HIV

What is HIV?

Human immunodeficiency virus, a viral pathogen transmitted in infected sexual fluids and blood, through shared contaminated needles, and from a mother to her child during pregnancy, birth or breast-feeding. It infects and reduces the lymphocytes responsible for antibody production, so immune defence weakens over time.

This definition is part of the Disease and Immunity chapter in Cambridge O Level Biology.

Concepts related to HIV

• lymphocyte
• AIDS
• Antiretroviral Treatment

Common mistakes with HIV

• "HIV and AIDS are two names for the same thing." One is a virus; the other is a condition that may develop after that virus has weakened the immune system over time. Write HIV is the virus. AIDS is the condition in which the immune system is so weakened that susceptibility to other infections and diseases is greatly increased.
• "HIV can be spread by sharing utensils or by an insect bite." Neither moves infected blood or sexual fluids into another person's bloodstream, and that is the only way the virus is transmitted. Write HIV is transmitted in infected sexual fluids or blood, through shared contaminated needles, or from mother to child. Ordinary social contact does not transmit it.
• "Antiretroviral treatment cures HIV." It reduces the reproduction of the virus in the body. The virus is not removed. Write Treatment reduces the amount of virus, slows the loss of lymphocytes and lowers the chance of transmission; it is not a cure.