Practice Final Part 2

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

Trichomonas infection

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

Trichomonas vaginalis

What is the name of the antifungal drug that Nate is taking?

ketoconzale

In the dormant cyst form, Giardia is protected from the environment by a shell composed of __________.

chitin

Candida albicans can establish opportunistic infections of the

eyes, liver, mouth, skin, and other organs

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

falciparum

A large number of antifungal agents are available for treating fungal infections.

false

Dermatophytes, which live on the surface of the skin, are always pathogenic.

false

Fungi that cause systemic mycoses are uniformly acquired by ingesting contaminated food.

false

Amoebae are a group of protozoa that move and feed using __________.

lobe-shaped pseudopods

A person who shares a hairbrush with other family members is most likely to be at risk for which of the following mycoses?

favus

Trypanosoma cruzi is introduced into the body by

feces containing trypomastigotes contaminating a bite wound.

Elephantiasis is caused by

filarial roundworms.

What is the intermediate host for this disease?

freshwater snails

Most mycoses are difficult to treat because

fungal cells provide few targets for selective toxicity.

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

mechanical

What is the treatment for cutaneous leishmaniasis?

meglumine antimonite intramuscular injections

What medication should this man receive to treat this disease?

melarsoprol

All of the true pathogen fungi discussed in this chapter are

members of the Ascomycota and are dimorphic.

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

mosquito

Peanut butter was prepared using peanut on which Aspergillus had grown. Several people who ate it suffered from (mycetismus/mycetoma/mycotoxicosis).

mycotoxicosis

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

giardiasis.

What tools would the doctor use to diagnose this disease?

identification of the budding yeast in KOH-prepared samples of skin scrapings or sputum from the patient

The number of cases of schistosomiasis has decreased over the past few decades due to which of the following?

improvement in water systems

What was the source of the infection?

inhalation of spores from the bat guano

Nematodes such as Ascaris infect the __________ by way of the __________.

intestinal tract; lungs

Histoplasma capsulatum

is an intracellular parasite.

The pathogen, Giardia intestinalis, is diplomonad meaning __________.

it has 2 nuclei

Which of the following is NOT a means of preventing leishmaniasis?

keeping dogs as pets in human homes

In cestodes, gravid proglottids are found __________.

nearest the end of the strobila

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

Which of the following contributes to infection with Trichomonas vaginalis?

preexisting disease (chlamydia, for example)

Greasy, frothy diarrhea with the smell of __________ may indicate giardiasis.

rotten eggs

What is the vector for this disease?

sand flies

Most fungi exist as (parasites/saprobes/autotrophs) and function as the major decomposers of organic material.

saprobes

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

What is the treatment for this woman's condition?

triclabendazole

All tapeworms are intestinal parasites that completely lack digestive systems.

true

Anemia is a common consequence of hookworm infestation.

true

Aspergillus​ causes both mycoses and mycotoxicosis.

true

Histoplasma and Coccidioides produce tuberculosis-like damage to the lungs that can be seen on X-ray images.

true

Leishmania species cause systemic disease as well as superficial diseases.

true

What is the vector for African sleeping sickness?

tsetse flies

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

Enterobius vermicularis

There are four species of Plasmodium that cause the disease malaria, of which P. falciparum is the most virulent. P. falciparum is transmitted by a mosquito vector to a human host. Can all mosquitoes transmit malaria? Why or why not?

Only female Anopheles mosquitoes can transmit the malarial parasite to a human host because they are the only ones who take a blood meal from the host.

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

Acanthamoeba

What is the mortality rate for untreated cases of African sleeping sickness?

100%

Giardiasis is one of the more common GI diseases in the United States. Both animals and humans are at risk for developing this disease. In which of these cases would a human be most likely to become infected by this pathogen?

A family hiking in the woods allows its dog to drink from a nearby stream. When they return home, the dog becomes sick with diarrhea in the house and family members must clean up the mess.

90-95% of the population of the Ohio River Valley has been exposed to Histoplasma capsulatum, but relatively few individuals are diagnosed with histoplasmosis. Why is this so?

A healthy immune system clears the infection before signs and symptoms can appear in these individuals.

Patty returns later and says she found amoeba trophozoites and cysts. Since amoebae are not uncommon in fresh water and they are not generally pathogenic, she has done a serological test using antibodies and, unfortunately, has discovered that the organism is Entamoeba histolytica. Which of the following should be employed to avoid further problems with the Entamoeba histolytica?

Advise people that have been drinking the lake water, but do not have symptoms, to visit their doctor and ask about a prescription for paromomycin. Post warning that the water should be filtered before drinking. Advise doctors to prescribe iodoquinol to people who have been drinking the lake water and now have diarrhea.

The tsetse fly is responsible for the spread of

African sleeping sickness

What is the name of the disease this man is suffering from?

African sleeping sickness

Antibody tests are commonly used for rapid diagnosis of many types of infection. However, they are NOT particularly useful for diagnosis of histoplasmosis. Why is this so?

Antibody tests are not useful because in endemic areas over 95% of the population has been infected without contracting the disease

An avid gardener in eastern North America begins to have a fever and cough. A sample from her lungs contains yeast cells and pus. She may be infected with

Blastomyces dermatitidis.

Which of the following is an opportunistic pathogenic fungus in humans?

Candida albicans

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

Chagas' disease.

A patient infected with a protozoan parasite who also exhibits congestive heart failure is most likely in the final stages of which of the following diseases?

Chagas's disease

Which of the following can mimic tuberculosis by causing the formation of large cavities in the lungs when the infection becomes chronic?

Coccidioides

Although John never liked math and science in high-school, in college, a really great environmental science professor changed his mind. Before he knew it, he was taking courses in math, biology, chemistry, microbiology, and limnology (freshwater science). The limnology course really made use of all the biology, chemistry, and environmental science. He joined the environmental science club and started taking an interest in environmental issues. One day the environmental science professor (who also sponsored the club) told him about an internship with a local environmental consulting company. John applied for and was awarded the internship. He was hired by the company immediately after the internship was complete. Now, three years later, John still likes his job. He is assigned to the water quality group. The consulting company has contracts associated with two small lakes, two creeks, and one large river. He gets to hike into these areas for sample collection and checking monitoring equipment. This company is unique in that it has a small lab and runs many of the basic chemistry and biological laboratory tests onsite. John likes performing the lab tests. Periodically, he also has to investigate environmental contamination complaints and he always has to maintain careful records, not his favorite part of the job, but necessary. Today the weather outside is perfect; John is looking forward to hitting the trail to collect samples at Lake Timba. Lake Timba is nestled serenely in the woods and the water is crystal clear; there are not too many visitors--mostly just day hikers and fisherman. John is heading there today because there have been complaints about people getting diarrhea after drinking the lake water. Which of the following organisms can cause water-borne diarrheal disease?

Cryptosporidium enteritis Entamoeba histolytica Vibrio cholerae

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

Entamoeba

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

Entamoeba histolytica

A 40-year-old female of Cambodian descent was admitted to the hospital with fatigue, constipation, weight loss, abdominal pain, and abdominal swelling. Before the onset of symptoms, the woman was healthy, as were the majority of her close relatives. Laboratory testing indicated signs of liver dysfunction, prompting a CT scan. Multiple hepatic lesions and inflammation of the bile ducts were evident. Stool samples examined over several successive days revealed the presence of numerous eggs. The woman had visited Cambodia recently, but her symptoms had begun before she traveled there. What is distinctive about the ova of Fasciola hepatica?

Fasciola hepatica ova are most likely to be found in fecal sedimentation preps. The ova have an operculum.

Nate lives an exciting life. His part of Kentucky is beautiful, and he has opportunities for adventure with his friends in Boy Scout Troop 138. They have been hiking, climbing, backpacking, and mountaineering and just 10 days ago had spent all night in a cave deep below the town. After watching what seemed like millions of bats rush and swoop out of the cave, the troop had entered the cavern system through another entrance - a "squeeze entrance." Nate wasn't sure what a squeeze entrance was until he had to inch forward for over a hundred feet with his arms stretched in front of him, pulling with his fingertips as his back scraped the ceiling. That had been the worst part. But, after clearing the entrance, the teenagers had explored, scrambled, and crawled the whole night. They had even eaten underground. It was extreme, though it was a little spooky—with bizarre geological formations, pools of ice-cold water, and total darkness—but the guys were still talking about the time they stayed up all night inside the Earth. Today, though, Nate doesn't feel so excited. His nonproductive coughing hurts; he likely has a fever, though he feels cold; and he has red bumps on the skin of his legs. His dad takes him to the doctor, who prescribes a medicine that neither Nate nor his parents had heard of—keto-something. This disease is also known as Spelunker's Disease and Cave Disease. What is the most likely cause of Nate's illness?

Histoplasma capsulatum

Is this a contagious disease?.

No. Acquisition of the disease depends on the ingestion of metacercariae, not person-to-person contact.

Why are subcutaneous mycoses uncommon?

Injury is necessary to introduce the fungus into the tissue.

Which of the following statements about Candida is FALSE?

It is easily treated with topical antifungals in immunocompromised patients.

How likely is it that other scouts were infected during the caving camp out?

It is highly likely that 90% or more of the scouts will show evidence of infection (antibody formation). Only a small percentage of these will get sick.

How serious cases of giardiasis currently treated in the United States?

Metronidazole

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

Naelgeria

Which of the following fungal infections was extremely rare prior to the AIDS epidemic?

Pneumocystis pneumonia

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

Schistosoma mansoni.

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

Snails are the intermediate host.

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

Taenia

What is the best way to prevent disease caused by Aspergillus species?

The best way to prevent disease caused by Aspergillus species is to take steps to maintain a healthy immune system.

A child with a pinworm infection is successfully treated, but later suffers a relapse. Which of the following best explains the relapse?

The child's clothing and bedding were not properly laundered.

In the life cycle of Giardia intestinalis, the small intestine plays a pivotal role. What is the importance of the small intestine in the development of giardiasis?

The small intestine is where the Giardia cyst releases the trophozoite and it can adhere to the epithelial cells and begin to multiply.

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

They all have non-human intermediate hosts.

Pathogenically, how does Giardia produce symptoms in humans?

They attach to large areas of the intestines.

A 20-year-old student was admitted to his college's student health center with headaches and fever shortly after beginning the fall semester. He had spent his summer working with an international aid organization in Nigeria and had returned to the United States only a week earlier. Gross examination revealed a diffuse rash and numerous insect bites. The young man had spent most of his summer outdoors in rural areas, had taken no prophylactic antimalarial medication, and had spent some time on African game reserves working with the families of local guides. The patient could not specifically remember receiving any of the bite wounds on his body, and he did not always use insect repellent in the field. The young man was admitted to the local hospital, where intermittent fever, nausea, and headache continued. Initial blood smears proved negative for malaria Look carefully at the peripheral blood smear. What parasite is present in the blood?

Trypanosoma brucei

When does the dormant cyst excyst in the human body?

Upon entry into the intestines.

Which of the following nematodes can be transmitted by mosquitoes?

Wuchereria bancrofti

The organism appears to be

an amoeba

The parasites classified as Nematodes

are known as roundworms.

Opportunistic fungi

are normal microbiota for many individuals.

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

ascariasis

After an initial infection with Naegleria, what body system will be invaded by the parasite next?

central nervous system

A 20-year-old soldier serving in Iraq reports to his medic and complains of several large painless sores on his head and face. Some of the ulcers have healed, leaving scars. A sample taken from a lesion and examined microscopically shows the presence of flagellated protozoa. Based on the clinical history and presentation, what disease is this soldier most likely to have?

cutaneous leishmaniasis

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

cyclospora

The infectious stage of a beef tapeworm for humans is the

cysticerci in beef.

Infections with (dermatophytes/pathogens/opportunists) are commonly acquired by person-to-person direct contact.

dermatophytes

Ringworm is caused by

dermatophytes growing in the outer dead tissue layers of the skin (epidermis).

The cell membranes of fungi contain (cholesterol/ergosterol/fatty acid) which is a target of some antifungal treatments.

ergosterol

Blastomyces dermatitidis occurs in the (southeastern/central/southwestern/western) part of North America.

southeastern

Which of the following poses the greatest risk of contracting schistosomiasis?

swimming in contaminated water

Which of the following types of fungal disease is primarily the result of ingestion?

toxicosis

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

trematodes

To prevent infection with giardiasis, one should __________ when drinking from a possible contaminated water source.

use a filter

What food is most often associated with Fasciola hepatica infections?

watercress

The definitive host of a parasite is

where the mature form of the parasite occurs.