Development of Breeding Populations of Rhesus Macaques (Macaca mulatta) That Are Specific Pathogen-free for Rhesus Cytomegalovirus

Development of breeding colonies of rhesus macaques (Macaca mulatta) that are specific pathogen-free (SPF) for rhesus cytomegalovirus (RhCMV) is relatively straightforward and requires few modifications from current SPF programs. Infants separated from the dam at or within a few days of birth and cohoused with similarly treated animals remain RhCMV seronegative indefinitely, provided they are never directly or indirectly exposed to a RhCMV-infected monkey. By systematically cohousing seronegative animals into larger social cohorts, breeding populations of animals SPF for RhCMV can be established. The additional costs involved in expanding the current definition of SPF status to include RhCMV are incremental compared with the money already being spent on existing SPF efforts. Moreover, the large increase in research opportunities available for RhCMV-free animals arguably would far exceed the development costs. Potential new areas of research and further expansion of existing research efforts involving these newly defined SPF animals would have direct implications for improvements in human health.Abbreviations: HCMV, human cytomegalovirus; NHP, nonhuman primate; RhCMV, rhesus cytomegalovirus; SPF, specific pathogen-freeThe impetus for expanding the current SPF definition to include RhCMV is 2-fold. The first is the increasing number of studies involving infection of rhesus macaques with RhCMV as a nonhuman primate (NHP) model of human infection with human cytomegalovirus (HCMV). The second is the recognition that the current SPF protocols result in animals that are also uninfected with RhCMV, such that a relatively minor change in derivation can generate monkeys that meet the current SPF definition and that are uninfected with other endemic viruses, including RhCMV and simian foamy virus.