Relationship of density of Culiseta melanura mosquitoes to infection of wild birds with eastern and western equine encephalitis viruses.

Abstract

Culiseta melanura and wild birds collected from the Pocomoke Cypress Swamp, Maryland in 1968 were infected with eastern and western equine encephalitis viruses. The period of virus transmission extended at least from late July through October. Vector densities and the incidence of antibodies in birds were greater at sites deep in the swamp than at sites bordering the swamp. Most virus isolations were obtained from mosquitoes and birds collected from the deep swamp. We suggest that areas with characteristics similar to the innermost swamp are most suitable for surveillance in forecasting EEE and WEE epizootics of possible public health concern.