Widespread distribution of Aedes aegypti larvae, a potential risk of arbovirus transmission in the Grand Lomé health region, Togo, West Africa

Abstract

Background Understanding the population dynamics and geographic range of Aedes aegypti is of high importance for arbovirus vector surveillance and control. Little is known about the current distribution and seasonality of Ae. aegypti in Grand Lomé, Togo. Methods Mosquito oviposition traps (n = 70) were deployed in houses in the thirteen communes in Grand Lomé health region and examined weekly between May 2022 and April 2023. Generalized linear mixed models (GLMM) were applied to investigate the relationship between larval collections and seasonality. The European Space Agency (ESA) World cover 10m 2020 product was used to represent different land cover classes and determine whether sites with higher larval numbers differed from sites with lower numbers. Results A total of 52,768 Ae. aegypti larvae were collected in Grand Lomé. The highest incidence of Ae. aegypti larvae was observed in the commune of Bè-Ouest (= 122.74 per 1,000 population). Agoè-Nyivé was the commune with the lowest incidence over the entire study period. Eight land-use classes were represented by the ESA 10 m product in Grand Lomé. The chi-square test to determine whether larval abundance categories and land cover classes were associated revealed a significant relationship (X² = 2883.5, df = 14, p < 0.005). Conclusion This study provided information on the seasonal distribution of Ae. aegypti larvae in the health region of Grand Lomé. The results of this study could be useful in guiding disease vector surveillance and control efforts.