Do scientists know when the AIDS virus first appeared?
Although doctors first identified cases of acquired immune deficiency syndrome (AIDS) in Los Angeles and New York City in 1981, they have since traced cases of the disease back to 1969. The human immunodeficiency virus (HIV), which causes AIDS, is transmitted through sexual contact, shared hypodermic needles, infected blood from transfusions, and from infected mothers to babies through breast milk. Researchers have been unable to ascertain the origin of the disease, but since the virus is similar to an immunodeficiency virus that affects monkeys, some speculate that the disease was somehow transmitted from monkeys to humans. AIDS first appeared in Africa during the 1960s and 1970s, and it has spread to epidemic (widespread outbreaks) proportions on that continent. Millions of cases have been diagnosed worldwide, and every country in the…
