GREEN MONKEY PLURISPECIFIC ASSOCIATIONS I N SENEGAL - THE INTERSPECIFIC TRANSMISSION OF SIVAGM MUST OCCUR FREQUENTLY IN THE WILD

The similarities of HIV2 with SIV raise thr question of natural inters pecific transmission of retrovirus amongst Primates. This study tries to evaluate the possibilities of natural interspecific transmission Of SIV within a Green and a Patas monkey population of the Fathala fores t (Saloum Delta National Park, Senegal). Methods include a description and a quantification of the interspecific relations between Green and Paras monkeys. Demographic structure and SIV seroepidemiology of the population are also studied. The tendency of Green monkeys to associat e with Patas monkeys was measured using two methods : (I) measuring pr oportion of time spent in association with Paras Monkeys by one focus Green Monkeys troop; and (2) generalisation of the result by measuring proportion of troops containing Green monkeys associated with Paras M onkeys. Direct observation of interspecific interactions focused on co ntacts and exchange of biologic fluids. On the basis of 12 days uninte rrupted observation, one focus troop of green monkeys spent a mean of 2 h 26 mn per day in association with Patas monkeys, which corresponds to 19 % of their day time. On the basis of 114 independent troops enc ounters, 18 % (57 % of plurispecific troops) of the troops include mix ed individuals of Green and Paras Monkeys. This value allows the exten sion of the result to the whole monkey population of the Fathala fores t. All kinds of social behaviour, hedonic and agonistic, have been obs erved between Green and Paras monkeys. Retrovirus transmission risk be haviour included mucous membrane contact with biologic fluids: biting and genital grooming. One easily identified female Paras is known to h ave given birth to five infants from Green monkeys father(s), arguing for the existence of interspecific sexual relations. On the basis of p reliminary results of one group of Green Monkeys intensive study, freq uency of retrovirus transmission risk behaviour could be estimated at more than 50 per year. Sexual transmission of SIVagm, and transmission by biting, have previously been shown. Natural infection of yellow ba boons and experimental infection of Patas Monkeys with Green Monkey SI Vagm have also been reported. Data show that naturally occurring inter specific transmission of SIVagm from Green to Paras monkeys in the Wil d must occur frequently.