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Map of the study area in Gamo zone, Southwest Ethiopia. Administrative boundaries, USGS Earth Explorer: (https://earthexplorer.usgs.gov), Roads, Water (River, lakes))-from DIVA-GIS (https://www.diva-gis.org/gdata), Central Stastical Agency and Regional of Finance and Economies Development). https://doi.org/10.1371/journal.pntd.0010999.g001
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Tsetse flies are the vector of protozoan parasite of the genus Trypanosoma, the causative agent of human African sleeping sickness and animal trypanosomiasis. Traps such as Nguruman (NGU), biconical and sticky traps are in use for tsetse flies sampling and monitoring. However, there is no evidence regarding their comparative efficiency in catching...
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Tsetse flies are obligate hematophagous vectors of animal and human African trypanosomosis. They cyclically transmit pathogenic Trypanosoma species. The endosymbiont Sodalis glossinidius is suggested to play a role in facilitating the susceptibility of tsetse flies to trypanosome infections. Therefore, this study was aimed at determining the preval...
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... In instances where traps were monitored for periods exceeding 8 days with only one tsetse fly trapped, these were treated as if no flies were caught. While it is known that the number of tsetse flies entering a trap is usually low (Lindh et al., 2009) and that bi-conical traps are less efficient in trapping G. pallidipes compared to the NGU trap (Asfaw et al., 2022;Dransfield and Brightwell, 2001), this adjustment allowed us to align the data and facilitate meaningful comparisons across all monitoring periods, excluding the effect of monitoring effort. For modeling purposes, we converted the FTD-values into log 10 (FTD + 1) to address data skewness and variance stabilization (Feng et al., 2014); adding +1 to avoid undefined numbers in case of no observations). ...
... G56 and G304 isolates were very closely and closely related to sensitive IL3000 from Genbank. G-135 was distantly related to IL3000 Fig. 4 (Malele et al. 2007;Asfaw et al. 2022). However, during the dry season, the difference was not significant, and our explanation for this is the low population of flies in the dry season, making the performance of the two traps unable to be distinguished. ...
Tsetse flies are major arthropod vectors of trypanosomes that cause debilitating African animal trypanosomiasis. The emergence of drug-resistant trypanosomes is a common problem in sub-Saharan Africa. This study aimed to identify tsetse flies’ seasonal variation in apparent densities and their infection rates and the occurrence of drug-resistant trypanosomes. Tsetse flies were collected from Lambwe, Kenya, during May and September 2021. Genomic DNA was extracted from them, and the ITS1 gene was amplified to detect Trypanosoma infection with subsequent species determination. Transporter genes DMT, E6M6, TbAT/P2, and TcoAde2 were targeted to detect polymorphisms associated with drug-resistance, using sequencing and comparison to drug-sensitive trypanosome species referenced in Genbank. A total of 498 tsetse flies and 29 non-tsetse flies were collected. The apparent density of flies was higher in wet season 6.2 fly per trap per density (FTD) than in the dry season 2.3 FTD (P = 0.001), with n = 386 and n = 141 flies caught in each season, respectively. Male tsetse flies (n = 311) were more numerous than females (n = 187) (P = 0.001). Non-tsetse flies included Tabanids and Stomoxys spp. Overall, Trypanosoma infection rate in tsetse was 5% (25/498) whereby Trypanosoma vivax was 4% (11/25), Trypanosoma congolense 36% (9/25), and Trypanosoma brucei 20% (5/25) (P = 0.186 for the distribution of the species), with infections being higher in females (P = 0.019) and during the wet season (P < 0.001). Numerous polymorphisms and insertions associated with drug resistance were detected in DMT and E6M6 genes in two T. congolense isolates while some isolates lacked these genes. T. brucei lacked TbAT/P2 genes. TcoAde2 sequences in three T. congolense isolates were related to those observed in trypanosomes from cattle blood in our previous study, supporting tsetse fly involvement in transmission in the region. We report Trypanosoma associated with trypanocidal drug-resistance in tsetse flies from Lambwe, Kenya. Female tsetse flies harbored more Trypanosoma infections than males. Tsetse transmission of trypanosomes is common in Lambwe. Risk of trypanosome infection would seem higher in the wet season, when tsetse flies and Trypanosoma infections are more prevalent than during the dry season. More efforts to control animal trypanosome vectors in the region are needed, with particular focus on wet seasons.
