What information can a longitudinal survey carried out in a single multi-host site provide on mosquito dynamics and their drivers in peri-urban Antananarivo, Madagascar?

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Guis, Hélène | Tantely, Michaël Luciano | Raharinirina, Manou Rominah | Ambinintsoa, Maminirina Fidelis | Randriananjantenaina, Iavonirina | Velonirina, Haja Johnson | Révillion, Christophe | Herbreteau, Vincent | Tran, Annelise | Girod, Romain

Edité par CCSD -

International audience. Madagascar is endemic to several diseases of public health importance such as malaria, dengue, chikungunya, Rift Valley fever (RVF), West Nile fever (WNF) or lymphatic filariasis. This study aims to assess, in a resource limited setting, what information a longitudinal entomological study carried out in a multi-host single-site can provide on mosquito population dynamics and transmission risk in the vicinity of Antananarivo, the capital city.A fortnightly collection of mosquitoes using six CDC-light traps was set up between January 2017 to April 2018 in a multi-host farm in peri-urban area of Antananarivo. Multivariable generalized linear models were developed using indoor and outdoor densities of the predominant mosquito species as response variables and moon illumination, environmental and climatic data as the explanatory variables.Overall, 46,737 mosquitoes belonging to at least 20 species were collected. Culex antennatus (68.9%), Culex quinquefasciatus (19.8%), Culex poicilipes (3.7%) and Anopheles gambiae s.l. (2.3%) were the most abundant species. Mosquito densities were observed to be driven by moon illumination and climatic factors interacting at different lag periods. The outdoor models demonstrated biweekly and seasonal patterns of mosquito densities, while the indoor models demonstrated only a seasonal pattern.Results show that (1) an important diversity of mosquitoes exists in the peri-urban area of Antananarivo, (2) the four main species (>94% individuals) are major or potential vectors of viruses (WN and/or RVF viruses) and/or parasites (Plasmodium, Wuchereria) (3) despite a decline in winter of three of these species, they are present all year round. The main drivers of their abundance were temperature, relative humidity and precipitation, as well as, for outdoor abundance only, moon illumination. Identifying these drivers is a first step towards the development of pathogen transmission models (R0 models) which are key to inform public health stakeholders on the periods at risk of vector-borne diseases.

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