Abstract:
BACK GROUND
Tsetse-transmitted African trypanosomiasis is a debilitating and fatal disease of humans
and livestock if left untreated. While knowledge of the spatial distribution patterns of tsetse is
essential for the development of risk-based vector control strategies, existing distribution
maps in Zambia are more than 40 years old and were based on coarse spatial resolution
data. The recently developed vehicle-mounted sticky trap (VST) provides an alternative
sampling device to aid in updating existing distribution maps but has not been applied outside
an experimental setting and is limited to motorable tracks. Therefore, the objective of
the present study was to demonstrate the effectiveness of utilizing the VST for area-wide
surveys of Glossina morsitans and to use the occurrence records to predict its spatial distribution
in Zambia under current environmental conditions using Maxent.
METHODOLOGY PRINCIPAL FINDINGS
Two-sided all-blue VST baited with butanone and 1-octen-3-ol was used to survey 692 and
1020 km of transect routes in G. m. centralis Machado and G. m. morsitans Westwood previously
published distribution in Zambia. Maxent species distribution technique was used to
predict the potential distribution of the two subspecies using current climatic and environmental
data which was then compared to the historical distribution. A total of 15,602 tsetse
were captured with G. m. morsitans (58%) being the most abundant. G. m. centralis and G.
pallidipes Austin represented 39 and 2% of the catch respectively, and G. brevipalpis Newstead
was also detected. The predicted potential distribution for G. m. centralis was 80,863
km2 while that of G. m. morsitans was 70,490 km2 representing a 47 and 29% reduction compared to their historical distributions, respectively.
CONCLUSION/PRINCIPAL FINDINGS
The VST is effective for sampling G. morsitans outside experimental settings and is
recommended for use as an additional tsetse survey tool. The spatial distribution of G. morsitans in Zambia has reduced by 101,051 km2 due to temperature and land cover
changes.
