Towards the implementation of a tsetse control operation at the interface of the Vwaza Marsh Wildlife Reserve and Rumphi District, Malawi

A surge in Human African Trypanosomiasis (HAT) has recently been reported in Rumphi district, Malawi, despite significant reductions prior to 2014. Since 2014 there have been approximately 30 HAT cases per year but in late 2019 there was a three-fold increase. The hypothesized factors for the recent surge in Rhodesian Human African Trypanosomiasis (rHAT) cases in Malawi include: 1) changes in weather patterns and in particular, a warmer climate 2) non-existent or insufficient tsetse control interventions and 3) improved diagnostic capacity by the Rumphi district health office (DHO) to detect rHAT cases courtesy of Fexinidazole trial underway in the district. Currently, efforts to manage the disease rely largely on case detection and treatment. There is, at the moment, little vector control in Vwaza limited to just 50 targets. This presents a pressing need to conduct a monitoring and evaluation project surrounding the Vwaza game reserve to understand the drivers of rHAT cases and potential for vector control. Strengthening tsetse control would contribute to preventing rHAT risk but needs to be based on knowledge of local tsetse fly density, climate, land-use, wildlife patterns and trypanosome infection rates. We will gather this information as part of this study and in doing so, develop a plan for tsetse fly control in Vwaza with applicability to other game reserves in Malawi.

Study objectives: The overall objective of this project is to gather evidence to implement a tsetse control operation at the interface of the Vwaza Marsh Wildlife Reserve and Rumphi District. Specifically, the project seeks to:

  1. Determine the density of livestock and wildlife hosts within Vwaza and in communities along the reserve’s perimeter.
  2. Estimate seasonal abundance of tsetse flies within Vwaza and in communities along the reserve’s perimeter
  3. Determine the host range of tsetse from Vwaza and surrounding communities.
  4. Determine trypanosome infection rates in tsetse flies from Vwaza and surrounding communities.
  5. Design a spatially targeted tsetse control strategy and model the potential impact on HAT risk.

Methodology: The study will be divided into three sub-sections: (1) tsetse ecology, (2) trypanosome infection rates and (3) operational control. Entomological studies will be conducted within game reserve itself and in communities alongside the perimeter. Laboratory analyses will investigate the host range of the vector and prevalence of Trypanosoma spp.

Expected findings and dissemination of research findings: The findings of the study will provide data for the understanding the driver of HAT and implementation of operational tsetse control in Malawi. The results will be presented to the project’s stakeholders and at various academic forums for critical reviews. Results will also be shared with the College of Medicine’s Research Ethics Committee (COMREC) in the form of annual progress reports. Publications arising from the study will submitted to international peer reviewed journals