Sixteen arbovirus isolates were obtained from 21 golden hamsters exposed in five different locations in an area of tropical rain forest of Panamá during February and March 1966. This animal proved to be a successful sentinel for the detection of Venezuelan equine encephalitis, Ossa, Madrid, Patois, and Guamá viruses during the low transmission period of 1966. Mosquito collections on the exposed hamsters seemed to point to Culex mosquitoes of the subgenus Melanoconion, and to C. vomerifer in particular, as the vectors of the bulk of the viruses isolated from hamsters. Solutions are suggested for problems, such as feed-back of virus from the sentinel hamsters to wild mosquitoes, which may develop from the use of this method.
Gorgas Memorial Laboratory, Panamá, R. P.
Department of Microbiology, Cornell University Medical College, New York, N. Y.