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 Capsid RNA 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 cell dead T cell antibody activated B 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