Mastering Micro ch. 30

d.

An animal disease transmitted to humans by direct contact, inhalation of aerosols, or bites is called __________. a. epizootic b. enzootic c. a zoophyte d. a zoonosis

d.

Animal-transmitted diseases are generally spread to accidental hosts by a. bites. b. aerosols. c. direct contact. d. all the above

c.

West Nile Virus is an arbovirus that can be transmitted by birds because they develop viremia when infected. In contrast, infected humans cannot spread the disease because they do not develop viremia. Why is viremia associated with the ability to transmit the disease? a. Because white blood cells are found in the blood, any virus in the blood would be attacked by the immune system. With no viral particles available for the immune system to attack, the virus cannot be spread. b. The virus is only found within red blood cells if there is no viremia, so it cannot be spread by mosquitoes that do not consume those cells. c. If there are no (or only very few) viral particles in the blood, then they are not picked up by vectors feeding on the blood in sufficient amounts to cause infection. d. Direct contact with blood is required for infection. If there are no viral particles in the blood, then infection can't occur using this mechanism.

c.

Bacillus anthracis is an endospore-forming bacterium. Which of the following is most likely? a. B. anthracis spores can be killed by boiling water. b. B. anthracis spores require a moist environment in order to stay dormant for an extended time. c. B. anthracis spores can remain dormant for hundreds of years without needing nutrients. d. B. anthracis uses spores to reproduce, so spores develop into new offspring.

a.

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

a.

If you were exposed to a sick animal that was found to have negri bodies in its nervous system in a postmortem examination, how would you be treated to prevent disease? a. passive and active immunization against rabies b. antiviral medication c. antibiotics to treat Lyme disease d. observation to detect tick or lice bites

a.

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

c.

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

c.

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

true

T/F? If Lyme disease is not treated early, it can infect the central nervous system.

False

T/F? Tetanus is highly contagious through person-to-person contact.

true

T?F? The study of hantaviruses requires biosafety level (BSL) 4 precautions.

d.

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

d.

The common methods to control the spread of West Nile virus include __________. a. wearing loose-fitting clothes when outside b. a vaccine for humans c. providing water in yards for birds to drink d. using insect repellents

a.

The primary disease reservoir for plague is a. rats. b. mosquitoes. c. fleas. d. humans.

a.

There are three forms of human anthrax. Which of the following choices contains a form of human anthrax correctly matched with its description? a. cutaneous: easily treatable b. respiratory: most common form c. intestinal: always fatal d. cutaneous: least severe form

b.

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? a. it has a cell wall b. it has a linear chromosome c. it has flagella d. it has ribosomes

b.

Clostridium species that can be associated with gas gangrene include __________. a. Clostridium tetani b. Clostridium novyi c. Clostridium botulinum d. none of the listed species

a.

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? a. Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow. b. C. tetani can only survive when other bacteria are available to consume oxygen and to keep oxygen levels low. c. It doesn't survive; it simply releases toxin as it dies. d. 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.

d.

Control of certain diseases is nearly impossible, because we cannot a. control reservoir animals. b. eradicate organisms from the soil. c. control vector animals. d. all the above

a.

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

a.

Tetanus develops from a puncture wound because a. endospores germinate in anoxic conditions. b. the organism needs access to the circulatory system and deep connective tissues. c. the organism gains access to the circulatory system and then invades the nervous system. d. the organism digests deep connective tissues.

b.

Which of the choices shows the correct progression of bubonic plague? 1. Human is bitten by infected flea. 2. Rodent is infected with Yersinia pestis. 3. Yersinia travels to lymph nodes. 4. Flea is infected with Yersinia pestis. 5. Septicemia occurs. 6. Yersina pestis reproduces in intestine of infected organism. 7. Human is bitten by infected rodent. Which of the choices shows the correct progression of bubonic plague? a. 2, 4, 6, 7, 3, 5 b. 2, 4, 6, 1, 3, 5 c. 4, 2, 6, 1, 3, 5 d. 4, 2, 6, 7, 3, 5

c.

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

d.

Which of the following statements about hantaviruses is true? a. They are related to Ebola and other hemorrhagic viruses. b. They are single-stranded, segmented, negative-sense RNA viruses. c. They are transmitted to humans by contaminated rodent droppings. d. All of the listed statements are true.