Advanced Clinical Parasitology Practice Exam

Humans, especially children, are occasional hosts of this cestode parasite of dogs, cats, and wild carnivora. Transmission results from accidental swallowing of infected fleas from dogs or cats. Finding the proglottids or eggs in the feces is diagnostic. This parasite is:

Dipylidium caninum

Echinococcus granulosus

Hymenolepis diminuta

Toxocara canis

None of the above

Dipylidium caninum

The egg shown below may cause infection by hand-to-mouth transfer or by internal autoinfection. This small worm most often infects children, and finding the egg in feces is diagnostic. Identify the parasite.

Ascaris lumbricoides

Enterobius vermicularis

Hookworm

Hymenolepis diminuta

Hymenolepis nana

hymenolepis nana

A tapeworm scolex is shown below. Select the best description of a gravid proglottid of this species.

Barrel shape with double genital pores

Longer than wide, with less than 14 main
uterine branches per side

Longer than wide, with more than 14 main
uterine branches per side

Wider than long with a rosette-shaped uterus

None of the above

Wider than long with a rosette-shaped uterus

The best direct diagnosis of Echinococcus granulosus infection in man is made by identification of:

Adult worms in the intestine

Adult worms in tissues

Eggs in feces

Hydatid cysts in tissues

Larvae in feces

Hydatid cysts in tissues

Which stage of Taenia saginata is usually infective for man?

Cysticercus larva

Embryonated egg

Filariform larva

Plerocercoid larva

Rhabditiform larva

Cysticercus larva

Important diagnostic information can be provided by correct identification of the gravid proglottid shown below. Which tapeworm species produces this type of proglottid?

Diplyllobothrium latum

Hymenolepis diminuta

Hymenolepis nana

Taenia saginata

Taenia solium

taenia saginata

Enterobius vermicularis infection is usually diagnosed by:

Finding adult worms in feces

Finding larvae in feces

Finding larvae in perianal specimens

Finding eggs in the feces

Finding eggs in perianal specimens

Finding eggs in perianal specimens

Visceral larval migrans is associated with which of the following organisms?

Ancylostoma duodenale

Dracunculus medinensis

Onchocerca volvulus

Toxocara canis

Trichinella spiralis

toxocara canis

Which of the following is frequently helpful in differentiating an immature cyst of Entamoeba histolytica from Entamoeba coli?

A well-defined glycogen mass

Ingested red blood cells

Ingested bacteria

Blunt chromatoidal bars

All of the above

blunt chromatoidal bars

Which of the following is the most important vector for Plasmodium vivax in Africa?

Fleas

Ticks

Sand flies

Mosquitoes

Tsetse flies

mosquitoes

Important diagnostic information may be provided by the accurate identification of a tapeworm proglottid found in a stool specimen. The gravid proglottid shown below is typical of which of the following species?

Diphyllobothrium latum

Hymenolepis diminuta

Hymenolepis nana

Taenia saginata

Taenia solium

taenia solium

Which species of Plasmodium may readily be identified when crescent-shaped gametocytes are found in stained blood films?

P. vivax

P. falciparum

P. malariae

P. ovale

P. cynomolgi

P. falciparum

Rectal biopsy or sigmoidoscopy may be used to detect invasive parasitic infection. Which of the following is true of sigmoidoscopic material?

Helpful in diagnosing amebiasis

Can prepare permanent stains

Can detect motile trophozoites in direct mounts

Swabs should not be used to collect sample

All of the above

all of the above

Zinc sulfate flotation is not recommended for concentration of:

Oocysts of Cryptosporidium

Cysts of Giardia lamblia

Cysts of Entamoeba histolytica

Eggs of Hymenolepis nana

Eggs of Schistosoma mansoni

eggs of hymenolepis nana

Identify the 90 x 70 µm egg shown below.

Diphyllobothrium latum

Fasciola hepatica

Hymenolepis diminuta

Paragonimus westermani

Schistosoma japonicum

schistosoma japonicum

Name the species of malaria parasite that usually produce(s) a mature schizont with 8 or 10 merozoites in a rosette, or irregular cluster, that practically fills a normal-sized erythrocyte.

Plasmodium falciparum

Plasmodium ovale

Plasmodium vivax

Plasmodium malariae

None of the above

Plasmodium malariae

The rhabditiform larva of Strongyloides stercoralis:

Is rarely passed in the feces

Has a prominent genital primordium

Has a notched tip of tail

Has a long buccal cavity

Is infective for man

has a prominent genital primordium

Babesia microti is an organism that has been recovered recently in a number of human infections in New England. In an examination of stained blood films, these organisms are likely to resemble:

Leishmania donovani

Plasmodium falciparum

Toxoplasma gondii

Trypanosoma cruzi

None of the above

plasmodium falciparum

On Sept. 9, 1981, a 72-year-old man from Edinburg, Texas, developed fever and weakness 16 days after being bitten by flies during 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 Sept. 20. 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 (CSF) contained 12 red cells and 18 mononuclear cells/mm³, with a normal protein level (32 mg/dL). Laboratory tests revealed a hemoglobin level of 10.7 g/dL, a white cell count of 2400/mm³, and a platelet count of 75,000/mm³. The diagnosis was made by finding the extracellular flagellate parasite in a peripheral blood smear. Which of the following is the most probaG¾ôäZh>ble etiologic agent of this infection?

Leishmania donovani

Plasmodium falciparum

Toxoplasma gondii

Trypanosoma cruzi

Trypanosoma brucei rhodesiense

Trypanosoma brucei rhodensiense

A free-living ameba that causes primary amebic meningoencephalitis is:

Amoeba proteus

Entamoeba gingivalis

Entamoeba histolytica

Entamoeba polecki

Naegleria fowleri

Naegleria fowleri

The usual habitat of Trichinella spiralis adults in man is:

Blood

Intestine

Liver

Lymph

Muscle

intestine

For which of the following diseases do reduviid bugs serve as vectors?

African sleeping sickness

Chagas' disease

Kala-azar

Malaria

Oriental sore

Chagas’ disease. Also known as the kissing bug

An adult helminth parasite occasionally expelled by mouth, especially by children with fever, is:

Ascaris lumbriocoides

Echinococcus granulosus

Entamoeba gingivalis

Enterobius vermicularis

Trichomonas tenax

Ascaris lumbricoides

Decontamination of drinking water, fruits, and vegetables before consumption is necessary in countries without well-developed public sanitation. Which of the following diseases would probably be least affected by that kind of precaution?

Amebiasis

Ascariasis

Fasciolopsis infection

Giardiasis

Tapeworm infection

tapeworm infection

For which of the following diseases is close contact with an infected human host the most important mechanism of transmission?

Coenurosis

Schistosomiasis

Trichinosis

Trichomoniasis

Toxoplasmosis

Trichomoniasis. It is an STI caused by trichimonas vaginalis

Identify this small protozoan cyst.

Chilomastix mesnili

Endolimax nana

Entamoeba hartmanni

Giardia lamblia

Trichomonas vaginalis

chilomastix mesnili

Identify this 12 µm parasite.

Balantidium coli

Chilomastix mesnili

Giardia lamblia

Trichomonas hominis

None of the above

Chilomastix mesnili

Filariform larvae

Rhabditiform larva

third infective stage of certain worms capable of penetrating the skin.

non-infective, free living stage. Nematodes

The egg shown below is the diagnostic stage of an intestinal parasite. What is the infective stage of this helminth?

egg as shown here

A fully embryonated egg

A filariform larva

A rhabditiform larva

None of the above

a filariform larva

The egg shown below was detected in a preemployment stool specimen submitted by a kitchen worker who has never traveled outside the United States. He denied symptoms of gastrointestinal illness. Identify the parasite.

ylostoma duodenale

Ascaris lumbriocoides

Enterobius vermicularis

Fasciola hepatica

Paragonimus westermani

ascaris lumbricoides

The presence or absence of a sheath on a microfilaria seen in a peripheral blood smear is an important clue to species identity. In which of the following tissue nematodes are the microfilariae not sheathed?

Brugia malayi

Loa loa

Wuchereria bancrofti

Onchocerca volvulus

All of the above

Onchocera volvulus

Hydatid cyst in humans is due to ingestion of a tapeworm stage normally infective for herbivores. This stage is the:

Cercaria

Cercocystis

Cysticercus

Embryonated egg

Sparganum

embryonated egg

Which of the following is not a typical habitat of Trichomonas vaginalis?

Prostatic secretions

Vaginal discharge

Urine

Urethral discharge

Feces

Feces

An elderly Russian woman who had recently immigrated to Israel visited her brother living in the United States. While in the United States the woman was found to have a severe anemia. The egg shown below, measuring 60 x 50 µm, was found in her stool specimen. Identify the parasite.

ris lumbricoides

Diphyllobothrium latum

Echinococcus granulosus

Fasciolopsis buski

Paragonimus westermani

Diphyllobothrium latum

A Giemsa-stained thick blood film showed many ring forms with no older stages, and a number of the rings had double chromatin dots. These findings are characteristic of:

Plasmodium cynomolgi

Plasmodium vivax

Plasmodium malariae

Plasmodium ovale

Plasmodium falciparum

Plasmodium falciparum

The formalin-ethyl acetate sedimentation concentration method is recommended for routine use primarily because it:

Preserves most parasites

Recovers protozoa

Recovers larvae

Is safer than formalin-ether sedimentation method

All of the above

All of the above

Which of the following helminths produces an elongate, barrel-shaped egg (50 x 22 µm) with a colorless polar plug at each end?

Ascaris lumbricoides

Dipylidium caninum

Hymenolepis nana

Necator americanus

Trichuris trichiura

Trichuris trichiura

This amebic cyst has an average size of 6-8 µm 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 karyosomes. Chromatoidal bars with bluntly rounded ends are often present. Name the species.

olimax nana

Entamoeba coli

Entamoeba hartmanni

Entamoeba histolytica

Iodamoeba bütschlii

Entamoeba hartmanni

Identify this 20 µm amebic trophozoite.

Entamoeba coli

Entamoeba hartmanni

Entamoeba histolytica

Entamoeba polecki

None of the above

Entamoeba coli

This ameba is more easily identified by its quadrinucleate cyst. Identify its 9 µm trophozoite shown below:

Dientamoeba fragilis

Endolimax nana

Entamoeba hartmanni

Entamoeba histolytica

Iodamoeba bütschlii

endolimax nana

Because of fecal contamination a urine specimen may contain the flagellate:

Balantidium coli

Entamoeba coli

Trichomonas hominis

Trichomonas tenax

Trichomonas vaginalis

Trichomonas hominis

The large, operculate egg shown below is characteristic of:

Heterophyes heterophyes

Diphyllobothrium latum

Fasciola hepatica

Paragonimus westermani

Clonorchis sinensis

fasciola hepatica

A dog parasite that almost never develops to an adult in humans has been found in some persons as a cause of a subcutaneous nodule or a solitary peripheral nodule in the lung. This nematode is:

Ancylostoma braziliense

Dipylidium caninum

Dirofilaria inmitis

Echinococcus granulosus

Onchocerca volvulus

Dirofilaria inmitis

"River blindness" is a parasitic disease affecting many people in Africa, Central America, and northern South America who live within 5 miles of the rapidly flowing small streams where the black fly vectors of the causative parasite breed. The parasite causing river blindness is:

Leishmania tropica

Loa loa

Onchocerca volvulus

Toxocara canis

Trypanosoma brucei

Onchocerca volvulus

Which is the most dependable procedure for the accurate, specific diagnosis of an intestinal amebic infection?

Direct saline wet mount

Iodine-saline wet mount

Formalin-ether sedimentation technique

Permanently stained smear

Quensel's vital stain

Permanently stained smear

Elephantiasis is a complication associated with which of the following?

Cysticercosis

Guinea worm

Hydatid cyst disease

Filariae

Ascariasis

Filariae

Which Plasmodium species often causes "malignant tertian malaria" as a fulminating, fatal infection?

P. ovale

P. vivax

P. malariae

P. falciparum

P. knowlesi

P. falciparum

Which of the following pairs of helminths cannot be reliably differentiated by appearance of their eggs?

Trichuris trichiura and Trichinella spiralis

Hymenolepis nana and H. diminuta

Necator americanus and Ancylostoma duodenale

Diphyllobothrium latum and Dipylidium caninum

Ascaris lumbricoides and N. americanus

Necator americanus and Ancylostoma duodenale

Identify this 17 µm ameoba.

Dientamoeba fragilis

Endolimax nana

Entamoeba coli

Entamoeba hartmanni

Entamoeba histolytica

Entamoeba histolytica

Sanitary disposal of human feces is the most important factor in decreasing the incidence of most infections with intestinal parasites. Which of the following diseases would not be affected by that kind of sanitation?

Ascariasis

Hookworm infection

Schistosomiasis

Taeniasis

Trichinosis

Trichinosis, acquired by eating raw or under cooked meat

Knowledge of its nocturnal periodicity is especially important in the diagnosis of infection with which of the following tissue roundworms?

Dracunculus medinensis

Loa loa

Onchocerca volvulus

Wuchereria bancrofti

Mansonella ozzardi

Wuchereria bancrofti

Chagas' disease is caused by:

Trypanosoma rhodesiense

Trypanosoma cruzi

Leishmania braziliensis

Mansonella perstans

Brugia malayi

Trypanosoma cruzi

Hematuria is one typical sign of human infection caused by:

Onchocerca volvulus

Trichinella spiralis

Trichomonas vaginalis

Schistosoma haematobium

Trypanosoma cruzii

Schistosoma haematobium

Because of the possibility of drug resistance or the persistence of extra erythrocytic (EE) parasites, identification of the causative species can be important in the choice of treatment for malaria. Which species of Plasmodium may have extraerythrocytic stages capable of causing relapses up to 3 or more years after initial infection?

P. falciparum

P. ovale

P. malariae

P. cyomolgi

P. knowlesi

P. ovale

Various species of the sandflies (genus Phlebotomus or Lutzomyia) serve as vectors for:

African trypanosomiasis

Chagas' disease (American trypanosomiasis)

Filariasis

Leishmaniasis

Toxoplasmosis

Leishmaniasis

What is the recommended test for diagnosing congenital toxoplasmosis?

PCR

Hemagglutination inhibition (HI)

IgM capture enzyme immunoassay (EIA)

IgG indirect immunofluoresence assay (IIF)

Immunoblot (IB)

PCR

Identify the 20 µm cyst shown below.

Balantidium coli

Endolimax nana

Entamoeba coli

Entamoeba histolytica

Entamoeba polecki

entamoeba coli

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?

Anemia

Leukopenia

Neutropenia

Eosinophilia

Lymphocytosis

Eosinophilia

A 15 µm, 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:

Chilomastix mesnili

Enteromonas hominis

Giardia lamblia

Retortamonas intestinalis

Trichomonas hominis

Giardia lamblia

Which of the following nematode (round-worm) parasites is acquired from eating inadequately cooked, infected pork?

Strongyloides stercoralis

Taenia solium

Taenia saginata

Trichinella spiralis

Necator americanus

trichinella spiralis

Which of the following is the most important vector for Toxoplasma gondii?

Fleas

Ticks

Flies

Mosquitoes

None of the above

None of the above. Transmission through ingesting contaminated food or water.

In December 1990 a resident of Staunton, Virginia, presented to his physician with fever, muscle pain, periorbital edema, and eosinophilia. The case history revealed the patient had consumed pork sausage about 10 days previously. From what disease is this patient most likely suffering?

Chaga's disease

Cryptosporidiosis

Trichinosis

Taeniasis

Giardiasis

trichinosis

Identify the 7 µm cyst shown below.

Endolimax nana

Entamoeba hartmanni

Entamoeba histolytica

Entamoeba polecki

Iodamoeba bütschlii

Endolimax nana

In which specimen is the 85 x 53 µm egg shown below most likely to be found?

Anal swab

Duodenal aspirate

Rectal biopsy

Sputum

Urine

sputum

The World Health Organization currently has a campaign to eliminate step wells to prevent transmission of the nematode parasite that is thought to have been the "fiery serpent" of the ancient Israelites. This parasite, which has various species of Cyclops as its intermediate host, is:

Dicrocoelium dendriticum

Dipetalonema perstans

Diphyllobothrium latum

Dipylidium caninum

Dracunculus medinensis

Dracunculus medinensis

Which of the following would be most helpful in controlling Necator americanus infections?

Good personal hygiene

Immunization

Thoroughly cooking food

Use of insecticides

Sanitary sewage disposal

sanitary sewage disposal

Which of the following is the most important vector for Babesia sp?

Reduviid bugs

Ticks

Lice

Mosquitoes

Rats

ticks

Cutaneous larva migrans, or "creeping eruption," is characterized by intracutaneous serpiginous lesions caused by certain nemotode larvae. The most common cause of this dermatitis is:

Ancylostoma braziliense

Ancylostoma duodenale

Necator americanus

Toxocara canis

Toxocara cati

Ancylostoma braziliense

Which of the following is typical in cysts of Iodamoeba bütschlii?

A glycogen mass

Blunt chromatoidal bars

Four nuclei with large karyosomes

Many ingested bacteria

Red blood cells

A glycogen mass

This ciliated intestinal parasite measures 50 µm. What is its identity?

Cercaria of Fasciolopsis buski

Coracidium of Diphyllobothrium latum

Trophozoite of Balantidium coli

Miracidium of Schistosoma japonicum

None of the above

Trophozoite of balantidium coli

Which stage of Trichuris trichiura is infective for man?

Egg in freshly passed feces

Filariform larva

Fully embryonated egg

Rhabditiform larva

None of the above

fully embryonated egg

Which species of malaria parasite usually has growing trophozoites with ameboid cytoplasm and produces small reddish dots in the red blood cell cytoplasm?

Plasmodium ovale

Plasmodium falciparum

Plasmodium malariae

Plasmodium vivax

None of the above

Plasmodium vivax

Species identification of an immature amebic cyst can be very difficult. This parasite stage would not, however, be found in infections caused by:

Dientamoeba fragilis

Endolimax nana

Entamoeba coli

Entamoeba histolytica

Iodamoeba bütschlii

dientamoeba fragilis

Which of the following is the most important vector for Loa loa?

Fleas

Lice

Mango flies

Mosquitoes

Rats

mango flies

Cysticercosis is caused by the disseminated larvae of:

Echinococcus granulosus

Hymenolepis nana

Necator americanus

Taenia solium

Toxocara canis

taenia solium

The egg shown below is the diagnostic state of an important parasite found in Puerto Rico and some other islands in the West Indies and in parts of northern South America and Africa. This helminth infects humans by:

Ingestion of the embryonated egg

Ingestion of the encysted larvae

Larval penetration of the skin

Vector injection of infective larvae

None of the above

larval penetration of the skin

With which species of malarial parasite are Schüffner's dots found in the infected erythrocytes?

Plasmodium falciparum

Plasmodium knowlesi

Plasmodium malariae

Plasmodium vivax

None of the above

Plasmodium vivax

Immunocompromised hosts have been found to have increased susceptibility to certain parasitic diseases. This has been found to be true for infections caused by:

Babesia

Cryptosporidium

Isospora

Strongyloides

All of the above

all of the above

The observation of embryonic flame cell activity is recommended to demonstrate the viability of eggs of:

Clonorchis

Fasciola

Necator

Schistosoma

Taenia

schistosoma

A recently recognized parasitic disease of humans is caused by ingestion of viable, third-stage larval nemotodes in the flesh of some saltwater fish such as herring. When the ingested larvae attempt to migrate through the wall of the gastrointestinal tract, a severe inflammatory reaction is produced at the site of penetration. These larvae have been found during gastroscopies and during surgery for intestinal obstruction or perforation. The name of the human zoonosis is:

Anisakiasis

Ascariasis

Dracunculosis

Filariasis

Toxocariasis

anisakiasis

In which specimen is the large egg shown below most likely to be found?

Feces

Perianal swab

Sputum

Urine

None of the above

urine

Identify this 15 µm protozoan cyst.

Balantidium coli

Chilomastix mesnili

Endolimax nana

Entamoeba histolytica

Giardia lamblia (duodenalis)

giardia lamblia (duodenalis)

Which of the following is a stage of Toxoplasma gondii infective for man?

Cercocyst

Gonad

Leptomonad

Oocyst

Plasmodium

oocyst

Which of the following forms of Toxoplasma gondii are produced in infected humans?

Bradyzoites

Merozoites

Sporoblasts

Oocysts

Macrogamete

bradyzoites

Eggs or larvae that are recovered in the stool are routinely used to diagnose infections caused by all of the following helminths, except:

Ascaris lumbriocoides

Necator americanus

Strongyloides stercoralis

Trichinella spiralis

Trichostronglylus colubriformis

trichinella spiralis

The string test (Entero-Test) for obtaining a small specimen of duodenal contents for parasitic infection would be most appropriate with:

Chilomastix mesnili

Endolimax nana

Entamoeba histolytica

Giardia lamblia

Iodamoeba bütschlii

giardia lamblia

Identify the 55 x 26 µm egg shown below.

Ancylostoma duodenale

Ascaris lumbricoides

Enterobius vermicularis

Necator americanus

Trichuris trichiura

enterobius vermicularis

Which of the following would be most helpful in controlling infection due to Enterobius vermicularis?

Good personal hygiene

Immunization

Thoroughly cooking food

Preventive medication

Providing safe drinking water

good personal hygiene