Evaluating the efficacy of various traps in catching tsetse flies at Nech Sar and Maze National Parks, Southwestern Ethiopia: An Implication for Trypanosoma Vector Control

Abstract

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 flies using olfactory cues. Therefore, the present study aimed to evaluate the efficiency of different types of traps in catching tsetse flies at Nech Sar and Maze National Parks, Southwestern Ethiopia. The study was done for six consecutive months from February to July 2019. Briefly, a 3×4 Latin square design was performed, and tsetse flies were collected for three days each month in four different vegetation types, including wood grassland, bush land, forest, and riverine forest. To avoid trapping position bias, rotation of traps has been done every day. Almost all (99.5%) of the flies were Glossina pallidipes and the remaining were G. fuscipes. The latter were present only at Maze national park. NGU traps were the most efficient type with 12.1 flies/trap/day at Nech Sar National Park and it was 2.2 flies/trap/day at Maze National Park followed by biconical and sticky traps. The number of tsetse flies collected by biconical trap was three-fold lower than NGU trap, and it was four-fold lower in sticky trap than NGU trap in both Nech Sar and Maze National Parks. A substantial number (41%) of G. pallidipes were collected from woody grassland (WGL). In conclusion, G. pallidipes monitoring and evaluation activities could consider NGU trap model as it performed better in most vegetation types in the region.

Trypanosome infection rate and blood-feeding patterns of tsetse fly in an area with a recent human African trypanosomiasis outbreak in Southwest Ethiopia

“…These two species are among the five Glossina species found in Ethiopia, particularly in the South Regional State [4]. Both species were recently documented in the Dame River Valley [18]. There is a high risk of tsetse fly invasion from the Omo River Valley into the Dame River Valley, and without adequate control, re-invasion is also likely.…”

Modelling the spatial and temporal distribution of tsetse flies for targeted control

“…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 biconical traps are less efficient in trapping G. pallidipes compared to the NGU trap (Dransfield and Brightwell, 2001;Asfaw et al, 2022), this adjustment allowed us to align the data and facilitate meaningful comparisons across all monitoring periods, excluding the effect of monitoring effort.…”