The
emergence and pandemic spread of the AIDS- Acquired Immunodeficiency Syndrome-
have posed the greatest challenge to public health in modern times. It was
first recognized in the United
States in 1981, as a sudden outbreak of two
very rare diseases – Kaposi’s sarcoma and Pneumocystis carinii pneumonia
in young adults who were homosexuals or addicted to injected narcotics. They
appeared to have lost their immune competence, rendering them vulnerable to
fatal infections with relatively avirulent microorganisms, this condition was
given the name acquired immunodeficiency syndrome. Isolation of the
etiological agent was first reported in 1983 by Luc Montagnier and colleagues
from Pasteur Institute, Paris. They isolated a retrovirus from a West African
patient with persistent generalized lymphadenopathy and called it
lymphadenopathy associated virus (LAV). In 1984 Robert Gallo and colleagues
isolated a retrovirus called HTLV-3. two antigenic types of HIV– HIV-1 & HIV-2.
Virions
of the family Retroviridae possess reverse transcriptase enzyme, hence the
name. This family has been divided into 3 genera - Retrovirus (HTLV-1 &
HTLV-2, oncogenic viruses), Lentivirus (HIV-1 & HIV-2 causes AIDS) and
Spumavirus (Human foamy virus).
