An update of the tsetse fly (Diptera: Glossinidae) distribution and African animal trypanosomosis prevalence in north-eastern KwaZulu-Natal, South Africa
Venter, Gert J.; De Beer, Chantel J.; Green, Karin Kappmeier; Esterhuizen, Johan; De Klerk, Daniel G.; Ntshangase, Jerome; Vreysen, Marc J.B.; Pienaar, Ronel; Motloang, Makhosazana; Ntantiso, Lundi; Latif, Abdalla A.
An unpredicted outbreak of African animal trypanosomosis or nagana in 1990 in north-eastern
KwaZulu-Natal necessitated an emergency control programme, utilising the extensive cattledipping
system in the area, as well as a reassessment of the tsetse and trypanosomosis problem
in the province. Since 1990, sporadic blood sampling of cattle at the dip tanks in the naganainfested
areas were undertaken to identify trypanosome species involved and to determine the
infection prevalence in cattle. The distribution and species composition of the tsetse populations
in the area were also investigated. From November 2005 to November 2007 selected dip tanks
were surveyed for trypanosome infection prevalence. During April 2005 to August 2009 the
distribution and abundance of tsetse populations were assessed with odour-baited H traps.
The tsetse and trypanosome distribution maps were updated and potential correlations
between tsetse apparent densities (ADs) and the prevalence of trypanosomosis were assessed.
Glossina brevipalpis Newstead and Glossina austeni Newstead were recorded in locations where
they have not previously been collected. No significant correlation between tsetse relative
abundance and nagana prevalence was found, which indicated complex interactions between
tsetse fly presence and disease prevalence. This was epitomised by data that indicated that
despite large differences in the ADs of G. austeni and G. brevipalpis, trypanosome infection
prevalence was similar in all three districts in the area. This study clearly indicated that both
tsetse species play significant roles in trypanosome transmission and that it will be essential
that any control strategy, which aims at sustainable management of the disease, should target