c. AIDS-Related Complex (ARC). HIV infection in some people leads to an
illness in which the patient develops some of the nonspecific symptoms of AIDS but not
the typical opportunistic infections. This illness is sometimes mistakenly labeled pre-
AIDS. The illness may progress to AIDS.
d. Opportunistic Infections. These are infections caused by organisms that do
not ordinarily cause disease because the body's immune system successfully fights the
organism. A weakened immune system, typical of the AIDS patient, cannot fight off the
organism, and the organism infects the person.
The Centers for Disease Control defined AIDS in 1981 as a syndrome
characterized by unusual opportunistic infections and rare malignancies in
otherwise healthy individuals with no other reason for immune system
compromise. This definition helped public health officials monitor the fast
growing AIDS epidemic even though its cause was unknown. Research to
date indicates that AIDS is caused by a human retrovirus.
a. No one is absolutely certain how AIDS originated, but many scientists believe
that it began in central Africa. One theory is that the AIDS virus first infected monkey
colonies in central Africa and then spread to humans in Africa in the mid-1970's.
Scientists hypothesize that the virus was transmitted to humans by a Green Monkey
scratch or bite. From Africa, the AIDS virus may have been carried across the Atlantic
Ocean by Haitians who once lived in or visited central Africa. The spread of AIDS from
Haiti may have occurred in two ways: first, by Haitian immigrants and second, by
vacationing American homosexual males, who often traveled to Haiti. In the U.S., AIDS
was first seen as pneumonia of a rare type in primarily, but not limited to, homosexual
b. The AIDS virus did not suddenly arrive in its present deadly state as a
completely new virus. Research indicates that this virus is the result of a different virus
which has gone through some changes. Originally, there was either a disease-causing
human virus with a different capability or a virus in some animal reservoir. Virologists
believe that this virus changed and developed in some isolated primate stock in an
isolated area where animal and human populations are scattered and remote. (Of
possible areas, central Africa is most plausible because the first documented cases of
AIDS were either Africans or individuals with some connection to central Africa.) A
logical conclusion is that, over a period of time the original virus went through several
changes to become the deadly AIDS virus (HIV) we know today.