Ch. 14

Five

In the last segment of the animation, how many regions of the world experience the pandemic during April of year four?

January of year three

In the last segment of the animation, when does the first epidemic occur?

The disease occurs at a higher rate than what would normally be expected in this region.

In the sixth segment of the animation, why is the disease epidemic in North America?

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.

The 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?

epidemic: a disease that is endemic across the world

Which of the following definitions is INCORRECT?

tetanus

Which of the following is NOT a communicable disease?

Contact, vehicle, and vector transmission

Which of the following is considered a major category of transmission of disease?

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

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

An infected toy

Which of the following would be considered a fomite?

A fly carrying disease from fecal matter to food

Which of the following would be considered a vector?

These procedures allow microbes from the skin to enter the bloodstream of the patient.

Why are invasive procedures likely to increase the risk of nosocomial infections?

The presence of Listeria on undercooked chicken served for dinner

Which is an example of vehicle disease transmission?

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

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

- common physical requirements between the organisms - life cycle coordination between the host and symbiont

Which of the following characteristics do commensalism, mutualism, and pathogenicity have in common? Select all that apply.

may also be an opportunistic pathogen.

A commensal bacterium

latent.

A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as

- Microorganism X might not be linked to floppy ear disease, because the inoculated mouse remained healthy. - A laboratory mouse might not be an appropriate, susceptible host; an experiment with a laboratory rabbit may be needed.

A rabbit was found to have floppy ear disease, which causes long-ear infections. Its etiology (cause) is unknown. Unknown Microorganism X from the infected rabbit's right ear is successfully isolated and cultured on laboratory growth media. The ear of a healthy laboratory mouse is then inoculated with isolated microorganism, and after a period of time, no disease is observed. Which of the following statements accurately describe(s) the conclusion(s) that can be drawn from this experiment?

20%

According to the animation, surgical infections account for what percentage of nosocomial infections?

Coxiella burnetii.

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. The etiologic agent of the disease in the situation is

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

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?

Etiology -the study of the cause of a disease Infectious Disease -disease directly caused by microorganisms and not by other means, for example, genetic or degenerative diseases Germ theory of disease -this theory states that microorganisms cause infectious diseases Kosch's postulates -experimental requirements for identifying the agent of an infectious disease

Etiology and Infectious Disease

the expected occurrence of a disease based on past observations

Expected prevalence of a disease is

Diseased or dead animal -original source of the infectious microbial agent Healthy laboratory animal -organism injected with a potential infectious agent microscope -tool used to view and identify individual microorganisms growth media -nutrient-rich environment for isolating and culturing microorganisms

Experimental Approaches for Understanding Disease

Practice more stringent aseptic techniques

How can health care workers reduce the occurrence of nosocomial infections?

Antibiotics can be used in aerosols, thereby entering the environment.

How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?

endemic

If a disease occurs at a fairly stable rate, it is said to be

illness.

If a prodromal period exists for a certain disease, it should occur prior to

-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.

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?

antagonistic bacteria.

The yeast Candida albicans does not normally cause disease because of

Benefit -The steps are designed to systematically link a pathogen to a specific infectious disease -laboratory findings provide experimental evidence that support the germ theory of disease -healthy, susceptible animals can be used as model organisms for testing many ...blah blah blah Limitation -Some infectious agents have specific.... -some pathogens cause several...... -different pathogens can produce the same.....

This activity asks you to sort statements that describe the benefits and limitations of using Koch's postulates to determine the etiology of infectious diseases. For each of the following statements, determine whether it describes a benefit or a limitation of Koch's postulates.

-The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal. -The same pathogen must be present in every case of the disease. -The pathogen must be isolated from the inoculated animal and must be shown to be the original organism. -The pathogen must be isolated from the diseased host and grown in pure culture.

Understanding Koch's Postulates This activity asks you to identify Koch's postulates for determining the etiology of infectious diseases. Which statements accurately describe Koch's postulates?

-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.

What features of West Nile virus make it an emerging disease of special concern? Select all that apply.

Bacteremia

What type of nosocomial infection is likely to arise from intravenous catheterizations?

contact transmission.

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered

urinary tract infections

In which of the following diseases can gender be considered a viable predisposing factor?