ch 23
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
a
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.
a
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
a
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.
a
The ________ stage of a protozoan is the actively feeding and reproducing stage. A) trophozoite B) cyst C) cysticercus D) encysted E) merozoite
a
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.
a
The tsetse fly is responsible for the spread of A) African sleeping sickness. B) Chagas' disease. C) filariasis. D) kala-azar. E) toxoplasmosis.
a
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.
a
Which of the following is a ciliated pathogen of the intestinal tract? A) Balantidium B) Plasmodium C) Trypanosoma D) Leishmania E) Giardia
a
Which of the following is transmitted by the fecal-oral route? A) Entamoeba histolytica B) Plasmodium C) Schistosoma D) Trichomonas E) Schistosoma and Trichomonas
a
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
a
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.
a
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
a
The most common nematode infection worldwide is (ascariasis/filariasis/pinworms).
ascariasis
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
b
The ________ spreads more parasitic diseases to humans than any other vector. A) kissing bug B) mosquito C) tick D) louse E) mite
b
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.
b
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.
b
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.
b
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.
b
Triatoma, commonly called "kissing bugs," are vectors of A) African sleeping sickness. B) Chagas' disease. C) Cyclosporiasis. D) Leishmania. E) schistosomiasis.
b
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.
b
Which of the following is an accidental parasite of humans? A) Ascaris lumbricoides B) Acanthamoeba C) Balantidium coli D) Entamoeba histolytica E) Plasmodium
b
Which of the following is the most common parasitic disease in industrialized nations? A) giardiasis B) Trichomonas infection C) schistosomiasis D) toxoplasmosis E) balantidiasis
b
Damage to the (brain/heart/liver) is the primary result of fetal infection with Toxoplasma gondii.
brain
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.
c
Balantidium coli uses ________ to penetrate the intestinal mucosa. A) adhesion discs B) flagella C) cilia D) pseudopodia E) suckers
c
Elephantiasis is caused by A) blood flukes. B) liver flukes. C) filarial roundworms. D) tapeworms. E) flatworms.
c
The only helminth disease of humans spread by an insect vector is A) ascariasis. B) fascioliasis. C) filariasis. D) hydatid disease. E) schistosomiasis.
c
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
c
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
c
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. Answer: C
c
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.
c
An intestinal parasite that is an emerging disease in North America, (Cryptosporidium/Cyclospora/Entamoeba) causes a watery diarrhea with fever.
cyclospora
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.
d
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.
d
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.
d
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.
d
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.
d
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.
d
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
d
Which of the following helminth parasites do humans acquire by eating undercooked saltwater fish? A) Schistosoma B) Fasciola C) Echinococcus D) Anisakis E) Ascaris
d
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
d
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
d
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
d
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.
e
The vectors of ________ are sand flies. A) beaver fever B) Chagas' disease C) filariasis D) giardiasis E) leishmaniasis
e
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
e
Humans are the only reservoir for (Balantidium/Entamoeba/Giardia), an intestinal parasite that causes diarrhea.
entamoeba
The most severe form of malaria, called "blackwater fever" is caused by Plasmodium (falciparum/malariae/ovale/vivax).
falciparum
3) All tapeworms are intestinal parasites that completely lack digestive systems.
false
All flukes are monoecious.
false
Contact with infected cats and their feces is the only mode of transmission of Toxoplasma to humans.
false
Entamoeba histolytica can cause keratitis if it is introduced through an abrasion in the conjunctiva.
false
Plasmodium reproduces by binary fission.
false
The (brain/heart/liver) is the organ most severely damaged by Trypanosoma cruzi.
heart
The (definitive/intermediate/primary) host is where immature stages of parasites develop.
intermediate
A housefly can transmit diseases as a (biological/fomite/mechanical) vector.
mechanical
Acanthamoeba and (Entamoeba/Naegleria/Plasmodium) cause rare and usually fatal infections of the brain.
naegleria
Enterobius vermicularis are commonly known as (pinworms/hookworms/tapeworms) because of the shape of the female's tail.
pinworms
Eating undercooked (fish/pork/snails/vegetables) can result in infestation with Taenia solium
pork
Apicomplexans reproduce asexually by (mitosis/schizogony/fission).
schizogony
The (proglottid/scolex/strobila) of an adult tapeworm is its anchor to the hosts intestine.
scolex
The (cestodes/nematodes/trematodes) are helminths with an incomplete digestive system.
trematodes
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
trichomonas
6) Several species of Plasmodium cause malaria in humans.
true
Anemia is a common consequence of hookworm infestation.
true
Balantidium coli is the only ciliate known to cause disease in humans.
true
Humans can be accidental intermediate hosts for some tapeworms.
true
Leishmania species cause systemic disease as well as superficial diseases.
true
