MARKERS OF FOAMY VIRUS-INFECTIONS IN MONKEYS, APES, AND ACCIDENTALLY INFECTED HUMANS - APPROPRIATE TESTING FAILS TO CONFIRM SUSPECTED FOAMYVIRUS PREVALENCE IN HUMANS

Foamy viruses (FVs) persist in healthy individuals of various mammalia n species, including nonhuman primates. Laboratory markers of FV infec tion are (1) virus in throat epithelium or peripheral blood lymphocyte s (PBLs), (2) proviral DNA sequences in PBLs and various solid organs, and (3) antibodies reactive to viral antigens on Western blots, in ra dioimmunoprecipitation tests, and in immunofluorescence assays. Using ]PCR and serological tests, we readily detected FV markers in naturall y infected African green monkeys, rhesus monkeys, and chimpanzees, as well as in accidentally infected humans. Transmission of simian foamy viruses to humans (by bite or inadvertant laboratory infection) leads to viral markers, without affecting the recipient. Reports on FV-assoc iated clinical disorders (e.g., thyroid or neurological) have remained controversial. In this study we failed to detect, by PCR, viral seque nces in the samples from 223 patients, including 16 HIV-infected Afric ans, 46 Graves' disease patients, and 28 patients with de Quervain's t hyroiditis. Evaluation of 2688 sera from suspected high-risk areas (e. g., Central and East Africa, or high-risk groups such as HIV-infected individuals and patients with AIDS, thyroid, and neurological disorder s) did not reveal FV-specific antibodies in a single case. Previously reported FV seroprevalence in various populations has never been verif ied by appropriate confirmatory tests. The strain of ''human foamy vir us'' has remained a unique isolate. In conclusion, FVs are unlikely-at present-to circulate in human populations.