The Geographical Distribution of Immunity to Yellow Fever among the Primates of Brazil

Summary 1. A survey of natural immunity to yellow fever among the primates of Brazil has been going on for the past 15 years, more than 5,800 sera have been examined in all. 2. Sixty-five per cent were obtained from monkeys and 35 per cent from marmosets. 3. Immune primates have been found almost everywhere except in the seven states of the northeast, no extensive surveys having yet been carried out in that region. 4. The wide extent of specific immunity among primates captured in nature confirms the fact that jungle yellow fever has prevailed throughout most of Brazil during the past decade and a half.