Parasitology – Protozoan & Helminthology (Week 5)

100 fill-in-the-blank flashcards covering key protozoan and helminthology concepts from Week 5 lecture notes.

The two main life-cycle stages of most intestinal protozoa are the trophozoite and the __.

cyst

During diarrheic episodes, the diagnostic stage seen in stool is the __ form of the parasite.

trophozoite

Entamoeba histolytica is transmitted primarily by ingestion of a mature __ cyst.

quadrinucleate

Entamoeba histolytica is the only known __ intestinal amoeba of humans.

pathogenic

Amoebic liver abscesses are an example of __ amoebiasis caused by E. histolytica.

extraintestinal

Flies and __ can mechanically transmit Entamoeba histolytica cysts.

cockroaches

For asymptomatic E. histolytica infection, the drug of choice is __.

Paromomycin

Iodoquinol is recommended for treating the __ form of E. histolytica infection.

symptomatic

Quadrinucleate cysts of E. histolytica are resistant to ordinary __ in water supplies.

chlorination

The nonpathogenic species that is morphologically similar to E. histolytica is Entamoeba __.

dispar

Entamoeba hartmanni trophozoites characteristically lack ingested __.

red blood cells

Entamoeba __ is found worldwide in both warm and cold climates and is nonpathogenic.

coli

Entamoeba polecki is primarily a parasite of pigs and __.

monkeys

Treatment of human E. polecki infection often combines metronidazole with __ furoate.

diloxanide

The most common mature cyst of Endolimax nana contains __ nuclei.

four

Entamoeba gingivalis has __ known cyst stage.

no

Transmission of E. gingivalis may occur by mouth-to-mouth contact or sharing contaminated __.

utensils

Naegleria fowleri causes primary __ meningoencephalitis (PAM).

amoebic

Naegleria fowleri is usually acquired by __ in warm fresh water.

swimming

The recommended drug for PAM includes intravenous __ B.

Amphotericin

Acanthamoeba trophozoites possess spinelike pseudopods called __.

acanthopodia

Contact-lens wearers are at particular risk for Acanthamoeba __.

keratitis

Calcofluor white is a useful stain for detecting Acanthamoeba __ in corneal scrapings.

cysts

The most successful treatment of Acanthamoeba infections uses the drug __.

propamidine

Giardia intestinalis attaches to the duodenal wall by means of a ventral __ disk.

sucking

Giardia cysts are notable for their resistance to routine __ in water treatment.

chlorination

Tinidazole or nitazoxanide are first-line agents for treating __.

giardiasis

Double-strength saturated __ solution can render contaminated water safe from Giardia.

iodine

Chilomastix mesnili infection follows ingestion of contaminated food or __.

water

Dientamoeba fragilis may be transmitted inside the eggs of __ vermicularis.

Enterobius

The Brownian movement of granules in D. fragilis trophozoites is called the __ phenomenon.

Hakansson

Iodoquinol is the treatment of choice for symptomatic __ fragilis infection.

Dientamoeba

Trichomonas hominis has __ cyst stage in its life cycle.

no

Trichomonas hominis may be acquired by ingestion of infected __.

milk

Trichomonas tenax inhabits the oral cavity and is spread via shared __ or droplets.

utensils

Trichomonas vaginalis is most commonly transmitted through __ intercourse.

sexual

In women, T. vaginalis often produces a foul-smelling, __-yellow vaginal discharge.

greenish

Metronidazole (Flagyl) is the standard therapy for __ vaginalis infections.

Trichomonas

The infective stage of Leishmania for humans is the __ injected by sandflies.

promastigote

The diagnostic tissue stage of Leishmania observed in macrophages is the __.

amastigote

Leishmania braziliensis complex causes __ leishmaniasis involving mucosal tissues.

mucocutaneous

Vectors of L. braziliensis belong to the sandfly genus __.

Lutzomyia

Sodium stibogluconate (Pentostam) is an antimony compound used to treat __ infection.

Leishmania

Visceral leishmaniasis (kala-azar) is caused by the __ donovani complex.

Leishmania

A positive __ skin test can indicate exposure to visceral leishmaniasis.

Montenegro

Amphotericin B is considered the drug of choice for severe __ leishmaniasis.

visceral

Cutaneous leishmaniasis of the New World, also called chiclero ulcer, involves Leishmania __ complex.

mexicana

Leishmania mexicana infections are typically treated with pentavalent __.

antimonials

Old World cutaneous leishmaniasis is transmitted by the __ fly.

Phlebotomus

A Giemsa-stained aspirate of ulcer fluid is diagnostic for Leishmania __ complex infection.

tropica

Trypanosoma brucei gambiense causes West African __ sickness.

sleeping

The tsetse fly species __ palpalis transmits T. b. gambiense.

Glossina

Postcervical lymphadenopathy in Gambian trypanosomiasis is called __ sign.

Winterbottom’s

Heightened pain sensitivity known as __ sign occurs in late Gambian trypanosomiasis.

Kerandel’s

Eflornithine is one medication used to treat West African __ sickness.

sleeping

Trypanosoma brucei rhodesiense causes the more acute __ African sleeping sickness.

East

Glossina morsitans is a principal vector of T. b. __.

rhodesiense

American trypanosomiasis is another name for __ disease.

Chagas

The reduviid or “kissing” bug transmits Trypanosoma __.

cruzi

Unilateral periorbital edema in acute Chagas disease is called __ sign.

Romaña’s

The drug __ (Lampit) is commonly used to treat Chagas disease.

Nifurtimox

Paroxysms in Plasmodium vivax malaria recur every __ hours.

48

Plasmodium malariae produces paroxysms every __ hours (quartan pattern).

72

Plasmodium malariae infections lack the stippling known as __ dots.

Schüffner’s

Blackwater fever with hemoglobinuria is a severe complication of Plasmodium __ infection.

falciparum

The zoonotic species Plasmodium __ is treated effectively with artemisinin.

knowlesi

Optimal malaria blood films are prepared during the patient’s __ stage of fever.

paroxysmal

Babesia merozoites form a characteristic __-cross pattern in red cells.

Maltese

Human babesiosis is commonly transmitted by ticks of the genus __.

Ixodes

Severe human babesiosis in Europe is usually caused by Babesia __.

divergens

The reservoir host for Babesia microti is the __-footed mouse (Peromyscus leucopus).

white

Combination therapy with clindamycin and __ is effective for babesiosis.

quinine

The only ciliate known to infect humans is __ coli.

Balantidium

Domestic __ serve as the main reservoir for Balantidium coli.

pigs

Oxytetracycline followed by iodoquinol is recommended therapy for __.

balantidiasis

Oocysts of Isospora belli are best visualized with a modified __-fast stain.

acid

Humans are the only definitive host of Isospora __.

belli

Severe isosporiasis responds well to therapy with __ (TMP-SMX).

SXT

Oocysts of Sarcocystis hominis contain __ sporocysts, each with four sporozoites.

two

Humans become definitive hosts of S. hominis by eating undercooked __ or cattle.

pig

Cryptosporidium parvum oocysts lack internal __.

sporocysts

Self-limiting watery diarrhea lasting about two weeks is typical of __ infection.

cryptosporidiosis

Produce such as contaminated lettuce is a common vehicle for Cyclospora __.

cayetanensis

Cats are the definitive host in the life cycle of __ gondii.

Toxoplasma

Rapidly dividing __ cause the acute tissue damage in toxoplasmosis.

tachyzoites

Trisulfapyrimidines combined with __ is classic therapy for toxoplasmosis.

pyrimethamine

Blastocystis hominis most often presents as a vacuolated form that reproduces by __.

sporulation

Iodoquinol or __ are drugs frequently used to treat symptomatic Blastocystis infection.

metronidazole

Pneumocystis jiroveci causes atypical interstitial __ cell pneumonia.

plasma

Person-to-person transmission of Pneumocystis jiroveci occurs via inhaled __ droplets.

pulmonary

First-line therapy for pneumocystosis in AIDS patients is high-dose __ (TMP-SMX).

Bactrim

A parasite that requires only one host to complete its life cycle is termed __.

monoxenous

Parasites that cannot survive without a host are classified as __ parasites.

obligate

Parasites located within the intestinal lumen are referred to as __.

enterozoic

The host that harbors the adult or sexual stage of a parasite is called the __ host.

definitive

Thick and thin blood films are basic laboratory methods for detecting __ parasites.

hematozoic

At least __ stool specimens, collected every other day, are recommended for routine ova-and-parasite exams.

three

Intestinal protozoan cysts are most likely found in __ or soft stools.

formed

Liquid stool must be examined within __ minutes of passage to detect motile trophozoites.

30