Deck 33: Eukaryotic Pathogens: Fungi, Protozoans, and Helminths

Question 1

An untreated Entamoeba histolytica infection can invade the

A) liver.
B) lungs.
C) brain.
D) liver, lungs, and brain.

Answer 1

D

Question 2

A common method used in the diagnosis of giardiasis is detection of Giardia

A) cysts in stool.
B) antigens in blood.
C) antigens in stool.
D) cysts or antigens in stool.

Answer 2

D

Question 3

The organism causing giardiasis is a

A) gram-negative spirochete.
B) flagellated protozoan.
C) retrovirus.
D) type of yeast.

Answer 3

B

Question 4

What is the infective form of Entamoeba histolytica and Giardia intestinalis?

A) cysts
B) trophozoites
C) merozoites
D) sporozoites

Question 5

The most serious types of fungal infections are

A) subcutaneous infections.
B) mycotoxic infections.
C) systemic mycoses.
D) superficial mycoses.

Question 6

Athleteʹs foot is an example of a

A) protozoal infection.
B) superficial fungal infection.
C) superficial parasitic infection.
D) hypersensitivity reaction.

Question 7

Trichomoniasis vaginalis is a sexually transmitted disease that can also survive on moist surfaces and in urine for several hours. As a result, trichomoniasis

A) is difficult to treat.
B) is not a good candidate for eradication.
C) can be spread by contact with contaminated toilet seats, sauna benches, and towels.
D) is more common in males.

Question 8

Many fungi produce ________ that can cause significant disease.

A) cellulases
B) mycotoxins
C) endotoxins
D) chitinases

Question 9

Which of the following is the most common cause of fungal infections in HIV/AIDS patients?

A) Candida albicans
B) Giardia intestinalis
C) Leishmania tropica
D) Schistosoma mansoni

Question 10

The microorganism Cryptosporidium parvum is a

A) fungus.
B) bacterium.
C) protozoan.
D) virus.

Question 11

Malaria is

A) the most common cause of death due to infectious disease worldwide.
B) prevented or treated with chloroquine.
C) controlled by reducing the population of the mosquito vector.
D) the most common cause of death due to infectious disease worldwide, although it can be controlled by reducing the population of the mosquito vector and prevented or treated with chloroquine.

Question 12

Which approach is most effective for controlling malaria?

A) vaccination with DNA vaccines
B) vaccination with recombinant particle vaccines
C) taking measures to reduce tick populations, such as cutting tall grass
D) taking measures to reduce mosquito populations, such as draining swamps

Question 13

The initial infective stage of the malarial parasite is the

A) sporozoite.
B) merozoite.
C) schizont.
D) plasmodyite.

Question 14

All fungal infections can broadly be termed

A) benign.
B) systemic.
C) superficial.
D) mycoses.

Question 15

Which of the following types of vaccines are currently in development for malaria?

A) synthetic peptide vaccines
B) recombinant particle vaccines
C) DNA vaccines
D) synthetic peptide, recombinant particle and DNA vaccines

Question 16

Cryptosporidium parvum oocysts are highly resistant to

A) heat.
B) filtration.
C) desiccation.
D) chlorine.

Question 17

The treatment regimen for people with normal immunity recovering from cryptosporidiosis includes

A) multiple antibiotics.
B) antihelmenthic chemotherapy.
C) multiple antibiotics and careful monitoring of fluid levels.
D) oral rehydration only.

Question 18

Naegleria fowleri is a free-living ________ that causes infection by ________.

A) amoeba / entering through the nose and burrowing into the brain
B) fungus / entering the lungs when contaminated soil is disturbed
C) flagellated protist / crossing the intestinal mucosa into the blood
D) protist / entering the vagina in women, the prostate and seminal vesicles of men, or the urethra of both males and females

Question 19

A common mechanism for fungal diseases is

A) endotoxin production.
B) intracellular invasion.
C) hypersensitivity reactions.
D) red blood cell lysis.

Question 20

Giardia cysts are unusual because they are capable of withstanding

A) chemical disinfection.
B) filtration.
C) clarification.
D) chemical disinfection, filtration, and clarification.

Question 21

Schistosoma and Plasmodium species both require

A) direct sexual contact for transmission.
B) immunocompromised hosts.
C) transmission by insect vectors.
D) two hosts to complete their life cycle and reproduce.

Question 22

Based on the life cycle of Schistosoma species, which of the following would be most effective in controlling schistosomiasis?

A) elimination of stagnate water
B) bed nets
C) proper sewage and water treatment
D) frequent sanitization of shared toilets, showers, and saunas

Question 23

Humans are incidental hosts for ________ and infected humans do not spread the disease.

A) Toxoplasma gondii
B) Trichomoniasis vaginalis
C) Entamoeba histolytica
D) Plasmodium vivax

Question 24

Which of the following is the most common mode of transmission of infections caused by non-fungal eukaryotic parasites?

A) direct person-to-person contact
B) contaminated fomites
C) contaminated food or water
D) contaminated needles and syringes

Question 25

A malarial parasite growing within erythrocytes is more resistant to the drug chloroquine than a free parasite.

Question 26

Which of the following filariases are transmitted by insect vectors?

A) elephantiasis
B) river blindness
C) trichinosis
D) elephantiasis and river blindness

Question 27

The most effective malarial control measure is to interrupt the life cycle of the parasite by eliminating the obligate host, the Anopheles mosquito.

Question 28

Which of the following is considered an opportunistic pathogen?

A) Toxoplasma gondii
B) Trichomoniasis vaginalis
C) Candida albicans
D) Plasmodium vivax

Question 29

Which of the following filariases can be controlled by thoroughly cooking pork and wild game?

A) elephantiasis
B) river blindness
C) trichinosis
D) schistosomiasis

Question 30

Hemoflagellates that cause tropical diseases such as sleeping sickness and Chagasʹ disease are all transmitted by

A) contact with fecal contaminated soil.
B) contact with contaminated water.
C) insect vectors.
D) sexual contact.

Question 31

Systemic fungal infections are most commonly transmitted by

A) accidental inhalation of spores.
B) ingestion of contaminated food.
C) direct contact with skin lesions.
D) sexual contact.

Question 32

How are trypanosome diseases similar to malaria?

A) They are transmitted by insect vectors.
B) They cause intermittent fevers.
C) They are acute, self-limiting diseases.
D) They are all endemic to Africa.

Question 33

Giardia intestinalis and Trichomoniasis vaginalis lack ________ and have ________.

A) flagella / cilia instead
B) mitochondria / an anaerobic metabolism
C) cell walls / rigid cell membranes instead
D) cysts / sporozoites instead

Question 34

A patient arrives at the emergency room feeling extremely sick, with cycles of high fevers and chills and a severe headache. However, these symptoms are nonspecific and malaria may not be suspected if the patient is in a region where malaria is uncommon. If the medical professionals did not immediately consider malaria, which of the following test results would most strongly suggest the need for malaria testing (such as microscopic analysis of a blood smear)?

A) the patient has a high platelet count
B) the patient develops vomiting as well
C) a complete blood count (CBC) shows progressively worsening severe anemia
D) an x-ray suggests an enlarged liver and unusually small spleen

Question 35

Trypanosoma and Leshmania species are transmitted by

A) direct person-to-person contact.
B) insect vectors.
C) contaminated food or water.
D) contaminated needles and syringes.

Question 36

Most fungi are harmless to humans, although certain superficial infections are quite common.

Question 37

Plasmodium vivax causes a more serious form of malaria than does P. falciparum.

Question 38

As a malarial infection by Plasmodium falciparum progresses, gametocytes are formed. The gametocytes unite in the bloodstream before being picked up by the insect vector.

Question 39

Roughly half of all adults in the United States are infected with ________ but are asymptomatic.

A) Toxoplasma gondii
B) Trichomoniasis vaginalis
C) Cryptosporidium parvum
D) Cyclospora cayetanensis

Question 40

Chagas disease is caused by which pathogen?

A) Plasmodium vivax
B) Toxoplasma gondii
C) Trypanosoma cruzi
D) Cryptosporidium parvum

Question 41

Fifteen high school students visited a local farm in central Wisconsin for a weekend where they enjoyed petting farm animals, riding horses, and campfire meals. With sanitation in mind, only one individual remembered to wash her hands with water pumped from a well after petting the animals before dinner. After two weeks of the girl passing out at random occasions, she was rushed into the emergency room where doctors determined she was severely dehydrated. Explain how it took direct observation of a fecal sample to solve this potential life-threatening disease and how this disease was treated in the otherwise healthy girl. Also mention any necessary precautions the individual should have taken after being diagnosed with the disease.

Question 42

How does insect ecology and the life cycle of Plasmodium impact the epidemiology and pathogenesis of classic malaria?

Question 43

Patients with malaria often have splenomegaly.

Question 44

Giardia cysts are found in most surface water sources in the United States.

Question 45

Balantidium coli is usually transmitted by a vector.

Question 46

Toxoplasma gondii usually causes only mild illness, but can cause severe symptoms such as brain damage in some cases (especially when the host is immunocompromised).

Question 47

The most common major systemic mycosis in the United States is coccidiomycosis.

Question 48

The most common form of leishmaniasis is visceral leishmaniasis.

Question 49

Elderly individuals are more likely to develop systemic mycoses because cell-mediated immunity generally decreases with age.

Question 50

Systemic fungal infections are difficult to treat because active antifungal drugs may have significant host toxicity.

Question 51

Anopheles mosquitoes ingest malarial gametocytes, which do not mature into gametes until transferred to the blood of a mammalian host.

Question 52

With respect to their life cycles, how are fungal pathogens different than bacterial pathogens?

Question 53

Why do so many eukaryotic pathogens cause highly refractory and long-term chronic infections that are difficult to treat in contrast with prokaryotic pathogens?

Question 54

Meningoencephalitis caused by Naegleria fowlerii is always fatal.

Question 55

Parasitic helminths only disease in tropical regions; they do not cause disease in subtropical or temperate regions.

Question 56

Eukaryotic human parasites are all respiratory aerobes.

Question 57

Giardia is especially difficult to kill because they have cell membranes that are resistant to common disinfecting chemicals.

Question 58

Trichomoniasis can be transmitted through contact with fomites, such as towels, because the causative agent can survive for a relatively long time outside of the human body.

Question 59

Sporotrichosis is a subcutaneous mycosis.

Question 60

You and your friends are hiking the Appalachian trail in North Carolina. You run out of water and your friends want to fill up from a beautiful clear stream in the middle of the forest. What precautions should you take before drinking the water and why?

Question 61

Why are systemic fungal infections seen only in a subset of the population, even though most people contact fungi and fungal spores in soil and dust all of the time? Contrast the epidemiology of systemic fungal infections with giardiasis, which infects virtually everyone that comes in contact with the pathogen.

Question 62

How are trypanosome diseases similar to malaria? How are they different than malaria?

Question 63

Use the events in the life cycle of Schistosoma mansoni to propose two different strategies to reduce the incidence of snail fever.