AIDS L2 Biology

What is AIDS? AIDS = Acquired Immunodeficiency Syndrome Deadly disease caused by: HIV – Human Immunodeficiency virus                                                                                     

Structure of HIV gp 120 gp 41 RNA 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 6 4

Steps of an HIV infection: Virus attaches to Helper T cell (one of the white blood cells in the immune system). Virus sends its RNA into cell. RNA codes back to DNA – needs reverse transcriptase (enzyme). DNA becomes part of the cell’s DNA – needs integrase. Cell starts to make parts for new HIV particles. 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 life-threatening 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? Asymptomatic – May last years. 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. When T-cell count is too low, then the person gets life-threatening infections - AIDS

Symptoms: 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 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 End The End