Herpes B virus-specific pathogen-free breeding colonies of macaques: serologic test results and the B-virus status of the macaque.

The demand by the biomedical research community for B virus-free macaques is growing. The availability of B virus-free macaques has never been greater but still falls short of the current demand. Providing resources depends on the definitions of a specific pathogen-free (SPF) macaque, a B virus-free macaque, and a serologically negative macaque. Many colony managers define a B virus-free macaque in light of the serologic status of the breeding colony, because virus identification is a more complex issue. The lack of a standardized definition of a B virus-free macaque is compounded by the fact that all assays inherently result in some false antibody-positive or -negative data, and reconciliation is equivocal. Long-term follow-up of a colony in which elimination of B virus is actively being attempted will necessarily result in a relatively small sample within the population being incorrectly categorized with regard to antibody status. The goal of this study was to determine whether serially collected serologic data demonstrated patterns that could be used to predict whether an animal was genuinely in the process of B virus antibody seroconversion. The best indication of seroconversion was an ELISA titer of > 1:500 or a positive result on a confirmatory test. Patterns of seroreactivity are more useful in identifying B virus-positive macaques during the screening phase of SPF colony development than during the maintenance phase.