Principles of Disease (Lec. 17)

Question 1

Define mutualism

Answer 1

Symbiosis that is beneficial to both organisms involved

Question 2

Define commensalism

Answer 2

Symbiosis that is beneficial to one organism and does not positively or negatively affect the other organism

Question 3

Define parasitism

Answer 3

One organism lives on or inside another organism, causing it some harm

Question 4

Define pathology

Answer 4

the science of the causes and effects of diseases

Question 5

Define etiology

Answer 5

the cause, set of causes, or manner of causation of a disease or condition

Question 6

Define pathogenesis

Answer 6

the manner of development of a disease

Question 7

Define infection

Answer 7

the invasion and growth of microorganisms in the body

Question 8

Define disease

Answer 8

any process, infectious or non-infectious, which disrupts normal bodily functions

Question 9

Define infectious disease

Answer 9

an illness caused by the spread of harmful microorganisms

Question 10

Define symptoms

Answer 10

a subjective experience only the patient can feel

Question 11

Define signs

Answer 11

Objective evidence of a disease that can be observed by others

Question 12

Define duration

Answer 12

the average time a person has a disease, from diagnosis until they are cured or die

Question 13

Define acute disease and chronic disease

Answer 13

Acute diseases are severe and sudden in onset, and last a short time. Chronic diseases develop slowly and persist for an extended period.

Question 14

Define subacute disease

Answer 14

falling between acute and chronic in character especially when closer to acute; symptoms are less severe but last longer

Question 15

Define latent disease

Answer 15

a condition that is present but not active or causing symptoms

Question 16

Define incubation period

Answer 16

the period between exposure to an infection and the appearance of the first symptoms

Question 17

Define prodromal period

Answer 17

begins with the appearance of the first symptoms (usually mild and nonspecific); the body’s immune response is activated

Question 18

Define communicable disease and non–communicable disease

Answer 18

Communicable diseases can be spread from one organism to another (tuberculosis, measles, etc.) and non-communicable diseases cannot be (cancer, cardiovascular disease, etc.)

Question 19

Define zoonosis

Answer 19

a disease which can be transmitted between humans and animals

Question 20

Define reservoir

Answer 20

a place where a pathogen lives, grows, and multiplies

Question 21

Define vector-borne transmission

Answer 21

the process by which a disease is spread to humans and other animals through a living organism (a vector) that carries the disease

Question 22

Define vertical transmission

Answer 22

transfer of a microbial symbiont directly from parent to offspring

Question 23

Define epidemiology

Answer 23

the branch of medicine which deals with the incidence, distribution, and possible control of diseases and other factors relating to health

Question 24

Define endemic and sporadic disease

Answer 24

Sporadic diseases are seen only occasionally, and usually without geographic concentration. Endemic diseases are consistently present but limited to a particular region.

Question 25

Define epidemic vs. pandemic

Answer 25

An epidemic is a disease outbreak which is rapidly spreading in a limited region. A pandemic is an epidemic actively spreading to multiple regions across the world.

Question 26

Define emerging pathogen

Answer 26

Newly identified agents or pathogens that previously caused only sporadic cases

Question 27

Define re-emerging pathogen

Answer 27

An infectious agent that was under control but is now resurfacing

Question 28

Define incidence

Answer 28

measures number of new cases of a condition over a specified time period

Question 29

Define prevalence

Answer 29

measures the proportion of a population with a condition in a specific time period, regardless of when they actually contracted the condition

Question 30

Define reproductive number (R0)

Answer 30

the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection

Question 31

Define case fatality ratio (C F R)

Answer 31

the proportion of cases of a disease or condition that are fatal within a specified period of time

Question 32

Define notifiable disease

Answer 32

diseases that the CDC recommends reporting to government health agencies

Question 33

Define reportable disease

Answer 33

diseases that are on a state or local tracking list

Question 34

Define morbidity

Answer 34

Number of people affected in relation to the total population in a given time period

Question 35

Define mortality

Answer 35

Number of deaths from a disease in relation to the total population in a given time period

Question 36

Define endogenous vs. exogenous

Answer 36

Endogenous: pathogen came from one's own body. Exogenous: pathogen was external to host

Question 37

Describe how Robert Koch helped shape the germ theory of disease; list his postulates.

Answer 37

Koch's postulates are a methodology to determine the specific etiological agent of an infectious disease. 1) Microorganisms must be isolated from a diseased or dead animal 2) Microorganisms must be grown in pure culture. 3) Microorganisms must be inoculated into a healthy lab animal 4) Disease must be reproduced in the laboratory animal 5) The microorganisms must be isolated from this animal and grown in a pure culture again

Question 38

Describe the various modes of transmission of disease

Answer 38

Direct contact: person-to-person transmission (touching, saliva, sex); zoonotic transmission (contact with animals/animal products); vertical transmission (passed from mother to child in utero, during delivery, or through breastmilk). Indirect contact: airborne transmission (particles carry pathogen); droplet transmission (droplets expelled from nose/mouth); foodborne transmission (pathogen found in food and/or water, aka oral-fecal transmission); vector-borne transmission (insect, arthropod).

Question 39

Put the following in proper sequence, according to the pattern of disease: period of decline, period of convalescence, period of illness, prodromal period, incubation period

Answer 39

1) Incubation period 2) Prodromal period 3) Period of illness 4) Period of decline 5) Period of convalescence

Question 40

Contrast human, animal, and nonliving reservoirs, and give one example of each

Answer 40

Human reservoir: human who is hosting a pathogen and can transmit it to others e.g. measles Animal reservoir: animal that is hosting a pathogen and can transmit it to others e.g. bats are a reservoir for coronaviruses Non-living reservoir: inanimate object where a pathogen can survive and multiply e.g. soil can host Clostridium tetani

Question 41

Define healthcare-acquired infections and explain their importance

Answer 41

HAI are infections that develop while receiving care in a healthcare setting. Can cause serious illness and death.

Question 42

List several probable reasons for emerging infectious diseases, and name one example for each reason.

Answer 42

Ecological changes: Valley fever and many other fungal diseases are expanding into new geographic areas because of rainfall patterns, temperatures, and extreme weather events. Human behavior: it is thought that humans were first infected with HIV due to close contact with chimpanzees (perhaps bushmeat hunting) in isolated areas of Africa. Travel: West Nile virus was likely introduced to North America via an infected mosquito carried into New York.