Essential Terms- Lectures 1 + 2

Question 1

Define Pathogen

Answer 1

a microorganism capable of causing disease

Question 2

Define Pathogenicity

Answer 2

a microorganism’s ability to cause disease, how effective pathogen is

Question 3

Define Pathogenesis

Answer 3

steps or mechanisms involved in the development of the disease

Question 4

Define Pathology

Answer 4

study of the structural and functional manifestations of the disease

Question 5

Define Infection

Answer 5

successful colonization by a microorganism

Question 6

Define Infectious Disease

Answer 6

disease caused by a microbe, microbes that cause this disease are collectively called pathogens

Question 7

Describe HPV

Answer 7

Human Papilloma Virus, responsible for warts and genital warts by attacking keratinocytes, long incubation period, can cause various cancers

Question 8

Robert Koch + 4 postulates

Answer 8

formulated Koch’s postulates, all must be satisfied to prove that an infectious agent causes a disease

1. Suspected agent present in all cases of disease
2. Agent isolated and grown in pure culture
3. Cultured agent must be able to cause disease when introduced into healthy host
4. Same agent able to be re-isolated from diseased host

Question 9

Describe the Triangle of Relationships

Answer 9

3-way interaction between microbes, humans, and drugs, resistance occurs continually because all 3 are constantly adapting

Question 10

Communicability + 4 factors affecting it

Answer 10

infectious disease that can be transmitted (directly or indirectly)

1. Source of infection, including carriers
2. Number of infectious agents released from host
3. Capable of surviving between hosts
4. Percent of host population susceptible to the agent

Question 11

Describe spreading factors/invasins

Answer 11

large family of enzymes that affect tissues and intercellular spaces to aid the spread of the pathogen eg. collagenase

Question 12

Define Exotoxin

Answer 12

toxin secreted by a pathogenic microorganism into the environment, good immunogen (strong immune response)

Question 13

Define Endotoxin

Answer 13

complex polysaccharides (LPS) that are part of the bacterial cell wall, poorly immunogenic, heat stable, released when cells lyse

Question 14

Define Immunogen

Answer 14

describes ability to cause an immune response, good immunogen causes a strong immune response

Question 15

Describe A-B Toxins and their mode of action

Answer 15

toxins active inside cells, A chain is inhibitory active against vital function, B chain binds receptor and promotes entry of A chain.
toxin inhibits protein synth., inhibits neurotransmitter release, or causes hypersecretion

Question 16

Define Virulence

Answer 16

degree of pathogenicity
highly virulent=always cause disease
less virulent=only cause disease in immunocomprimised hosts or when present in large numbers

Question 17

Define Mutualism

Answer 17

both members benefit from interaction, it may or not be a required relationship eg. bacteria in human colon

Question 18

Define Commensalism

Answer 18

one member benefits from interaction while the other is unaffected eg. Staph epidermis on the skin

Question 19

Define Parasitism

Answer 19

parasite gains positive benefits from the host, while host receives damage, may be minor or as severe as death eg. tuberculosis in the lungs

Question 20

Define Resident Flora

Answer 20

remain as a part of the normal microbiota throughout the hosts’ life, most are commensal, feeding on wastes and causing no harm

Question 21

Define Transient Flora

Answer 21

only remain in the body for a limited time before leaving, cannot remain due to body’s defenses, competition with microorganisms, or changes in the hosts’ body

Question 22

Define Opportunistic Pathogen

Answer 22

microorganism which normally would not cause disease, but may given various situations:

• introduction to unusual site in the body
• immunocomprimised host
• changes in normal microbiota

Question 23

Define Sign

Answer 23

subjective characteristics that are felt by the patient but not easily measured eg. headache

Question 24

Define Symptom

Answer 24

objective characteristics that are easily measured eg. fever temperature

Question 25

Define Syndrome

Answer 25

collection of signs and symptoms that describe a specific disease or condition

Question 26

Define Incubation Period

Answer 26

in infectious disease process, stage from infection to appearance of first signs or symptoms of disease

Question 27

Define Prodromal Period

Answer 27

in infectious disease process, this is a short period of mild generalized signs and symptoms before illness

Question 28

Define Illness

Answer 28

in infectious disease process, this is the most severe period of signs and symptoms of disease

Question 29

Define Decline

Answer 29

in infectious disease process, period where body is gradually returning to normal, immune response and treatment are destroying invading microorganisms

Question 30

Define Convalescence

Answer 30

in infectious disease process, patient recovers, tissues and systems are repaired and return to normal

Question 31

Define Dead End Host

Answer 31

host from which infectious agents are not spread to other hosts

Question 32

Define Nosocomial Disease

Answer 32

disease acquired in a healthcare facility

Question 33

Define Iatrogenic Disease

Answer 33

subset of nosocomial disease that is a result of treatment or procedure, such as surgery

Question 34

Define Zoonotic Disease

Answer 34

disease spread from an animal host to a human

Question 35

Define Exogenous Disease

Answer 35

acquired in healthcare environment but was not already present in body

Question 36

Define Endogenous Disease

Answer 36

already had pathogen present, but being in healthcare facility triggered it, opportunistic pathogen

Question 37

Define Descriptive Epidemiology

Answer 37

careful recording of data concerning a disease

Question 38

Define Analytical Epidemiology

Answer 38

detailed investigation of the disease, including analysis of data, probable cause, mode of transmission and means of treatment

Question 39

Define Experimental Epidemiology

Answer 39

testing of hypotheses resulting from analytical epidemiology to determine the cause of the disease

Question 40

Define Epidemiology

Answer 40

study of occurrence, distribution, and spread of disease in humans

Question 41

Define Incidence

Answer 41

number of new cases of a disease in a given area or population during a given period of time

Question 42

Define Prevalence

Answer 42

total number of cases of a disease in a given area/population in a given period of time

Question 43

Define LD50

Answer 43

lethal dose 50, minimum # of bacteria required to kill 50% of population

Question 44

Define mode of disease transmission (contact, vehicle, vector)

Answer 44

indirect-touching intermediate objects between people | direct-coughing on someone over a meter away

Question 45

Define Mononuclear Cells

Answer 45

macrophages or dendritic cells, induced by cytokine action

Question 46

Define Neutrophil

Answer 46

type of granulocyte, does phagocytosis, agent in innate immune response

Question 47

Define Opsonizing

Answer 47

antimicrobial proteins called opsonins coating a pathogen to make them more vulnerable to phagocytes

Question 48

Define Agglutinating

Answer 48

clumping caused when antibodies bind to two antigens, hindering activity of the pathogen and increasing chance of phagocytosis

Question 49

Define Reservoir of Infection

Answer 49

living or nonliving continuous source of infection