Frequent Simian Foamy Virus Infection in Persons Occupationally Exposed to Nonhuman Primates

Abstract

The recognition that AIDS originated as a zoonosis heightens public health concerns associated with human infection by simian retroviruses endemic in nonhuman primates (NHPs). These retroviruses include simian immunodeficiency virus (SIV), simian T-cell lymphotropic virus (STLV), simian type D retrovirus (SRV), and simian foamy virus (SFV). Although occasional infection with SIV, SRV, or SFV in persons occupationally exposed to NHPs has been reported, the characteristics and significance of these zoonotic infections are not fully defined. Surveillance for simian retroviruses at three research centers and two zoos identified no SIV, SRV, or STLV infection in 187 participants. However, 10 of 187 persons (5.3%) tested positive for SFV antibodies by Western blot (WB) analysis. Eight of the 10 were males, and 3 of the 10 worked at zoos. SFV integrase gene (int) and gag sequences were PCR amplified from the peripheral blood lymphocytes available from 9 of the 10 persons. Phylogenetic analysis showed SFV infection originating from chimpanzees (n ‫؍‬ 8) and baboons (n ‫؍‬ 1). SFV seropositivity for periods of 8 to 26 years (median, 22 years) was documented for six workers for whom archived serum samples were available, demonstrating long-standing SFV infection. All 10 persons reported general good health, and secondary transmission of SFV was not observed in three wives available for WB and PCR testing. Additional phylogenetic analysis of int and gag sequences provided the first direct evidence identifying the source chimpanzees of the SFV infection in two workers. This study documents more frequent infection with SFV than with other simian retroviruses in persons working with NHPs and provides important information on the natural history and species origin of these infections. Our data highlight the importance of studies to better define the public health implications of zoonotic SFV infections.

Diverse Contexts of Zoonotic Transmission of Simian Foamy Viruses in Asia

“…At-risk populations include veterinarians; laboratory, temple, and zoo workers; pet owners; and bushmeat hunters (16)(17)(18)(19)(20). SFV prevalence in these populations is 1%-6%.…”

Complete nucleotide sequence and evolutionary analysis of a Gorilla foamy virus

“…This could result in a potential threat even with the virus being non-pathogenic in its natural host. These potential dangers are highlighted by the fact that, at least for SFVcpz and SFVora, such inter-species transmissions are not rare events and were even observed for SFVgor as well (Calattini et al, 2007;Heneine et al, 1998;Switzer et al, 2004). In this regard it should be noted that the prototype foamy virus (PFV), which was supposed to be a specific human isolate, is most probably a transmission from chimpanzees (Epstein, 2004).…”

Experimental therapy of allogeneic solid tumors induced in athymic mice with suicide gene-transducing replication-competent foamy virus vectors

“…Although there is so far no evidence that FV become pathogenic and spread among humans, 13 the risk of adaptation and development of a new human retroviral infection cannot be excluded. 27,28 The AIDS pandemic arose by trans-species transmission of monkey and ape retroviruses to humans. 29 Bearing this risk in mind we regard it to be not opportune to proceed with this approach into the direction of clinical studies in humans.…”