The authors, Eric A. Engels and coworkers at the National Cancer Institute, National Institutes of Health, Rockville, MD, the Centers for Disease Control and Prevention, Atlanta, GA, and The Johns Hopkins University School of Medicine, Baltimore, MD, studied 254 zoo workers, 109 of whom handled primates extensively and the remainder not at all. An antibody assay showed that SV40 reactivity was more common among primate workers (23 percent) than among the other workers (10 percent). These low rates, which suggested absence of ongoing SV40 replication, contrasted with assay results showing 85 percent and 56 percent reactivity, respectively, for two other polyomaviruses, BK and JC, which are highly prevalent in humans and establish lifelong infection.
When the investigators used particles of SV40, BK, and JC to evaluate whether SV40-positive reactions were specific or represented cross-reacting antibody responses, only 14 of 29 subjects demonstrated specific reactivity. Engels and coworkers commented that this suggested that much of their SV40-positive results were probably due to BK or JC virus cross-reactivity.
The investigators cautioned that there is as yet no definitive evidence that SV40 can persistently infect humans, and that the health consequences of SV40 exposure, including the risk of cancer, are still unknown. Nevertheless, they concluded that their study "suggests that individuals who work closely with nonhuman primates are occupationally exposed to SV40," and t
Contact: Steve Baragona
Infectious Diseases Society of America