We investigated 322 North American zoo workers in an anonymous serosurvey f
or antibodies to simian foamy viruses to establish the potential risk of zo
onotic transmission by these retroviruses. 4 of 133 (3%) individuals who wo
rked specifically with mammals including primates were seropositive, primar
ily with chimp-like viruses, indicating the importance of work practices to
reduce exposure to these agents.