The virology of human immunodeficiency virus (HIV) infection is reviewed. The transmission of HIV is restricted to direct contact with the blood or other body fluids of infected human beings. Ordinary social contact with infected individuals holds no risk but in the health care setting all patients must be considered to be potentially infectious and universal precautions taken. The replication of HIV in cells of the immune system carrying the CD4 receptor creates a complex relationship between the virus infection and the host immune response. The pathogenesis and the principles of the laboratory diagnosis of HIV infection are reviewed. Since its discovery HIV has quickly become one of the most studied and best characterized of human pathogens. The diagnosis of HIV infection, because of its implications, has been made more accurate than for any other infection. This understanding has significantly improved treatment but has yet to provide curative therapy, and prevention of infection is still the basis of the fight against AIDS.
PIP: HIV can be acquired only through direct contact with the blood or other body fluids of infected individuals. There is therefore no risk of contracting or transmitting HIV through normal social contact with HIV-infected individuals. However, in health care settings, universal precautions must be applied with all patients under the assumption that they could be infected with HIV and are therefore infectious. The virology of HIV infection is reviewed in sections on virology, transmission, life cycle, pathogenesis, and laboratory diagnosis. The diagnosis of HIV infection is more accurate than for any other infection, reflecting the importance of HIV as an infectious agent and the implications of infection. While treatment against HIV and AIDS has improved, curative therapy remains to be developed. Preventing HIV infection therefore remains the central strategy against AIDS.