ROBERT HARR Flashcards by Dead Braincells

In a patient with diarrhea, occasionally Entamoeba histolytica/E. dispar (four nucleated cysts, no chromatoidal bars) are identified as being present; however, these cells, which are misdiagnosed as protozoa, are really:
A. Macrophages
B. Polymorphonuclear leukocytes
C. Epithelial cells
D. Eosinophils

Polymorphonuclear leukocytes

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Charcot–Leyden crystals in stool may be associated with an immune response and are thought to be formed from the breakdown products of:
A. Neutrophils
B. Eosinophils
C. Monocytes
D. Lymphocytes

Eosinophils

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The incorrect match between organism and the appropriate diagnostic procedure is:
A. Onchocerca volvulus—examination of skin snips
B. Cryptosporidium—modified acid-fast stain
C. Echinococcus granulosus—routine ova and parasite examination
D. Schistosoma haematobium—examination of urine sediment

Echinococcus granulosus—routine ova and parasite examination

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Parasitic organisms that are most often transmitted sexually include:
A. Entamoeba gingivalis
B. Dientamoeba fragilis
C. Trichomonas vaginalis
D. Diphyllobothrium latum

Trichomonas vaginalis

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The incorrect match between the organism and one method of acquiring the infection is:
A. Trypanosoma brucei rhodesiense—bite of sand fleas
B. Giardia lamblia—ingestion of water contaminated with cysts
C. Hookworm—skin penetration of larvae from soil
D. Toxoplasma gondii—ingestion of raw or rare meats

Trypanosoma brucei rhodesiense—bite of sand fleas

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Upon examination of stool material for
Cystoisospora belli, one would expect to see:
A. Cysts containing sporozoites
B. Precysts containing chromatoidal bars
C. Oocysts that are modified acid-fast variable
D. Sporozoites that are hematoxylin positive

Oocysts that are modified acid-fast variable

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Which specimen is the least likely to provide
recovery of Trichomonas vaginalis?
A. Urine
B. Urethral discharge
C. Vaginal discharge
D. Feces

Feces

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Which of the following is the best technique to
identify Dientamoeba fragilis in stool?
A. Formalin concentrate
B. Trichrome-stained smear
C. Modified acid-fast–stained smear
D. Giemsa’s stain

Trichrome-stained smear

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One of the following protozoan organisms has
been implicated in waterborne and foodborne
outbreaks within the United States. The suspect organism is:
A. Pentatrichomonas hominis
B. Dientamoeba fragilis
C. Giardia lamblia
D. Balantidium coli

Giardia lamblia

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A Gram stain from a gum lesion showed what
appeared to be amoebae. A trichrome smear
showed amoebae with a single nucleus and
partially digested PMNs. The correct
identification is:
A. Trichomonas tenax
B. Entamoeba histolytica/E. dispar
C. Entamoeba gingivalis
D. Entamoeba polecki

Entamoeba gingivalis

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An Entamoeba histolytica trophozoite has the
following characteristics:
A. Central karyosome in the nucleus, ingested
RBCs, and clear pseudopodia
B. Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane
C. Ingested RBCs, clear pseudopodia, and large
glycogen vacuoles in cytoplasm
D. Large, blotlike karyosome, ingested white blood cells (WBCs), and granular pseudopods

Central karyosome in the nucleus, ingested
RBCs, and clear pseudopodia

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A 12-year-old girl is brought to the emergency
department with meningitis and a history of
swimming in a warm-water spring. Motile
amoebae that measure 10 μ in size are seen in
the CSF and are most likely:
A. Iodamoeba bütschlii trophozoites
B. Endolimax nana trophozoites
C. Dientamoeba fragilis trophozoites
D. Naegleria fowleri trophozoites

Naegleria fowleri trophozoites

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Characteristics of the rhabditiform (noninfective) larvae of Strongyloides stercoralis include a:
A. Short buccal capsule and large genital
primordium
B. Long buccal capsule and pointed tail
C. Short buccal capsule and small genital
primordium
D. Small genital primordium and notch in tail

Short buccal capsule and large genital
primordium

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Visceral larva migrans is associated with which of the following organisms?
A. Toxocara—serology
B. Onchocerca—skin snips
C. Dracunculus—skin biopsy
D. Angiostrongylus—CSF examination

Toxocara—serology

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The following organisms are linked with
specific, relevant information. The incorrect
combination is:
A. Strongyloides stercoralis—internal autoinfection
B. Echinococcus granulosus—hydatid examination
C. Toxoplasma—serology
D. Balantidium coli—common within the
United States

Balantidium coli—common within the
United States

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Examination of 24-hour unpreserved urine
specimen is sometimes helpful in the
recovery of:
A. Trichomonas vaginalis trophozoites
B. Schistosoma haematobium eggs
C. Enterobius vermicularis eggs
D. Strongyloides stercoralis larvae

Schistosoma haematobium eggs

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The examination of sputum may be necessary to diagnose infection with:
A. Paragonimus westermani
B. Trichinella spiralis
C. Wuchereria bancrofti
D. Fasciola hepatica

Paragonimus westermani

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Two helminth eggs that may resemble one
another are:
A. Diphyllobothrium latum and Paragonimus
westermani
B. Opisthorchis sinensis and Fasciolopsis buski
C. Taenia saginata and Hymenolepis nana
D. Ascaris lumbricoides and Trichostrongylus

Diphyllobothrium latum and Paragonimus
westermani

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Eating poorly cooked pork can lead to an
infection with:
A. Taenia solium and Trichinella spiralis
B. Taenia saginata and Hymenolepis nana
C. Trichuris trichiura and Hymenolepis diminuta
D. Diphyllobothrium latum and Ascaris lumbricoides

Taenia solium and Trichinella spiralis

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An operculated cestode egg that can be recovered from human feces is:
A. Clonorchis sinensis
B. Diphyllobothrium latum
C. Paragonimus westermani
D. Dipylidium caninum

Diphyllobothrium latum

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The adult tapeworm of Echinococcus granulosus is found in the intestine of:
A. Dogs
B. Sheep
C. Humans
D. Cattle

Dogs

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In infections with Taenia solium, humans can
serve as the:
A. Definitive host
B. Intermediate host
C. Either the definitive or the intermediate host
D. None of these options

Either the definitive or the intermediate host

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Humans acquire infections with 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

Ingestion of raw freshwater fish

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Humans can serve as both the intermediate and definitive host in infections caused by:
A. Enterobius vermicularis
B. Hymenolepis nana
C. Schistosoma japonicum
D. Ascaris lumbricoides

Hymenolepis nana

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Babesia 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. Microsporidial spores

Plasmodium falciparum rings

Organisms (and infections) that under normal conditions cannot be transmitted in the laboratory are: A. Cryptosporidium—cryptosporidiosis B. Taenia solium—cysticercosis C. Ascaris lumbricoides—ascariasis D. Enterobius vermicularis—pinworm infections

Ascaris lumbricoides—ascariasis

Toxoplasma gondii is characterized by: A. Possible congenital infection and ingestion of oocysts B. Cosmopolitan distribution and possible difficulties with interpretation of serological results C. Neither A nor B D. Both A and B

Both A and B

Oocysts of Cryptosporidium spp. can be detected in stool specimens using: A. Modified Ziehl–Neelsen acid-fast stain B. Gram stain C. Methenamine silver stain D. Trichrome stain

Modified Ziehl–Neelsen acid-fast stain

Which microfilariae are usually not found circulating in the peripheral blood? A. Brugia malayi B. Wuchereria bancrofti C. Onchocerca volvulus D. Loa loa

Onchocerca volvulus

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

Plasmodium falciparum

Organisms that should be considered in a nursery school outbreak of diarrhea include: A. Endolimax nana, Giardia lamblia, and Entamoeba coli B. Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp. C. Cryptosporidium spp., Trichomonas vaginalis, and Entamoeba coli D. Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana

Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp.

The incorrect match between disease and symptoms is: A. Paragonimiasis—hemoptysis B. Cryptosporidiosis—watery diarrhea C. Toxoplasmosis in compromised host—central nervous system symptoms D. Enterobiasis—dysentery

Enterobiasis—dysentery

The formalin–ether (ethyl acetate) concentration procedure for feces is used to demonstrate: A. Motility of helminth larvae B. Protozoan cysts and helminth eggs C. Formation of amoebic pseudopods D. Trophozoites

Protozoan cysts and helminth eggs

Cysts of Iodamoeba bütschlii typically have: A. Chromatoidal bars with rounded ends B. A heavily vacuolated cytoplasm C. A large glycogen vacuole D. Many ingested bacteria and yeast cells

A large glycogen vacuole

The miracidial hatching test helps to demonstrate the viability of eggs of: A. Taenia species B. Schistosoma species C. Hookworm species D. Opisthorchis species

Schistosoma species

Organisms that should be considered in a waterborne outbreak of diarrheal disease include: A. Giardia lamblia and Cryptosporidium spp. B. Endolimax nana and Entamoeba histolytica C. Blastocystis hominis and Trichomonas vaginalis D. Toxoplasma gondii and Schistosoma mansoni

Giardia lamblia and Cryptosporidium spp.

Fecal immunoassays have become more commonly used to diagnose infections with: A. Endolimax nana and Blastocystis hominis B. Giardia lamblia and Cryptosporidium spp. C. Ascaris lumbricoides and Trichuris trichiura D. Strongyloides stercoralis and Trichomonas vaginalis

Giardia lamblia and Cryptosporidium spp.

Primary infections with the microsporidia may originate in: A. The lung B. The nervous system C. The gastrointestinal tract D. Mucocutaneous lesions

The gastrointestinal tract

Eye infections with Acanthamoeba spp. have most commonly been traced to: A. Use of soft contact lenses B. Use of hard contact lenses C. Use of contaminated lens care solutions D. Failure to remove lenses while swimming

Use of contaminated lens care solutions

Select the most sensitive recovery method for Acanthamoeba spp. from lens care solutions or corneal biopsies. A. The trichrome staining method B. The use of monoclonal reagents for the detection of antibody C. The use of non-nutrient agar cultures seeded with Escherichia coli D. The Giemsa’s stain method

The use of non-nutrient agar cultures seeded with Escherichia coli

The microsporidia are protozoans (now classified with the fungi) that have been implicated in human disease primarily in: A. Immunocompromised patients B. Pediatric patients under the age of 5 years C. Adult patients with congenital immunodeficiencies D. Patients who have been traveling in the tropics

Immunocompromised patients

When staining Cystoisospora belli oocysts with modified acid-fast stains, the important difference between these methods and the acid-fast stains used for acid-fast bacilli (AFB) is: A. The staining time is much longer with regular AFB acid-fast stains B. The decolorizer is weaker than acid alcohol used for AFB decolorizing C. A counterstain must be used for the modified methods D. The stain is more concentrated when staining for AFB

The decolorizer is weaker than acid alcohol used for AFB decolorizing

The incorrect match between symptoms and disease is: A. Dysentery—amebiasis B. Malabsorption syndrome—giardiasis C. Cardiac involvement—chronic Chagas disease D. Myalgias—trichuriasis

Myalgias—trichuriasis

The incorrect match between organism and characteristic is: A. Chilomastix mesnili—Shepherd’s crook and lemon shape B. Plasmodium malariae—“band troph” C. Hymenolepis nana—striated shell D. Wuchereria bancrofti—sheathed microfilariae

Hymenolepis nana—striated shell

The incorrect match between method and method objective is: A. Direct wet examination—detection of organism motility B. Knott’s concentration—the recovery of operculated helminth eggs C. Baermann’s concentration—the recovery of Strongyloides D. Permanent stained fecal smear—confirmation of protozoa

Knott’s concentration—the recovery of operculated helminth eggs

The incorrect match between organism and characteristic is: A. Dientamoeba fragilis—tetrad karyosome in the nucleus B. Toxoplasma gondii—diagnostic serology C. Echinococcus granulosus—daughter cysts D. Schistosoma mansoni—egg with terminal spine

Schistosoma mansoni—egg with terminal spine

There are few procedures considered STAT in parasitology. The most obvious situation would be: A. Ova and parasite examination for giardiasis B. Baermann’s concentration for strongyloidiasis C. Blood films for malaria D. Culture of amoebic keratitis

Blood films for malaria

An immunosuppressed man has several episodes of pneumonia, intestinal pain, sepsis with gram-negative rods, and a history of military service in Southeast Asia 20 years earlier. The most likely cause is infection with: A. Trypanosoma cruzi B. Strongyloides stercoralis C. Naegleria fowleri D. Paragonimus westermani

Strongyloides stercoralis

In a pediatric patient, the recommended clinical specimen for recovery of Enterobius vermicularis is the: A. Stool specimen B. Sigmoidoscopy scrapings C. Duodenal aspirates D. Series of Scotch tape preparations

Series of Scotch tape preparations

Which parasite causes eosinophilic meningoencephalitis, a form of larva migrans causing fever, headache, stiff neck, and increased cells in the spinal fluid? A. Necator americanus B. Angiostrongylus cantonensis C. Ancylostoma braziliense D. Strongyloides stercoralis

Angiostrongylus cantonensis

“Cultures of parasites are different from bacterial cultures; no quality control is needed.” This statement is: A. True, if two tubes of media are set up for each patient B. True, if the media are checked every 24 hours C. False, unless two different types of media are used D. False, and organism and media controls need to be set up

False, and organism and media controls need to be set up

Protozoan cysts were seen in a concentration sediment and tentatively identified as Entamoeba coli. However, the organisms were barely visible on the permanent stained smear because: A. The organisms were actually not present in the concentrate sediment B. There were too few cysts to allow identification on the stained smear C. E. coli cysts were present but poorly fixed D. The concentrate and permanent stained smear were not from the same patient

E. coli cysts were present but poorly fixed

When humans have hydatid disease, the causative agent and host classification are: A. Echinococcus granulosus—accidental intermediate host B. Echinococcus granulosus—definitive host C. Taenia solium—accidental intermediate host D. Taenia solium—definitive host

Echinococcus granulosus—accidental intermediate host

A 45-year-old hunter developed fever, myalgia, and periorbital edema. He has a history of bear meat consumption. The most likely causative agent is: A. Toxoplasma gondii B. Taenia solium C. Hymenolepis nana D. Trichinella spiralis

Trichinella spiralis

In a condition resulting from the accidental ingestion of eggs, the human becomes the intermediate rather than the definitive host. The correct answer is: A. Trichinosis B. Cysticercosis C. Ascariasis D. Strongyloidiasis

Cysticercosis

A transplant patient on immunosuppressive drugs developed increasing diarrhea. The most likely combination of disease and diagnostic procedure is: A. Trichinosis and trichrome stain B. Microsporidiosis and modified trichrome stain C. Toxoplasmosis and Gram stain D. Paragonimiasis and wet preparation

Microsporidiosis and modified trichrome stain

After returning from a 2-year stay in India, a patient has eosinophilia, an enlarged left spermatic cord, and bilateral inguinal lymphadenopathy. The most likely clinical specimen and organism match is: A. Thin blood films—Leishmania B. Urine—concentration for Trichomonas vaginalis C. Thin blood films—Babesia D. Thick blood films—microfilariae

Thick blood films—microfilariae

Patients with severe diarrhea should use “enteric precautions” to prevent nosocomial infections with: A. Giardia lamblia B. Ascaris lumbricoides C. Cryptosporidium spp. D. Cystoisospora belli

Cryptosporidium spp.

A 60-year-old Brazilian patient with cardiac irregularities and congestive heart failure suddenly dies. Examination of the myocardium revealed numerous amastigotes, an indication that the cause of death was most likely: A. Leishmaniasis with Leishmania donovani B. Leishmaniasis with Leishmania braziliense C. Trypanosomiasis with Trypanosoma gambiense D. Trypanosomiasis with Trypanosoma cruzi

Trypanosomiasis with Trypanosoma cruzi

When malaria smears are requested, what patient information should be obtained? A. Diet, age, sex B. Age, antimalarial medication, sex C. Travel history, antimalarial medication, date of return to United States D. Fever patterns, travel history, diet

Travel history, antimalarial medication, date of return to United States

In an outbreak of diarrheal disease traced to a municipal water supply, the most likely causative agent is: A. Cryptosporidium spp. B. Cystoisospora belli C. Entamoeba histolytica D. Dientamoeba fragilis

Cryptosporidium spp.

Within the United States, sporadic mini-outbreaks of diarrheal disease have been associated with the ingestion of strawberries, raspberries, fresh basil, mesclun (baby lettuce leaves), and snow peas. The most likely causative agent is: A. Dientamoeba fragilis B. Cyclospora cayetanensis C. Schistosoma mansoni D. Cystoisospora belli

Cyclospora cayetanensis

Which of the following statements is true regarding onchocerciasis? A. The adult worm is present in the blood B. The microfilariae are in the blood during the late evening hours C. The diagnostic test of choice is the skin snip D. The parasite resides in the deep lymphatics

The diagnostic test of choice is the skin snip

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

Enterobius vermicularis, the pinworm

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

Trichuris trichiura

Ingestion of which of the following eggs will result in infection? A. Strongyloides stercoralis B. Schistosoma japonicum C. Toxocara canis D. Opisthorchis sinensis

Toxocara canis

Plasmodium vivax and Plasmodium ovale are 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

Exhibit Schüffner’s dots and have a true relapse in the life cycle

The term internal autoinfection can be associated with the following parasites: A. Cryptosporidium spp. and Giardia lamblia B. Cystoisospora belli and Strongyloides stercoralis C. Cryptosporidium spp. and Strongyloides stercoralis D. Giardia lamblia and Cystoisospora belli

Cryptosporidium spp. and Strongyloides stercoralis

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

Ingestion, inhalation, and direct contamination

An immunocompromised patient continues to have diarrhea after repeated ova and parasites (O&P) examinations (sedimentation concentration, trichrome permanent stained smear) were reported as negative; organisms that might be responsible for the diarrhea include: A. Cryptosporidium spp., Giardia lamblia, and Cystoisospora belli B. Giardia lamblia, microsporidia, and Endolimax nana C. Taenia solium and Endolimax nana D. Cryptosporidium spp. and microsporidia

Cryptosporidium spp. and microsporidia

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

Evidence of the polar tubule

Early ring stages of the fifth human malaria, Plasmodium knowlesi, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax

Plasmodium falciparum

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

Cryptosporidium spp. oocysts

Older developing stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowlesi, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax

Plasmodium malariae

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

Cyclospora cayetanensis oocysts

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

Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease

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

Light microscopy and modified trichrome stains

Although the pathogenicity of Blastocystis hominis remains controversial, newer information suggests that: A. Most organisms are misdiagnosed as artifacts B. Numerous strains/species are included in the name, some of which are pathogenic and some are nonpathogenic C. The immune status of the host is solely responsible for symptomatic infections D. The number of organisms present determines pathogenicity

Numerous strains/species are included in the name, some of which are pathogenic and some are nonpathogenic

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

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

The necessity to lake the RBCs during or prior to staining

ROBERT HARR Flashcards

(80 cards)