Seasonal Changes in the Distribution and Relative Abundance of the Dengue Vector, Aedes albopictus in Two Villages in Mauritius: Implications for a Sterile Release Programme

Abstract

Weekly ovitrap surveys were conducted from February 2013 to May 2015 in Pointe des Lascars and Panchvati, two villages in Mauritius, as part of a study investigating the possible use of the sterile insect technique (SIT) to control Aedes albopictus mosquitoes, the sole vector of Chikungunya and Dengue virus in the country. A high presence of this species was noted in both villages with 64 to 100 % of ovitraps being positive for eggs throughout the year. Monthly ovitrap productivity did not differ significantly between the two villages (t49 = –1.19, P >0.05), indicating their suitability to be used as paired sites. An important but unstable population of Ae. albopictus was also noted on the outskirt of Panchvati. The overall ovitrap productivity (for the three sites together) was highest from December to March (ranging from 101 to 272 eggs/ovitrap/week) and lowest from July to September (ranging from 13 to 126 eggs/ovitrap/week). Sterile releases could hence be initiated during the months of July to September when Ae. albopictus is at its lowest incidence and after ensuring that the species is still reproductively active during the low season. Moreover, before sterile males are released in Panchvati, the establishment of a buffer zone around the village must be contemplated to prevent the migration of feral females from the outskirt region. Ovitrap positivity and ovitrap productivity in both villages were positively correlated with temperature, relative humidity and rainfall while temperature was the major significant factor influencing oviposition, thereby highlighting the possibility of using meteorological variables to construct predictive models of vector incidence in the region.