Seasonal Patterns: Bovine Trypanosomosis, Glossina pallidipes Density, and Infection in Rift Valleys of Gamo Zone, Southern Ethiopia

Abstract

Bovine trypanosomosis is a parasitic disease causing serious economic losses in livestock productivity and agricultural development. The disease has been reported in different parts of Ethiopia. However, seasonal pattern of trypanosomosis, tsetse fly apparent density, and infection are very limited in the southern rift valley of the country, particularly in Gamo Zone. Therefore, the objective of this cross-sectional study design was to estimate seasonal prevalence of bovine trypanosomosis, assessing tsetse fly apparent density and its infection by trypanosomes. For the parasitological study, a total of 600 cattle (300 in each season) were sampled and assayed using the buffy coat technique. A total of 80 standard NGU traps were deployed around the watering and grazing areas for the entomological survey. An overall prevalence of trypanosomosis was 10.17% (61/600), of which 7.33% (22/300) and 13% (39/300) accounted for the dry and wet seasons, respectively. The prevalence of trypanosomosis was significantly higher during the wet season (OR = 2.47; p < 0.05), in black coat color (OR = 7.2, p < 0.05), and poor body-conditioned (OR = 3.15; p < 0.05) animals. Two species of trypanosomes, Trypanosoma congolense, 68.85% (42/61), and Trypanosoma vivax, 31.15% (19/61), were circulating in the area. The mean PCV value in infected animals (22.56 ± 4.61) was significantly lower than in non-infected animals (25.3 ± 4.75). Entomological result indicated that Glossina pallidipes (G. pallidipes) was the only species of tsetse found in the study area. Totally, 3,789 flies were caught of which 81.42% (3,085/3,789) belong to G. pallidipes and 18.58% (704/3,789) were other biting flies. The overall apparent density of G. pallidipes was 12.85 flies/trap/day (FTD). Relatively higher G. pallidipes/trap/day were caught in the wet season (13.64 F/T/D) than in the dry season (12.07F/T/D). Of the flies caught, 342 G. pallidipes were randomly selected and dissected. The overall proportion of G. pallidipes infection was 18.42% (63/342) of which 12.28% (21/171) and 24.56% (42/171) were accounted in the dry and wet seasons, respectively. Infection in G. pallidipes was significantly higher during the wet season (OR = 2.32; p < 0.05) and in park grazing areas (OR = 2.45; p < 0.05). In conclusion, trypanosomosis is the major challenge for cattle productivity in the district. So this study warrants the need for strengthening the vector and parasite control interventions in the area.

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

“…Majority of G. pallidipes flies were collected in WGL and the lowest was in the riverine forest of the two sites. The current result is consistent with earlier studies in Nech Sar National Park [12,22]. Similar results were reported by other studies [18,22].…”

Glossina pallidipes Density and Trypanosome Infection Rate in Arba Minch Zuria District of Gamo Zone, Southern Ethiopia

“…The livelihood of the society largely depends on mixed crop and livestock production system [ 1 , 23 ]. Also, the study area is highly infested with G. pallidipes and biting flies like Stomoxys and Tabanus [ 13 , 15 , 16 ]. Tsetse flies to be examined in the present study were caught from two kebeles of the district, namely, Ganta Kanchama and Kola shara, and Nech Sar National Park, which is one of highly tsetse-infested areas in the country.…”

“…Almost all cattle in and adjacent to the district are at risk of acquiring the disease at any time. As a result, people in the district suffer from low level of draught power and productivity of their animals [ 13 , 17 – 19 ].…”

“…The disease has been reported in different parts of the country with apparent prevalence ranging from 1.38 to 17.15% [10]. Currently, about 220,000 km 2 of the above-mentioned regions of the country are infested by five Glossina species, namely, G. pallidipes, G. morsitans submorsitans, G. fuscipes fuscipes, G. tachinoides, and G. longipennis [11][12][13]. In the country, the most commonly reported and important trypanosoma species affecting cattle include T. congolense, T. vivax, and T. brucei [11,12].…”

“…Arba Minch Zuria district of Southern Ethiopia is one of the well-known tsetse belts of East Africa. The district is highly infested with Glossina pallidipes and biting flies like Tabanus and Stomoxys [13,[15][16][17]. In turn, bovine trypanosomosis is one of the most important livestock diseases in the district, which poses a serious threat to the lives and livelihood of entire communities.…”