Tsetse Bloodmeal Analyses Incriminate the Common Warthog Phacochoerus africanus as an Important Cryptic Host of Animal Trypanosomes in Smallholder Cattle Farming Communities in Shimba Hills, Kenya.

Faith I Ebhodaghe,Armanda D S Bastos,Shewit Kalayou,Daniel K Masiga,Michael N Okal

doi:10.3390/pathogens10111501

Faith I Ebhodaghe, Armanda D S Bastos + Show 3 more

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https://doi.org/10.3390/pathogens10111501

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Abstract

Trypanosomes are endemic and retard cattle health in Shimba Hills, Kenya. Wildlife in the area act as reservoirs of the parasites. However, wild animal species that harbor and expose cattle to tsetse-borne trypanosomes are not well known in Shimba Hills. Using xeno-monitoring surveillance to investigate wild animal reservoirs and sources of trypanosomes in Shimba Hills, we screened 696 trypanosome-infected and uninfected tsetse flies for vertebrate DNA using multiple-gene PCR-High Resolution Melting analysis and amplicon sequencing. Results revealed that tsetse flies fed on 13 mammalian species, preferentially Phacochoerus africanus (warthogs) (17.39%, 95% CI: 14.56–20.21) and Bos taurus (cattle) (11.35%, 95% CI: 8.99–13.71). Some tsetse flies showed positive cases of bloodmeals from multiple hosts (3.45%, 95% CI: 2.09–4.81), including warthog and cattle (0.57%, 95% CI: 0.01–1.14). Importantly, tsetse flies that took bloodmeals from warthog had significant risk of infections with Trypanosoma vivax (5.79%, 95% CI: 1.57–10.00), T. congolense (7.44%, 95% CI: 2.70–12.18), and T. brucei sl (2.48%, 95% CI: −0.33–5.29). These findings implicate warthogs as important reservoirs of tsetse-borne trypanosomes affecting cattle in Shimba Hills and provide valuable epidemiological insights to underpin the parasites targeted management in Nagana vector control programs in the area.

Highlights

Wildlife are reservoirs of a plethora of pathogens including parasites that are transmitted from wildlife to humans and livestock through habitat sharing or dissemination by haematophagous arthropod-vectors [1]
In sub-Saharan Africa, the tsetse-transmitted trypanosomes responsible for Nagana cattle disease and human sleeping sickness are examples of arthropod-borne parasites harbored by asymptomatic wildlife hosts [2,3,4,5]
The proportion of trapped tsetse flies that had detectable bloodmeals was higher in females [54.80% (251/458)] than males [40.76% (97/238)] [Binomial-Generalized Linear Model (BGLM]: p < 0.05) and in Glossina pallidipes [53.42% (281/526)] and G. austeni [62.50% (25/40)] than G. brevipalpis [32.31% (42/130)] (B-GLM: p < 0.05) (Table 1)

Summary

Introduction

Wildlife are reservoirs of a plethora of pathogens including parasites that are transmitted from wildlife to humans and livestock through habitat sharing or dissemination by haematophagous arthropod-vectors [1]. In sub-Saharan Africa, the tsetse-transmitted trypanosomes responsible for Nagana cattle disease and human sleeping sickness are examples of arthropod-borne parasites harbored by asymptomatic wildlife hosts [2,3,4,5]. Warthogs harbored the widest diversity of animal trypanosomes and were thought to be the source of trypanosomes detected in cattle in the area. These results support suggestions that warthogs are among the wildlife species that contribute to maintaining endemicity and transmission of trypanosome infections in the Luangwa Valley, Zambia [2]

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