Vector and Soilborne Diseases

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

Lyme disease is caused by ____________ and is transmitted by ___

B. burgdorferi; Ixodes

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.

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

a zoonosis

Tetanus develops from a puncture wound because

endospores germinate in anoxic conditions.

There are several different virus-specific treatments and vaccines available to treat or prevent hantavirus infections.

f

Controlling most rickettsial diseases involves managing

he vector.

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

The introductory passage describes the death of an individual due to rabies exposure. Rabies is almost always lethal after symptoms appear, so prevention is critical. Choose the correct word for each sentence to describe the most effective prevention for the disease listed.

Hantavirus can be prevented by avoiding rodent habitats and reducing rodent populations in human dwellings. Rabies can be prevented through vaccination or immediate post-exposure prophylactic treatment following a mammal bite. Anthrax can be prevented with a vaccine for those at highest risk (such as military personnel who may be exposed through bioterrorism). Tetanus can be prevented through toxoid vaccination or, if symptomatic, can be treated with antibiotics and an antitoxin. Lyme disease can be prevented through avoiding tick habitat, using tick repellants, removing ticks before they become embedded, and using post-exposure antibiotic treatment. Yellow fever can be prevented by vaccination before traveling to areas in which it is endemic and by avoiding mosquito bites.

If mosquitoes are the mode of transmission for West Nile virus, why did the students in Bill's virology class focus on finding the virus in the dead birds rather than collecting mosquitoes to examine?

The students tried to isolate and identify West Nile virus from birds because they are an amplifying host for the virus, making it more likely that the virus can be isolated from these animals.

Based on the concept map, which of the following must happen during Lyme disease?

There is an adaptive immune response.

Which of the following best describes why West Nile Virus is considered to be an emerging infectious disease?

West Nile virus outbreaks have increased in number and affected areas since 1937

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

Yersinia pestis.

Lyme disease and syphilis are similar in that they

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

Animal-transmitted diseases are generally spread to accidental hosts by

direct contact, aerosols, and bites.

The primary disease reservoir for plague is

rats

Emerging diseases are a problem worldwide, even in highly developed regions of the world.

t

The introductory passage discusses the concern that vampire bats could become an important rabies vector species in the United States as a result of climate change. What other species discussed in the chapter has specifically become a greater concern in the United States due to climate change, resulting in warmer average temperatures, as opposed to other reasons for range expansions?

Aedes aegypti and Aedes albopictus, vectors for Dengue fever

Which of the following statements about hantaviruses is true?

All of the listed statements are true.

During his research on West Nile virus, Bill learned that this virus is placed within a functional grouping known as arboviruses. What is meant by the term arbovirus?

An arbovirus is an arthropod-borne virus. n arbovirus is maintained in nature through biological transmission.

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

Borrelia burgdorferi / Ixodes sp. (deer tick)

he brain tissue of the birds indicated the possibility of encephalitis. What is encephalitis, and why should this type of infection cause concern among health care professionals?

Encephalitis is an inflammation of the brain tissue. It is a concern to health care professionals because an infection in the brain means the virus has breached protective measures.

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.

Which of the following is the best mode of controlling the spread of West Nile infections?

Limit exposure to mosquitoes to prevent the transmission of West Nile virus.

While all of the pathogens discussed in this chapter are vector- or soil-borne, the specifics of their transmission vary. Choose the correct method of transmission for each pathogen.

Rabies is transmitted through contact with blood or other bodily fluids from infected endotherms, generally through bites or contact with mucous memo ranes. Hantavirus is contracted through contact with rodents, including inhalation of dust from mouse excreta. Rocky Mountain spotted fever is transmitted by bites from ticks. Dengue fever is transmitted by mosquito bites. Anthrax can be contracted in several ways, but the most serious form of illness develops after spores are inhaled. Bubonic plague is transmitted by bites from fleas. Tetanus occurs after the causative pathogen gains access to the body through a soil-contaminated, deep wound.

Following possible exposure to rabies (e.g., following a bite from a potentially infected animal), several steps should be taken. If a human is bitten by a domestic animal, such as a dog, the animal should be quarantined. What treatment is recommended for an exposed human if the animal either can't be tested or quarantined, or if the animal shows evidence of rabies during quarantine?

The human should be injected with rabies immune globulin. The human should be injected with a rabies vaccination.

What features of West Nile virus make it an emerging disease of special concern?

West Nile virus is an arthropod-borne virus transmitted by mosquitoes. West Nile virus has a high mortality rate in immunosuppressed humans and infects many species of birds in southern Europe, the Mediterranean basin, and North America. West Nile virus is maintained in nature through biological transmission between susceptible hosts by blood-feeding arthropods.

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

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?

passive and active immunization against rabies

Which of the following diseases CANNOT easily be controlled by vector elimination?

rabies

Rabies is an important vector-borne disease. Like the pathogen that causes rabies, the other vector and soil borne pathogens discussed in the chapter can be classified as viruses or bacteria as well. Choose the correct classification for the causative pathogen for each disease.

single stranded minus sense: rabies, hantavirus single stranded plus sense: yellow fever and west nile fever bacteria: rocky mountain spotted fever, lyme, anthrax, tetanus

Inhalation anthrax is the only form of anthrax for which there is no effective treatment.

t

Only high-risk individuals such as scientists working with the organism, livestock workers, and military personnel are vaccinated for anthrax.

t

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

t

Virtually ALL cases of tetanus occur in individuals who have failed to receive tetanus toxoid booster immunizations.

t

A patient exhibiting arthritis secondary to Lyme disease is likely in which phase of the infection?

third

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

typhus

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. Which of the following places would you be most likely to find the parasites in a living organism during the course of infection?

within macrophages

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

Of the arthropod-borne diseases, there is a vaccine to preven

yellow fever

Animal diseases transmissible to humans are known as

zoonoses.