Notwithstanding, more data are needed before SFV can be proclaimed a "virus without a disease." First, SFV infection has not been extensively studied in immunocompromised persons, so whether SFV has a more aggressive course in an immunologically "permissive" environment is unknown. Two persons died shortly after receiving baboon Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 11, No. 7, July 2005 ) , and SFV-3agm is a published sequence from an African green monkey (Cercopithecus aethiops). SFVcpz is a published sequence from a chimpanzee (Pan troglodytes) and was used an outgroup for this tree. The SFV human strain (BH66) clustered with an SFV sequence amplified from BP6 one of the macaques at the Sangeh monkey temple. The SFV DNA tree was created with the neighbor-joining method by using the PHYLIP program (DNAdist; Neighbor). Bootstrap replicates were 1,000. Bootstrap values were calculated by using Seqboot, DNAdist, Neighbor, and Consense (PHYLIP programs). Bootstrap values 60% are shown. The SFV tree was plotted in Treeview. liver transplants in 1994, and SFV was detected in the blood and tissues of both at autopsy (39) . More research in this area is needed. Moreover, little is known about the epizootiology of SFV among wild primates. Although SFV infection in humans has not culminated in any observable symptoms, SFV strains may differ in their capacity to infect or cause disease in humans. Finally, whether SFV can adapt in humans after transmission and potentially lead to disease needs to be examined.