Download AIDS

L2 Biology
What is AIDS?
• AIDS = Acquired Immunodeficiency Syndrome
• Deadly disease caused by:
– HIV – Human Immunodeficiency virus
Structure of HIV
gp 120
RNA
gp 41
p24
p17
Enzyme*
Enzyme*
*Enzymes – reverse transcriptase,
integrase and protease
Gp = glycoprotein; p = protein (number is how big it is)
How does HIV attack a cell?
1
2
3
5
4
6
Steps of an HIV infection:
1. Virus attaches to Helper T cell (one of the white
blood cells in the immune system).
2. Virus sends its RNA into cell.
3. RNA codes back to DNA – needs reverse
transcriptase (enzyme).
4. DNA becomes part of the cell’s DNA – needs
integrase.
5. Cell starts to make parts for new HIV particles.
6. New HIV parts come together in cell (needs
protease) and “bud” out of cell membrane –
takes a part of cell membrane to become the
virus’ envelope.
Click here for an HIV animation:
Helper T cells
• These are the cells that start the immune response
by alerting the other cells that there is a foreign
protein (like a virus or bacteria cell) in the body.
• When a lot of them die because they are making
HIV instead of the proteins they need, then the
person can’t fight infections.
• If the Helper T cell count gets below 500 cells/ml,
the person gets opportunistic infections. Below
200 cells/ml, the person has AIDS and gets lifethreatening infections.
How do you get HIV?
• Sexual activity – unprotected sex passes
infected fluids from a person with HIV to a
person without it.
• Contaminated needles – IV drug users
share needles – if the person who just used
it has HIV, then the next person to use it can
get HIV.
• Mother to baby –during the birth
process or breastfeeding
HIV cannot be caught by:
• Coughing and sneezing droplets in the
air
•
Kissing, touching or shaking hands
• Sharing eating utensils or glasses
• Contact with toilet seats
• Insect or animal bites
• Swimming pools
• Eating food prepared by someone with
HIV
How do you prevent HIV?
• ABSTINENCE !!!!!!!!
• Never have unprotected sex
• Have only one sex partner who is free of the
disease
• Don’t use iv drugs
• Stay away from unknown blood – fights and
rough sports can expose you.
• Pregnant mothers who are HIV+ should get
treatment to prevent the baby from getting it.
What happens during the disease?
1. Asymptomatic – May last years.
2. Eventually – swollen glands, slight
infections – may seem like the flu, may
recover, then symptoms return and stay.
During this time, T-cells are being
destroyed. The infections are those that a
person with a normal immune system
would not get. AIDS-related complex.
3. When T-cell count is too low, then the
person gets life-threatening infections AIDS
Symptoms:
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•
•
•
Fever
Swollen glands
Night sweats
Unexplained weight loss
Kaposi sarcoma – reddish/brown
cancer on skin
• Many others
Diagnosis:
• Blood test can tell if your body has made
antibodies against HIV – if they’re in your
blood – you have been exposed to HIV
• Be careful – the test might be given too
soon after infection – you may not have
made enough antibodies to give a positive
test, even though you have HIV.
• Test results are private and confidential.
Treatment
• Enzyme inhibitors –
– Reverse transcriptase inhibitor
– Integrase inhibitor
– Protease inhibitor
• Many kinds of drug combinations are in use
today – expensive and have many bad side
effects.
Click here for an HIV animation
including drug treatments:
AIDS statistics - People living with
AIDS in the US:
• At the end of 2003, the CDC estimates that
405,926 persons were living with AIDS, of
these:
36% were white
42% were black
20% were Hispanic
2% were of other race/ethnicity.
• Of the adults and adolescents in the US
with AIDS, 77% were men. Of these men:
58% had sex with men (MSM)
22% were injection drug users (IDU)
11% were exposed through
heterosexual contact
8% were both MSM and IDU.
Of the 88,815 adult and adolescent
women in the US with AIDS:
• 63% were exposed through heterosexual
contact
• 35% were exposed through injection drug
use.
• An estimated 1,998 children were living
with AIDS in the US at the
end of 2003.
• Persons with AIDS are surviving longer and
are contributing to a steady increase in the
number of people living with AIDS. This
trend will continue as long as the number of
people with a new AIDS diagnosis exceeds
the number of people dying each year.
How can you
avoid getting
AIDS?
•The
The End
End