Lecture 3: Microbes and Disease Flashcards
test of malignancy in the 1950s
take cells out of body, and they continue to live
test of malignancy in the 1950s
take cells out of body, and they continue to live
dengue fever
athropod (mosquitos)
having an immune response is pretty bad… the virus infects B or T cells
so its hard to figure out a vaccine
Florida
Norovirus
aersolized
easily infects people in close quarters
Smallpox
dsDNA, enveloped… very stable virus
first virus to be erradiacted
we don’t even vaccinate against it anymore
pretty large genome
why don’t we vaccinate against smallpox?
1 in a million people die from the vaccine
why risk dying for a disease we dont have anymore?
Whats special about smallpox
its as close to living as a virus gets
just doesn’t have ATP or ribosomes… otherwise like its living
smallpox stability
doesn’t mutate much bc dsDNA… most stable form
what does smallpox have
it brings a ton of proteins with it
so it can do all catabolism and metabolism by itself… just needs host ribosomes and ATP
has own polymerases (DNA and RNA)
ease of vaccinating against smallpox
target the different
easy to target it’s protiens
vaccine is cheap to make
smallpox lifecycle
enter cell uncoating transcription (viral RNA polymerase) DNA replication (viral DNA polymerase--only group with this) viral packaging cell lysis (causes pox)
hosts of smallpox
no Non-human hosts
so once you erradicate it, its gone
how vaccine was discovered
milkmaids never got smallpox, just cowpox on their hands
the word vaccine
from Vaccina virus: cowpox virus…80% identical to smallpox virus
How smallpox was erradicated
mointoring the disease
when someone gets sick, vaccinate everyine within a 10 mile radius
Larry Brillant
RNA viruses
very UNSTABLE… high rate of mutations
because it lacks PROOFREADING ability… because of its two enzymes
the reason we have a core genome of DNA?
its more stable than RNA
also, DNA has proofreading abilities
RNA enzymes
RNA dependent RNA polymerase (RNA to RNA)
Reverse Transcriptase (RNA to DNA to RNA)
NEITHER CAN PROOFREAD
HIV
retrovirus
reverse transcriptase
(+) ssRNA, enveloped
infects many cell types
reverse transcriptase
insert viral genome into host DNA
HIV
retrovirus reverse transcriptase (+) ssRNA, enveloped infects many cell types no vaccine
reverse transcriptase
insert viral genome into host DNA
HIV and CD4 T cells
helper T cells regulate immune system
AIDS and CD4 T cells
you’re sick all the time beacuse your CD4T cells cant fight anything off
even food can make you sick (Tfolic? or Treg?)
AIDS
depletion of immune cells the disease (HIV is the infection)
AIDS and Kaposi Sarcoma Virus (herpesvirus)
Kaposi Sarcoma Virus is carried by 40% of people, its often transmitted, but RARELY CAUSES DISEASE
but if you have AIDS, it causes cancer
review graph on slide 12
12
ways HIV is transmitted
sex blood transfusion birth needles blood to blood contact basically
HIV Replication
- enveloped virus fuses with and enters cell
- makes dsDNA in cytosol, then gets into nucleus (Reverse transcription of RNA to DNA)
- integrates into host genome
- viral RNA replicated
- translation to pro-protein
- viral protease cleavage
- viral reconstruction and egress
How does HIV work
converts cell into HIV factory bc goes to nucleus
all virions are a little different
different HIV virions… what does this mean for immune system
immune system looks for molecular patterns… but changes mean there are differnt patterns that may not be recognized
if you do figure out a good immune response, the virus will mutate around it
How does HIV work
converts cell into HIV factory bc goes to nucleus
all virions are a little different
virus shed like crazy
send a bunch of stuff out… lots of it different (high mutation rate)
different HIV virions… what does this mean for immune system
immune system looks for molecular patterns… but changes mean there are differnt patterns that may not be recognized
if you do figure out a good immune response, the virus will mutate around it
How we treat HIV
HAART drugs
3 different drugs that target 3 different parts of the virus simultaneously
you have to take the virus consistently, or the virus can become resistant or get a chance to mutate
where is HIV?
in EVERY nation-worldwide
its a Pandemic
we expect 0 HIV
review slide 15
15
point of graph on 15?
number of new infected decreasing
number of deaths decreasing
number living with HIV decreasing
THIS MEANS PEOPLE AREN’T DYING AS MUCH FROM HIV
Magic johonson effect
at first safe sex
when he didnt die, people think HIV is not a death sentence, unprotected sex and STIs increase
Magic johonson effect
at first safe sex
when he didnt die, people think HIV is not a death sentence, unprotected sex and STIs increase
Patient Zero
a flight attendant who slept with 2500 people in North American even though he knew he had HIV
where did HIV come from
jump from human to chimps around 1900–railroad to heart of congo
it had probably jumped before, but now it could get out into the world
butchering chimps..lots of blood
arose in chimps half a million years ago… 2 viruses recombined to make HIV
US and spread of HIV
US spread it to a TON of other countries
US and spread of HIV
US spread it to a TON of other countries
infection
thing gets into body
HIV
NOT the disease, NOT the ability to cause disease
Disease
immune response
set of symptoms
age could be considered a disease
AIDS
Pathogenesis
study of how pathogens cause disease
measurement of disease causing potential
eitological agent
cause of disease
pathogenesis
bacterium, virus, other organism causing disease
Germ theory of disease
all diseases have microbial origin
this isnt entirely correct
when does infection cause disease
when immune system responds or the infection causes damgae
virulence
measure of disease causing potential
more virulent=more disease in more people
Virulence factors
genes that increase virulence of organism
ID 50
infectious dose 50%: amount needed to transmit the disease among 50% of people exposed
LD 50
Lethal Dose 50%: amount needed to kill 50% of people
LD 50
Lethal Dose 50%: amount needed to kill 50% of people
is homosexuality a cause of HIV
NO
its literally just blood to blood contact
is homosexuality a cause of HIV
NO
its literally just blood to blood contact
we’ve been talking about HIV-1, theres also HIV-2
HIV-2 in Africa
from Mangabes monkeys
