Seasonal Variation in Abundance of Dengue Vector in the Southern Part of the Baja California Peninsula, Mexico

Abstract

Environmental factors that affect Aedes sp. mosquitoes should be considered to optimize control. The study assessed the association between the abundance of Aedes aegypti (L. 1762) (Diptera: Culicidae) and temperature, rainfall, and relative humidity of the State of Baja California Sur, Mexico. Total Mosquito eggs collected each week for 3 years from ovitraps at La Paz and Los Cabos was 3,129,203; mean number of eggs, ovitrap positivity index, and egg density index were calculated, showing the three entomological indices were greater at La Paz than at Los Cabos (P < 0.005). The means of eggs per month differed statistically only at La Paz (P < 0.0001), with less abundance in January and March but more in October. Although monthly differences were not detected from January to December at Los Cabos, increase occurred from September to November during the 3 years. Results showed statistical association between egg abundance and minimum temperature at both locations during the 3 years of study; more activity was observed during the summer and fall when more precipitation and thus greater relative humidity occurred, but they were statistically associated only with precipitation at La Paz (P < 0.01). The number of eggs was statistically significant with minimum temperatures at both locations (P < 0.01) and with rainfall only at La Paz (P < 0.01). Therefore, management should be more intense during winter-spring when insects were less abundant and hence management strategies used would be more effective.