SPECIES DIVERSITY OF BLOOD MEALS, TRYPANOSOMES AND ENDOSYMBIONTS OF Glossina austeni AND PERCEPTION OF SMALL HOLDER FARMERS ON TRYPANOSOMIASIS ALONG THE KENYAN COAS

Abstract

Background: Animal African trypanosomiasis (AAT) is a disease of both domestic and wild animals that is caused by trypanosomes transmitted by tsetse flies (genus Glossina). AAT causes huge agricultural losses in sub-Saharan Africa. Trypanosome transmission depends on the reservoirs (mammalian hosts) that sustain the parasites' cryptic cycle and provide tsetse flies with blood. The host-feeding preference of Glossina austeni, diversity of trypanosome infections and endosymbionts as well as the community knowledge on tsetse flies and trypanosomiasis along the Kenyan coast is limited. We hypothesised that host-feeding preference of Glossina austeni, affected the endosymbiont diversity and trypanosome infections. In addition, community knowledge and attitudes influenced tsetse fly and trypanosomiasis control practices. The study aims were to: i) determine farmers' knowledge, attitudes, perceptions, and control practices (KAP) regarding tsetse flies and trypanosomiasis (T&T) around Arabuko Sokoke Forest Reserve (ASFR); and to determine the Kenyan coastal G. austeni’s ii) blood meal sources; iii) trypanosome species; iv) endosymbionts and v) to evaluate the relationship between endosymbionts and trypanosome infections. Methods: The study was done in two phases: phase I and II. During phase I, a cross-sectional study collected data from 404 cattle-rearing households using structured questionnaires. Farmers' KAP on T&T and the associated demographic factors were assessed using logistic regression models. The second phase involved a cross-sectional study to determine the blood meal sources, trypanosome and endosymbiont diversity in G. austeni sampled from ASFR and Shimba Hills National Reserve (SNHR) ecosystems. The relationship between these factors was assessed through multivariate analysis, while chi-square test compared trypanosome infections between the two ecosystems (ASRF and SHNR). Results: The results show only 16% of the participants had adequate knowledge on T&T, which was associated with the participants’ (i) age; 15–24 years (aOR 2.88 (95% CI 1.10–7.52), (ii) level of education; secondary (aOR 2.46 (95% CI 1.43–4.24)); tertiary (aOR 3.80 (95% CI 1.54–9.37)), and (iii) employment status; self employed farmers (aOR 6.54 (95% CI 4.36–9.80)). Overall, the key blood meal source included the bushbuck (33.8%), African elephant (17.6%), African buffalo (0.3%), bushpig (7.4%), human being (8.8%), waterbuck (8.1%), warthog (5.1%), and porcupine (0.7%), while 8.1% of the bloodmeal hosts were not identified. Glossina austeni’s blood meal hosts in ASFR and SHNR were significantly different (p<0.001). The bushbuck accounted for 49.4% of the blood meals in SHNR, and only 2.2% in ASFR. The African elephant accounted for 53.3% of the hosts in ASFR but no elephant blood was identified in SHNR. Morevover, buffalo blood accounted for 26.7% of the blood meals in ASFR and only 2.2% SHNR. The trypanosome species in the tsetse flies sampled included T. congolense 75.1%, T. vivax 19.1% and T. b. brucei group 5.8%. The bushbuck was associated with approximately 3 times odds of testing positive for trypanosomes (OR 2.92 (95% CI 1.24 ‒ 6.90)). Further, Sodalis endosymbiont infection was associated with trypanosome infection in multivariable analysis (OR 2.68 (95% CI 1.10‒ 6.55)). However, flies infected by Wolbachia were not significantly associated with trypanosome infection (p = 0.46). Conclusion: Training of the small-scale farmers around ASFR on T&T would bridge the knowledge gap and improve disease prevention and control. The bushbuck was shown to be the main blood meal host and the key potential reservoir host for T. congolense, the major trypanosome species. This study elucidated that Sodalis endosymbiont increases the susceptibility of G. austeni to trypanosome infection. There is need for further studies across seasons to evaluate environmental and biological confounding factors that may affect the trypanosome development in the hematophagous vector, the tsetse fl