Modelling and observing the role of wind in Anopheles population dynamics around a reservoir

https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2197-5Background: Wind conditions, as well as other environmental conditions, are likely to in uence malaria transmission through the behaviours of Anopheles mosquitoes, especially around water-resource reservoirs. Wind-induced waves in a reservoir impose mortality on aquatic-stage mosquitoes. Mosquitoes’ host-seeking activity is also in uenced by wind through dispersion of CO2. However, no malaria transmission model exists to date that simulated those impacts of wind mechanistically.
Methods: A modelling framework for simulating the three important e ects of wind on the behaviours of mosquito is developed: attraction of adult mosquitoes through dispersion of CO2 (CO2 attraction), advection of adult mosquitoes (advection), and aquatic-stage mortality due to wind-induced surface waves (waves). The framework was incorpo- rated in a mechanistic malaria transmission simulator, HYDREMATS. The performance of the extended simulator was compared with the observed population dynamics of the Anopheles mosquitoes at a village adjacent to the Koka Reservoir in Ethiopia.
Results: The observed population dynamics of the Anopheles mosquitoes were reproduced with some reasonable accuracy in HYDREMATS that includes the representation of the wind e ects. HYDREMATS without the wind model failed to do so. O shore wind explained the increase in Anopheles population that cannot be expected from other environmental conditions alone.
Conclusions: Around large water bodies such as reservoirs, the role of wind in the dynamics of Anopheles popula- tion, hence in malaria transmission, can be signi cant. Modelling the impacts of wind on the behaviours of Anopheles mosquitoes aids in reproducing the seasonality of malaria transmission and in estimation of the risk of malaria around reservoirs.