Impact of El Niño on malaria vector dynamics in Tanzania: observation, improvement and unleashing forecasting potential

El Niño weather events have been shown to impact significantly on many mosquito-borne diseases (VBDs), including malaria, dengue, Rift Valley fever and others. While the link between El Niño and disease is well established, the mechanism underlying it is not fully understood, but probably involves impact of the change in rainfall patterns (often drought and then heavy rain, or vice versa) or altered temperatures brought by El Niño on the vectors themselves. Here the researchers aim to take advantage of the collection over the past 9 years of detailed entomological data on one VBD to detect a perturbation to vector dynamics caused by the current El Niño event. The strength of the current El Niño, the existence of high quality entomological data, the inclusion of the team responsible in this proposal, and access to local meteorological data provide a unique opportunity to understand how El Niño events trigger the emergence of VBDs. The researchers focus on malaria, which remains the VBD with the greatest impact on human mortality and morbidity, and propose new fieldwork in the Kilombero valley area of central Tanzania, where there is a 30% prevalence of infection in people. The spatial limits of malaria distribution, its seasonal activity and the mosquito vector dynamics are very sensitive to climate factors, as well as the local capacity to control the disease. New and standard technologies will be used to measure mosquito vector properties within the Kilombero Valley. The researchers will undertake 12 months of detailed entomological study in a number of previously-studied villages in the region, in the expectation of detecting a change or perturbation to vector dynamics or behaviour caused by El Niño. These new data will be analysed in the context of the 9 years of historic data already collected between 2006-2015 (this field campaign ended in May 2015), as well as malaria clinical data and different climate datasets, ranging from regional scale satellite estimates to local scale meteorological station data available for the studied region. Detailed weather data for the areas are available from a local weather station and will be supported by temperature/humidity data collection in the study villages. Based on the findings, we will develop a better understanding of how El Niño impacts on malaria and its vectors (with applicability to a wider range of VBDs) and build a prototype early warning system for malaria risk in Tanzania. This will be a useful resource for local decision makers and public health specialists to target and allow vector control resources in future. Demonstrating that the link between El Niño and Vector Borne Diseases lies in the dynamics of the vector itself, and is triggered by weather, will enable control measures (against the vector) to be implemented earlier, or other mitigation measures to be undertaken. This is carried out to better understand how El Niño affects malaria, in order to build an early warning system prototype for malaria risk in Tanzania.

Impact of El Niño on malaria vector dynamics in Tanzania: observation, improvement and unleashing forecasting potential

Grant details

Climate Change
Surveillance
Vector Control

Apr 2016 — Dec 2017

$373,704

Tanzania