The human immunodeficiency virus
The human immunodeficiency virus, which destroys a subgroup of white blood cells (the helper T-cells,
or CD4 lymphocytes), resulting in suppression of the body’s immune response. HIV infection is essentially
sexually transmitted; the two other main routes of spread are via infected blood or blood products and from
an infected woman to her fetus (it may also be acquired from maternal blood during childbirth or be transmitted in breast milk). Acute infection following exposure to the virus results in the production of antibodies, their presence indicating that infection has taken place. Some people who are HIV-positive progress to chronic infection.
This can include the AIDS-reiated complex – persistent generalized involvement of the lymph nodes marked by intermittent fever, weight loss, diarrhoea, fatigue, and night sweats – and AIDS itself, in which the individual is susceptible to opportunistic infections – especially pneumonia caused by the protozoan Pneumocystis carinii, cytomegalovirus (CMV) infections, generalized candidiasis or other fungal infections, and tuberculosis – and/or tumours, such as Kaposi’s sarcoma.
Although there is currently no cure for HIV infection, a combination of two nucleoside reverse transcriptase
inhibitors and either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor
has been shown to be effective in delaying the progress of the disease.