ABSTRACT
Greater than 70% of all new human infections have a zoonotic origin, including inuenza, SARS, and HIV [1]. Nearly all nonhuman primate (NHP) species, including prosimians, New World and Old World monkeys and apes all harbor distinct and species-specic clades of simian foamy virus (SFV) [2-6]. The cospeciation of simian host and SFV inferred to have occurred at least 30 million years ago suggests an ancient origin for this RNA virus [3,5]. However, evidence supporting the existence of a human-specic foamy virus (FV) is not yet available. Early reports describing widespread infection of healthy and sick humans with FV were not conrmed [2]. In contrast, all FV infections documented in humans are of zoonotic origin and are identied in persons occupationally and naturally exposed to NHP [2-6]. The introduction of SFV into humans raises several public health questions regarding disease outcomes and potential for human-to-human transmissibility. The data available from a limited number of SFVinfected humans suggest that these infections may not be pathogenic and are not easily transmissible [2-6]. Additional studies are needed to better dene the prevalence, natural history, and public health consequences of SFV in humans.
