Genetic diversity of Glossina fuscipes fuscipes along the shores of Lake Victoria in Tanzania and Kenya: implications for management

Abstract

BackgroundTsetse flies (Diptera: Glossinidae) are sole vectors for trypanosomiasis, which affect human health and livestock productivity in Africa. Little is known about the genetic diversity of Glossina fuscipes fuscipes, which is an important species in Tanzania and Kenya. The main objective of the study was to provide baseline data to determine the genetic variability and divergence of G. f. fuscipes in the Lake Victoria basin of Tanzania and Kenya in order to guide future vector control efforts in the region.FindingsTwo hundred and seventy five G. f. fuscipes from 8 sites along the shores of Lake Victoria were screened for genetic polymorphisms at 19 microsatellite loci. Samples were collected from two sites in Kenya and six sites in Tanzania. Four of the Tanzanian sites were located in the Rorya district, on the eastern shores of Lake Victoria, while the other two sites were from Ukerewe and Bukoba districts from the southern and western Lake Victoria shores, respectively. Four genetically distinct allopatric clusters were revealed by microsatellite analysis, which sorted the sampling sites according to geography, with sites separated by as little as ~65 km belonging to distinct genetic clusters, while samples located within ~35 km from each other group in the same cluster.ConclusionOur results suggest that there is ongoing genetic admixture within sampling sites located ~35 km from each other, while sites located ~65 km apart are genetically isolated from each other. Similar patterns emerged from a parallel study on G. f. fuscipes analyzed from the Lake Victoria Uganda shores. From a control perspective these results suggest that for sites within the same genetic cluster, control efforts should be carried out in a coordinated fashion in order to avoid re-invasions. Future work should focus on better quantifying the extent and spatial patterns of the observed genetic discontinuities of the G. f. fuscipes populations along the Tanzanian shores. This will aid in their control by providing guidelines on the geographical extent of the area to be treated at the same time.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2201-x) contains supplementary material, which is available to authorized users.

Effect of zebra skin-derived compounds on field catches of the human African trypanosomiasis vector Glossina fuscipes fuscipes

“…Unlike Rusinga (connected to the mainland by a 100 m causeway) and Manga islands, the Chamaunga islands are not inhabited by humans (Omolo et al, 2009). Rainfall patterns in the study area are bimodal, long rains occur from March to May and short rains from October to December (Manangwa et al, 2017). The experiments were carried out after the long rainy season.…”

Negative Density-dependent Dispersal in Tsetse Flies: A Risk for Control Campaigns?

“…In the last decade, several data sets have provided the opportunity for such inferences for different tsetse fly species in different countries in Africa: Glossina palpalis 3 gambiensis along the northern reaches [13] and the southern reaches of the Mouhoun River [14] in Burkina-Faso (in one dimension=1D, see Box 2); G. palpalis palpalis in Cameroon (two dimensions=2D, see Box 2) [11,15]; G. palpalis gambiensis and G. tachinoides in Southern Burkina Faso (2D) across river basins [9]; G. tachinoides in Ghana (2D) [7]; G. fuscipes fuscipes from Uganda [12,16], in Tanzania and Kenya [17] (2D); G. pallidipes from Kenya Nguruman escarpment and Ruma [18] and from the Serengeti Park Reserve in Tanzania (2D) [10]. This offered the opportunity to check if any relationship existed between these different inferences of population density and dispersal.…”

“…We kept only data with 2D population structure regressions [7,[9][10][11]. For some studies [12,[15][16][17][18], we needed to re-compute several statistics, as explained in detail in supplementary file S1. Only two studies where 1D dispersal inferences were available along the Mouhoun River in Burkina Faso [13,14] were not included.…”