Biology -Immune system - The AIDS virus

HIV(human immunodeficiency virus) is the virus that causes the disease known as AIDS(acquired immunodeficiency syndrome). This virus attacks the immune system, in particular the white blood cells(lymphocytes) responsible for destroying it. The virus invades the white blood cells and remains dormant for a long period of time, sometimes up to 10 years. A trigger signal causes the virus to become active multiplying and destroying the white blood cell. As the immune system is severely weakend other diseases, such as cancer and infections from pathogens take hold. The body is soon overcome and death results.

Fortunately for us the virus is not as easy to spread as the flu virus. The HIV has a fragile protein coat that is easily damaged when exposed to the air. Unlike the tough flu virus that can be transmitted by coughing and sneezing the HIV needs to be transported in body fluids, such as blood and semen. The HIV does not appear to be transmitted by kissing or sharing drinking glasses.

Transmission is most likely to occur through such practices as:

Having unprotected sexual intercourse with someone who has the virus
Sharing needles or syringes with someone with the virus
Receiving a blood transfusion from someone infected with the virus
Getting HIV-infected blood, semen, vaginal secretions into open wounds or sores.
Receiving an organ or tissue from an infected person
Having artificial insemination with the sperm from an infected person
Becoming accidentally punctured or cut with a needle or surgical instrument contaminated with the virus
The virus may pass from a woman to her fetus during pregnancy and may also be passed to an infant through the mother's breast milk.

Reference was made to http://aidshistory.nih.gov

The AIDS virus.
HIV(human immunodeficiency virus) is the virus that causes the disease known as AIDS(acquired immunodeficiency syndrome). This virus attacks the immune system, in particular the white blood cells(lymphocytes) responsible for destroying it. The virus invades the white blood cells and remains dormant for a long period of time, sometimes up to 10 years. A trigger signal causes the virus to become active multiplying and destroying the white blood cell. As the immune system is severely weakend other diseases, such as cancer and infections from pathogens take hold. The body is soon overcome and death results. Fortunately for us the virus is not as easy to spread as the flu virus. The HIV has a fragile protein coat that is easily damaged when exposed to the air. Unlike the tough flu virus that can be transmitted by coughing and sneezing the HIV needs to be transported in body fluids, such as blood and semen. The HIV does not appear to be transmitted by kissing or sharing drinking glasses. Transmission is most likely to occur through such practices as: Having unprotected sexual intercourse with someone who has the virus Sharing needles or syringes with someone with the virus Receiving a blood transfusion from someone infected with the virus Getting HIV-infected blood, semen, vaginal secretions into open wounds or sores. Receiving an organ or tissue from an infected person Having artificial insemination with the sperm from an infected person Becoming accidentally punctured or cut with a needle or surgical instrument contaminated with the virus The virus may pass from a woman to her fetus during pregnancy and may also be passed to an infant through the mother's breast milk. Reference was made to http://aidshistory.nih.gov
The HIV attaches to a T-lymphocyte (a type of white blood cell). Viral DNA is released and enters the nucleus where it takes control of the cell. Viral protein and genetic material is produced and asembled into new viruses. The new virus particles bud out from the cell to infect other cells. Slight changes in the shape of the new viruses make them resistant to attack by the antibodies already in the blood. The T-lymphocyte is eventually destroyed.
Why did AIDS spread so quickly through the gay community? The answer is in the physiology of the human body. The rectum is designed to absorb water back into the body and prevent dehydration. For this purpose the wall of the rectum is very thin and easily damaged during anal intercourse. White blood cells patrol close to the surface, engulfing any bacteria that may enter the body. Any damage to the wall of the rectum exposes white blood cells to infected semen.
It is not the HIV that will kill an infected person but most likely cancer. Explain why? It is unlikely that infected blood spilled on the hand can infect a person. Why?