The Relationship between the Human Immunodeficiency Virus and the Acquired Immunodeficiency Syndrome (Draft)

DRAFT
the United States were reported in the early 1980s, and, retrospectively, in the late 1970s
(CDC, 1982e; Pape et al., 1983, 1993).
Between 1981 and 1983, clinical epidemics of chronic, life-threatening enteropathic
diseases ("slim disease"), cryptococcal meningitis, progressive KS, and esophageal
candidiasis were recognized in the African nations of Rwanda, Tanzania, Uganda, Zaire, and
Zambia, and in 1983 the first AIDS cases among Africans were reported (Quinn et al., 1983;
Essex, 1994). The earliest blood sample from Africa from which HIV has been recovered is
from a possible AIDS patient in Zaire, tested in connection with a 1976 Ebola virus outbreak
(Getchell et al., 1987; Myers, 1992), although serologic data have suggested the presence of
HIV infection as early as 1959 (Quinn et al., 1986.)
Lentiviruses
As a retrovirus, HIV is an RNA virus that codes for the enzyme reverse transcriptase,
which transcribes the viral genomic RNA into a DNA copy that ultimately integrates into the
host cell genome (Fauci, 1988). Within the retrovirus family, HIV is classified as a lentivirus,
having genetic and morphologic similarities to animal lentiviruses such as those infecting cats
(feline immunodeficiency virus), sheep (visna virus), goats (caprine arthritis-encephalitis virus),
and lower primates (simian immunodeficiency virus) (Stowring et al., 1979; Gonda et al., 1984;
Haase, 1986; Temin, 1988, 1989; Levy, 1993). Like HIV in humans, these animal viruses
primarily infect cells of the immune system, including T lymphocytes and macrophages
(Haase, 1986, 1990; Gallo, 1991 b; Levy, 1993).
Lentiviruses often cause immunodeficiency in their hosts in addition to slow,
progressive wasting disorders, neurodegeneration, and death (Haase, 1986, 1990). SIV, for
example, infects several subspecies of macaque monkeys, causing diarrhea, wasting, CD4+ T
cell depletion, opportunistic infections and death (Desrosiers, 1990; Fultz, 1993). HIV is
closely related to Sly, as evidenced by viral protein cross-reactivity and genetic sequence
similarities (Franchini et al., 1987; Hirsch et al., 1989; Desrosiers, 1990; Myers, 1992, 1993).

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