CIULLA Flashcards
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
Eggs in perianal specimens
The best direct diagnosis of Echinococcus granulosus infection in humans is made by identification of
A. Adult worms in the intestine
B. Adult worms in tissues
C. Eggs in feces
D. Hydatid cysts in tissues
Eggs in feces
Which statement is correct for specimen collection and processing?
A. Stool samples can contain urine.
B. Stools can be frozen without affecting parasitic structure.
C. Liquid stools are best for detecting ameba and flagellate trophozoites.
D. Unpreserved stools can remain at room temperature for up to 72 hours.
Liquid stools are best for detecting ameba and flagellate trophozoites.
Cysts are the infective stage of this intestinal flagellate.
A. Balantidium coli
B. Dientamoeba fragilis
C. Entamoeba coli
D. Giardia lamblia
Dientamoeba fragilis
Eggs or larvae recovered in the stool are not routinely used to diagnose infections caused by which one of the following
helminths?
A. Trichinella spiralis
B. Strongyloides stercomlis
C. Necator americanus
D. Ascaris lumbricoides
Necator americanus
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
Definitive host
Species identification of an immature amebic cyst can be very difficult. The presence of a large glycogen mass is
sometimes seen in
A. Dientamoebafragilis
B. Endolimax nana
C. Entamoeba coli
D. Entamoeba histolytica
Entamoeba histolytica
Which of the following is typical in cysts of lodamoeba biitschlii?
A. A glycogen mass
B. Blunt chromatoidal bars
C. Four nuclei with large karyosomes
D. Many ingested bacteria
A glycogen mass
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 the cyst
C. Shape of the karyosome
D. Distinguishing surface antigens by immunologic assays
Distinguishing surface antigens by immunologic assays
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. Neutropenia
Lymphocytosis
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 a temperature of 38.9°C (102°F), a morbilliform rash of the trunk, and right-
sided, anterior cervical lymphadenopathy. Cerebrospinal fluid contained 12 red cells 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 109/L, and a platelet count of
75 X 109/L. The diagnosis was made by finding the extracellular flagellate parasite in a peripheral blood smear. Which of the following is the most probable etiologic agent of this infection?
A. Leishmania donovani
B. Trypanosoma brucei
C. Tiypanosoma cruzi
D. Toxoplasma gondii
Trypanosoma brucei
Which species of malaria parasite usually has ameboid trophozoites and produces small reddish dots in the red blood cell cytoplasm?
A. Plasmodium knowlesi
B. Plasmodium falciparum
C. Plasmodium malariae
D. Plasmodium vivax
Plasmodium vivax
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 acetate sedimentation
technique
Permanently stained smear
In an examination of stained blood films, Babesia spp. are likely to resemble
A. Leishmania donovani
B. Plasmodiumfalciparum
C. Toxoplasma gondii
D. Trypanosoma cruzi%
Plasmodium falciparum
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
Polyvinyl alcohol
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. Cyclospom
C. Isospora
D. Microsporidia
Cyclospom
A 22-year-old male presents to his family physician complaining of fatigue, muscle pain, periorbital edema, and fever. He denies travel outside the U.S. The physician suspects infectious mononucleosis; however, serologic tests for infectious mononucleosis are negative. The complete blood count revealed a slightly elevated white blood 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
Trichinella spiralis
Which Schistosoma species has a large terminal spine?
A. S. haematobium
B. S.japonicum
C. S. mansoni
D. S. mekongi
S. mansoni
Elephantiasis is a complication associated with which of the following?
A. Cysticercosis
B. Guinea worm
C. Hydatid cyst disease
D. Filariae
Filariae
A patient with history of human immunodeficiency 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 (am in diameter. The most likely pathogen is
A. Blastocystis hominis
B. Cryptosporidium sp.
C. Isospora sp.
D. Microsporidium
Cryptosporidium spp.
A 55-year-old female presents to her physician complaining of a fever that “comes and goes” and fatigue. A complete blood count reveals decreased red blood cell count and hemoglobin. History reveals the patient recently traveled
through Europe and Africa. You should suspect
A. Cutaneous larval migrans
B. Filariasis
C. Malaria
D. Trichinella
Filariasis
The disease most commonly associated with Acanthamoeba sp. is
A. Diarrhea
B. Keratitis
C. Liver abscess
D. Meningoencephalitis
Keratitis
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 urn in diameter
C. Blue ovals, 4-6 urn in diameter
D. Fluorescent circles, 8-12 um in
diameter
Pink ovals, 1-3 urn in diameter
Hydatid cysts in humans are due to ingestion of a tapeworm stage normally found in canines. This stage is the
A. Cercaria
B. Cercocystis
C. Cysticercus
D. Embryonated egg
Cercaria