Success Ch. 8 Parisitology

Which of the following is typical in cysts of Iodamoeba buschlii? A. A glycogen mass B. Blunt chromatoidal bars C. Four nuclei w/ large karyosomes D. Many ingested bacteria

A. A glycogen mass

Refer to Color Plate 38. This is a photomicrograph of a trichrome stain of a fecal smear, magnification 400x. The parasite measures 65x45 um. What is the identification of this parasite? A. Balantidium coli B. Diphyllobothrium latum C. Giardia lamlia D. Schistosoma japonicum

A. Balantidium coli

Which of the following is the largest intestinal protozoa infecting humans? A. Balantidium coli B. Dientamoeba fragilis C. Entamoeba histolytica D. Giardia lamblia

A. Balantidium coli

An intestinal parasite is see in an iodine-stained fecal wet mount that is described as being 25 um in diameter with a homogenously stained central body surrounded by a thin ring of cytoplasm containing a number of nuclei. The best describes A. Blastocystis hominis B. Endolimax nana C. Entamoeba dispar D. Iodamoeba butschlii

A. Blastocystis hominis

Which of the following forms of Toxoplasma gondii are produced in infected humans? A. Bradyzoites B. Macrogametes C. Sporoblasts D. Oocysts

A. Bradyzoites

Oocysts, the infective stage of Toxoplasma gondii, is found in A. Cat feces B. Human feces C. Undercooked pork D. Undercooked beef

A. Cat feces

Cysts of Giardia lamblia A. Contain four nuclei B. Are motile by flagella C. Have an undulating membrane D. Are rarely found in stool specimens

A. Contain four nuclei

Which stage of Taenia saginata is usually infective for humans? A. Cysticercus larva B. Embryonated egg C. Filariform larva D. Rhabditiform larva

A. Cysticercus larva

This parasitic infection may result in vitamin B12 deficiency, and individuals with pernicious anemia are predisposed to more severe symptoms. A. Diphyllobothrium latum B. Echinococcus granulosus C. Hymenolepis diminuta D. Taenia saginata

A. Diphyllobothrium latum

Which of the following is the preferred anticoagulant for preparing blood smears for diagnosing malaria? A. EDTA B. Heparin C. Sodium citrate D. Sodium fluoride

A. EDTA

Enterobius vermicularis infection is usually diagnosed by finding A. Eggs in perianal specimens B. Larvae in perianal specimens C. Larvae in feces D. Eggs in the feces

A. Eggs in perianal specimens

Which of the following findings in a peripheral blood smear is especially associated with tissue-invading helminths but may also be found in a variety of allergic conditions and other diseases? A. Eosinophilia B. Leukopenia C. Lymphocytosis D. Neutopenia

A. Eosinophilia

Refer to Color Plate 43. This is a photomicrograph of an iodine wet mount from a fecal sample. The maginification is 400x. The ovum is approx. 70x38 um. What is the identification of this parasite? A. Hookworm B. Ascaris lumbricoides C. Diphyllobthrium latum D. Taenia solium

A. Hookworm

Which species of Plasmodium may readily be identified when crescent-shaped gametocytes are found in stained blood films? A. P. falciparum B. P. malariae C. P. ovale D. P. vivax

A. P. falciparum

A Giemsa-stained thick blood film showed many ring forms with no olderstages, and a number of a rings had double chromatin dots. These findings are characteristic of A. Plasmodium falciparum B. Plasmodium vivax C. Plasmodium malariae D. Plasmodium ovale

A. Plasmodium falciparum

Which Schistosoma species has a large terminal spine? A. S. haematobium B. S. japonicum C. S. mansoni D. S. mekongi

A. S. haematobium

Migration of larva through the skin can sometimes produce allergic reactions called larva migrans; this is associated with A. Strongyloides stercoralis B. Dracunculus medinensis C. Onchocerca volvulus D. Loa loa

A. Strongyloides stercoralis

Eggs or larvae recovered in the stool are not routinely used to diagnose infections caused by which one of the following helmiths? A. Trichinella spiralis B. Strongyloides stercoralis C. Necator americanus D. Ascaris lumbricoides

A. Trichinella spiralis

A patient w/ history of human immuno-deficiency virus infection presents with a 5-day history of diarrhea and weight loss. A series of stool specimens is collected and examined for the presence of ova and parasites. An acid-fast stain on direct smear reveals pink-stained round structures approximately 4 um in diameter. The most likely pathogen is A. Blastocystis hominis B. Cryptosporidium sp. C. isospora sp. D. Microsporidium

B. Cryptosporidium sp.

Examination of a fecal smear following acid fast stain reveals round acid-fast positive structures 8-10 um in diameter. You should suspect A. Cryptosporidium B. Cyclospora C. Isospora D. Microsporidia

B. Cyclospora

Many parasites have different stages of growth within different hosts. The host where the sexual reproductive stage of the parasites exists is called the A. Commensal B. Definitive host C. Intermediate host D. Vector

B. Definitive host

Refer to Color Plate 40. This is a photomicrograph of an iron hematoxylin stian from a fecal smear. The magnification is 1000x. The parasite is approximately 20 um ling and 15 um wide. What is the identification of this parasite? A. Chilomastix mesnili trophozoite B. Giardia lamblia trophozoite C. Trichomonas hominis trophozoite D. Trichomonas tenax trophozoite

B. Giardia lamblia trophozoite

The disease most commonly associated with Acanthamoeba sp. is A. Diarrhea B. Keratitis C. Liver disease D. Meningoencephalitis

B. Keratitis

Which species of Plasmodium can have exoerythrocytic stages capable of causing relapses months or years after initial infection? A. P. falciparum B. P. ovale C. P. malariae D. P. cynomolgi

B. P. ovale

A modified trichrome stain of a fecal smear can be used to detect microsporidia. Which of the following would describe the appearance of this parasite in this stain? A. Purple circles, 10-15 um in diameter B. Pink ovals, 1-3 um in diameter C. Blue ovals, 4-6 um in diameter D. Fluorescent circles, 8-12 um in diameter

B. Pink ovals, 1-3 um in diameter

In an examination of stained blood films, Babesia spp. are likely to resemble A. Leishmania donovani B. Plasmodium falciparum C. Toxoplasma gondii D. Trypanosoma cruzi

B. Plasmodium falciparum

Refer to Color Plate 45.. This is a photomicrograph of a blood smear stained with Wright's stain. Identify the parasite. A. Babesia sp. B. Plasmodium malariae C. Plasmodium falciparium D. Trypanosoma cruzi

B. Plasmodium malariae

A 48 year old man from Texas developed fever and weakness 16 days after a hunting trip in northwest Tanzania. Several days after the onset of fever, he noticed a raised, tender, erythematous nodule (6-8 cm in diameter) on the posterior aspect of his right arm. He was hospitalized in Africa and treated for 5 days with a cephalosporin for presumed cellulitis. After little improvement, he returned to Texas. On arrival, the patient had atemperature of 38.9*C (102*F), a morbilliform rash of the trunk, and right-sided anterior cervical lymphadenopathy. CSF contained 12 RBCs and 18 mononuclear cells/uL and a normal protein level (32 mg/dL). Laboratory tests of peripheral blood revealed a hemoglobin level of 107 g/L, a white cell count of 2.4 x 10^9/L, and a platelet count of 75 x 10^9/L. The diagnosis was made by finding the extracellular flagellate parasite in the peripheral blood smear. Which of the following is the most probable etiologic agent of this infection? A. Leishmania donovani B. Trypanosoma brucei C. Trypanosoma cruzi D. Toxoplasma gondii

B. Trypanosoma brucei

Chagas disease (American trypanosomiasis) is caused by A. Trypanosoma brucei B. Trypanosoma cruzi C. Leishmania braziliensis D. Dracunculus medinensis

B. Trypanosoma cruzi

The rhabditiform larvae of Strongyloides stercoralis A. Mate and produce ova B. Are infective for humans C. Are the diagnostic form found in feces D. Are found in the blood of infected humans

C. Are the diagnostic form found in feces

Refer to Color Plate 41. This is a photomicrograph of an iron hematoxylin stain from a fecal smear. The magnification is 1000x. The parasite is approximately 12 um in diameter. What is the identification of this parasite? A. Entamoeba histolytic trophozoite B. Entamoeba hartmanni trophozoite C. Dientamoeba fragilis trophozoite D. Entamoeba coli trophozoite

C. Dientamoeba fragilis trophozoite

Refer to Color Plate 42. This is a photomicrograph of an iodine wet-mount from a fecal sample. The parasite is approx. 25 um in diameter. What is the identification of this parasite? A. Entamoeba histolytic trophozoite B. Entamoeba hartmanni trophozoite C. Dientamoeba fragilis trophozoite D. Entamoeba coli trophozoite

C. Dientamoeba fragilis trophozoite

Species identification of an immature amebic cyst can be very difficult. The presence of a large glycogen mass is sometimes seen in A. Dientamoeba fragilis B. Endolimax nana C. Entamoeba coli D. Entamoeba histolytica

C. Entamoeba coli

Decontamination of drinking water, fruits, and vegetables before consumption is necessary in countries w/o well-developed public sanitation. Which of the following diseases would probably be least affected by the kind of precaution? A. Amebiasis B. Ascariasis C. Filariasis D. Giardiasis

C. Filariasis

A 15 um pear-shaped flagellate with a visible parabasal body and "falling leaf" motility in a direct saline mount of a diarrheal stool specimen is most probably A. Balantidium coli B. Chilomastix mesnili C. Giardia lamblia D. Trichomonas hominis

C. Giardia lamblia

Which statement is correct for specimen collection and processing? A. Stool samples can contain urine B. Stools can be frozen w/o affecting parasitic structure C. Liquid stools are best for detecting ameba and flagellate trophozites D. Unpreserved stools can remain at room temp for up to 72 hours

C. Liquid stools are best for detecting ameba and flagellate trophozites

A 55 year old presents to her physician complaining of a fever that "comes and goes" and fatigue. A CBC reveals decreased RBC count and hgb. History reveals the patient recently traveled through Europe and Africa. You should suspect A. Cutaneous larval migrans B. Filariasis C. Malaria D. Trichinella

C. Malaria

Knowledge of nocturnal periodicity is especially important in the diagnosis of certain infections caused by A. Babesia B. Plasmodium C. Microfilariae D. Trypanosoma

C. Microfilariae

Which of the following pairs of helmiths cannot be reliably differentiated by the appearance of their eggs? A. Ascaris lumbricoides and Necator americanus B. Hymenolepis nana and H. diminuta C. Necator americanus and Ancylostoma duodenale D. Diphyllobothrium latum and Fasciola hepatica

C. Necator americanus and Ancylostoma duodenale

With a fecal specimen, which one of the following is the most dependable procedure for the accurate, specific diagnosis of an intestinal amebic infection? A. Direct saline wet mount B. Direct iodine wet mount C. Permanently stained smear D. Formalin-ethyl

C. Permanently stained smear

Which of the following is the vector for Babesia? A. Fleas B. Lice C. Ticks D. Mosquitoes

C. Ticks

A 2 year old male presents to his family physician complaining of fatigue, muscle pain, periorbital edema and fever. He dinies travel outside the US. The physician suspects infections mononuclosis; however, serologic tests for infectious mononucleosis are negative. The CBC revealed a slightly elevated WBC count, and there were 10% eosinophils on the differential. Which of the following should be considered part of the differential diagnosis? A. Ascaris lumbricoides B. Taenia solium C. Trichinella spiralis D. Trypanosoma cruzi

C. Trichinella spiralis

Sanitary disposal of human feces is the most important factor in decreasing the incidence of most infections caused by intestinal parasites. Which of the following diseases would not be affected by that kind of sanitation? A. Ascariasis B. Taeniasis C. Trichinosis D. Hookworm infection

C. Trichinosis

Refer to Color Plate 39. This is a photomicrograph of an iodine wet prep made from a stool sample; magnification is 400x. THe ovum is about 70x50 um. What is the identification of the parasite? A. Hookworm B. Enterobius vermicularis C. Trichuris trichiura D. Ascaris lumbricoides

D. Ascaris lumbricoides

Refer to Color Plate 44. This is a photomicrograph of a trichrome stain from a fecal smear. The magnification is 1000x. The parasite is approx. 15 um in diameter. What is the identification of this parasite? A. Entamoeba hartmanni B. Dientamoeba fragilis C. Iodamoeba butschlii D. Blastocystis hominis

D. Blastocystis hominis

Which of the following is the most important feature in differentiating cysts of Entamoeba histolytica from E. dispar? A. Number of nuclei B. Size of cyst C. Shape of the karyosome D. Distinguishing surface antigens by immunologic assays

D. Distinguishing surface antigens by immunologic assays

Hydatid cysts in humans are due to ingestion of a tapeworm stage normally found in canines. The stage is the A. Cercaria B. Cercocystis C. Cysticercus D. Embryonated egg

D. Embryonated egg

Which stage of Trichuris trichiura is infective for humans? A. Proglottid B. Filariform larva C. Rhabditiform larva D. Embryonated ovum

D. Embryonated ovum

This amebic cyst has an average size of 6-8 um and is usually spherical. When mature, it has four nuclei, but immature cysts with one or two nuclei are often seen. The nuclei have fine uniform granules of peripheral chromatin and small, discrete, usually central karyososmes. Chromatoidal bars with bluntly rounded ends are sometimes present. Name the species. A. Endolimax nana B. Entamoeba coil C. Entamoeba hartmanni D. Entamoeba histolytica

D. Entamoeba histolytica

Elephantiasis is a complication associated with which of the following? A. Cysticercosis B. Guinea worm C. Hydatid cyst disease D. Filariae

D. Filariae

Cysts are the infective stage of this intestinal flagellate A. Balantidium coli B. Dientamoeba fragilis C. Entamoeba coli D. Giardia lambia

D. Giardia lambia

The best direct diagnosis of Echinococcus granulosus infection in humans is made by identification of A. Adult worms in the intestines B. Adult worms in tissues C. Eggs in feces D. Hydatid cysts in tissues

D. Hydatid cysts in tissues

A free-living ameba that causes primary amebic meningoencephalitis is A. Dientamoeba fragilis B. Entamoeba coli C. Entamoeba histolytica D. Naegleria fowleri

D. Naegleria fowleri

Which species of Plsmodium is characterized by the presence of Schuffner's dots in the infected erythrocytes? A. Plasmodium falciparum B. Plasmodium knowlesi C. Plasmodium malariae D. Plasmodium ovale

D. Plasmodium ovale

Which species of malaria parasite usually has ameboid trophozoites and produces small reddish dots in the RBC cytoplasm? A. Plasmodium knowlesi B. Plasmodium falciparum C. Plasmodium malarie D. Plasmodium vivax

D. Plasmodium vivax

Which of the following is a mercury-containing fixative used to preserve parasites in stool specimens? A. Formalin B. Sodium acetate C. Buffered glycerol D. Polyvinyl alcohol

D. Polyvinyl alcohol

Hematuria is a typical sign of human infection casued by A. Trypanosoma cruzi B. Trichinella spiralis C. Trichinella vaginalis D. Schistosoma haematobium

D. Schistosoma haematobium

Which of the following nematode parasites is acquired from eating inadequatly cooked, infected pork? A. Strongyloides stercoralis B. Taenia saginata C. Taenia olium D. Trichinella spiralis

D. Trichinella spiralis

For which of the following diseases is close contact with an infected human host the most important mechanism of transmission? A. Schistosomiasis B. Toxoplasmosis C. Trichinosis D. Trichomoniasis

D. Trichomoniasis

Which of the following helminths produces an enlongate, barrel-shaped egg (50x22 um) with a colorless polar plug at each end? A. Ascaris lumbricoides B. Hymenolepis nana C. Necator americanus D. Trichuris trichiura

D. Trichuris trichiura