Simian foamy virus infection by whole-blood transfer in rhesus macaques: potential for transfusion transmission in humans

Abstract

Background: Cross-species infection of humans with simian foamy virus (SFV) has been reported in European and North American nonhuman primate (NHP) handlers, primarily due to wound injuries involving infected animals in research centers and zoos. Additionally, African hunters have been found to be infected with SFV by exposure to body fluids, blood, or tissues of infected NHPs in the wild. The persistence of infectious virus in peripheral blood mononuclear cells (PBMNC) and the recent identification of some infected blood donors has raised safety concerns regarding potential virus transmission by blood transfusion.

Study design and methods: SFV infection by blood transfusion was evaluated by whole-blood transfer from two naturally-infected rhesus macaques (designated as D1 and D2) to retrovirus-free monkeys. Blood from D1 was transfused to two recipient monkeys R1 and R2 and from D2 to monkeys R3 and R4. Virus transmission was evaluated by immunoassays, polymerase chain reaction assays, and coculture of PBMNC for SFV isolation.

Results: SFV infection was seen in R1 and R2 based on development of virus-specific antibodies, identification of SFV sequences in monkey PBMNC, and isolation of infectious virus from PBMNC. Furthermore, both R1 and R2 remained SFV-positive at about 1 year after transfusion, which was the last time tested. No evidence of SFV infection was seen in R3 and R4.

Conclusion: SFV transmission in macaques occurred by transfusion of blood from one of two infected donor animals. These results indicate the potential of SFV transfusion transmission in humans, which may depend on virus-specific or donor-related factors.