X, Human Disease and Epidemiology

Question 1

Science dealing with the study of diseases.

Answer 1

Pathology

Question 2

Entry of an infectious agent into the host.

Answer 2

Infection

Colonization

Question 3

Invasion by an infectious agent resulting in the manifestation of signs and symptoms in the host.

Answer 3

Disease

Question 4

Objective changes in the host as observed and measured by a physician (e.g. blood pressure, fever etc.)

Answer 4

Signs

Question 5

Changes in bodily function felt by the patient (e.g. pain, malaise)

Answer 5

Symptoms

Question 6

A specific group of signs and symptoms accompanying a particular disease. (e.g. AIDS)

Answer 6

Syndrome

Question 7

The cause of an infectious disease process, the causative agent.

Answer 7

Etiology

Question 8

Manner by which a disease develops. (mechanisms and

microbe-host dynamics)

Answer 8

Pathogenesis

Question 9

A relationship in which microbes establish permanent residence in the host without producing disease.

Answer 9

Symbiosis

Question 10

Normal microbiota prevent overgrowth of pathogens by competing for nutrients and producing inhibitory substances such as bacteriocins produced by E. coli against Salmonella and Shigella.

Answer 10

Microbial antagonism

Question 11

A symbiotic relationship that benefits one organism while the other is not affected.

Answer 11

Commensalism

Question 12

A relationship in which both organisms are benefited.

Answer 12

Mutualism

Question 13

A relationship in which one organism is benefitted at the expense of another.

Answer 13

Parasitism

Question 14

A harmless organism becomes pathogenic due to the

suppression of normal microbiota or when host’s immune response is impaired.

Answer 14

Opportunism

Question 15

Two microbes acting together have greater effect than either acting alone (e.g. Mycoplasma infected cells are susceptible to death from viral
infections).

Answer 15

Syngergism

Question 16

Koch’s postulates must be fulfilled in order to demonstrate that a specific microbe is the cause of a specific disease

Answer 16

The same pathogen must always be present in every case of the disease.
The pathogen must be isolated from the diseased host in pure culture on artificial media.
The pathogen recovered in pure culture must cause the disease when inoculated into a healthy susceptible laboratory animal.
The pathogen must be isolated from the infected animal again and must be shown to be the same pathogen as the original organism.

Question 17

Spread of disease directly or indirectly from one host to another (e.g. tuberculosis)

Answer 17

Communicable diseases

Question 18

Disease caused by microbes that cannot be spread from one host to another (e.g. tetanus via rusty nail)

Answer 18

Non-communicable diseases

Question 19

Diseases that are easily spread from one person to another (e.g. flu)

Answer 19

Contagious disease

Question 20

Fraction of the population (number of new cases/total

population) experiencing the disease during a certain period of time (e.g. 5-years of AIDS in the U.S., 2001-2005)

Answer 20

Incidence of a disease

Question 21

Fraction of the population that has the disease at a given time (e.g. influenza during in winter)

Answer 21

Prevalence of a disease

Question 22

Occasional occurrence of a disease (e.g. Legionnaire’s disease occurring at the American Legion Convention)

Answer 22

Sporadic

Question 23

Constantly present in the population (e.g. Malaria is in Africa)

Answer 23

Endemic

Question 24

Occurrence of disease beyond the normal experience of the population within a short period of time (e.g. cholera in Bangladesh after the tsunami)

Answer 24

Epidemic

Question 25

Develops rapidly and lasts for a short time (e.g. Influenza)

Answer 25

Acute disease

Question 26

``` Develops slowly but continuous and recurrent for long periods of time (e.g. leprosy) ```

Answer 26

Chronic disease

Question 27

A category falling in between acute and chronic disease | e.g. bacterial endocarditis –SBE

Answer 27

Subacute infection

Question 28

``` Pathogen is inactive for some time but becomes active later to produce symptoms (e.g. genital herpes) ```

Answer 28

Latent infection

Question 29

A phenomenon when many people in the community are | immune to a certain disease (e.g. milkmaids vs. smallpox)

Answer 29

Herd immunity

Question 30

Diseases that are new or changing, showing an | increase incidence in recent past or a potential for increase in the future (e.g. E. coli O157:H7)

Answer 30

Emerging infectious diseases

Question 31

Invading microbes are limited to a small area of the body (e.g. boils and pimples)

Answer 31

Local infection

Question 32

A local infection/microbes that spreads to other parts of the body via the blood and lymphatic system (e.g. Streptococcus sanguis introduced during a dental procedure)

Answer 32

Focal infection | Systemic or generalized infection

Question 33

Presence of bacteria in the blood Rapid multiplication of bacteria in the blood Presence of toxins in the blood

Answer 33

Bacteremia Septicemia Toxemia

Question 34

Acute infection causing the initial illness (e.g. Flu)

Answer 34

Primary infection

Question 35

Caused by an opportunist after the primary infection | weakened the host’s defenses (e.g. pneumonia after the flu)

Answer 35

Secondary infection

Question 36

Gender, genetic background, climate, age and nutrition = any factor that can greatly affect the occurrence of diseases in individuals.

Answer 36

Predisposing factors

Question 37

Time between onset of infection and the appearance of | signs and symptoms.

Answer 37

Incubation period

Question 38

Follows incubation period (in some diseases) as mild | symptoms of the disease.

Answer 38

Prodromal period

Question 39

Overt signs and symptoms appear.

Answer 39

Period of illness

Question 40

Signs and symptoms subside

Answer 40

Period of decline

Question 41

Patient regains his pre-diseased state.

Answer 41

Period of convalescence

Question 42

Continual source of the pathogen (e.g. animal or fomites)

Answer 42

Reservoir of infection

Question 43

People harboring pathogens and transmitting these to others. | If they are diseased they are obvious transmitters. If asymptomatic, carriers.

Answer 43

Human reservoirs

Question 44

Wild and domestic animals that serve as sources of pathogens causing zoonotic infections. Through direct contact, contaminated food and water, consumption of infected animal products, insect borne, or contact with contaminated fur or hide.

Answer 44

Animal reservoirs

Question 45

Soil (e.g. tetanus), water contaminated with human | and animal feces (e.g. Salmonellosis)

Answer 45

Nonliving reservoirs

Question 46

Transmission involving kissing, handshaking, bites or sexual intercourse.

Answer 46

Direct contact

Question 47

Transmission in which agents of disease are spread over short distances, less than a meter. e.g. droplets of saliva or mucus from coughing sneezing.

Answer 47

Droplet infection

Question 48

Transmission that involves an inanimate object such as drinking cup or soiled linen, also called fomites.

Answer 48

Indirect contact

Question 49

Inanimate reservoirs such as food, water or blood that | serve as means of transmission of disease.

Answer 49

Vehicle transmission

Question 50

Microbes in droplet nuclei or on dust carried over | distances beyond 1 meter (e.g. spores of fungi)

Answer 50

Airborne transmission

Question 51

Arthropods that carry pathogens from host to another.

Answer 51

Vectors

Question 52

Insects like flies that carry pathogens on their hairy bodies to food that is later swallowed by the host.

Answer 52

Mechanical vectors

Question 53

Pathogens develop inside the insect and transmitted by bite or feces introduced into the bite wound.

Answer 53

Biological vectors

Question 54

Routes by which a pathogen leaves the body (e.g. feces)

Answer 54

Portals of exit

Question 55

.Most often caused by opportunistic pathogens on compromised patients due to broken skin or mucous membrane, suppressed immune system, impaired cell defense. Previously caused by gram+ bacteria, gram- such as Pseudomonas aeruginosa and E. coli now predominate. The emergence of MRSA and VRE has complicated the problem.

Answer 55

Nosocomial infections

Question 56

Science which deals with the study of the frequency and spread of occurrence of diseases.

Answer 56

Epidemiology

Question 57

Involves the collection of data such as geographical distribution, demographics, and the causative agent (where and when the disease occurred in the population)

Answer 57

Descriptive epidemiology

Question 58

Epidemiologists look for common factors among the affected individuals in the population that might have preceded the disease outbreak.

Answer 58

Analytical epidemiology

Question 59

Tests a hypothesis by experimentation (e.g. clinical trials for Ciprofloxacin using a double-blind study)

Answer 59

Experimental epidemiology

Question 60

Central source for epidemiological information in the U.S. Publishes the Morbidity and Mortality Weekly Report (MWWR), which contains data about the morbidity (relative incidence of the disease) and mortality (deaths from a disease)

Answer 60

Centers for Disease Control (CDC) in Atlanta, Georgia

Question 61

Those that physicians must report to the U.S. Public Health Service=USPHS. (e.g. anthrax, typhoid fever). The CDC is a branch of this agency.

Answer 61

Notifiable diseases

Question 62

Coordinates public health efforts worldwide

Answer 62

World Health Organization. WHO