PHYLOGENETIC ANALYSIS OF SIV AND STLV TYPE-I IN MANDRILLS (MANDRILLUSSPHINX) - INDICATIONS THAT INTRACOLONY TRANSMISSIONS ARE PREDOMINANTLY THE RESULT OF MALE-TO-MALE AGGRESSIVE CONTACTS

Natural SIVmnd and STLVmnd infections of mandrills in a colony at the Centre International de Recherches Medicales de Franceville (CIRMF) in Gabon were investigated by genetic analysis to determine the extent o f intracolony transmission. SIVmnd pol sequence analysis indicates tha t the six strains present in the colony belong to the SIVmnd lentiviru s subgroup previously defined according to the only available prototyp e sequence (SIVmndGB1), which originated from the same colony. The int raanimal nucleotide diversity (1.1-3.1%) was similar in range to that reported in individuals infected by other HIV/SIVs, The interanimal di versity (0.5-4.3%) was not significantly different from that observed in each individual mandrill, indicating an epidemiological link among the SIVmnd isolates of distinct animals within the colony. Phylogeneti c analysis of these isolates, together with seroepidemiological and be havior surveillance within the colony, indicates a predominant male-to -male transmission of SIVmnd that probably occurred during bouts of in teranimal aggression. Moreover, our results suggest one case of vertic al transmission of SIVmnd from a naturally infected founder female to one of her six offspring. The first genetic analysis of STLV isolates from mandrills is also reported here. Partial tax/rex sequences were u sed to evaluate the diversity between seven STLVmnd isolates and their phylogenetic relationships with other known strains of human and nonh uman primate T cell leukemia virus, types I and II (PTLV-I/II). They a ll belong to the PTLV-I subtype, but two genetically distinct STLVmnd groups were evidenced within the mandrill colony. The phylogenetic ana lyses of the STLVmnd isolates, together with seroepidemiological and b ehavior surveillance of the mandrills, indicate that intracolony trans missions of STLVmnd are also predominantly the result of male-to-male aggressive contacts.