The development and licensing of a screening test in 1985 was a major step forward in the fight against HIV. The test measures antibodies to the virus, which begin to appear 3 to 6 weeks after the original infection. This test is relatively fast and inexpensive; it is a sensitive screening test, giving the first indication that the individual may be HIV positive.


The test is used for three purposes: diagnosing individuals at risk to determine whether they are infected so that they may be appropriately counseled and, if necessary, treated; monitoring the spread of HIV in various populations via epidemiologic studies; and screening donated blood or organs to ensure that they do not transmit HIV to a recipient of a transfusion or transplant. A major drawback of the antibody screening test is the absence of antibodies in the blood during the initial 3- to 6-week period after infection.


Billions of viruses are made, and millions of T4 cells are destroyed daily. As if new viruses and drug-resistant bacteria were not worrisome enough, a novel form of infectious disease grabbed headlines in the 1990s. Creutzfeldt-Jakob disease (CJD) is a rare and devastating disorder in which the patient becomes demented and ultimately dies, and the brain appears spongy on autopsy because many brain cells have died.