Quiz 10

Hantaviruses are most commonly transmitted by ________ of virus-contaminated rodent ________. inhalation / saliva inhalation / excreta ingestion / excreta ingestion / saliva

inhalation / excreta

The most severe and fatal form of anthrax is cutaneous anthrax. zoonotic anthrax. intestinal anthrax. inhalation anthrax

inhalation anthrax

The rate of contaminant microbial growth during the exponential phase in food depends on the nutrient value of the food. temperature. water content. temperature, nutrient value, and water content

temperature, nutrient value, and water content

Many West Nile virus infections are not properly identified because the disease is frequently fatal. the disease mimics malaria. the symptoms are often subacute. most physicians and diagnosticians are not aware of this disease.

the symptoms are often subacute.

Controlling most rickettsial diseases involves managing human behavior. food safety procedures. the vector. immunization strategies.

the vector.

Soldiers or refuges in crowded unsanitary conditions are MOST susceptible to which rickettsial disease? Q fever typhus Lyme disease Rocky Mountain spotted fever

typhus

The MOST important potential common source of infectious disease is arthropod reservoirs found near surface water supplies. industrial waste. water. human and animal wastes

water.

Vibrio cholerae primarily infects the stomach. small intestine. rectum. large intestine.

small intestine.

The Staphylococcus aureus toxins are neurotoxins. endotoxins. ectotoxins. superantigen toxins.

superantigen toxins.

Hantavirus pulmonary syndrome is a viral respiratory disease caused by contact with mosquitoes. rat fleas. rodents. bats.

rodents.

At what temperature are most household freezers kept? -20°C 4°C -80°C 0°C

-20°C

Which of the following explains why treatment of symptomatic tetanus requires an antitoxin and an antibiotic? Because the toxin is within the cell wall of the bacteria, it can only be eliminated by killing the bacteria. It is always better to use multiple treatments to elicit a stronger response. Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more. The tetanus toxin binds irreversibly, causing damage to axons. The only way to heal the axons is with an antitoxin.

Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more.

Although cholera can be treated with antibiotics, data suggest that antibiotic treatment alone is NOT the most effective therapy. Which of the following statements describes the most likely reason for supplementing antibiotic therapy? The production of cholera toxin helps V. cholerae resist antibiotic treatment. Because V. cholerae is a gram-negative organism, it is not very effectively treated with antibiotics. As with V. cholerae, the acidic environment of the stomach can have a negative impact on antibiotic activity. Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae

Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae

The causative agent of Lyme disease is ________, which is carried primarily by the ________. Rickettsia prowazekii / Culex species (mosquito) Borrelia burgdorferi / Ixodes sp. (deer tick) a flavivirus / Ixodes sp. (deer tick) Yersinia pestis / Xenopsylla cheopis (rat flea)

Borrelia burgdorferi / Ixodes sp. (deer tick)

Clostridium tetani is an obligate anaerobe that can cause tetanus. When it enters the human body, it can produce tetanus toxin. Considering that C. tetani is an obligate anaerobe, which of the following explains how it can survive and cause disease in the human body? C. tetani can't access atmospheric oxygen, so it can grow as long as it stays on the surface of the skin rather than in well-oxygenated deeper tissues. C. tetani can only survive when other bacteria are available to consume oxygen and to keep oxygen levels low. Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow. It doesn't survive; it simply releases toxin as it dies.

Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

Food that is heavily salted or candied does not need to be refrigerated. Why not? Extremely concentrated solutions are very hypertonic and therefore desiccate microorganisms. As a result, there is no need for lower temperatures through refrigeration to slow growth. Extremely concentrated solutions are very hypotonic and cause microbes to desiccate. As a result, there is no need for lower temperatures through refrigeration to slow growth. Having a high concentration of salt or sugar lowers the food's pH, making it too acidic for common pathogens to grow. As a result, there is no need for refrigeration to slow growth. The sugar used is of a type that cannot be used by microbes, leaving a lack of suitable nutrition for them. As a result, there is no need for refrigeration to slow growth.

Extremely concentrated solutions are very hypertonic and therefore desiccate microorganisms. As a result, there is no need for lower temperatures through refrigeration

T/F: Erythema migrans is associated with typhus.

False

Tests to monitor water safety often report the number of fecal coliform bacteria found in samples. Which of the following statements accurately reflects water safety recommendations based upon fecal coliform levels? If the level of fecal coliform bacteria is high, then the water is safe for drinking and recreational purposes. If the level of fecal coliform bacteria is high, then the water is safe for drinking and recreational purposes. If the level of fecal coliform bacteria is low, then the water may still be unsafe because of the presence of other pathogens. If the level of fecal coliform bacteria is low, then the water was probably contaminated by sewage.

If the level of fecal coliform bacteria is low, then the water may still be unsafe because of the presence of other pathogens.

Which of the following bacterial pathogens is found in aquatic environments and is commonly present in air conditioning systems? Legionella pneumophila Klebsiella pneumoniae Vibrio cholerae Enterobacter aerogenes

Legionella pneumophila

Which of the following pathogens is spread by infected lice? Plasmodium falciparum Borrelia burgdorferi Yersinia pestis Rickettsia prowazekii

Rickettsia prowazekii

Salmonellosis is most frequently caused by Salmonella enterica serovar Typhimurium. Salmonella enterica serovar Enteritidis. Salmonella enterica serovars Typhimurium and Enteritidis. Salmonella enterica serovar Typhi.

Salmonella enterica serovars Typhimurium and Enteritidis.

Disease research and epidemiology bring together many different facets to help us better understand disease pathology and spread. Which of the following statements are true? Select all that apply. The ID50 value refers to the number of microbes needed to cause half of an infected population to die. The interactions that occur between a microbe and host influence the evolution of both. Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host. Intoxications result from a bacterial infection in which a large amount of bacterial toxin is produced. The terms pathogenicity and virulence can be used interchangeably to describe the severity of an infection. Some pathogens are able to cause disease within a host without penetrating the body

The interactions that occur between a microbe and host influence the evolution of both. Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host. Some pathogens are able to cause disease within a host without penetrating the body

Some studies have indicated that the ID50 for Vibrio cholerae can be as high as 108 organisms. Which of the following most likely explains the requirement for this relatively high ID50? Because V. cholerae cells are relatively small compared to host cells, thousands of bacteria must infect each cell to cause disease. To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach. V. cholerae does not produce enough virulence factors to overcome the host response and cause disease. Because the major virulence factor of V. cholerae is cholera toxin, large numbers of bacteria are required to produce enough toxin to cause disease

To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach.

T/F: Cholera can be transmitted by water or food.

True

T/F: Not all coliforms are pathogenic.

True

T/F: Various Ixodes spp., as well as various Borrelia spp., may be involved in the transmission and cause of Lyme disease.

True

Which of the following are properties of exotoxins? Select all that apply. Exotoxins are extremely heat stable. Very small amounts of exotoxin can be lethal. Exotoxins are released from the cell during death or replication. Exotoxins target specific cellular structures or molecules. Exotoxins are protein molecules. Exotoxins are produced primarily by gram-negative bacteria.

Very small amounts of exotoxin can be lethal. Exotoxins target specific cellular structures or molecules. Exotoxins are protein molecules.

In bubonic plague, buboes are swellings formed in the lymph nodes and filled with Yersinia pestis. Rickettsia prowazekii. Xenopsylla cheopis. Clostridium tetani.

Yersinia pestis.

Vibrio cholerae is a human pathogen that causes cholera. It has an unusual shape distinctive of its genus. Considering that it does not have one of the most common bacterial shapes, what is the shape of this species? a straight rod a spherical shape a curved rod a rigid spiral shape

a curved rod

Lyme disease and syphilis are similar in that they __________. are both caused by spirochetes and are chronic infections that involve the nervous systems are both chronic infections that involve the nervous system are both contracted by person-to-person contact are both caused by spirochetes

are both caused by spirochetes and are chronic infections that involve the nervous systems

A person is MOST likely to contract diseases such as Rocky Mountain spotted fever and ehrlichiosis if he or she visits/participates in camping and hiking in the backcountry. European countries. snow skiing. metropolitan cities.

camping and hiking in the backcountry.

The degree of susceptibility a food has to microbial activity is determined by its water content. physical characteristics. chemical characteristics, physical characteristics, and water content. chemical characteristics.

chemical characteristics, physical characteristics, and water content.

In the United States, individuals become infected with Vibrio cholerae most commonly by drinking contaminated water. eating contaminated vegetables. person-to-person contact. consuming contaminated shellfish

consuming contaminated shellfish

Legionella pneumophila is generally transmitted by contaminated water in coolers, pools, and domestic water systems. contaminated drinking water. contaminated food. personto-person contact.

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

Animal-transmitted diseases are generally spread to accidental hosts by direct contact. aerosols. bites. direct contact, aerosols, and bites.

direct contact, aerosols, and bites.

Coliforms in a water sample indicate ________ contamination. arthropod industrial or chemical fecal All of the answers are correct.

fecal

Severe cases of Staphylococcus aureus food poisoning may require treatment with cleansing enemas. with powerful antibiotics. for dehydration. for dehydration, along with powerful antibiotics and cleansing enemas.

for dehydration.

Staphylococcus aureus is a common foodborne disease, because it produces several heat-stable enterotoxins. grows on common foods. grows on many foods, is present in some humans that work in food processing, and produces several heat-stable enterotoxins. is present in some humans that work in food processing.

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

Verotoxin can cause hemorrhagic diarrhea. liver failure. brain damage. hemorrhagic diarrhea, liver failure, and brain damage.

hemorrhagic diarrhea.

What type of diseases require biosafety level (BSL) 4 procedures and facilities when working with samples that may be infected? diseases for which no treatment or vaccine exist diseases with high mortality highly infectious diseases highly infectious diseases with high mortality for which no treatment or vaccine exist

highly infectious diseases with high mortality for which no treatment or vaccine exist

The presence of specific ________ signals that a given water source might be contaminated with pathogens endotoxins indicator microorganisms chemical compounds exotoxins

indicator microorganisms

Borrelia burgdorferi is an interesting spirochete that is unusual when compared to other bacteria. Which of the following is the reason that it is so unusual? it has a linear chromosome it has a cell wall it has flagella it has ribosomes

it has a linear chromosome

Which of the following would be the best strategy to prevent the spread of yellow fever and dengue fever into the southern United States? vaccination mosquito avoidance and eradication tick avoidance monitoring bird populations

mosquito avoidance and eradication

The MOST common source of individual foodborne botulism outbreaks are due to consumption of egg and meat salads. dairy products. honey. nonacid, home-canned vegetables

nonacid, home-canned vegetables

Clostridium botulinum is a gram- ________ rod that produces an ________. positive endospore-forming / exotoxin negative / endotoxin negative / exotoxin positive endospore-forming / endotoxin

positive endospore-forming / exotoxin

The primary disease reservoir for plague is fleas. mosquitoes. humans. rats.

rats.

The principle behind salt or sugar preservation is to introduce a microbicide in anticipation of contaminating bacteria or fungi. introduce a mechanical barrier to microbial invasion. accomplish all of the described functions depending on the food being preserved. reduce water activity (aw).

reduce water activity (aw).

Psychrotolerant microorganisms can survive and grow at boiling temperatures. high salt or sugar concentrations. refrigeration temperatures. extreme fluctuations in water availability.

refrigeration temperatures.

Which of the following is NOT characteristic of a coliform? resistant to chlorination facultatively aerobic gram-negative rod shaped

resistant to chlorination

A student travels to Brazil by boat on the Amazon River, without visiting the doctor prior to traveling for recommended vaccinations for travel to South America. The student becomes ill during the trip and is quarantined. Which of the diseases listed below does the student most likely have? Q fever Ebola yellow fever hantavirus

yellow fever

Of the arthropod-borne diseases, there is a vaccine to prevent __________. yellow fever dengue fever West Nile fever Lyme disease

yellow fever

Animal diseases transmissible to humans are known as radicals. zoonoses. ferals. vectors.

zoonoses.