Transmission studies with simian immunodeficiency virus of macaques; persistent infection of baboons.

The host range of SIVmac was investigated in three monkey species. Blood-borne and cell-adapted virus inocula obtained from a rhesus macaque infected with SIVmac251 were compared. African green monkeys were not susceptible to infection, whereas baboons and rhesus macaques became persistently infected and showed similar patterns of seroconversion. However, in contrast to the macaques, no clinical or histopathological evidence of disease was seen in the baboons 2 years after virus inoculation. Thus baboons could be used as an alternative to macaques in vaccine development studies with this particular isolate of SIVmac. Furthermore, this system may be useful for the investigation of factors responsible for disease progression.