Parasitology Practice Questions & Ratio

MEDICAL LABORATORY SCIENCE • PARASITOLOGY PRACTICE QUESTIONS • • • • • • • • • • A free-living amoeba can infect man through the following routes, except: a. Skin b. Eyes c. Ingestion (fecal-oral) d. Olfactory What is the most frequent parasite encountered in the urine? a. T. vaginalis b. T. spiralis c. E. coli A parasite that may reach the eyes: a. E. granulosus b. T. saginata c. T. solium d. E. multilocularis Number of stool specimens collected for ova and parasite examination (O&P): a. 1 b. 2 c. 3 d. 4 Specimens are more likely to contain trophozoites and should be examined within 30 minutes of passage: a. Liquid/diarrheic stool → trophozoites b. Soft stool → trophozoites and cysts c. Formed stool → cysts d. None of these May contain both trophozoites and cysts: a. Liquid stool b. Diarrheic stool c. Soft stool d. Formed stool Stool specimens kept under refrigeration when preservatives are not available; these specimens are suitable for: a. Egg b. Egg & parasite c. Antigen testing only → refrigerated stool Soil-transmitted helminth: a. Ascaris lumbricoides b. Enterobius vermicularis c. Strongyloides stercoralis d. Wuchereria bancrofti → Common soil-transmitted helminths: ▪ A. lumbricoides ▪ T. trichiura ▪ Hookworms The eggs of Trichostrongylus are very similar to those of: a. Ascaris b. Enterobius c. Trichuris d. Hookworms The worms are incapable of maturation within the human host and migrate aimlessly, causing tissue damage and inflammation: a. Echinococcus granulosus b. Gnathostoma spinigerum c. Taenia solium d. Trichinella spiralis • • • • • • Transmission of the fluke to humans is by ingestion of aquatic plants, such as water chestnuts, containing infective metacercariae: a. Clonorchis sinensis b. Fasciolopsis buski c. Heterophyes heterophyes d. Paragonimus westermani → Fasciola hepatica - water cress → The intestinal attachment site of the adult worms often become locally inflamed and ulcerated and may hemorrhage. Moderate to heavy infections may cause abdominal pain diarrhea, intestinal obstruction, an edema of the abdomen and lower extremities and may result in inadequate absorption of vit. B12. Eosinophilia is common → Vit. B12 deficiency - assoc. w/ D. latum and F. buski Risk factors included a history of drinking impure water, eating frog or snake meat, or using frog or snake meat as a poultice: a. Echinococcus granulosus b. Spirometra mansonoides c. Taenia saginata d. Taenia solium For laboratory diagnosis of malaria, which of the following should be fixed with methanol: a. Thick blood film b. Thin blood film c. Both of these d. None of these → Blood film - gold standard for malaria ▪ Giemsa - preferred stain for blood parasites ▪ Thick blood film • Not fixed • Dehemoglobinized ▪ Thin blood film • Fixed with methanol All spills and potential surface contamination with Cryptosporidium oocysts should be disinfected using the following protocol: After removing organic material from the contaminated surface (e.g., by using a conventional laboratory detergent/cleaner) and absorbing the bulk of the spill with disposable paper towels, flood and completely cover the surface with undiluted _______. a. Ethyl alcohol b. Formalin c. 3% hydrogen peroxide d. 30% hydrogen peroxide Preferred stain for the detection of blood parasites a. Giemsa b. Trichrome c. Calcofluor white d. Prussian blue Which of the following amoeba has chromatoid bodies in the cyst stage? a. Endolimax b. Iodamoeba c. Dientamoeba d. Entamoeba Amoebiasis is caused by: a. I. butschii b. E. polecki c. E. histolytica d. E. coli 1 • • • • • • • • • The incorrect match between organism and the appropriate diagnostic procedure is: a. Ochocerca volvulus - examination of skin snips b. Cryptosporidium - modified acid fast stain c. Echinococcus granulosus - routine ova and parasite exam d. Schistosoma haematobium - examination of urine sediment Charcot-Leyden crystals in stool may be associated w/ an immune response and are thought to be the breakdown products of: a. Neutrophils b. Eosinophils c. Monocytes d. Lymphocytes Parasitic organisms that are most often transmitted sexually include: a. Entamoeba gingivalis b. Dientamoeba fragilis c. Trichomonas vaginalis d. Diphyllobothrium latum One of the following protozoan organisms has been implicated in waterborne and foodborne outbreaks within the U.S. The suspect organism is: a. Trichomonas hominis b. Dientamoeba fragilis c. Giardia lamblia d. Balantidium coli A 12-yr-old girl is brought to the ER w/ meningitis and a history of swimming in a warm-water spring. Motile amoebae that measure 10 um in size are seen in the CSF and are most likely: a. Iodamoeba butschlii trophs b. Endolimax nana trophs c. Dientamoeba fragilis trophs d. Naegleria fowleri trophs The examination of sputum may be necessary to diagnose infection w/: a. Paragonimus westermani b. Trichinella spiralis c. Wuchereria bancrofti d. Fasciola hepatica Eating poorly cooked pork can lead to an infection with: a. Taenia solium and Trichinella spiralis b. Taenia saginata and Hymenolepsis nana c. Trichuris trichiura and Hymenolepsis diminuta d. Diphyllobothrium latum and Ascaris lumbricoides The adult tapeworm of Echinococcus granulosus is found in the intestine of: a. dogs b. sheep c. humans d. cattle Humans can acquire infections w/ Diphyllobothrium latum adult worms by: a. ingestion of freshwater crabs b. skin penetration of cercariae c. ingestion of water chestnuts d. ingestion of raw freshwater fish • • • • • • • • • Humans can serve as both the intermediate and definitive host in infections caused by: a. Enterobius vermicularis b. Hymenolepsis nana c. Schistosoma japonicum d. Ascaris lumbricoides Babesia is an organism that has been implicated in disease from both splenectomized and nonsplenectomized patients. Morphologically, the parasites resemble: a. Plasmodium falciparum rings b. Leishmania donovani amastigotes c. Trypanosoma cruzi trypomastigotes d. Pneumocystis carinii cysts Which microfilariae are usually NOT found circulating in the peripheral blood? a. Brugia malayi b. Wuchereria bancrofti c. Onchocerca volvulus d. Loa loa Massive hemolysis, blackwater fever, and central nervous system involvement are most common with: a. Plasmodium vivax b. Plasmodium falciparum c. Plasmodium ovale d. Plasmodium malariae Cysts of Iodamoeba butschlii typically have: a. Chromatoidal bars w/ rounded ends b. a heavily vacuolated cytoplasm c. a large glycogen vacuole d. many ingested bacteria and yeast cells The miracidial hatching test helps to demonstrate the viability of eggs of: a. Taenia species b. Schistosoma species c. Hookworm species d. Opisthorchis species BAL specimens have become much more widely used in: a. any suspect patient w/ both toxoplasmosis and cryptosporidiosis b. pediatric patients w/ pulmonary paragonimiasis c. AIDS patients w/ suspected Pneumocystis pneumonia d. Immunocompromised patients w/ disseminated strongyloides The microsporidia are protozoans that have been implicated in human disease primarily in: a. immunocompromised patients b. pediatric patients under the age of 5 c. adult patients w/ congenital immunodeficiencies d. patients who have been traveling to the tropics Laboratory diagnosis of Clonorchiasis is usually: a. Microscopic examination (gold standard) b. Molecular method c. Serologic testing d. Skin test → Diagnosis is usually based on microscopic identification of eggs in stool specimens. However, the eggs of Clonorchis are practically indistinguishable from those of Opisthorchis. → Adult flukes have been recovered at surgery or may be spontaneously passed after anthelmintic treatment. Morphologic examination of the intact adult fluke allows definitive species identification. 2