The overall objective of this program is to maintain and expand on existing breeding colony of SPF (Herpes B Virus, SIV, SRV and STLV1) rhesus monkeys. The offspring from this colony will be available to the scientific community for use in biomedical research with priority given to NIH sponsored AIDS related studies. Specific Aim: 1 Main the SPF status of the colony by submission of samples to NIH approved laboratories at intervals of six months or less. Specific Aim: 2 Expand the breeding colony by retention of selected offspring. Specific Aim: 3 Initiate a pilot program to determine the feasibility of eliminating Simian Foamy Virus infection from all or a subunit of the colony. The colony should provide 125-150 eighteen month old animals for research each year. The utilization of these animals would essentially eliminate the danger of Herpes B Virus transmission from the monkey to research personnel and provide a dependable source of simian retrovirus free animals for critical AIDS related research.