Landing periodicity of Aedes aegypti with implications for dengue transmission in Trinidad, West Indies

The diel landing/biting periodicity of the Trinidad strain of Aedes aegypti (L.) was monitored using human-bait during January-August 1999. Hourly lig ht intensities were measured both indoors and outdoors at both urban and ru ral sites. The periodicity of females was diurnal and nocturnal, with 90% a rriving during daylight and twilight and 10% during the night. The pattern of landing was trimodal, with consistent peaks at 0700h, 1100h and 1700h. T he diel periodicities at indoor and outdoor urban sites were virtually iden tical. In contrast, the periodicities in rural areas differed, with no noct urnal activities being recorded at indoor and outdoor sites. At both urban and rural sites, larger numbers of adults were collected outside than insid e houses. A significant correlation between light intensities and mosquito landing patterns was observed. The implications of the changing landing pat terns of Ae. aegypti within urban areas are discussed in light of the epide miology and control of dengue fever in Trinidad.