Quiz 10

The most severe and fatal form of anthrax is

inhalation anthrax.

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

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

true

Soldiers or refuges in crowded unsanitary conditions are MOST susceptible to which rickettsial disease?

typhus

The MOST important potential common source of infectious disease is

water

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?

yellow fever

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?

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

Which of the following are properties of exotoxins?

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

At what temperature are most household freezers kept?

-20°C

The ability of Vibrio cholerae to cause disease depends on a number of factors. Which of the following are requirements for causing disease within a host?

-gaining access to the host via a portal of entry - adherence to host tissues - evasion of host defenses

The causative agent of Lyme disease is ________, which is carried primarily by the ________.

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?

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.

Which of the following pathogens is spread by infected lice?

Rickettsia prowazekii

Lyme disease and syphilis are similar in that they __________.

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.

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

chemical characteristics, physical characteristics, and water content.

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

consuming contaminated shellfish.

Legionella pneumophila is generally transmitted by

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

Animal-transmitted diseases are generally spread to accidental hosts by

direct contact, aerosols, and bites.

Erythema migrans is associated with typhus.

false

Coliforms in a water sample indicate ________ contamination.

fecal

The presence of specific ________ signals that a given water source might be contaminated with pathogens.

indicator microorganisms

Vibrio cholerae primarily infects the

small intestine.

The Staphylococcus aureus toxins are

superantigen toxins.

The rate of contaminant microbial growth during the exponential phase in food depends on

temperature, nutrient value, and water content.

Many West Nile virus infections are not properly identified because

the symptoms are often subacute.

Controlling most rickettsial diseases involves managing

the vector.

Cholera can be transmitted by water or food.

true

Not all coliforms are pathogenic.

true

Hantavirus pulmonary syndrome is a viral respiratory disease caused by contact with

rodents

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?

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

Which of the following explains why treatment of symptomatic tetanus requires an antitoxin and an antibiotic?

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

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 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

Salmonellosis is most frequently caused by

Salmonella enterica serovars Typhimurium and Enteritidis.

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?

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

In bubonic plague, buboes are swellings formed in the lymph nodes and filled with

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 curved rod

Severe cases of Staphylococcus aureus food poisoning may require treatment

for dehydration.

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.

Verotoxin can cause

hemorrhagic diarrhea.

What type of diseases require biosafety level (BSL) 4 procedures and facilities when working with samples that may be infected?

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

Hantaviruses are most commonly transmitted by ________ of virus-contaminated rodent ________.

inhalation / excreta

Which of the following would be the best strategy to prevent the spread of yellow fever and dengue fever into the southern United States?

mosquito avoidance and eradication

The MOST common source of individual foodborne botulism outbreaks are due to consumption of

nonacid, home-canned vegetables.

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

positive endospore-forming / exotoxin

The primary disease reservoir for plague is

rats

The principle behind salt or sugar preservation is to

reduce water activity (aw).

Psychrotolerant microorganisms can survive and grow at

refrigeration temperatures.

Which of the following is NOT characteristic of a coliform?

resistant to chlorination

Of the arthropod-borne diseases, there is a vaccine to prevent __________.

yellow fever

Animal diseases transmissible to humans are known as

zoonoses.