Predictive Mapping of Transmission Risk of a Soil-Transmitted Helminth across East Africa: Findings from Community Prevalence Surveys

Abstract

Background: Despite being identified as a major health concern and neglected tropical disease, Ascariasis, caused by Ascaris lumbricoides, a soil-transmitted helminth, ranks among the most common infections worldwide. 

Methods: Based on prevalence data from the community surveys across East Africa for 1975-2009, we used ecological niche modeling to summarize and predict the spatial distribution of A. lumbricoides’ transmission risk. 

Results: Projection of this model across East Africa identified 51.4% of the region as suitable for A. lumbricoides transmission, with least suitable areas in the Sahara and the Somali-Chalbi deserts. Partial area under the curve (AUC) tests based on independent data showed that our model predictions were better than random expectations in predicting infection risk of A. lumbricoides; the model successfully identified areas of high and low infection risk in Ethiopia and Eritrea. 

Conclusions: Although preliminary, this occurrence-environment mapping approach provides predictions that can guide education and mitigation efforts in the broader East African region.