MCB3023 Ch 18

The emergence of HIV/AIDS disease was most likely a result of:

a rare zoonotic transfer of a retrovirus strain to humans.

How is the protozoan Plasmodium falciparum transmitted from host to host?

a vector-borne route

Pathogens may cause damage to the host by ALL of the following mechanisms EXCEPT:

replication in the host.

Borrelia burgdorferi, the agent of Lyme disease, is found in nature in the white-footed mice and deer. Mice and deer are said to be _______________ for this pathogen.

reservoirs

Which disease listed below is NOT an example of a propagated disease?

salmonellosis

what does a high case-to-infection ratio (CI) indicate?

that most people infected by the pathogen will develop the disease

which of these is true of an attenuated strain of a pathogenic microbe infecting a susceptible healthy host?

the microbe will replicate in the host but not cause disease

Which of these would need to occur for a disease to be considered infectious?

an infectious agent causes damage to the host and can be transmitted to another host

When the virulence of a pathogen is decreased to such a degree that it no longer can cause disease it is termed a(n) _______________ strain.

avirulent

All of the following are components that may be used by a pathogen for attachment to a host cell EXCEPT:

chitinases.

Term for newly identified infectious diseases or those with a recent significant increase in incidence.

emerging diseases

A(n) _____________ disease is one that is always present in a population.

endemic

When the incidence of a disease occurs at a level higher than expected, it is called a(n) ______________.

epidemic

Pathogens that have the ability to change their surface antigens are better able to do which of the following?

evade host defenses

A(n) ________________ is a toxin made inside the pathogen and excreted into the external environment.

exotoxin

The measure of the ability of a pathogen to cause severe disease in a host is called _______________.

virulence

Term for pathogen properties that aid it in causing disease.

virulence factors

A(n) _____________________ disease is an infectious disease of animals that can be transmitted to a human.

zoonotic

Endotoxins are toxins that are made in the cell and excreted to the external environment.

False

Individuals that are carriers of a particular pathogen but do not develop the disease cannot transmit the pathogen to other individuals.

False

Primary pathogens are distinguished from opportunistic pathogens in that they always cause a more severe disease.

False

The ability of Staphylococcus aureus to become antibiotic resistant is referred to as antigenic variation.

False

Term for the number of NEW cases of a disease within a population during a specific time period.

incidence

The replication of a microbial pathogen on or within a host is called a(n) __________________.

infection

How does vertical transmission of a pathogen occur?

From mother to offspring.

Which one of the following statements is NOT one of Koch's postulates?

Identify virulence factors from the isolated microbe.

Which of these is an example of a common-source epidemic?

Several cases of food poisoning from a wedding.

What often determines the host range of a pathogen?

The ability of pathogen to attach to a host cell

Pathogenic E. coli strain O157:H7 evolved from a non-pathogenic strain as a result of this genetic change.

The acquisition of virulence genes from Shigella.

The Herpes simplex I virus is able to avoid detection by the host immune system through this mechanism.

The establishment of latency in sensory neurons.

Which of these outcomes is the focus of molecular Koch's postulates?

The identification of virulence factor genes.

What is the morbidity rate of a disease?

The number of cases of the disease within a specified number of the population.

What is studied in the field of epidemiology?

The study of patterns of all diseases.

A fomite is an inanimate object used for the transmission of a pathogenic agent.

True

A pathogen that causes disease in a healthy host when displaced from its usual location in the body could be termed opportunistic.

True

A single mutation in a pathogenic gene may cause the pathogen to become avirulent.

True

Koch's Postulates still play an important role today in identifying the causative agents of emerging diseases.

True

Most pathogens need to avoid host defenses and attach to host cells before they are able to replicate and establish the disease state in the host.

True

The incidence of a disease is the number of new cases of the disease in a population over a specific period of time.

True

Vertical transmission of a pathogenic agent occurs from mother to child.

True

The emergence of Lyme disease was most likely a result of:

a change in human activity that allowed for an increased risk for contact with the pathogen.

Which of these is true of an endemic disease?

It is constantly present in a given population.

This is an example of a pathogen that has become more of a threat because it is increasingly harder to control with antimicrobials.

MRSA

in order to cause disease, successful infectious pathogens must be able to do ALL of the following except:

kill the host

The number of deaths due to a specific disease over a specified number in the population is referred to as the ______________ rate.

mortality

Term for an epidemic that occurs on multiple continents.

pandemic

Term for a clustering of virulence genes on the chromosome of a pathogenic microbe.

pathogenicity island