From: Pat Fallon (pfallon@postoffice.ptd.net)
Date: Fri Mar 07 1997 - 11:59:15 MST
>One of Koch's postulates is that you should be able to cause the same
>disease by injecting the supposed agent into a new victim. Obviously, this
>has been tough to prove with HIV because nobody wants to volunteer as a test
>case. However, recently chimpanzees injected the human HIV virus have been
>coming down with AIDs like symptoms, declining T-cells, and at least one
>appears to have died of the disease. The latency period is every bit as
>long in chimps as it is in people, making these difficult and expensive
>experiments to carry out. But they now appear to satisfy the most important
>of Koch's postulates.
>Steve Edwards
I'd appreciate it if you could reference this new chimp study. I'd particularly
like to read about HIV infected chimps coming down with "AIDS-like
symptoms" after latency periods "every bit as long as it is in people."
I would like to read it since it is so at odds with earlier experiments I am
familiar with.
These past studies reveal important differences in the diseases of
infected monkeys from that of HIV in human AIDS:
(1) The absence of antiviral antibodies predicted the incidence of diseases
in monkeys, while the opposite is claimed for humans infected with HIV
[Kestler et al. 1990]. Another study has confirmed that monkey's risk
of disease is directly proportional to the titer of SIV [Futz et al., 1990].
(2) The simian retroviruses barely reduce the T-cell levels of ill monkeys
[Kestler et al., 1991], while HIV is claimed to deplete T-cells in humans.
(3) The spectrum of diseases observed in the SIV-infected monkeys is
different from AIDS, including bacteremia and lacking, among others,
Kaposi's sarcoma and dementia [Kestler et al., 1990; Fultz et al., 1990].
(4) In follow-up studies, SIV failed to cause disease in rhesus and
mangabey monkeys despite extensive sequence variation of the virus
which is thought to enhance pathogenicity [Fultz et al., 1990; Burns
and Desrosiers, 1991; Villinger et al., 1991].
(5) Since SIV has never caused any disease in wild monkeys, although
about 50% are naturally infected [Blattner et.al, 1988; Fultz et al., 1990;
Burns and Drosiers, 1991; Villinger et al., 1991] it is not an appropriate
model for the hypothesis that HIV causes AIDS in naturally infected
humans.
Regards,
Pat Fallon
pfallon@bigfoot.com
References:
Kestler, H., T. Kodoma, D. Ringler, M. Marthas, N. Pederson, A. Lackner,
D. Regier, P. Sehgal, M. Daniel, N. King, and R. Desrosiers. Induction of AIDS
in rhesus monkeys by molecularly cloned simian immunodeficiency virus,
Science 248 (1990): 1109-1112.
Fultz, P.N., R.B. Stricker, H.M. McClure, D.C. Anderson, W.M. Switzer,
and C. Horaist. Humoral response to SIV/SMM infection in macaque and
mangabey monkeys. J. AIDS 3 (1990) 319-329.
Burns, D.P.W. and R.C. Desrosiers. Selection of genetic variants of
simian immunodeficiency virus in persistently infected rhesus monkeys.
J. Virol. 65 (1991): 1843-1854.
Villinger, F., J.D. Powell, T. Jehuda-Cohen, N. Neckelmann, M. Vuchetich,
B. De, T.M. Folks, H.M. McClure, and A.A. Ansari. Detection of occult
simian immunodeficiency virus SIV smm infection in asymptomatic
seronegative nonhuman primates. J. Virol. 65 (1991) 1855-1862.
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