Int Conf AIDS. 1992 Jul 19-24;8(3):36 (abstract no. PuA 6154). Unique
ISSUE/PROBLEM: Lack of animal models for AIDS as seen in humans.
DESCRIPTION OF PROJECT: To review syphilis animal models from the work
of Brown and Pierce in the 1920s to the present, looking at lesion
susceptibility and response to (under)treatment, natural course, the
introduction of penicillin, the immunology assumed to be operative, and
finally, the so-called symptomless model. RESULTS: This symptomless
animal model is described as a lack of serologic response (VDRL) and
endarteritis obliterans (the classical lesion). However, in this model a
chronic debilitating course and premature death from other infections
regularly occurred in those animals which had become infected with
Treponema pallidum without the usual reaction. Mice, certain guinea pigs
and rabbits, and certain primates could be induced to suffer this way
either upon one inoculation or with superinfection, and with or without
(adequate) therapy, depending upon the model chosen. DISCUSSION AND
CONCLUSIONS: The classical approach to syphilis animal models has not
recognized the course of symptomless syphilis. Recent use of PCR, DFA,
and techniques to demonstrate actual Treponema pallidum, suggest
infection with syphilis has been going on in HIV-infected persons in the
absence of the normal and assumed serologic and clinical sensitivity of
diagnosis. The epidemiology of syphilis in sexual risk groups is very
suggestive: in the United States, specialists in the syphilis field have
suggested that up to half a million cases of untreated or inadequately
treated and post-secondary syphilis existed in gay males by 1981 and
that the new infection rate was at least 100 times the national average.
The serology of syphilis is also problematical in HIV-infected persons:
in AIDS epicentres, polyclonal activated individuals often selectively
lose all syphilis antibody, treponemal and non-treponemal. Deliberate
human inoculation with T-pallidum has repeatedly suggested that the
non-treponemal tests may not react upon reinfection in the majority of
post-secondary syphilitics, whether treated or not. Post-secondary
syphilis is confounded by many autoimmune phenomena. Several research
tools besides PCR and DFA may help and will be reviewed.
Acquired Immunodeficiency Syndrome/COMPLICATIONS/DIAGNOSIS/ *IMMUNOLOGY
Animal *Disease Models, Animal Guinea Pigs Human Mice Primates
Rabbits Syphilis/*COMPLICATIONS/DIAGNOSIS/IMMUNOLOGY ABSTRACT