Spatial dispersion of adult mosquitoes (Diptera : Culicidae) in a sylvaticfocus of Venezuelan equine encephalitis virus

We studied the spatial localization of mosquitoes in a sylvatic focus of Ve nezuelan equine encephalitis virus in western Venezuela to identify mosquit o species potentially involved in the hypothesized transport of viruses out of enzootic foci. The following criteria were used to identify species wit h potential for virus export: (1) common in the forest and surrounding area , (2) feeding on a wide range of vertebrates; (3) long dispersal capabiliti es, and (4) established vectorial competence for enzootic or epizootic VEE viruses. CDC traps baited with light/CO2 were operated for four and 12-h in tervals to collect mosquitoes at four stations along two forest/open area t ransects from September to November 1997. We collected 60,444 mosquitoes be longing to 11 genera and 34 species. The most common species were Aedes ser ratus (Theobald), Ae. scapularis (Rondani), Ae. fulvus (Wiedmann), Culex ni gripalpus Theobald, Cc. (Culex) "sp ", Cx. mollis Dyar & Knab, Cr, spissipe s (Theobald), Cx. pedroi Sirivanakarn and Belkin, Psorophora ferox (Humbold t), Ps. albipes (Theobald), and Ps. cingulata (F.). Very few mosquitoes wer e captured during the day in the open area outside the forest, suggesting t hat any virus export from the forest may occur at night. The following mosq uitoes seemed to be mostly restricted to the forest habitat: Ae. serratus, Ps. ferox, Ps. albipes, sabethines, Cx. spissipes, Cx. pedroi, Cx. durum Dy ar, and Ae. fulvus. The main species implicated in potential virus export w ere Cx. nigripalpus, Ae. scapularis, and Mansonia titillans (Walker).