucking disk/trophozoite

Ventral sucking disk/trophozoite

Which of the following protozoa have an undulating membrane? Trichomonas Trypanosoma Chilomastix Trichomonas and Trypanosoma

Trichomonas and Trypanosoma

A pear-shaped flagellate with jerky motility that is found in a urine specimen is identified as: Trichomonas hominis Trichomonas vaginalis Escherichia coli Leptospira

Trichomonas vaginalis

Eighty (80) percent of the trophozoites of Dientamoeba fragilis have: 2 nuclei 3 nuclei 1 nuclei No nuclei

2 nuclei

The only bilaterally symmetrical protozoan is: Trichomonas Dientamoeba Giardia Balantidium

Giardia

Which of the following is the vector of African sleeping sickness? Reduviid bug (Triatoma) Sandfly (Phlebtomus) Tsetse fly (Glossina) Ticks

Tsetse fly (Glossina)

How is Trypanosma cruzi transmitted? Inhalation Bite of the tsetse fly Bite of the reduviid bug Sexual contact

Bite of the reduviid bug

In the laboratory diagnosis of Leishmania donovani, which is the preferred specimen in which to find Leishman-Donovan bodies? Bone marrow Blood Vaginal secretions Cerebrospinal fluid

Bone marrow

Which of the following is the only ciliate that is pathogenic in humans? Babesia Isospora Balantidium coli Entamoeba coli

Balantidium coli

Structure used for motility of Balantidium coli: Flagella Cilia Pseudopodia Undulating membrane

Cilia

Which nucleus of the trophozoite of Balantidium coli is the reproductive one? Micronucleus Macronucleus Both of these None of these

Micronucleus

Which of the malarial organisms presents as pale, very AMOEBOID RING TROPHOZOITE, infecting a large pale red blood cell with dot of hemoglobin? Plasmodium ovale Plasmodium malariae Plasmodium falciparum Plasmodium vivax

Plasmodium vivax

Which of the malarial organism preferentially invades reticulocytes? Plasmodium falciparum Plasmodium malariae Plasmodium vivax All of the above

Plasmodium vivax

The malarial organism whose schizont resembles a “fruit pie” in which the merozoites form a rosette around the malarial pigment is: Plasmodium malariae Plasmodium vivax Plasmodium ovale Plasmodium falciparum

Plasmodium malariae

Which malarial organism characteristically has a BAND FORM trophozoite stretching across the red blood cell? Plasmodium malariae Plasmodium ovale Plasmodium vivax Plasmodium falciparum

Plasmodium malariae

Which malarial organism features ring trophozoites that have double chromatin dots, applique forms, and often have multiple parasites in the infected red blood cells? Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium ovale

Plasmodium falciparum

Which malarial organism has large, coarse, red dots within a large, pale red blood cell with fimbriated edges? Plasmodium vivax Plasmodium falciparum Plasmodium ovale Plasmodium malariae

Plasmodium ovale

The sexual reproduction cycle in Plasmodium and coccidian is referred to as: Sporogony Schizogony Sporocyst None of the above

Sporogony

What is the infective stage of malarial parasite to the vector? Cryptozoites Trophozoites Gametocyte Ookinete

Gametocyte

What is the infective stage of malarial parasite to humans? Gametocytes Cryptozoites Schizonts Sporozoites

Sporozoites

In which type of malaria is there synchronized rupture of the red blood cells every 72 hours? P. falciparum P. ovale P. vivax P . malariae

P . malariae

Which hemoglobin is incompatible with malaria parasite survival? Hb CC Hb F Hb SS Hb A

Hb SS

What is the name of the laboratory test that allows laboratory-bred reduviid bugs to feed on patients suspected of having Chagas’ disease? Complement fixation Serodiagnosis Xenodiagnosis Western blot

Xenodiagnosis

What is both the definitive and intermediate host of Toxoplasma gondii? Dog Cow Cat Chicken

Cat

What constitutes a positive result in the Sabin-Feldman dye test? Toxoplasma becomes nonmotile Toxoplasma can no longer be demonstrated as an intracellular organism Toxoplasma loses its affinity for methylene blue dye The mouse into which the immune serum is injected does not die from toxoplasmosis

Toxoplasma loses its affinity for methylene blue dye

Which of the following tests is used for the detection of Cryptosporidium? Sabin-Feldman dye test G-6-PD test Xenodiagnosis Sheather’s sugar flotation

Sheather’s sugar flotation

Direct examination of stool specimens stained with iodine make the trophozoite of the protozoa stain what color? Yellow Brown Trophozoites are destroyed by iodine Do not stain

Trophozoites are destroyed by iodine

The modified acid-fast stain is most often used in parasitology to identify: Protozoan cysts and trophozoites Helminth eggs Plasmodium Cryptosporidium and other coccidia

Cryptosporidium and other coccidia

What morphological characteristic differentiates trichomonads from other intestinal flagellates? Sucking disc Undulating membrane Cytostome Axonemes

Undulating membrane

Shown to be related to GAY BOWEL SYNDROME: Giardia lamblia Entamoeba histolytica Balantidium coli Isospora belli

Giardia lamblia ## Footnote Important risk factors for Giardiasis include: poor hygiene, poor sanitation, overcrowding, immunodeficiency, bacterial and fungal overgrowth in the small intestine, and homosexual practices. Giardiasis has been shown to be related to the “GAY BOWEL SYNDROME.”

Which of the following is the most important feature in differentiating cysts of Entamoeba histolytica from E. dispar? Number of nuclei Size of the cyst Shape of the karyosome Distinguishing surface antigens by immunologic assays

Distinguishing surface antigens by immunologic assays ## Footnote E. histolytica and E. dispar cannot be morphologically differentiated. The cyst stage of both organisms has four nuclei with a centrally located karyosome. E. histolytica is a well recognized intestinal parasite, whereas E. dispar is considered nonpathogenic. Immunologic assays to detect antigens or molecular biology assays are necessary to differentiate these two species.

Which of the following is the preferred anticoagulant for preparing blood smears for diagnosing malaria? EDTA Heparin Sodium citrate Sodium fluoride

EDTA ## Footnote Collection of blood by finger stick is preferred for preparing blood smears for the detection of malaria. When a venipuncture is performed, the preferred anticoagulant for malarial blood smears is EDTA. Heparin can be used, but it may cause distortion of some parasite forms.

A free-living ameba that causes primary amebic meningoencephalitis is: Dientamoebafragilis Entamoeba coli Entamoeba histolytica Naegleria fowleri

Naegleria fowleri ## Footnote Naegleria fowleri is found in freshwater ponds and lakes, especially those with disturbed or suspended soil. It has caused a number of cases of meningoencephalitis in people who have swum in these bodies of water. Essentially, all these infections have been fulminating and fatal, and they are often not diagnosed until autopsy.

Which of the following is the best technique to identify Dientamoeba fragilis in stool? Formalin concentrate Trichrome-stained smear Modified acid-fast–stained smear Giemsa stain

Trichrome-stained smear ## Footnote Because there is no known cyst form, the best technique to recover and identify D. fragilis trophozoites would be the trichrome-stained smear.

Entamoeba gingivalis ## Footnote E. gingivalis is known to be an inhabitant of the mouth and is characterized by morphology that resembles Entamoeba histolytica/E. dispar. However, E. gingivalis tends to ingest PMNs, whereas Entamoeba histolytica/E. dispar do not.

In an outbreak of diarrheal disease traced to a municipal water supply, the most likely causative agent is: Cryptosporidium spp. Cystoisospora belli Entamoeba histolytica Dientamoeba fragilis

Cryptosporidium spp. ## Footnote Cryptosporidium oocysts have been transmitted through contaminated municipal water supplies. Such outbreaks have been well documented.

Plasmodium vivax and Plasmodium ovale are similar because they: Exhibit Schüffner’s dots and have a true relapse in the life cycle Have no malarial pigment and multiple rings Have true stippling, do not have a relapse stage, and infect old red cells Commonly have appliqué forms in the red cells

Exhibit Schüffner’s dots and have a true relapse in the life cycle ## Footnote Both P. vivax and P. ovale infect young red cells, have true stippling (Schüffner’s dots), contain malarial pigment, and have a true relapse stage in the life cycle.

Early ring stages of the fifth human malaria, Plasmodium knowlesi, resemble those of: Plasmodium malariae Plasmodium ovale Plasmodium falciparum Plasmodium vivax

Plasmodium falciparum ## Footnote The early ring stages of Plasmodium knowlesi resemble those of P. falciparum

Older developing stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowlesi, resemble those of: Plasmodium malariae Plasmodium ovale Plasmodium falciparum Plasmodium vivax

Plasmodium malariae ## Footnote The older developmental stages of Plasmodium knowlesi (trophs, schizonts) resemble those seen in infections with P. malariae (band forms, rosette schizonts).

Cyclospora cayetanensis oocysts ## Footnote Autofluorescence requires no stain and is often recommended for confirmation of Cyclospora cayetanensis oocysts.