Tsetse fly distributions in a changing world: The possible impacts of climate change on Glossina subgenus Morsitans in Kenya

Background/Question/Methods

Tsetse flies are the primary vector for African trypanosomiasis, a neglected tropical disease that affects both humans and livestock across the continent of Africa. Several factors can lead to an expansion or contraction of tsetse spatio-temporal distributions (DeVisser et al., 2010), however, given tsetse flies sensitivity to temperature, we have attempted to identify possible changes in tsetse distributions over the next 40 years using projected climate change for East Africa. To accomplish this we used the Tsetse Ecological Distribution (TED) Model in conjunction with projected A1B climate change scenario from the Regional Atmospheric Modeling System (RAMS) parameterized for East Africa. The TED Model is a raster based dynamic species distribution model that predicts tsetse distributions at a 250 m spatial resolution and 16-day intervals, based on habitat suitability and fly movement rates. Although the TED Model can be parameterized to any tsetse subgenus / species requirements, for the purpose of this study the TED Model was parameterized to identify suitable habitat for Glossina subgenus Morsitans.

Results/Conclusions

Based on the projected change in minimum and maximum temperature from RAMS, the TED Model predicts that tsetse distributions in Kenya will have a net expansion of roughly 0.93% (5,356 km²) by 2050. In addition, 3.7% of Kenya (21,804 km²) is predicted to experience an increase and 2.9% of Kenya (17,362 km²) is predicted to experience a decrease in the probability of tsetse presence. Of particular concern are the Kenyan highland regions, where tsetse flies have not been historically found.