Exam 4 Ch 18 Flashcards

1
Q

Zoonotic transfer

A

Spread of a infectious agent from its natural animal host to a human

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

vector-borne transmission

A

Spread of an infectious agent from an infected individual to another organism such as an insect that then transmits the infectious agent to a different susceptible host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

reservoir host

A

Natural host that supports replication of a pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Epidimieology

A

study of patterns of disease within populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

morbidity rate

A

Rate of disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

mortality rate

A

Rate of death associated with disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

incidence

A

Number of new cases of a disease appearing in a population during a specific time period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

prevalence

A

Total number of cases of a disease in a population at a particular time or during a particular time period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

endemic disease

A

Disease that is normally present in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

epidemic

A

Significant rise in incidence of a disease above that normally expected in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Outbreak

A

Cluster of cases appearing within a short period of time in a localized population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

pandemic

A

Global epidemic, usually on more than one continent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

primary pathogen

A

Microbe that causes disease in otherwise healthy hosts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

opportunistic pathogen

A

Microbe that causes disease only when a host has been compromised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

virulence

A

Degree of severity of disease a pathogen is capable of causing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pathogenecity

A

Relative measurement of the ability of a microbe to cause disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Virulence vs pathogenicity

A

Virulence describes directly how harmful a pathogen (SEVERITY) it is. Pathogenicity describes the overall process of infection such as transmission (ABILITY TO INFECT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Case-to-infection (CI) ratio

A

The proportion of infected individuals who develop the disease. Used to measure pathogenicity

19
Q

pathogenesis

A

Process by which a pathogen causes disease

20
Q

symptom

A

Subjective disease state, such as muscle aches

21
Q

sign

A

Objective disease state that can be readily observed or measured, such as a rash or fever

22
Q

symptom vs sign

A

symptom is subjective and sign is objective

23
Q

virulence factor

A

Product made by a pathogen that enhances its ability to cause disease

24
Q

antigenic variation

A

Change in molecules on the surface of a pathogen to which the immune system responds; can allow pathogen to avoid immune detection

25
latent infection
Infection characterized by a delay or cessation of disease; in viral disease, characterized by limited transcription of the viral genome; results in reduced immune response; see also latency
26
autophagy
Intracellular degradation in which materials to be destroyed are encased in a membrane and sent to the lysosome
27
toxin
Substance of biological origin that damages a host
28
apoptosis
Cell death accomplished through a highly ordered and tightly controlled cascade of chemical-signaling events within the cell that results in its destruction without the release of damaging cell constituents or triggering of inflammation
29
necrosis
Cell death that occurs through chemical or physical cell injury or loss of oxygen supply; results in cell rupture and the release of toxic cellular contents and cytokines to the surrounding tissues, producing further cell death and triggering inflammation
30
fomite
Inanimate object via which pathogens may be transferred to a susceptible host aka water or food
31
Indirect trasmission
Spread of an infectious agent from one individual to another via an object, like a contaminated inanimate object, water, food, or an insect
32
Direct transmission
Spread of an infectious agent via physical contact between an infected individual and a susceptible individual
33
Koch's postulates
Guideline for demonstrating that a specific microbe causes a specific disease: 1. The suspected microbe should exist in every individual with the disease and account for the signs and symptoms of the disease. 2. The microbe should not be fortuitously associated with other diseases as a non-pathogen. 3. After being isolated and grown in a pure culture, the microbe should cause the same disease following inoculation of a healthy host. A fourth postulate, stating that the suspected microbe then should be re-isolated from an experimentally inoculated host, often has been added to this original list.
34
Molecular Koch's postulates
Guideline using molecular tools to demonstrate that a specific microbial product is a virulence factor: - The virulence factor gene should be present and expressed in pathogenic strains of the microbe. - Experimental inactivation of the virulence factor gene should lead to a decrease in virulence. - Experimental reversion of this inactivating change should result in a restoration of virulence. - The virulence factor gene should be expressed during an infection. Resistance to the virulence factor must provide protection.
35
prevalence vs incidence
prevalence is the total number of cases over a period of time or at a specific time. Incidence is the number of new cases over a period of time. Ex: There were 500 cases of the flu during November. 400 started in November. The 500 cases are the prevalence, and the 400 new ones are the incidence.
36
horizontal trasmission
Spread of an infectious agent between members of a species that are not parent and offspring
37
vertical trasnmission
Spread of an infectious agent from parent to child
38
pathogenic islands and their role in making new pathogenic microbes through horizontal gene transfer
Region of a chromosome containing multiple virulence factor genes. They are sometimes transferred to non-pathogenic bacteria creating new pathogens
39
Be familiar with horizontal gene transfer mechanisms: transduction, transformation, conjugation.
Transduction: the process by which DNA is transferred from one bacterium to another by a virus. Transformation: a process where bacteria can uptake foreign extra-cellular DNA conjugation: DNA is transferred from a donor to a recipient bacterium by direct contact
40
Steps of a microbe causing disease
1. Gain entry into host 2. Attach to target organism/cells 3. Evade host defenses 4. Obtain nutrients from the host 5. Exit the host
41
How does attachment occur
Most commonly through protein-to-protein interactions: viruses tend to bind to specific host cell receptors Less commonly attachment occurs through generalized interactions: rice blast fungus attaching to hydrophobic surfaces like cells
42
How do microbes evade host defenses
Antigenic variation, latency, capsules, phage evasion, or phage defense
43
exotoxins
produced by bacteria that cause immune responses
44
endotoxins
part of the microbial itself