Deck 30: Parasitology

Question 1

Trypanosoma brucei gambiense is not endemic to the United States because the appropriate

A) reservoir hosts do not exist.
B) vector does not exist.
C) intermediate host does not exist.
D) sanitation practices are employed.

Answer 1

vector does not exist.

Question 2

A parasite that is capable of infecting both man and animal increases its chances of survival. It is described as

A) an endoparasite.
B) symbiotic.
C) enzoonotic.
D) a facultative parasite.

Answer 2

enzoonotic.

Question 3

Review the image provided of a trichrome stained fecal specimen.
Source: CDC
How is the structure in the center of the image best distinguished from an amoeba?

A) The image is an amoeba.
B) The nuclear material: cytoplasm ratio is smaller in human cells.
C) The nuclear material: cytoplasm is greater in human cells.
D) White blood cells usually only have one nucleus.

Answer 3

The nuclear material: cytoplasm is greater in human cells.

Question 4

Review the image provided and identify it.
Source: CDC

A) Pollen granule
B) Taenia spp. ova
C) Plant cell
D) Yeast cell

Question 5

A physician suspects her patient has Paragonimus westermani based on the patient's physical and history. A stool sample is submitted for ova and parasite examination and is negative. You suggest the collection of a/an __________ specimen to assist with the diagnosis.

A) duodenal aspirate
B) blood
C) urine
D) sputum

Question 6

A stool specimen is submitted for ova and parasite examination. Which of the following organisms will not be recovered in this specimen type?

A) Balantidium coli
B) Trichomonas hominis
C) Schistosoma japonicum
D) Trichinella spiralis

Question 7

Which of the following microfilarial larvae is not diagnosed using peripheral blood?

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

Question 8

Review the image provided.
Source: CDC
What laboratory procedure was used to recover this organism?

A) Vaspar swab prep of perianal region
B) Wet prep of concentrated stool
C) Trichrome stain of stool smear
D) Wet prep of duodenal aspirate

Question 9

Review the image provided.
Source: CDC
In the life cycle of this organism, man serves as the ________________ host.

A) intermediate
B) definitive
C) vector
D) reservoir

Question 10

Which of the following organisms is the causative agent of sleeping sickness?

A) Trypanosoma brucei rhodesiense
B) T. cruzi
C) Leishmania donovani
D) a and b

Question 11

The presence of blood and pus in the urine is often associated with infection with

A) Trichomonas vaginalis.
B) Schistosoma hematobium.
C) S. japonicum.
D) Entamoeba histolytica.

Question 12

An HIV-positive 33-year-old female presents with fever, chills, muscle pain, and swollen lymph nodes. She relates that she also has severe headaches and trouble with her vision. Routine, fungal, and viral cultures of the CSF and blood were negative. A stool specimen for ova and parasite examination was also negative. An ELISA test demonstrated a significant increase in titer for antibodies against a specific parasite. Which causative agent do you suspect?

A) Sarcocystis spp.
B) Isospora belli
C) Enterocytozoon spp.
D) Toxoplasma gondii

Question 13

A 28-year-old female missionary has just returned from Africa where she spent three months in the field. While she is not exhibiting any signs or symptoms of illness, a stool sample is submitted as part of her physical on her return. The ova and parasite examination reveals the organism in the image provided.
Source: CDC
This organism measures 15 $\mu$ m by 10 $\mu$ m. Given this information, you would

A) identify the organism as Entamoeba histolytica.
B) identify the organism as E. coli.
C) report the O & P as negative for pathogens.
D) perform an ELISA test.

Question 14

A 20-year-old male with leukemia presents with watery diarrhea of two weeks duration, nausea, weight loss, and anorexia. A stool sample is submitted for routine culture and ova and parasite examination. The routine culture is negative for Salmonella, Shigella, Campylobacter, Yersinia enterocolitica, and shiga-toxin producing E. coli. The concentrated wet mount exam and trichrome stained stool smear are negative. Additional testing revealed the organism as seen in the image provided.
Source: CDC/DPDx - Melanie Moser
Knowing the organism measures 9 $\mu$ m, you would identify it as

A) Cryptosporidium parvum.
B) Cyclospora cayetanensis.
C) microsporidia.
D) yeast.

Question 15

A 47-year-old male, who lives in Bangor, ME, returns from a trip to Southeast Asia. He visits his physician with fever, chills, headache, and malaise. His fevers seem to appear every 48 hours. A blood smear reveals the organism as seen on the image provided.
Source: CDC/Steven Glenn, Laboratory Training & Consultation Division
Given this information, you would report the organism as

A) Plasmodium vivax.
B) P. ovale.
C) P. malariae.
D) Babesia microti.

Question 16

Prior to his kidney transplant, a 56-year-old male is tested for ova and parasites. One of three stools submitted demonstrates the organisms seen in the image provided.
Source: CDC/Dr. Mae Melvin
You would identify the organisms as

A) Hookworm spp. filariform larvae.
B) Strongyloides stercoralis filariform larvae.
C) Hookworm spp. rhabditiform larvae.
D) Strongyloides stercoralis rhabditiform larvae.

Question 17

An astute hematologist notes the organism in the image provided on a stained blood smear.
Source: CDC/Dr. Mae Melvin
She calls you over to confirm its identification. She asks what disease is associated with this organism. You tell her

A) river blindness.
B) visceral larval migrans.
C) elephantiasis.
D) Calabar swellings.

Question 18

A 30-year-old male, who is a recent immigrant from Mexico, presents to a clinic saying he has long strands of what looks like cooked macaroni in his stool. A stool sample reveals the organism seen in the image provided.
Source: CDC/Dr. Mae Melvin
This individual is harboring

A) Taenia solium.
B) Taenia saginata.
C) A parasite that requires review of a proglottid.
D) A parasite that requires review of the scolex.

Question 19

Which of the following reports is considered a medical emergency and should be reported as a critical result?

A) Cryptosporidium parvum in an AIDS patient
B) Plasmodium falciparum in comatose individual
C) Babesia microti in an asplenic individual
D) Both a and b
E) Both b and c

Question 20

Which of the following organisms may not require treatment if there is a light infestation?

A) Schistosoma mansoni
B) Trichuris trichiura
C) Taenia solium
D) Anisakis spp.