WorksheetsParasitology Part 2
Total questions: 12
Worksheet time: 3hrs 0mins
The most prevalent helminth to infect humans is:
A. Enterobius vermicularis, the pinworm
B. Ascaris lumbricoides, the large intestinal roundworm
C. Taenia saginata, the beef tapeworm
D. Schistosoma mansoni, one of the blood flukes
A helminth egg is described as having terminal polar plugs. The most likely helminth is:
A. Hookworm
B. Trichuris trichiura
C. Fasciola hepatica
D. Diphyllobothrium latum
Plasmodium vivax and Plasmodium ovale are similar because they:
similar because they: A. Exhibit Schüffner’s dots and have a true relapse in the life cycle
B. Have no malarial pigment and multiple rings
C. Commonly have appliqué forms in the red cells
D. Have true stippling, do not have a relapse stage, and infect old red cells
Microsporidia have been identified as causing severe diarrhea, disseminated disease in other body sites, and ocular infections. Routes of infection have been identified as:
A. Ingestion
B. Inhalation
C. Direct contamination from the environment
D. Ingestion, inhalation, and direct contamination
Confirmation of an infection with microsporidia can be achieved by seeing:
A. The oocyst wall
B. Sporozoites within the spore
C. Evidence of the polar tubule
D. Organisms stained with modified acid-fast stains
Parasite stages that are immediately infective for humans on passage from the gastrointestinal tract include:
A. Schistosoma spp. eggs
B. Toxoplasma gondii bradyzoites
C. Giardia lamblia trophozoites
D. Cryptosporidium spp. oocysts
Older developing stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowlesi,
A. Plasmodium malariae
B. Plasmodium ovale
C. Plasmodium falciparum
D. Plasmodium vivax
Autofluorescence requires no stain and is recommended for the identification of:
A. Entamoeba histolytica cysts
B. Toxoplasma gondii tachyzoites
C. Dientamoeba fragilis trophozoites
D. Cyclospora cayetanensis oocysts
Microsporidial infections can be confirmed using:
A. Light microscopy and modified trichrome stains
B. Phase contrast microscopy and routine trichrome stains
C. Electron microscopy and modified acid-fast stains
D. Fluorescence microscopy and hematoxylin stains
Potential problems using EDTA anticoagulant and holding the blood too long prior to preparation of thick and thin blood films include:
A. Changes in parasite morphology, loss of organisms within several hours, and poor staining
B. Loss of Schüffner’s dots, poor adherence of the blood to the glass slide, and parasites beginning the vector cycle within the tube of blood
C. Neither A nor B
D. All of these options
Which of the following is a key characteristic of the thick blood film?
A. The ability to see the parasite within the RBCs
B. The ability to identify the parasites to the species level
C. The examination of less blood than the thin blood film
D. The necessity to lake the RBCs during or prior to staining
Key characteristics of infection with Plasmodium knowlesi include:
A. Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease
B. Erythrocytic cycle limited to young RBCs and causes a relatively benign disease
C. The possibility of a true relapse from the liver, infection in older RBCs, and causes serious disease
D. Extended life cycle (72 hr), will infect all ages of RBCs, and disease is similar to that caused by P. ovale
