31.6 Diseases that Weaken the Immune System When the immune system is weakened, the body cannot fight off disease.
Jan 03, 2016
31.6 Diseases that Weaken the Immune System
When the immune system is weakened, the body cannot fight off disease.
31.6 Diseases that Weaken the Immune System
HIV- Human Immunodeficiency Virus
– Causes AIDS – Retro virus (contains RNA)– Attacks Helper T-cells– Came from butchering
chimps (mutated SIV)
31.6 Diseases that Weaken the Immune System
HIV Structure
CapsidRNA
Reverse Transcriptase
Viral Envelope
Protein
31.6 Diseases that Weaken the Immune System
HIV Replication
31.6 Diseases that Weaken the Immune System
Transmission• Blood• Semen• Vaginal Fluids• Breast Milk
Not Transmitted• Air• Sweat• Saliva• Insect bites• Tears• Urine
How Do You Get HIV?
31.6 Diseases that Weaken the Immune System
HIV infection leads to AIDS
HIV
T celldeadT cell
antibody
activatedB cell
– HIV reproduces in and destroys T cells.– Might NOT have symptoms for 10 years!– AIDS victims do NOT die from HIV they die of
other diseases
31.6 Diseases that Weaken the Immune System
When Helper T-Cell count drops below 200 per mm³ =
Acquired Immune Deficiency Syndrome (AIDS)
31.6 Diseases that Weaken the Immune System
Treatments
• Antiretroviral drugs- reduces
HIV in the body
• Expensive $$$
• No cure but…March 2013 one
child was cured!
31.6 Diseases that Weaken the Immune System
HIV/AIDS Statistics (2010)
• World 34 million infected (3.4 million children)
• USA 1.1 million infected (1 in 5 unaware)
• Africa 23 million infected