Deck 28: Diagnostic Parasitology

Question 1

A young man who returned a week ago from a family vacation to Kenya develops a high fever and delirium. Although he was compliant with his antimalarial medications, a blood sample is taken to rule out malaria. The laboratory scientist sees the following on the blood smear at 1000 $\times$ . This organism is most likely

A) Trypanosoma brucei.
B) Leishmania donovani.
C) Wuchereria bancrofti.
D) Loa loa.

Answer 1

Trypanosoma brucei.

Question 2

An international male student from Egypt comes to the campus clinic complaining of blood in his urine. A urinalysis reveals the parasite seen below at 400 $\times$ . This organism is

A) Schistosoma mansoni.
B) S. japonicum.
C) S. haematobium.
D) S. madurella.

Answer 2

S. haematobium.

Question 3

A woman who just returned from a trip to Southeast Asia has signs of biliary obstruction, which is confirmed by CT scan. Due to her recent travel history, the physician orders an ova and parasites examination before considering surgical intervention. The following element is found in her fecal sample at 400 $\times$ . The most likely identity of this organism is

A) Schistosoma mansoni.
B) Clonorchis sinensis.
C) Fasciola hepatica.
D) Heterophyes heterophyes.

Answer 3

Clonorchis sinensis.

Question 4

A recent emigrant from Somalia develops high fever, chills, and severe headache. Blood work on admission to the hospital reveals the following in his blood smear at 1000 $\times$ . This patient is most likely infected with

A) Plasmodium ovale.
B) P. malariae.
C) P. falciparum.
D) P. vivax.

Question 5

Five members of a family develop a sudden onset of watery diarrhea, nausea, vomiting, headache, and cramps. The family physician orders fecal cultures and complete ova and parasites analysis. Each sample reveals the presence of organisms seen below at 1000 $\times$ . The most likely cause of the infection is

A) Cryptosporidium parvum.
B) Isospora belli.
C) Cyclospora cayetanensis.
D) Encephalitozoon intestinalis.

Question 6

The following organism was found at 1000 $\times$ in the fecal sample of a patient with fever and diarrhea. This organism is most likely:

A) Entamoeba histolytica
B) E. hartmanni
C) Giardia lamblia
D) E. coli

Question 7

Several children at a daycare center are having trouble sleeping and are showing increasing signs of restlessness. Because one child was recently diagnosed with an intestinal parasite, the parents are informed that other children should be tested. The organism below is found at 400 $\times$ during examination. This organism is

A) Trichuris trichiura.
B) Enterobius vermicularis.
C) Ascaris lumbricoides.
D) Hookworm.

Question 8

A 4-year-old child has been complaining of a stomachache and has had intermittent episodes of diarrhea. Physical examination reveals an apparently healthy child with a mildly distended abdomen. Because of the diarrhea, a fecal sample is sent for culture and for ova and parasites examination. What is the identity of that found at 400 $\times$ in the child's fecal sample?

A) Ascaris lumbricoides
B) Strongyloides stercoralis
C) Hookworm
D) Schistosoma haematobium

Question 9

A housewife from the Great Lakes area presents to her family physician with fatigue and malaise. Blood tests show that she has enlarged but pale RBCs (megaloblastic anemia) along with a vitamin B₁₂ deficiency. Her history includes a dietary habit of making pickled fish, a family favorite. Because of this, an ova and parasites examination is also requested and reveals the following at 400 $\times$ . What is the identity of this parasite?

A) Hymenolepis nana
B) Taenia saginata
C) Diphyllobothrium latum
D) Taenia solium

Question 10

Identify the organism found in a peripheral blood thick smear at 1000 $\times$ :

A) Brugia malayi
B) Loa loa
C) Wuchereria bancrofti
D) Onchocerca volvulus

Question 11

A woman patient with history of travel to tropical Africa was noncompliant with her antimalarial medications. She now has a cyclical fever and paroxysm every 72 hours. The following organism is seen in her peripheral blood smear at 1000 $\times$ is consistent with an infection caused by

A) Plasmodium ovale.
B) P. vivax.
C) P. falciparum.
D) P. malariae.

Question 12

A 15-year-old boy spent most of the summer at the northern Minnesota family cabin on a lake in a densely wooded area. After returning to school in the fall, he was frequently tired and listless with periods of fever and chills. A blood sample revealed the following organism at 1000 $\times$ . The most likely identification is

A) Plasmodium ovale.
B) Babesia microti.
C) Plasmodium malariae.
D) Trypanosoma cruzi.

Question 13

A patient who has traveled to Puerto Rico comes to a clinic with a history of diarrhea for the past 2 weeks. A fecal sample collected for O&P shows the following parasite at 400 $\times$ . This organism is most likely

A) Schistosoma mansoni.
B) S. japonicum.
C) S. haematobium.
D) S. madurella.

Question 14

A patient finds a small ribbonlike object in his stool and reports this to his physician. The physician orders a fecal ova and parasite analysis that reveals the following egg in the sample at 400 $\times$ . The most likely identity of this parasite is

A) Hymenolepis nana.
B) Taenia spp.
C) Diphyllobothrium latum.
D) Paragonimus westermani.

Question 15

A patient comes to the emergency department stating that he has fever and chills every 48 hours. The patient has a history of travel to Central America in the past month and did not take any preventative measures against malaria. A complete blood count shows the following RBC inclusions at 1000 $\times$ . This organism is most likely

A) Plasmodium malariae.
B) P. ovale.
C) P. falciparum.
D) P. vivax.

Question 16

When a request is submitted to examine a blood sample for malaria, which of the following procedures should be performed?

A) A thick smear for maximum detection and to determine morphology
B) A PVA trichrome-stained blood smear
C) A Giemsa thick blood smear preparation for maximum detection and a thin smear for speciation
D) A formalin-ethyl acetate concentration for detection and a thin smear for speciation

Question 17

A patient with recent history of travel to the Philippines has bloody diarrhea. An ova and parasites examination of the stool shows the following at 400 $\times$ .

A) Schistosoma mansoni
B) S. japonicum
C) S. haematobium
D) S. madurella

Question 18

A farmer who raises sheep and cattle shows signs of jaundice. Along with elevated liver enzymes, he also has an elevated eosinophil count. A fecal sample for ova and parasites shows the parasite form seen below at 400 $\times$ . The organism causing this infection is

A) Paragonimus westermani
B) Heterophyes heterophyes
C) Schistosoma mansoni
D) Fasciola hepatica

Question 19

A young man from rural Brazil is visiting family in the United States when he becomes ill with muscle pains, high fever, and hepatosplenomegaly. A blood sample taken in the emergency department reveals the following organism at 1000 $\times$ . The most likely identification of this organism is

A) Leishmania donovani.
B) Babesia microti.
C) Plasmodium falciparum.
D) Trypanosoma cruzi.

Question 20

A patient with a history of eating wild game comes to the physician with a history of diarrhea over the past 3 weeks. In addition, he complains of fever, muscular pain and tenderness, headache, and general weakness. The patient also has a significant eosinophilia. A biopsy of a nodular area on his forearm is seen in the image below. This is consistent with a diagnosis of infection caused by

A) Leishmania donovani.
B) Wuchereria bancrofti.
C) Trichinella spiralis.
D) Loa loa.

Question 21

Some pathogens will not grow in culture and are usually unsuspected. This pathogen can be seen in the sputum and bronchoalveolar fluid of patients with a hyperinfestation syndrome. The name of this pathogen is

A) Strongyloides stercoralis.
B) Giardia lamblia.
C) Treponema species.
D) Leptospira species.