quiz 3

epidemic

a surges in cases of a particular disease in a population

what were epidemics first believed as

divine intervention as punishment for immoral behavior

now we know that epidemics are caused by

infectious agents

three disease agents that have likely caused most human deaths

smallpox virus, measles virus, plague bacterium

germ theory

the idea ontagious diseases are spread by microorganisms that infect susceptible people to cause disease

who is known as the father of epidemiology

john snow

koch’s postulates establish

a causative relationship between microbe and an infectious disease

what are the 4 major biological agents that cause infectious disease

viruses, bacteria, fungi, parasites

are viruses cellular

no - require host cell to replicate

what is bacteria

cellular organisms whos cells are different than ours. they can be free living or intracellular pathogens

what is fungi

cellular organisms whos cells are similar to ours that have a cell wall in addition to a membrane

what are parasites

organisms are are uni or multicellular. can be free living or intracellular

what type of treatment is used against viruses?

antivirals

What type of treatment is used against bacteria?

antibacterials

What type of treatment is used against fungi?

antifungals

What type of treatment is used against parasites?

antiparasitics

the microorganisms is always found

in host cells suffering from the disease

the microorganism must be isolated from

a diseased host and grown in pure culture

what does the cultured microorganism cuase

the same disease when introduced into a healthy individual

the microorganism can be re-isolated from a

diseased experimental host and shown to be identical to the original causative agent

epidemiology

branch of medicine that study diseases on the population level

transmission rates represents

the efficiency of transmitting the infectious agent from an infected individual to a suspectible person

what are the two factors that affect transmission rate

inherent efficiency and encounter rates

inherent efficiency

how easily a diease can infect someone who is susceptible

R₀

basic reproduction # - how many people are infected on avg by an infected indiv

the inherent efficiency is a

biological fact we cant control

encounter rate is between

an infected and uninfected person

how can encounter rates be reduced

intervention strategies

how does the influenza evolution evolve

drift and shift

what is influenza drift

mutations in the viral proteins that allow the virus to enter cells

what is influenza shift

major changes that occurs by mxing different viral strains

what is poliomyelitis

causative agents of children paralysis

who is the host of polio

humans

what are the 3 polio viruses

PV 1, 2, 3

Why did improved hygiene contribute to more severe polio disease?

delayed exposure to PV in later ages