Use of Aedes aegypti Oviposition Surveillance and a Geographic Information System for Planning Anti-Vectorial Measures

Abstract

Arboviruses transmitted by Aedes aegypti pose a threat to global public health. Because there are no vaccines or drugs available, the prevention of these diseases in Argentina is based on integrated vector control. In this work, the spatiotemporal dynamics of the vector distribution was analyzed by monitoring oviposition. This information allowed the planning of anti-vector interventions and the evaluation of their effect on the relative abundance of mosquito populations in San Ramón de la Nueva Orán. Observed data were compared with the eggs expected via a statistical model based on meteorological variables. The oviposition substrate preference of mosquito females was also evaluated, and the possible relationship between the relative abundance of the vector and sociodemographic and environmental variables (normalized difference vegetation index and normalized difference water index) was explored. A total of 4,193 eggs of Ae. aegypti were collected, and spatial clusters were detected for all months for which the presence of the mosquito was reported. The observed number of eggs was significantly less than the expected-corrected egg abundance. A significant correlation of oviposition activity was found with three sociodemographic variables, whereas no significant correlation was found with mean or median values of the environmental variables studied. This monitoring strategy made it possible to address the interventions and evaluate them, proposing them as good complementary tools for the control of Ae. aegypti in northern Argentina.

Figure 1.

(A) Location of the Department of Orán in the north of Argentina. (B) City of San Ramón de la Nueva Orán and the 104 sampling sites. This figure appears in color at www.ajtmh.org.

Figure 2.

Egg abundance of Ae. aegypti and spatial clusters of (A) October. (B) November. (C) December. (D) Jaunary. (E) February. (F) March. (G) April. (H) May. (I) accumulated throughout the monitored period. This figure appears in color at www.ajtmh.org.

Figure 3.

Observed, observed-corrected and expected (predicted by de model) oviposition activity measure as eggs number/90 ovitraps from August 2017 to May 2018. This figure appears in color at www.ajtmh.org.