Chapter 14: Pathogens, Disease, and Epidemiology

Question 1

Define: microbiome

Answer 1

the collection of fungi & archaea found (in) & on the human body

Question 2

Define: normal flora

Answer 2

REDIDENT FLORA
organisms colonized w/after birth stay w/you rest of life

Question 3

Define: transient flora

Answer 3

Occasionally picking up some pathogenic some aren’t
3:1 (microbial cells: human cells)

Question 4

Define: microbial antagonism

Answer 4

competition cover attachment sites that might be available to pathogen
Help develop the immune system

Question 5

Define: opportunistic
pathogen

Answer 5

microorganisms that cause disease when the immune system is suppressed when microbial antagonism is reduced or when introduced into an abnormal area of the body

Question 6

Define: reservoir of infection

Answer 6

a site where pathogens are MAINTAINED as a source of infection (for a long time)
1)human reservoirs
2)human carriers
3) nonliving reservoirs

Question 7

Define: virulence

Answer 7

the degree of pathogenicity of a microbe (how good it is @ causing disease)

Question 8

Define: virulence factor
Aviralent

Answer 8

traits that allow pathogens to cause disease → traits that aid growth & avoid immune cells
1) An Adhesion mechanism
2) Extracellular Enzymes
3) Toxins
4) Antiphagocytic Factors
Aviralent: pathogen that loses its ability to make a virulence factor (can’t cause disease)

Question 9

Define: fomites

Answer 9

objects inadvertently used to transfer pathogens to new hosts, such as glass or towel

Question 10

Define: epidemiology

Answer 10

the study of the spread of disease in population
-helps determine source of infection & control methods

Question 11

Define: incidence

Answer 11

of NEW cases of disease in a population or area

Question 12

Define: prevalence

Answer 12

total # (new+existing) of a disease in a given population/geographical area

Question 13

Define: endemic

Answer 13

disease that occurs in that REGION (always have some level of disease)

Question 14

Define: sporadic

Answer 14

rare

Question 15

Define: epidemic

Answer 15

can have disease
-more than normal # for specific population or area

Question 16

Define: pandemic

Answer 16

many epidemic occurring in different areas

Question 17

Define: disease

Answer 17

adverse body conditions that interferes w/normal body conditions

Question 18

Define: symptoms

Answer 18

SUBJECTIVE(things that can’t be measured)
-complaints, what pt feels, includes headache, nausea, pain

Question 19

Define: signs

Answer 19

OBJECTIVE (characteristics of a disease)
-can be seen by others
-swollen lymph nodes, fever, swelling

Question 20

Define: syndrome

Answer 20

when a group of symptoms & signs collectively characterize a disease (AIDS)

Question 21

Define: asymptomatic

Answer 21

if a disease has no symptoms (but may have signs)

Question 22

Define: acute

Answer 22

disease that is rapid onset, brief (duration of symptoms)

Question 23

Define: chronic

Answer 23

disease that is slow onset, continual or recurrent

Question 24

Define: latent

Answer 24

inactive for a long time (long period of inactive months, years, no definitive reoccurrence

Question 25

Describe the importance of the human microbiome.

Answer 25

WHERE DID ALL THESE MICROBES COME FROM?
-What microbes exist in certain diseases or pregnancy, bowel disease, type-2 diabetes

Question 26

Distinguish between contamination and infection

Answer 26

Infection successful invasion of the body’s defenses the microbe can grow & have change in immunity infection but no disease or can get disease

Contamination acquiring microbes (@ birth contaminated w/microbes may not cause disease)
-transient or normal flora

Question 27

List the 3 types reservoirs of infection in humans

Answer 27

1. Animal reservoirs: disease spread by animals area called ZOONES
   -Transmission: eating animal, contract w/waste, biological vectors (mosquito, flies), animal bites (transmit microbial pathogens)
   -can be hard to control if reservoir is large and sylvatic wild animals
2. Human carriers: asymptomatic infected individuals, may or may not have previously shown disease symptoms
   -Typhoid Mary
3. Nonliving reservoirs:
   Water (Giardia/E.Coli)
   Soil (Clostridium/Bacillus)
   Food (E.Coli)
   -fecal oral route

Question 28

List the portals of entry that organisms can use to get into the body

Answer 28

1) Skin (good barrier)
Direct(burrow, digest)
Hair follicles & sweat glands
2) Mucus Membrane
Easier to cross than skin
Most common
3) Placenta
Not good barrier

Question 29

List and describe the five stages of an infectious disease

Answer 29

INCUBATION PERIOD: time differ based on pathogen
PRODROMAL PERIOD: time of first mild, vague symptoms (# of microbes ↑)
ILLINESS PERIOD: symptoms are most severe & obvious most damaging to host ( highest # of pathogens)
DECLINE PERIOD: undergo treatment and/or full immune response to limit & destroy pathogen
CONVALESCENCE PERIOD: recovery w/ no signs/ symptoms there could be some pathogens in body. Tissue/damage is repaired

Question 30

List the portals of exit that pathogens use to get out of the body

Answer 30

SKIN (broken- blood)
MUCUS MEMBRANES
BODY SECRETIONS
BODY WASTES

Question 31

Describe the main types of virulence factors

o Describe the importance of adhesion to a pathogen.

Answer 31

1) Adhesion
infection requires attachment to a host
-adhesion factors ligands; bacteria
attachment proteins; viruses
provide host cell specificity
BIOFILMS indirect attachment via glycocalyx
2) Extracellular Enzymes
Secreted enzymes that aid the pathogens to survive in the host get nutrition/ evade immune cells
3)Toxins
chemicals that harm tissues or trigger immune responses that harm tissues
-Exotoxins secreted outside of cell/pathogen (s. aureus)
-Endotoxins: structural component of a pathogen (part of cell) that is released when the organism dies (lipid A)
4) Antiphagocytic Factors: against immune cells destroy invaders
-Chemicals or structures that prevent the completion of phagocytosis
-CAPSULES prevent phaygocyte from attaching pathogen

Question 32

Distinguish between contact, vehicle, and vector transmission of disease

o List an example of each mode of transmission

Answer 32

1) Contact: pathogens spread by people or objects (fomites) people have touched
-Direct: “person to person”
ex: kissing, sex, placenta
-Indirect: Via fomites inanimate objects that carry pathogens
ex: toys, needles, money
Droplet Transmission: droplets travel less that 1 meter

2) Vehicle: pathogens spread by air, food, water, or donated fluids
-Airborne: droplets that travel more than 1 meter (by AC)
-Waterborne: any contaminated water source (fecal oral route)
-Foodborne: spoilage in food
-Bodily Fluid: handled outside of the body
ex: blood products, clinical fluid samples

3) Vector: pathogen spread by insect
-Biological vectors: pathogen reproduces within vector transmission of pathogen when vector bites animals
ex: mosquito, ticks. fleas
-Mechanical vectors: pathogen doesn’t reproduce within vector pathogen on feet or other body parts
ex: cockroach houseflies crawl through contamination & crawl on food to contaminate)

Question 33

Explain how epidemiology is important to human health.

Answer 33

it helps determine the source of infection & control methods

Question 34

Define Symbiosis

Answer 34

two organisms living in assocatition w/one another

Question 34

Define Symbiosis

Answer 34

two organisms living in assocatition w/one another

Question 35

3 types of symbiotic relationships

Answer 35

1. Mutualism both organisms benefit
   ex bacteria in human colon
2. Commensalism: one benefits other neither benefits nor is harmed
   ex: staphylococcus on skin
3. Parasitism: one benefits other is harmed
   ex: tuberculosis bacteria in human lungs
   -parasite benefit @ harm of it’s host