HIV stands for human immunodeficiency virus, a retrovirus that infects cells of the human immune system. Infection with HIV has been established as the underlying cause of AIDS. HIV is the subject of intense scientific research and basic information about HIV and AIDS is constantly changing.
The first AIDS cases were described in 1981. The name HIV has been used since 1986.
UNAIDS estimated that at the end of 2004 there were 35.9-44.3 million people around the world living with HIV, of whom 25.4 million were in sub-Saharan Africa. Global estimates for new HIV infection in 2004 were 4.3-6.4 million.
Transmission of HIV
HIV is transmitted through penetrative (anal or vaginal) and oral sex; blood transfusion; the sharing of contaminated needles in health care settings and through drug injection; and, between mother and infant, during pregnancy, childbirth and breastfeeding. UNAIDS transmison
WHO estimated in 2000, between 15% and 20% of new HIV infections worldwide were the result of blood transfusions, where the donors were not screened or inadequately screened for HIV.
There is no evidence that HIV can be transmitted through hugging, shaking hands or other simple physical contact where there was no bleeding involved - including contact with carrier's sweat. There is no evidence that HIV can be spread through vectors such as mosquitoes. Proper use of physical barriers such as the latex condom, have been shown to greatly reduce the risk of transmission of sexually transmitted diseases including HIV. HIV, however, in rare instances, has been transmitted through kissing.
Signs and symptoms
Most people infected with HIV do not know that they have become infected, because no symptoms develop immediately after the initial infection. Some people have a glandular fever-like illness (with fever, rash, joint pains and enlarged lymph nodes), which can occur at the time of seroconversion. Seroconversion refers to the development of antibodies to HIV and usually takes place between 6 weeks and 3 months after an infection has occurred.
Despite the fact that HIV infection does not cause any initial symptoms, an HIV infected person is highly infectious and can transmit the virus to another person. The only way to determine whether HIV is present in a person's body is by HIV testing.