Geospatial forecast model for tsetse-transmitted animal trypanosomosis in Ethiopia

Abstract

The aims of this study were to develop a geographic information systems (GIS) forecast and risk assessment model for cyclically transmitted trypanosomosis in Ethiopia by matching features in the environment to available information on the preferences and limits of tolerance of the parasite and its vector, and validate and further develop the GIS model using data from current and historical prevalence survey data and habitat microenvironment studies from trypanosomosis endemic areas. Results indicate that GIS model developed for parasitic diseases based on growing degree day (GDD) concept can be applied to tsetse-transmitted trypanosomosis. GIS for animal trypanosomosis was created using Food and Agriculture Organization – Crop Production System Zones (FAO-CPSZ) database and Normalized Difference Vegetation Index (NDVI) and maximum temperature (Tmax) from the Global Land 1km dataset. The two datasets used to determine the risk of tsetse flies and consequently animal trypanosomosis in Ethiopia indicated the magnitude of the disease and possible expansion of the “fly belt” in the future. The GIS model indicated the distribution and importance of tsetse-transmitted trypanosomosis in Ethiopia. Spatial and statistical analysis verified the use of GDD concept and climate forecast system that was developed to determine the suitability of a given environment for the proliferation of a biotype, in this case tsetse and trypanosomes. Results presented here indicate the importance of GDD and the two climatic variables (NDVI and Tmax) in the development of forecast model for tsetse-transmitted trypanosomosis in Ethiopia.

Key words/phrases: Ethiopia, GIS, NDVI, Tmax, trypanosomosis

SINET: Ethiopian Journal of Science Vol.27(1) 2004: 1-8