HIV (Human Immunodeficiency Virus) is believed to have originated from simian immunodeficiency viruses (SIVs) found in primates in Central Africa. Scientific evidence indicates that HIV entered the human population through cross-species transmission and subsequently spread among people.
Genetic and historical research suggests that the major form of HIV-1 began spreading in Central Africa during the early 20th century. Population movement, urbanization, transportation and international travel later contributed to its spread to other parts of the world.
HIV/AIDS became recognized as a major global public-health issue during the 1980s. Since then, advances in medical research have significantly improved HIV testing, prevention and treatment.
Today, HIV can be effectively managed with modern medical treatment. With appropriate antiretroviral therapy (ART), many people living with HIV can live long and healthy lives.
HIV-positive, often written as HIV+, means that a person has been diagnosed with HIV infection. HIV-negative (HIV-) generally means that HIV was not detected by an appropriate test at the time of testing.
A person can have HIV without having AIDS. Early diagnosis and appropriate treatment can help prevent HIV from progressing to advanced disease.
No. HIV is not a hereditary or genetic disease. HIV is an infectious virus that can be transmitted through certain body fluids, including blood and other fluids capable of carrying the virus.
HIV transmission can be prevented through appropriate medical, behavioral and public-health measures.
HIV stands for Human Immunodeficiency Virus. HIV attacks the body's immune system, particularly CD4 cells, which play an important role in protecting the body against infections.
Without treatment, HIV can progressively weaken the immune system. Modern antiretroviral therapy (ART) can suppress HIV replication, protect the immune system and greatly reduce the risk of HIV-related illness.
A virus is a microscopic infectious agent that needs living cells to reproduce. HIV infects specific cells of the human immune system and uses those cells to make new copies of itself.
HIV is classified as a retrovirus. Its genetic material is RNA, and the virus uses an enzyme called reverse transcriptase during its replication process.
HIV can be transmitted when certain body fluids containing the virus enter another person's body. Important routes of transmission include:
HIV is not spread through ordinary social contact such as hugging, shaking hands, sharing food or water, or sitting together.
AIDS stands for Acquired Immunodeficiency Syndrome. It is the most advanced stage of HIV infection and can occur when HIV has severely weakened the immune system or when certain AIDS-defining conditions develop.
A CD4 count below 200 cells/mm³ is one important clinical criterion used in the classification of AIDS. However, HIV infection does not automatically mean that a person has AIDS. Effective treatment can prevent or delay progression to advanced disease.
At present, there is no generally available cure that eliminates HIV from the body. However, HIV can be effectively controlled with antiretroviral therapy (ART).
Treatment reduces the amount of HIV in the blood, helps protect the immune system and allows people living with HIV to live longer and healthier lives.
An important development in HIV treatment is that a person living with HIV who takes ART as prescribed and maintains an undetectable viral load does not transmit HIV through sexual activity.
This principle is commonly known as U=U (Undetectable = Untransmittable). Regular medical care and viral-load monitoring are important for maintaining viral suppression.
HIV can be prevented. Important prevention methods include:
The only reliable way to know a person's HIV status is through HIV testing. Different HIV tests can detect infection at different stages. People who may have had a recent exposure should discuss appropriate testing and testing windows with a qualified healthcare professional.
Anyone who receives a positive HIV test result should be connected with appropriate medical care for confirmation, treatment and ongoing support.
HIV treatment has changed the lives of millions of people. With effective and consistent ART, HIV can be managed as a chronic health condition. People living with HIV can work, study, have relationships and lead healthy and productive lives.
Accurate information, regular medical care and appropriate support can also help reduce HIV-related stigma and discrimination.