MCB 100- Chapter 23: Parasitic Protozoa, Helminths, and Arthropod Vectors

Which is the infective stage of an intestinal protozoan? a. A cyst b. A trophozoite c. The free-living protozoan d. The multicellular stage

a. A cyst -The cyst stage of protozoa is the resting stage that is infective.

What is the most common symptom of pinworm infestation? a. Anal itching b. Abdominal pain, nausea, and vomiting c. Sudden, violent abdominal pain d. Chronic anemia

a. Anal itching

Are tsetse flies and kissing bugs biological or mechanical vectors of Trypanosoma brucei and T. cruzi, respectively? a. They are both biological vectors. b. A tsetse fly is a biological vector, while a kissing bug is a mechanical vector. c. Both are mechanical vectors. d. A kissing bug is a biological vector, while a tsetse fly is a mechanical vector.

a. They are both biological vectors. - The insects are hosts to the parasites, so they are biological vectors.

What are the major characteristics of protozoa? a. They are single-celled, often motile eukaryotes. b. They are single-celled, usually nonmotile prokaryotes. c. They are multicellular, motile prokaryotes. d. They are multicellular, nonmotile eukaryotes.

a. They are single-celled, often motile eukaryotes.

Of Balantidium, Entamoeba, Acanthamoeba, and Naegleria species, which more commonly causes a deadly diarrhea? a. Balantidium b. Entamoeba c. Naegleria d. Acanthamoeba

b. Entamoeba

What is the best way to prevent amebiasis? a. Chemical treatment of drinking water b. Good personal hygiene c. Not using human waste as fertilizer d. Immunization

b. Good personal hygiene - Because humans are the only reservoir and the infectious cysts are hardy, good personal hygiene is the best way to prevent transmission of Entamoeba histolytica.

What type of disease does Trypanosoma cruzi cause? a. Respiratory disease b. Heart disease c. Meningoencephalitis d. Gastrointestinal disease

b. Heart disease

Which are the most important vectors of parasitic diseases in humans? a. Fleas b. Mosquitoes c. Ticks d. Bugs

b. Mosquitoes

Which drug is used in the United States to treat liver fluke infestations (Fasciola spp.)? a. Praziquantel b. Oral bithionol c. Triclabendazole d. Albendazole

b. Oral bithionol

Trichomonas vaginalis causes vaginosis. What is a difference between vaginosis and vaginitis? a. Vaginitis causes painful intercourse, vaginosis does not. b. Vaginitis involves inflammation, vaginosis does not. c. Vaginitis causes a fever, vaginosis does not. d. Vaginitis causes discharge, vaginosis does not.

b. Vaginitis involves inflammation, vaginosis does not.

How does a cestode attach to host tissues? a. With a proglottid b. With its scolex c. With its cuticle d. With a strobila

b. With its scolex -The scolex is the attachment organ with which the worms attach to host cells

Which group of protozoa is nonmotile? a. The amoebas b. The flagellates c. Apicomplexans d. The ciliates

c. Apicomplexans

What is the difference between cilia and flagella in eukaryotic cells? a. Cilia are filled with cytoplasm, while flagella are made up of protein. b. Cilia move in a whiplike fashion, while flagella rotate. c. Cilia are short, while flagella are long. d. Cilia are extensions of the cell, while flagella are external and anchored to the cytoplasmic membrane.

c. Cilia are short, while flagella are long. -Eukaryotic flagella and cilia are both inside the cells, surrounded by the cytoplasmic membrane and filled with cytoplasm, and they move in a whiplike fashion.

What is dysentery? a. Watery diarrhea with rice-like flecks b. Constipation with rice-like flecks c. Diarrhea with blood and mucus d. Constipation with blood and mucus

c. Diarrhea with blood and mucus

Which is the most common parasitic worm in the United States? a. Necator americanus b. Ancylostoma duodenale c. Enterobius vermicularis d. Ascaris lumbricoides

c. Enterobius vermicularis

How does tetracycline work to treat Balantidium coli infections? a. It prevents the diarrhea that B. coli causes, so the body's immune system can clear the infection. b. It inhibits protein synthesis in B. coli. c. It makes the intestines unsuitable for B. coli. d. It inhibits protein synthesis of intestinal epithelial cells so that B. coli cannot grow.

c. It makes the intestines unsuitable for B. coli.

Malaria is a parasitic disease transmitted to humans by mosquito bites. The sexual stage of the parasite occurs in the mosquito. What type of host and what type of vector are mosquitoes? a. Mosquitoes are intermediate hosts and mechanical vectors. b. Mosquitoes are definitive hosts and mechanical vectors. c. Mosquitoes are definitive hosts and biological vectors. d. Mosquitoes are intermediate hosts and biological vectors.

c. Mosquitoes are definitive hosts and biological vectors. -Mosquitoes are definitive hosts because the parasite completes the sexual stage of its life cycle in the mosquito, and they are biological vectors because they are a host for the parasite.

What is the role that snails play in the transmission of flukes? a. They are biological vectors. b. They are mechanical vectors. c. They are intermediate hosts. d. They are definitive hosts.

c. They are intermediate hosts.

What is the most common mode of transmission of Toxoplasma gondii? a. From a pregnant mother through the placenta to her fetus b. Contact with cat feces c. Through eating contaminated, undercooked meat d. Inhalation of contaminated soil

c. Through eating contaminated, undercooked meat

What is cysticercosis? a. When humans release pork tapeworm eggs in their feces b. When a beef tapeworm blocks the intestines of an infected person c. When larvae from a pork tapeworm encyst in a person's muscles d. When humans become intermediate hosts for a beef tapeworm

c. When larvae from a pork tapeworm encyst in a person's muscles

For which protozoan are humans the definitive host: Cyclospora cayetanensis, Toxoplasma gondii, Plasmodium falciparum, or Trypanosoma brucei? a. T. gondii b. P. falciparum c. T. brucei d. C. cayetanensis

d. C. cayetanensis

What term describes diseases that develop gradually and cause signs and symptoms for years after the initial infection, either recurring or continuous? a. Subacute b. Latent c. Acute d. Chronic

d. Chronic -Some parasitic diseases covered in this chapter can cause chronic infestations, with disease symptoms extending over a period of time.

Which stage of Plasmodium is formed within vesicles inside the liver and is released into the bloodstream? a. Sporozoites b. Schizonts c. Trophozoites d. Merozoites

d. Merozoites -Merozoites are formed in vesicles inside the liver and released directly into the bloodstream, where they invade red blood cells.

What is the most common way to diagnose ascariasis? a. Identification of adult worms that passed with the stool b. Biopsy of intestinal tissue to look for the worm c. X rays of the lower abdomen d. Microscopic identification of the eggs in the stool

d. Microscopic identification of the eggs in the stool

What signs and symptoms does toxoplasmosis cause in AIDS patients? a. Headache, muscle ache, sore throat, and enlarged lymph nodes b. Nausea, vomiting, and persistent diarrhea c. Epilepsy, intellectual disability, blindness, anemia, and jaundice d. Paralysis, myocarditis, encephalitis, and death

d. Paralysis, myocarditis, encephalitis, and death -In people with a weakened immune system, toxoplasmosis can cause paralysis, myocarditis, and death

Which species of Schistosoma can cause bladder cancer, and where is it endemic? a. S. mansoni, which is endemic in the Caribbean and South America b. S. japonicum, which is endemic in the Caribbean and South America c. S. japonicum, which is endemic in Asia d. S. haematobium, which is endemic in Africa and India

d. S. haematobium, which is endemic in Africa and India -S. haematobium is found only in Africa and India and can cause bladder cancer if the eggs calcify in the bladder

How is filariasis transmitted? a. By walking barefoot through infested soil b. Through walking or swimming in contaminated water c. By eating contaminated meat d. Through mosquito bites

d. Through mosquito bites

Which form of leishmaniasis is most likely to be fatal? a. Cutaneous leishmaniasis b. Mucocutaneous leishmaniasis c. Subcutaneous leishmaniasis d. Visceral leishmaniasis

d. Visceral leishmaniasis -In visceral leishmaniasis, the parasite affects internal organs of the body and can be fatal.