protazoa Flashcards
1
Q
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
(A) T. vaginalis
(B) E. vermicularis
(C) A. lumbricoides
(D) N. americanus
(E) E. histolytica
A
(B) E. vermicularis
2
Q
- Chagas disease is especially feared in Latin America because
of the damage that can occur to the heart and parasympathetic nervous system and the lack of an effective drug for the
symptomatic later stages. Your patient is planning to reside in
a Venezuelan village for 1–2 years. Which one of the following suggestions would be of special value for avoiding Chagas
disease?
(A) Boil or treat all of your drinking water
(B) Sleep under a bed net
(C) Do not keep domestic pets in your house
(D) Never walk barefoot in the village compound
(E) Do not eat lettuce or other raw vegetables or unpeeled fruit
A
(B) Sleep under a bed net
3
Q
- 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?
(A) Specific serologic test
(B) Ova and parasite fecal smear
(C) Wet mount of vaginal fluid
(D) Enzyme-linked immunoassay (ELISA) test of serum
(E) Stool culture
A
(C) Wet mount of vaginal fluid
4
Q
- You are working in a rural medical clinic in China and a 3-yearold 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
(A) Schistosomiasis
(B) Cercarial dermatitis
(C) Cyclosporiasis
(D) Hookworm infection
(E) Trichuriasis
(F) Ascariasis
A
(D) Hookworm infection
5
Q
- Pathologic effects of filariae in humans are caused by the adult
worms in all but one species. In this case, the principal damage
is caused by the microfilariae of
(A) B. malayi
(B) Mansonella ozzardi
(C) D. medinensis
(D) W. bancrofti
(E) O. volvulus
A
(E) O. volvulus
6
Q
- An 18-year-old male complains of abdominal pain, bloating, frequent loose stools, and loss of energy. He returned a month ago
from a 3-week hiking and camping trek to the Mount Everest Base
Camp in Nepal. The trek involved only high-elevation hiking,
since he flew in and out of the 12,000-ft starting point. Which of
the following is an important consideration for the diagnosis?
(A) Exposure to high-level UV radiation
(B) The source and purification of water
(C) The use of insect repellents while hiking
(D) The presence of domestic animals en route
(E) The degree of contact with villagers en route
A
(B) The source and purification of water
7
Q
- Which one of the following diagnostic tests should be conducted for the patient in Question 6?
(A) Blood and urine bacteriologic examination
(B) Series of ova and parasite tests and fecal smears
(C) ELISA or hemagglutination serologic tests for malaria
(D) Skin snip microfilarial test
(E) Endoscopic exam for whipworms
A
(B) Series of ova and parasite tests and fecal smears
8
Q
- The parasite most likely to be responsible for the illness of the
patient in Question 6 is
(A) L. major
(B) P. vivax
(C) T. vaginalis
(D) Naegleria gruberi
(E) G. lamblia
A
(E) G. lamblia
9
Q
- 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
(A) The prevalence of Ascaris infections in the population
(B) The prevalence of schistosomiasis in the population
(C) The presence of T. brucei gambiense in the villagers
(D) The presence of Giardia cysts in the drinking water
(E) The presence of T. solium in the pigs
A
(E) The presence of T. solium in the pigs
10
Q
- 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?
(A) T. gondii
(B) S. mansoni
(C) S. haematobium
(D) A. lumbricoides
(E) T. solium
A
(C) S. haematobium
11
Q
- What type of specimen was collected for laboratory analysis
based on the answer in the previous question?
(A) Thick blood smear
(B) Stool sample
(C) Urine sample
(D) Blood for serology
(E) Sputum sample
A
(C) Urine sample
12
Q
- A previously healthy 23-year-old woman recently returned from
her vacation after visiting friends in Arizona. She complained of
severe headaches, saw “flashing lights,” and had a purulent nasal
discharge. She was admitted into the hospital with a diagnosis of
bacterial meningitis and died 5 days later. Which of the following
parasites should have been considered in the diagnosis? She had
no prior history of travel outside of the United States.
(A) P. falciparum
(B) T. gondii
(C) S. stercoralis
(D) E. histolytica
(E) N. fowleri
A
(E) N. fowleri
13
Q
- How could the person have acquired the parasite in Question 12?
(A) Ingesting cysts from fecally contaminated drinking water
(B) Eating improperly cooked fish
(C) Eating improperly cooked beef
(D) Walking barefoot in the park
(E) Engaging in unprotected sexual intercourse
(F) Getting bitten by a sand fly
(G) Plunging into a natural hot spring
A
(G) Plunging into a natural hot spring
14
Q
- A 37-year-old sheep farmer from Australia presents with upper
right quadrant pain and appears slightly jaundiced. A stool
exam was negative for ova and parasites but a CT scan of the
liver reveals a large 14-centimeters cyst that appears to contain
fluid. Which of the following parasites should be considered?
(A) T. gondii
(B) T. solium
(C) T. saginata
(D) C. sinensis
(E) S. mansoni
(F) E. granulosus
(G) P. westermani
A
(F) E. granulosus
15
Q
- An apparently fatigued but alert 38-year-old woman spent
6 months as a teacher in a rural Thailand village school. Her chief
complaints include frequent headaches, occasional nausea and
vomiting, and periodic 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 P. falciparum malaria
based on a microscopic examination of the blood smear?
(A) Red blood cells containing trophozoites with Schüffner’s
dots
(B) Red blood cells containing >1 parasite per RBC
(C) Banana-shaped or crescent-shaped gametocytes
(D) Parasites within normal-sized red blood cells
(E) Parasites with double nuclei
A
(A) Red blood cells containing trophozoites with Schüffner’s dots
