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BioMed Research International
Volume 2013 (2013), Article ID 614721, 12 pages
http://dx.doi.org/10.1155/2013/614721
Research Article

Genetically Distinct Glossina fuscipes fuscipes Populations in the Lake Kyoga Region of Uganda and Its Relevance for Human African Trypanosomiasis

1Faculty of Science, Gulu University, Loroo Division, Gulu Municpality, Gulu, Uganda
2Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06520, USA
3School of Biological Sciences, Makerere University, Kampala University Rd, Kampala, Uganda
4National Livestock Resources Research Institute, P.O. Box 96, Old Busia Road, Tororo, Uganda
5Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA

Received 30 April 2013; Accepted 19 August 2013

Academic Editor: Harry P. De Koning

Copyright © 2013 Richard Echodu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Tsetse flies (Glossina spp.) are the sole vectors of Trypanosoma brucei—the agent of human (HAT) and animal (AAT) trypanosomiasis. Glossina fuscipes fuscipes (Gff) is the main vector species in Uganda—the only country where the two forms of HAT disease (rhodesiense and gambiense) occur, with gambiense limited to the northwest. Gff populations cluster in three genetically distinct groups in northern, southern, and western Uganda, respectively, with a contact zone present in central Uganda. Understanding the dynamics of this contact zone is epidemiologically important as the merger of the two diseases is a major health concern. We used mitochondrial and microsatellite DNA data from Gff samples in the contact zone to understand its spatial extent and temporal stability. We show that this zone is relatively narrow, extending through central Uganda along major rivers with south to north introgression but displaying no sex-biased dispersal. Lack of obvious vicariant barriers suggests that either environmental conditions or reciprocal competitive exclusion could explain the patterns of genetic differentiation observed. Lack of admixture between northern and southern populations may prevent the sympatry of the two forms of HAT disease, although continued control efforts are needed to prevent the recolonization of tsetse-free regions by neighboring populations.