BIOL 2051 - Chapter 32 HW

The common methods to control the spread of West Nile virus include __________.

using insect repellents

Rickettsia are obligate intracellular parasites that are transmitted by arthropods. In which of the following places would you most likely find the parasites living in the host organism during the course of infection?

within macrophages

Bacillus anthracis is an endospore-forming bacterium. Which of the following is most likely?

B. anthracis spores can remain dormant for hundreds of years without needing nutrients, remaining capable of causing anthrax when they germinate.

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.

Which of the following statements about hantaviruses is true?

Hantaviruses are an example of an emerging infectious disease. They are similar in disease presentation to Ebola and other hemorrhagic viruses. They are transmitted to humans by contaminated rodent droppings.

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?

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.

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

yellow fever

An animal disease transmitted to humans by direct contact, inhalation of aerosols, or bites is called __________.

a zoonosis

There are three forms of human anthrax. Which of the following forms are correctly matched with their description?

cutaneous: easily treatable

Everyone, but particularly individuals who are farmers, gardeners, foresters, or others who spend significant time outdoors, are urged to adhere to a tetanus booster vaccinations schedule, receiving a booster if planning to travel and cannot remember when his or her last one. Why?

Clostridium tetani typically causes infection when a wound is contaminated with soil, it's natural habitat.

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 that have become anoxic because of poor-to-no blood flow.

If a human is bitten by an animal that has rabies, then it is recommended that the human receive immune globin (human rabies antibodies) and a rabies vaccination (with inactive virus) as well. Which of the following is the best (and most specific) explanation for why both are recommended in this case? View Available Hint(s)

The rabies antibodies provide a rapid response but short-lived response while the vaccination provides slower but longer-lasting protection.

The yellow fever virus replicates in lymph nodes and in other immune system cells. How does it arrive in lymph nodes?

The yellow fever virus is phagocytosed by white blood cells, and then travels through the lymph vessels. Lymph nodes contain white blood cells and filter lymph as it moves through the lymph vessels. White blood cells with yellow fever virus can become established there. Some viruses, like the yellow fever virus, can replicate inside of white blood cells like those in lymph nodes.

Wild rodents are the major reservoir of the plague organism, Yersinia pestis, but pandemic plagues were historically associated with crowded, unsanitary urban areas. Why is this the case?

Yersinia pestis can be transmitted by fleas from wild rodents to urban rats, which quickly die of the disease. Humans are accidental hosts due to fleas seeking out blood meals after most rats have succumbed to the disease.

Lyme disease and syphilis are similar in that they __________.

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

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

The most important rickettsial diseases in humans include __________.

typhus fever