Ch. 32 Microbio

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

malaria

Which of the following human mutations correlates with resistance to plasmodial infections in West Africa?

hemoglobin S and particular class I and class II genes

Which items are MOST routinely irradiated in the United States?

herbs and spices

The degree of susceptibility a food has to microbial activity is determined by its

chemical characteristics, physical characteristics, and water content.

Giardia cysts are able to withstand

chemical disinfection

Cryptosporidium parvum oocysts are highly resistant to

chlorine

An individual infected with malaria will likely be treated with ________ to kill the Plasmodium vivax infection.

chloroquine and primaquine

Staphylococcus aureus is a common foodborne disease, because it

grows on many foods, is present in some humans that work in food processing, and produces several heat-stable enterotoxins.

Which of the following statements best describes why the treatment for Tori's fungal infection may result in side effects to her own cells?

Fungal cells and human cells have a nucleus, multiple organelles, and 80S ribosomes for protein synthesis.

Why do we see an increase in the levels of IgE antibody in Michael's (tapework patient) serum?

IgE is the class of antibodies involved in hypersensitivities such as allergies and parasitic infections.

hemoflagellate : insect vector

Trypanosoma cruzi: kissing bug

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

can be spread by contact with contaminated toilet seats, sauna benches, and towels.

Visceral leishmaniasis is __________.

caused by Leishmania donovani

Approximately how many species of fungi are known to cause disease in humans?

50

Plasmodium life cycle is very complex, involving two hosts

1. Mosquito bite occurs. 2. Plasmodium grows and develops sporozoites. 3. Plasmodium enters the liver. 4. Red blood cells are infected. 5. Red blood cells are destroyed. 6. Mosquito bite occurs.

T. solium/ pork tapeworm life cycle

1. eggs are produced by adult tapeworms living in the definitive host 2. eggs are released to the environment in the feces 3. pigs eat grass contaminated, or fertilized, with human feces 4. inside the intermediate host, the eggs mature into larvae and encyst in the host muscles 5. the definitive host ingests the larvae and becomes infected

The visceral parasites that are of great concern to people with compromised immune systems include __________.

Cryptosporidium

Amphotericin B is an antifungal medication. What might its mechanism of action be?

It binds to ergosterol.

Why is the tapeworm flat?

Tapeworms utilize diffusion to absorb nutrients from the host's digestive system.

T. solium treatment

Praziquantel or albendazole, drugs that target eukaryotic parasites with minimal side effects in the host.

To prevent the spread of pathogens that cause listeriosis, raw food and food-handling equipment can be decontaminated with

Radiation

How are trypanosome diseases similar to malaria?

They are transmitted by insect vectors.

Humans are incidental hosts for ________, thus infected humans CANNOT spread the disease.

Toxoplasma gondii

Which disease(s) can be contracted even from chlorinated drinking water?

cryptosporidiosis and giardiasis

Cryptosporidium parvum causes gastrointestinal

cryptosporidiosis.

In the developed countries of the world, MOST intestinal infections are transmitted via

food

Which is NOT a disease caused by a parasitic helminth?

leishmaniasis --- NOT onchocerciasis schistosomiasis trichinosis

Compared to malaria, schistosomiasis infections are ________ numerous and ________ deadly.

less / less

Psychrotolerant microorganisms can survive and grow at

refrigeration temperatures

What does the 48 hour chill-fever pattern in humans coincide with in the plasmodial life cycle?

release of merozoites from erythrocytes

Flatworm trematodes that cause ________ (or "snail fever") rely on transmitting eggs from infected individuals in BOTH feces and urine.

schistosomiasis

ALL fungal infections can broadly be termed

mycoses

Athlete's foot is an example of a ________ mycosis, because ONLY the surface layers of skin are infected. Candidiasis is a much more dangerous ________ mycosis, which can involve growth of the pathogen in internal body organs.

superficial / systemic

Athlete's foot is an example of a

superficial fungal infection

Which fungal genus is correctly matched to the class of disease it causes?

systemic mycosis: Candida

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

trichinosis

Giardia intestinalis produces highly resistant ________ that aid in its fecal-water transmission and attach to the lumen of the intestinal wall.

trophozoites

The MOST important potential common source of infectious disease is

water

Pickling is a type of food preservation utilizing

weak acids

C. albicans infections

yeast infection oral thrush fulminating disease

Where do Plasmodium merozoites reproduce?

human RBCs

Which fungus normally does NOT cause a systemic mycosis?

Aspergillus flavus Blastomyces dermatitidis Candida albicans Trichophyton spp --- NOT

T. solium is the tapeworm associated with eating undercooked pork.

Eggs and proglottids from the adult tapeworm are released in the intestines and can be observed in fecal samples

The genera ________ and ________ are amoebic human parasites that cause gastrointestinal and brain infections, respectively.

Entamoeba / Naegleria

True or False: In general, molds can be highly pathogenic, whereas yeasts RARELY cause disease in humans.

FALSE

True or False: Vaccinations exist for malaria and have effectively wiped it from the United States but have been ineffective in other areas with endemic problems, such as Africa.

FALSE

Entamoeba histolytica, transmitted by contaminated food, grows on and in the cells lining the intestine and later within the intestinal wall. This results in dysentery. What best describes the relationship between E. histolytica and its host?

It is a parasitic relationship.

You are examining a sample to determine whether there is a pathogen present that might explain symptoms in a patient. You find a unicellular organism that lacks mitochondria, having mitosomes instead. It has a flagellum and a nucleus. What is it?

It must be a eukaryotic protist because it has a nucleus.

Chagas' disease mainly occurs in ________ countries and is transmitted by the "kissing bug." Although the acute illness is self-limiting, chronic disease usually results in ________.

Latin American / heart disease

The human parasitic infection caused by a protozoan that enters through the nose is caused by __________.

Naegleria fowleri

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

amoeba / entering through the nose and burrowing into the brain

During malarial infection, splenomegaly can occur. What causes this?

The spleen filters the blood and destroys old erythrocytes.

Which parasite is commonly transmitted to humans through uncooked beef, lamb, or pork and through infection from cats, which serve as obligate hosts?

Toxoplasma gondii

The sexually transmitted infection trichomoniasis is identified by the presence of the motile ________ protists in a wet mount of fluid discharged from the patient.

Trichomonas vaginalis

Why was Dr. Clark worried about tapeworm infection in other body sites?

When tapeworm larvae escape the stomach, they can travel to other parts of the body such as muscles, the liver, the eye, and even the brain to form cysticerci. The presence of T. solium in the brain can result in neurocysticercosis, a serious condition which has symptoms resembling those of brain tumors or epilepsy.

How do pseudohyphae in yeasts differ from vegetative hyphae in filamentous fungi?

Yeasts use pseudohyphae to invade host tissue, whereas filamentous fungi use their vegetative hyphae for obtaining nutrients.

Bancroft's filariasis (also called "elephantiasis") is caused by Wuchereria bancrofti. The worm is normally transmitted to humans by

a mosquito bite.

Yeast infection treatment

a single oral dose of fluconazole a topical over-the-counter ointment, such as clotrimazole or miconazole

In the United States, individuals become infected with Vibrio cholerae most commonly by

consuming contaminated shellfish

Which of the following is NOT a major mechanism of pathogenesis invoked by fungi?

consuming host eukaryotic ribosomes

In which way are you MOST likely to become infected by the parasite Cyclospora cayetanensis?

contaminated fruits or vegetables

Legionella pneumophila is generally transmitted by

contaminated water in coolers, pools, and domestic water systems.

Which of the following is an example of a secondary systemic mycosis?

cryptococcosis that develops in the lungs of a patient with HIV/AIDS

Fungi that can grow in a yeast or a mold form depending on the conditions are termed __________.

dimorphic

From all of the individuals below exposed to Cryptococcus neoformans, who is MOST likely to develop a systemic mycosis?

elderly person

The vector that transmits Plasmodium spp. from person to person is the ________ mosquito.

female Anopheles

Trypanosoma and Leshmania species are transmitted by

insect vectors

Leishmania parasites live within leukocytes. Which type of cell is most likely to harbor them?

macrophages

Enteric bacteria such as Salmonella spp., Shigella spp., and Escherichia spp. most often contaminate and spoil

meat

A major cause of helminthic infectious blindness is __________.

onchocerciasis

Clostridium botulinum is a gram- ________ rod that produces an ________.

positive endospore-forming / exotoxin

Vibrio cholerae primarily infects the

small intestine

The fungal spores of Sporothrix schenckii from soil enter through a skin abrasion or cut and can cause a subcutaneous mycosis called

sporotrichosis.

How do blastoconidia and chlamydoconidia produced by yeast differ from bacterial endospores?

Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.

Which disease and parasitic organism(s) are INCORRECTLY matched below?

amebiasis - Entamoeba histolytica Chagas' disease - Trypanosoma cruzi malaria - Plasmodium spp. toxoplasmosis - Schistosoma mansoni --- WRONG

Malaria is caused by a protist that is transmitted by mosquitoes. During its life cycle, the protist goes through cycles of destroying erythrocytes. Which of the following medical consequences is most directly related to this cell damage?

anemia