Variation in Anopheles distribution and predictors of malaria infection risk across regions of Madagascar

Abstract

Background Deforestation and land use change is widespread in Madagascar, altering local ecosystems and creating opportunities for disease vectors, such as the Anopheles mosquito, to proliferate and more easily reach vulnerable, rural populations. Knowledge of risk factors associated with malaria infections is growing globally, but these associations remain understudied across Madagascar’s diverse ecosystems experiencing rapid environmental change. This study aims to uncover socioeconomic, demographic, and ecological risk factors for malaria infection across regions through analysis of a large, cross-sectional dataset. Methods The objectives were to assess (1) the ecological correlates of malaria vector breeding through larval surveys, and (2) the socioeconomic, demographic, and ecological risk factors for malaria infection in four ecologically distinct regions of rural Madagascar. Risk factors were determined using multilevel models for the four regions included in the study. Results The presence of aquatic agriculture (both within and surrounding communities) is the strongest predictive factor of habitats containing Anopheles larvae across all regions. Ecological and socioeconomic risk factors for malaria infection vary dramatically across study regions and range in their complexity. Conclusions Risk factors for malaria transmission differ dramatically across regions of Madagascar. These results may help stratifying current malaria control efforts in Madagascar beyond the scope of existing interventions.

Climatic, land-use and socio-economic factors can predict malaria dynamics at fine spatial scales relevant to local health actors: Evidence from rural Madagascar

“…These results suggest that malaria transmission is associated with rural areas in the district, which have higher agriculture and irrigation relative to more urbanized areas (larger towns). This is consistent with previous findings, with lower malaria prevalence in children in urban areas than in rural areas, across the sub-Saharan region [41] and Madagascar [39,42].…”

“…In south-eastern Madagascar, Anopheles mosquito species have been found to be rare in forested areas, while being very common in agricultural areas and near livestock pens [21]. Irrigated agriculture, in particular, has been identified as a strong predictor of Anopheles mosquito habitat across Madagascar [39], and the proportion of rice fields was positively associated with malaria in our spatiotemporal model as well. However, an increase in malaria with deforestation is characteristic of the frontier stage, when extensive changes in land use are occurring [38,40].…”

A habitat stronghold on the precipice: A call‐to‐action for supporting lemur conservation in northeast Madagascar

“…These teams have also carefully documented the prevalence of malaria in Makira and elsewhere (Rice et al, 2016, the distribution and abundance of larval mosquitoes that serve as vectors for infectious disease (Arisco et al, 2020), and ongoing research to • Support Madagascar conservation efforts through WWF. Donations help to support community-managed forestry associations, upscaling of successful models of sustainable financing for conservation from private companies, community-saving and loans groups and commune authorities, diversification of households' revenues and the promotion of sustainable agricultural techniques.…”

“…Beyond wild foods sourced from the forest, the MAHERY team has also documented the traditional medicines sourced from the forest (Golden et al, 2012), and created the first US‐copyrighted book written in Malagasy (Betsimisaraka dialect) preserving the oral history of traditional medicines with illustrations and recipes for the use of hundreds of different plant species to treat more than 80 different illnesses (Golden, Anjaranirina, et al, 2014). These teams have also carefully documented the prevalence of malaria in Makira and elsewhere (Rice et al, 2016, 2021), the distribution and abundance of larval mosquitoes that serve as vectors for infectious disease (Arisco et al, 2020), and ongoing research to evaluate the prevalence of mental health conditions including anxiety, depression, and trauma. Since 2014, the MAHERY team has been documenting health conditions for every individual in three communities in Makira and Masoala, assisting the work of the Ministry of Health in Madagascar.…”

Profiles of bacterial communities and environmental factors associated with proliferation of malaria vector mosquitoes within the Kenyan Coast

“…Research has suggested that proper management of mosquito breeding habitats in sub-Saharan Africa could help reduce vector populations and curb malaria transmission [ 18 ]. By analysing the choice of oviposition sites and its impact on the distribution and abundance of malaria vector mosquitoes, we may be able to explain differences in malaria transmission intensity across different regions [ 19 ]. This information is valuable in the creation of integrated control strategies for Anopheles mosquitoes and health education programmes at the community level, aimed at lowering mosquito populations and reducing the risk of human-vector contact.…”