Sudia, W. D., R. D. Lord, V. F. Newhouse, D. L Miller and R. E. Kissling (CDC, Atlanta, Ga. 30333). Vector-host studies of an epizootic of Venezuelan equine encephalomyelitis in Guatemala, 1969. Amer J Epidem 93: 137–143, 1971.—An epizootic of Venezuelan equine encephalitis (VEE) occurred in the equine population of Guatemala during the summer of 1969. VEE virus isolations were made from mosquitoes as follows: Psorophora conflnnis, 8; Culex nigripalpus, 5; Culex [Melano-conion) spp., 3; Mansonia titillans, 2; Psorophora cilipes, 2; and Aedes taeniorhyn-chus, 1. This and other studies indicate P. conflnnis to be an excellent vector and to have been a significant transmitter of the virus in areas where it was abundant. However, some of the other species probably served also as vectors, assisting in the rapid virus spread involving many thousands of horses over a short period of time. VEE virus was also isolated from a horse, mule and a young calf.