Deck 23: Parasitic Protozoa, Helminths, and Arthropod Vectors

Question 1

The protozoans known as apicomplexans

A) are motile.
B) reproduce by schizogony.
C) are intracellular parasites.
D) are motile intracellular parasites.
E) reproduce by schizogony and are intracellular parasites.

Answer 1

E

Question 2

Severe frothy diarrhea with a "rotten-egg" smell accompanied by abdominal pain,bloating,and fever are signs and symptoms consistent with

A) balantidiasis.
B) Chagas' disease.
C) cryptosporidiosis.
D) giardiasis.
E) leishmaniasis.

Answer 2

D

Question 3

Which of the following is a ciliated pathogen of the intestinal tract?

A) Balantidium
B) Plasmodium
C) Trypanosoma
D) Leishmania
E) Giardia

Answer 3

A

Question 4

Which of the following organisms can colonize the nasal cavity and enter the brain to cause meningoencephalitis?

A) Entamoeba histolytica
B) Acanthamoeba
C) Naegleria
D) Balantidium
E) Giardia

Question 5

After a trip to several South American countries,a middle-aged man becomes ill.He becomes anemic,loses weight,and runs a fever.The clinician notes a recently healed sore near his nose.Microscopic examination of a blood smear does not reveal anything other than the anemia.What parasitic infection is consistent with this scenario?

A) malaria
B) leishmaniasis
C) Chagas' disease
D) giardiasis
E) balantidiasis

Question 6

The definitive host of a parasite is

A) the host for immature stages of the parasite.
B) where the mature form of the parasite occurs.
C) also the vector for the parasite.
D) the host that the parasite name is based on.
E) the host for the dormant stage of the parasite.

Question 7

The ________ spreads more parasitic diseases to humans than any other vector.

A) kissing bug
B) mosquito
C) tick
D) louse
E) mite

Question 8

Which of the following is the same for both Trypanosoma cruzi and Trypanosoma brucei?

A) central nervous system infection
B) where the protozoan matures in the vector
C) type of arthropod vector
D) importance of early diagnosis and treatment
E) means of entry into the host

Question 9

Which of the following parasites is not generally microscopic in its mature form,even though microbiologists usually study them?

A) amoebae
B) toxoplasmas
C) helminths
D) leishmanias
E) cyclosporas

Question 10

Which of the following is the most common parasitic disease in industrialized nations?

A) giardiasis
B) Trichomonas infection
C) schistosomiasis
D) toxoplasmosis
E) balantidiasis

Question 11

The infectious stage of a beef tapeworm for humans is the

A) gravid proglottids in feces.
B) eggs in contaminated water.
C) larvae in feces.
D) cysticerci in beef.
E) mature worms.

Question 12

A contact lens wearer and cat owner begins to experience problems with her eye.The eye is inflamed and painful,and examination of the eye reveals that the conjunctiva is ulcerating.Which of the following parasites is most likely responsible?

A) Acanthamoeba
B) Cryptosporidium parvum
C) Entamoeba histolytica
D) Toxoplasma gondii
E) Trypanosoma cruzi

Question 13

Once infected with Trypanosoma brucei,the patient's immune system cannot clear the infection and develop immunity because the parasite

A) has flagella that allow it to travel all over the body.
B) matures into infectious trypomastigotes.
C) reproduces by binary fission.
D) changes its glycoprotein surface antigens every time it replicates.
E) invades the central nervous system.

Question 14

The ________ stage of a protozoan is the actively feeding and reproducing stage.

A) trophozoite
B) cyst
C) cysticercus
D) encysted
E) merozoite

Question 15

Which of the following species of Plasmodium causes cerebral malaria?

A) only P. falciparum
B) P. ovale and P. malariae
C) P. ovale and P. vivax
D) P. vivax and P. malariae
E) P. vivax, P. malariae, and P. vivax

Question 16

Which of the following is an accidental parasite of humans?

A) Ascaris lumbricoides
B) Acanthamoeba
C) Balantidium coli
D) Entamoeba histolytica
E) Plasmodium

Question 17

The presence of active motile multiflagellated trophozoites in vaginal or urethral secretion is indicative of infection with

A) Trichomonas vaginalis.
B) Chlamydia trachomatis.
C) Giardia intestinalis.
D) Acanthamoeba.
E) Balantidium coli.

Question 18

Which of the following statements concerning infection with Toxoplasma is FALSE?

A) It is one of the world's most widely distributed protozoan parasites in humans.
B) It is typically contracted by eating undercooked meat.
C) Even though it can be transmitted across the placenta, it is harmless to the fetus.
D) The majority of infected people are asymptomatic.
E) It usually results in no permanent damage and is self-limiting.

Question 19

Trypanosoma cruzi is introduced into the body by

A) feces containing trypomastigotes contaminating a bite wound.
B) the bite of a tsetse fly, which introduces the trypomastigotes into the body.
C) ingesting food contaminated with the parasite.
D) the bite of a sand fly that has ingested phagocytes containing the parasite.
E) wearing contact lenses cleaned with contaminated tap water.

Question 20

Which of the following parasitic infections can be diagnosed using a blood smear?

A) African sleeping sickness
B) toxoplasmosis
C) malaria
D) African sleeping sickness and malaria
E) toxoplasmosis and malaria

Question 21

Triatoma,commonly called "kissing bugs," are vectors of

A) African sleeping sickness.
B) Chagas' disease.
C) Cyclosporiasis.
D) Leishmania.
E) schistosomiasis.

Question 22

Which of the following is the most common parasitic worm in the United States?

A) Taenia saginata
B) Echinococcus granulosus
C) Schistosoma mansoni
D) Enterobius vermicularis
E) Ascaris lumbricoides

Question 23

A patient at a clinic complains of diarrhea that is occasionally bloody and has persisted for several days.A microscopic examination of a stool sample reveals the presence of very round cysts.These signs are consistent with infection by

A) Entamoeba histolytica.
B) Enterobius vermicularis.
C) Balantidium coli.
D) Giardia intestinalis.
E) Trypanosoma cruzi.

Question 24

Which of the following nematodes can be transmitted by mosquitoes?

A) Wuchereria bancrofti
B) Ascaris lumbricoides
C) Ancylostoma duodenale
D) Necator americanus
E) Enterobius vermicularis

Question 25

A person reports to a clinic complaining of fever and abdominal pain.The abdomen is swollen,and blood tests indicate liver damage.A stool sample is examined under a microscope and found to contain eggs with a spine projecting from its surface.The indications are consistent with infection with

A) Ancylostoma duodenale.
B) Enterobius vermicularis.
C) Echinococcus granulosus.
D) Schistosoma mansoni.
E) Taenia solium.

Question 26

Which of the following intestinal protozoa are considered parasites of humans only?

A) Entamoeba histolytica
B) Balantidium coli
C) Cyclospora cayentanensis
D) Giardia intestinalis
E) both Entamoeba histolytica and Cyclospora cayentanensis

Question 27

Why is snail fever a common name for infections with Schistosoma?

A) The worms look like snails.
B) They are contracted by eating snails.
C) Snails are the intermediate host.
D) Physical contact with snails may result in infection.
E) The larval stage looks like a snail.

Question 28

Balantidium coli uses ________ to penetrate the intestinal mucosa.

A) adhesion discs
B) flagella
C) cilia
D) pseudopodia
E) suckers

Question 29

A human fecal sample is examined and found to contain a few strobila.The person is probably infected with

A) Echinococcus granulosus.
B) Giardia intestinalis.
C) Taenia.
D) Schistosoma.
E) Necator americanus.

Question 30

The helminth parasite Schistosoma

A) is a cestode.
B) uses snails as an intermediate host.
C) has proglottids.
D) is a roundworm.
E) is a liver fluke.

Question 31

Elephantiasis is caused by

A) blood flukes.
B) liver flukes.
C) filarial roundworms.
D) tapeworms.
E) flatworms.

Question 32

A stool sample contains eggs that are oval and have no evidence of a spine.This observation is consistent with infestation with ________ species.

A) Fasciola
B) Wuchereria
C) Schistosoma
D) Taenia
E) Trypanosoma

Question 33

The parasites classified as Nematodes

A) are known as flukes.
B) are known as roundworms.
C) have males of the species larger than females of the species.
D) do not have a digestive system.
E) are all monoecious.

Question 34

What do Echinococcus granulosus,Entamoeba histolytica,and Enterobius vermicularis have in common?

A) they are transmitted by insect vectors.
B) they live in the intestines of their definitive host.
C) they are intracellular parasites.
D) they cause zoonoses in humans.
E) they are diagnosed by examination of a blood smear.

Question 35

The easiest way to prevent Taenia infection in humans is to

A) vaccinate cows and pigs.
B) vaccinate humans who are in contact with cows and pigs.
C) spray pastures and grazing lands with toxins that kill the parasite.
D) thoroughly cook or freeze meat.
E) identify patients with cysticerci in their muscles.

Question 36

The primary risk to humans infected with Echinococcus granulosus is

A) development of cysticerci.
B) formation of hydatid cysts.
C) intestinal obstruction.
D) anemia.
E) infection of the fetus.

Question 37

Humans become infected with Toxoplasma gondii primarily by

A) being bitten by a tick.
B) direct skin penetration.
C) ingesting food or water contaminated with cysts.
D) ingesting meat containing the parasite.
E) intimate contact with another person.

Question 38

Which of the following helminth parasites do humans acquire by eating undercooked saltwater fish?

A) Schistosoma
B) Fasciola
C) Echinococcus
D) Anisakis
E) Ascaris

Question 39

Which of the following is transmitted by the fecal-oral route?

A) Entamoeba histolytica
B) Plasmodium
C) Schistosoma
D) Trichomonas
E) Schistosoma and Trichomonas

Question 40

Humans become infected with Fasciola by

A) ingesting cysts on vegetation.
B) consuming cysticerci in contaminated meat.
C) ingesting water contaminated with eggs.
D) the penetration of cercariae through the skin.
E) the bite of infected mosquitoes.

Question 41

Balantidium coli is the only ciliate known to cause disease in humans.

Question 42

Acanthamoeba and (Entamoeba/Naegleria/Plasmodium)cause rare and usually fatal infections of the brain.

Question 43

All tapeworms are intestinal parasites that completely lack digestive systems.

Question 44

Which of the following contributes to infection with Trichomonas vaginalis?

A) contact with contaminated fomites
B) compromised immunity
C) careless handwashing habits
D) preexisting disease (chlamydia, for example)
E) living in an undeveloped area of the world

Question 45

Several species of Plasmodium cause malaria in humans.

Question 46

Which of the following regarding all of the tapeworms that infect humans is TRUE?

A) They all have non-human intermediate hosts.
B) The larva can directly infect humans upon contact with skin.
C) Humans are the normal intermediate hosts.
D) They are transmitted by insect vectors.
E) They reside in the muscle tissue of the definitive host.

Question 47

The only helminth disease of humans spread by an insect vector is

A) ascariasis.
B) fascioliasis.
C) filariasis.
D) hydatid disease.
E) schistosomiasis.

Question 48

Contact with infected cats and their feces is the only mode of transmission of Toxoplasma to humans.

Question 49

All flukes are monoecious.

Question 50

Humans are the only reservoir for (Balantidium/Entamoeba/Giardia),an intestinal parasite that causes diarrhea.

Question 51

Humans can be accidental intermediate hosts for some tapeworms.

Question 52

Anemia is a common consequence of hookworm infestation.

Question 53

Entamoeba histolytica can cause keratitis if it is introduced through an abrasion in the conjunctiva.

Question 54

An intestinal parasite that is an emerging disease in North America,(Cryptosporidium/Cyclospora/Entamoeba)causes a watery diarrhea with fever.

Question 55

Leishmania species cause systemic disease as well as superficial diseases.

Question 56

The (definitive/intermediate/primary)host is where immature stages of parasites develop.

Question 57

The vectors of ________ are sand flies.

A) beaver fever
B) Chagas' disease
C) filariasis
D) giardiasis
E) leishmaniasis

Question 58

The tsetse fly is responsible for the spread of

A) African sleeping sickness.
B) Chagas' disease.
C) filariasis.
D) kala-azar.
E) toxoplasmosis.

Question 59

The (brain/heart/liver)is the organ most severely damaged by Trypanosoma cruzi.

Question 60

Plasmodium reproduces by binary fission.

Question 61

A housefly can transmit diseases as a (biological/fomite/mechanical)vector.

Question 62

The (proglottid/scolex/strobila)of an adult tapeworm is its anchor to the hosts intestine.

Question 63

Why is self-reinfection commonly seen in children that suffer from pinworms?

Question 64

The most severe form of malaria,called "blackwater fever" is caused by Plasmodium (falciparum/malariae/ovale/vivax).

Question 65

Apicomplexans reproduce asexually by (mitosis/schizogony/fission).

Question 66

The parasite (Leishmania/Toxoplasma/Trichomonas)is an obligate parasite that is incapable of surviving long outside the human host and is transmitted almost exclusively via sexual activity.

Question 67

The most common nematode infection worldwide is (ascariasis/filariasis/pinworms).

Question 68

Damage to the (brain/heart/liver)is the primary result of fetal infection with Toxoplasma gondii.

Question 69

A hunter was camping with his dog near a mountain spring where beavers were building a dam,and many animals came to drink.After a month,he developed severe watery diarrhea,abdominal pain,bloating,vomiting,and low-grade fever.His stool had a "rotten-egg" smell of hydrogen sulfide.What is the most likely parasite causing this patient's condition,and how is diagnosis confirmed?

Question 70

Parasitic diseases have been considered uncommon in developed countries but many are now emerging diseases in these parts of the world.Discuss factors that contribute to this shift.

Question 71

Compare and contrast infection with Taenia saginata and Echinococcus granulosus in humans,including the consequences of the infections.

Question 72

Enterobius vermicularis are commonly known as (pinworms/hookworms/tapeworms)because of the shape of the female's tail.

Question 73

How does the life cycle for the Trypanosoma that causes sleeping sickness differ from the one that causes Chagas' disease?

Question 74

Eating undercooked (fish/pork/snails/vegetables)can result in infestation with Taenia solium.

Question 75

The (cestodes/nematodes/trematodes)are helminths with an incomplete digestive system.