Principles of Disease and Epidemiology

Question 1

People who transmit diseases, but who do not exhibit any symptoms of illness?

Answer 1

Carriers

Question 2

A disease that occurs only occasionally?

Answer 2

Sporadic. (vs. when it is constantly present, as it the common cold, it is termed ENDEMIC [the incidence and prevalence of a disease])

Question 3

A worldwide epidemic

Answer 3

Pandemic

Question 4

Diseases acquired in a hospital

Answer 4

Nosocomial

Question 5

Diseases that occur in animals and can be transmitted to humans?

Answer 5

zoonoses

Question 6

A simple presence of bacteria in the blood is known as?

Answer 6

bacteremia

Question 7

The science that deals with transmission of diseases in the human population, and when and where they occur, is called?

Answer 7

epidemiology

Question 8

An abscess is an example of a … type of infection?

Answer 8

local

Question 9

An infection in which the microorganisms or their products are spread throughout the body in the blood or lymphatic system is known as a … infection?

Answer 9

systemic

Question 10

Diseases intermediate between acute and chronic are described as?

Answer 10

subacute (vs. acute diseases e.g. influenza, or chronic diseases e.g. tuberculosis, syphilis, leprosy)

Question 11

A pathogen is found in all cases of a certain disease and is grown in pure culture; then it is inoculated into a laboratory animal. What is the next step in Koch’s postulates?

Answer 11

Isolate the pathogen from the animal and show that IT IS THE SAME AS THE ORIGINAL ORGANISM.

Question 12

What type of symbiotic relationship exists between normal microbiota and the host? Give two examples of contributions made by normal microbiota to the human host.

Answer 12

The relationship between normal microbiota and the host may be commensal or mutual. Examples of contributions made by normal microbiota include the synthesis of K and B vitamins by E.coli, and microbial antagonism in a healthy host.

Question 13

Discuss how an infant is colonized with normal microbiota.

Answer 13

In most pregnancies the fetus will remain germ-free until birth. The first microbiota that the infant will encounter will be Lactobacilli from the mother’s vagina. They will become the predominant organisms in the newborn’s intestines until the introduction of E.coli and other bacteria. Various other microbiota will become established as the infant comes in contact with its environment.

Question 14

An infection caused by an opportunist after the primary infection has weakened the body’s defenses?

Answer 14

secondary infection

Question 15

In this type of transmission of disease, an insect such as a fly carries the pathogen on its body to human food?

Answer 15

mechanical transmission

Question 16

Fomite? (Hint: indirect contact transmission, involves a nonliving object)

Answer 16

An inanimate object that may transmit disease (e.g. a drinking cup, towel)

Question 17

An inapparent disease that does not cause any noticeable illness is called?

Answer 17

a subclinical disease

Question 18

The cause of a disease is called?

Answer 18

Etiology

Question 19

The manner in which a disease develops is called?

Answer 19

Pathogenesis

Question 20

A change from a state of health, in which the body is not properly adjusted or capable of performing its normal functions is called?

Answer 20

Disease

Question 21

One of the organism is benefited and the other unaffected is called?

Answer 21

Commensalism

Question 22

One organism is benefited at the expense of another?

Answer 22

Parasitism

Question 23

The general relationship between the normal microbiota and the host?

Answer 23

Symbiosis

Question 24

A symbiosis that benefits both organisms?

Answer 24

Mutualism

Question 25

… refers to the competition that exists among a host’s normal microbiota for space and nutrients?

Answer 25

Microbial antagonism

Question 26

How does microbial antagonism contribute to a healthy host?

Answer 26

The process protects the host from colonization by potentially pathogenic organisms

Question 27

Example of Lactobacilli as a microbial antagonism?

Answer 27

Lactobacilli create an acidic environment that discourages the growth of Candida albicans (a common cause of vaginitis).

Question 28

Example of Streptococci as a microbial antagonism?

Answer 28

Streptococci living in the mouth prevent the growth of other gram-positive organisms

Question 29

Example of Bacteriocins as a microbial antagonism?

Answer 29

Bacteriocins produced by E.coli inhibit the growth of Shigella and Salmonella

Question 30

Example of normal microbiota of the intestines as a microbial antagonism?

Answer 30

Normal microbiota of the intestines inhibit growth of the pathogen Clostridium difficile

Question 31

The effect of two microbes acting together is greater than the effect of either acting alone?

Answer 31

Microbial synergism

Question 32

Two examples of microbial synergism?

Answer 32

1. Mycoplasma and HIV.
2. Oral streptococci (Streptococcus mutans) and the pathogens that cause periodontal disease and gingivitis (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, etc).