host pathogen co-evolution

Question 1

epidemiology

Answer 1

the study of distribution and determinants of disease

Question 2

morbidity vs mortality

Answer 2

morbidity: condition of suffering from a disease or medical condition, measure the rate of disease in a population (think “co-morbidities” dont kill ppl it just means they have something)

mortality: measure rate of death (mortal = limited life)

Question 3

case fatality rate

Answer 3

measure of death by a specific disease

Question 4

pathogen

Answer 4

an organism that causes disease. viruses, bacteria and other microbes.
can be facultative (the host is only one niche it can exploit to reproduce) or obligate (require hosts to fulfill life cycle)

Question 5

Host

Answer 5

living organism that acts as a harbour for invading pathogenic organisms. obtains nutrition and shelter

Question 6

co-evolution

Answer 6

evolutionary changes that occur within 2+ organisms as a response to interactions between them, and the mutual selective pressures that those interactions cause

Question 7

mode of transmission

Answer 7

how an infectious agent/pathogen can be transferred to a person, object, animal, etc.

Question 8

direct transmission

Answer 8

pathogen spreads from one host to another host
respiratory, fecal-oral, sexual, congenital, direct contact

Question 9

indirect transmission

Answer 9

requires an intermediary host or agent to facilitate transmission of the pathogen between humans
food-borne, soil-borne, vector-borne

Question 10

zoonotic disease

Answer 10

disease of other animals that occasionally infect humans

Question 11

what are pathogen-immune system strategies

Answer 11

• killed by innate immune defences
• resistant to innate but killed by adaptive immune defences
• resistant to adaptive

Question 12

R-naught

Answer 12

R0- basic reproductive number of pathogen
expected number of cases generated by one case
measure of how contagious it is
good measure of fitness in endemic diseases. selection favours early transmission and higher R0
genes that improve infectivity may increase or decrease virulence
must balance host survival and pathogen infectivity and virulence

Question 13

host and pathogens evolve differently, how?

Answer 13

hosts evolve to minimize fitness cost (virulence) of pathogen infections.
pathogens evolved to max their fitness, which means evolving traits that max their R0
pathogen virulence isn’t selected for, but is a byproduct of co-evolution

Question 14

Red queen hypothesis

Answer 14

species must continuously evolve just to keep up with each other
pathogens are under selection to infect more hosts, hosts are under selection to avoid infection

rare host genotype may have selective advantage, eventually this genotype will be common as they outcompete others

Question 15

dead end evolution

Answer 15

within host selection leads to growth of pathogens in critical organs and to increase in virulence even though it doesnt contribute to infectivity

kills host before it can spread the disease

Question 16

malaria life cycle

Answer 16

in human blood, pathogen multiplies. mosquito will drink the blood, taking in infected blood, and then bites/regurgitates blood into next victim.

sickle cell anemia may help protect the person from malaria, and is common in areas with high malaria

Question 17

what is sickle cell anemia?

Answer 17

genetic mutation that causes red blood cells to take on a different shape. theyre sticky and dont carry oxygen as well, but they dont allow for the virulence of malaria to take hold.

Question 18

how does antibiotic resistance happen?

Answer 18

many germs- some are resistant to drug
when all susceptible germs are killed, the resistant ones are left and take over. they can also give their drug resistance to other bacteria

Question 19

what is MDR?

Answer 19

multidrug resistant bacteria

Question 20

what is MRSA

Answer 20

a form of staph that is hard to treat because it is resistant to many antibiotics