AIDS is caused by a virus called HIV. An infected person will develop large amounts of HIV particles in the blood, seminal fluid and vaginal secretion. Common route of transmission is through sexual contact and sharing of needles and syringes among intravenous drug abusers. The disease can also be transmitted by an infected mother to the foetus during pregnancy.

Individuals will test HIV antibody positive two to three months after becoming infected. HIV is also found in their blood, that means they become HIV carriers. About 50% of the HIV carriers develop full- blown AIDS within ten years. Their immunity system is seriously damaged. Signs and symptoms of AIDS include high fever, profuse sweating, enlargement of the lymph nodes, loss of body weight, chronic cough, diarrhoea, and most of them will subsequently die of multiple infections.

Before AIDS is developed, most HIV carriers appear healthy with no sign or symptom of the illness. The only way to ascertain that they are the HIV carriers is through blood testing. In the early stage of infection, that is up to three months, HIV antibody may not be detected. Individuals engaged in high risk activities such as being sexually promiscuous, having male to male sex and intravenous drug usage should refrain from blood donation. All the blood collected is tested for the presence of HIV antibodies. Blood which is tested positive is discarded. All information and test results concerning a HIV carrier is treated in strict confidence, and the donor concerned is informed and with his or her consent referred to a specialist medical clinic for further follow up.