8.11 Flashcards
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 haemotobium-examination of urine sediment
C. Echinococcus granulosus-routine ova and parasite examination
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
B. Polymorphonuclear leukocytes`
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
B. Eosinophils
Parasitic organisms that are most often transmitted sexually include:
A. Entamoeba gingivalis
B. Dientamoeba fragilis
C. Trichomonas vaginalis
D. Diphyllobothrium latum
C. Trichomonas vaginalis
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 form soil
D. Toxoplasma gondii- ingestion of raw or rare meats
iA. Trypanosoma brucei rhodesiense- bite of sand fleas
Upon examination of stool material for Cytoisospora 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
C. Oocysts that are modified acid-fast variable
Which specimen is the least likely to provide recovery of Trichomonas vaginalis?
A. Urine
B. Urethral discharge
C. Vaginal discharge
D. Feces
D. Feces
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-satined smear
D. Giemsa’s stain
B. Trichrome-stained smear
One of the following protozoan organisms has been implicated in water borne and foodborne outbreaks within the United States. The suspect organism is:
A. Pentatrichomonas hominis
B. Dientamoeba fragilis
C. Giardia lamblia
D. Balantidium coli
C. Giardia lamblia
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
C. Entamoeba gingivalis
An Entamoeba histolytic 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
A. Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia
A 12-year0old girl is brought to the emergency department with meningitidis and a history of swimming in a warm-water spring. Motile amoebae that measure 10u in size are seen in the CSF and are most likely:
A. Iodamoeba butschlii trophozoites
B. Endolimax nan trophozoites
C. Dientamoeba fragilis trophozoites
D. Naegleria fowleri trophozoites
D. Naegleria fowleri trophozoites
Characteristics of the rhaditiform (noninfective) larvae of Stronglyoides 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
A. Short buccal capsule and large genital primordium
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
A. Toxocara-serology
The following organism 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
D. Balantidium coli-common within the United States
Examination of 24-hour unpreserved urine specimen is sometimes helpful in the recovery of:
A. Trichomonas vaginalis
B. Schistosoma haematobium eggs
C. Enterobius vermincularis eggs
D. Stronglyoides stercoralis larvae
B. Schistosoma haematobium eggs
The examination of sputum may be necessary to diagnose infection with:
A. Paragonimus westermani
B. Trichinella spiralis
C. Wuchereria bancrofti
D. Fasciola hepatica
A. Paragonimus westermani
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
A. Diphyllobothrium latum and Paragonimus westermani
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
A. Taenia solium and Trichinella spiralis
An operculated cestode egg that can be recovered form human feces is:
A. Clonorchis sinensis
B. Diphyloobothrium latum
C. Paragonimus westermani
D. Dipylidium caninum
B. Diphyloobothrium latum
The adult tapeworm of Echinococcus granulosus is found in the intestine of:
A. Dogs
B. Sheep
C. Humans
D. Cattle
A. Dogs
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
C. Either the definitive or the intermediate host
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
D. Ingestion of raw freshwater fish
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
B. Hymenolepis nana
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 trypomatigotes
D. Microsporidial spores
A. Plasmodium falciparum rings
Organism (and infections) that under normal conditions cannot be transmitted in the laboratory are:
A. Cryptosporidium-crytosporidiosis
B. Taenia solium- cysticercosis
C. Ascaris lumbricoides- ascariasis
D. Enterobius vermicularis- pinworm infections
C. 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
D. Both A and B
Oocysts of Cryptosporidium spp. can be detected is stool specimens using:
A. Modified Ziehl-Neelsen acid-fast stain
B. Gram stain
C. Methenamine silver stain
D. Trichrome stain
A. 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
C. 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
B. Plasmodium falciparum
Organism that should be considered in a nursery school outbreak of diarrhea include:
A. Endolimax nan, Giardia lamblia, and Entamoeba coli
B. Giardia lamblia, Dientamoeba fragilis, and Crytosporidium spp.
C. Crystosporidium spp., Trichomonas vaginalis, and Entamoeba coli
D. Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana
B. Giardia lamblia, Dientamoeba fragilis, and Crytosporidium spp.
The incorrect match between disease and symptoms is:
A. Paragonimiasis- hemoptysis
B. Crytosporidiosis- watery diarrhea
C. Toxoplasmosis in comprised host-central nervous system symptoms
D. Enterobiasis-dysentery
D. 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
B. Protozoan cysts and helminth eggs
Cysts of Iodamoeba butschlii 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
C. 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
B. Schistosoma species
Organisms that should be considered in a waterborne outbreak of diarrheal disease include:
A. Giardia lamblia and Crytosporidium spp.
B. Endolimax nana and Entamoeba histolytica
C. Blastocysitis hominis and Trichomonas vaginalis
D. Toxoplasma gondii and Schistosoma mansoni
A. Giardia lamblia and Crytosporidium 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
B. Giardia lamblia and Cryptosporidium spp.
Primary infections with the microsporidia may originate in:
A. The lung
B. The nervous system
C. The gastorintestinal tract
D. Mucocutaneous lesions
C. The gastorintestinal 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
C. 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 Wscherichia coli
D. The Giemsa’s stain method
C. The use of non-nutrient agar cultures seeded with Wscherichia coli
The microsporidia are protozoans (now classified with the fungi)t 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
A. 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 acid-fast stains
C. A counterstain must be used for the modified methods
D. The stain is more concentrated when staining for AFB
B. The decolorizer is weaker than acid alcohol used for AFB acid-fast stains
The incorrect match between symptoms and disease is:
A. Dysentery- amebiasis
B. Malabsorption syndrome- giardiasis
C. Cardiac involvement- chronic Chagas disease
D. Myalgias- trichuriasis
D. 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
C. 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
B. 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
D. 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
C. 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
B. Strongyloides stercoralis
In a pediatric patient, the recommended clinial specimen for recovery of Enterobius vermicularis is the:
A. Stool specimen
B. Sigmoidoscopy scrapings
C. Duodenal aspirates
D. Series of Scotch tape preparations
D. Series of Scotch tape preparations
Which parasite causes eosinophilic meningoencephalitis, a form of larva migrans causing fever, headache, stiff neck, and increase cells in the spinal fluid?
A. Necator americanus
B. Angiostrongylus cantonensis
C. Ancylostoma braziliense
D. Strongyloides stercoralis
B. 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
D. 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
C. 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
A. 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
D. 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
B. Cysticercosis
A transplant patient on immunosuppressive drugs developed increasings 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
B. 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
D. 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
C. 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
D. Trypanosomiasis with Trypanosoma cruzi
When malaria smears are requested, what patient information should be obtained?
A. Diet, aga, sex
B. Age, antimalarial medication, sex
C. Travel history, antimalaria medication, date of return to United States
D. Fever patterns, travel history, diet
C. Travel history, antimalaria 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. Dientamoaba fragilis
A. 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 cayetanesis
C. Schistosoma mansoni
D. Cystoisospora belli
B. Cyclospora cayetanesis
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
C. 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 tapeworm
D. Schistosoma mansoni, one of the blood flukes
A. Enterobius vermicularis, the pinworm
A helminth egg is described as having terminal polar plugs. The most likely helminth is:
A. Hookworm
B. Trichuris tirchiura
C. Fasciola hepatica
D. Diphyllobothrium latum
B. Trichuris tirchiura
Ingestion of which of the following eggs will result in infection?
A. Strongyloides stercoralis
B. Schistosoma japonicum
C. Toxocara canis
D. Opisthrochis sinensis
C. Toxocara canis
Plasmodium vivax and Plasmodium ovale are similar because they:
A. Exhibit Schuffner’s dots and have a true relapse in the life cycle
B. Have no malarial pigment and multiple rings
C. Commonly have applique forms in the red cells
D. Have true stippling, do not have a relapse stage, and infect old red cells
A. Exhibit Schuffner’s dots and have a true relapse in the life cycle
The term internal autoinfection can be associated with the following parasites:
A. Crystosporidium spp. and Giardia lamblia
B. Cytoisospora belli and Strongyloides stercoralis
C. Cryptosporidium spp. and Strongyloides stercoralis
D. Giardia lamblia and Cyroisospora belli
C. 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 form the environment
D. Ingestion, inhalation, and direct contamination
D. Ingestion, inhalation, and direct contamination
An immunocompromised patient continues to have diarrhea after repeated ova and parasites (O&P) examination (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. Crytosporidium spp. and microsporidia
D. Crytosporidium 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
C. 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
C. Plasmodium falciparum
Parasite stages that are immediately infective for humans on passage from the gastrointestinal tract include:
A. Schistosoma spp.
B. Toxoplasma gondii bradyzoites
C. Giardia lamblia trophozoites
D. Crytosporidium spp. oocysts
D. Crytosporidium spp. oocysts
Older developting stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowles, resemble those of:
A. Plasmodium malariae
B. Plasmodium ovale
C. Plasmodium falciparum
D. Plasmodium vivax
A. 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 cayetanesis oocysts
D. Cyclospora cayetanesis 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 cycle (72 hr), will infect all ages of RBCs, and disease is similar to that caused by P. ovale
A. 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
A. Light microscopy and modified trichrome stains
Although the pathogenicity of Blastocystis hominis remains controversial, newer information suggest that:
A. MOst organism 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
B. 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 organism within several hours, and poor staining
B. Loss of Schuffner’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
D. All of these options
Which of the following is a key characteristics 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
D. The necessity to lake the RBCs during or prior to staining
