Specific-pathogen-free status is associated with lower infant mortality rate in rhesus macaque (Macaca mulatta) colonies at the California National Primate Research Center

Background: Specific-pathogen-free (SPF) rhesus macaques, Macaca mulatta, are a valuable resource in biomedical research, and demographic analysis plays a significant role in colony management. Methods: Data collection included SPF levels, gender, birth year, season of birth, birth location, rearing condition, maternal pregnancy history, and maternal age. Infant mortality in SPF rhesus macaques was compared with that in non-SPF rhesus macaques at the California National Primate Research Center over a six-year period, using Cox proportional regression analysis. Results: In infants born to multiparous dams, the SPF infants had a significantly lower rate of mortality than non-SPF infants. There was no statistically significant difference in infant mortality between different SPF levels. Conclusions: Elimination of selected endemic viruses from breeding populations of rhesus macaques for the purpose of SPF colony development is associated with a significant reduction in the infant mortality rate.