A surveillance report on sylvan yellow fever in Panama from 1957 to 1961 is presented. The last known outbreak of yellow fever in this country occurred in June 1957 near the town of Buena Vista, located along the Transisthmian Highway a few miles east of the Panama Canal. During the outbreak, yellow fever virus was isolated from the blood of an acutely ill human and from forest, day-flying, arboreal mosquitoes.
Failure to isolate yellow fever virus from forest mosquitoes and vertebrates captured in various areas of Panama and results of neutralization tests on the blood of numerous primates and other vertebrates lead the authors to the conclusion that yellow fever virus has not been active in Panama since 1957.
Gorgas Memorial Laboratory, Panama, Republic of Panama.
University of Panama, School of Medicine, Panama, Republic of Panama.