Summary
Vectors of emerging infectious diseases have expanded their
distributional ranges in recent decades due to increased global travel,
trade connectivity, and climate change. Transboundary range shifts,
arising from the continuous movement of humans and livestock across
borders, are of particular disease control concern. Several tick-borne
diseases are known to circulate between eastern Uganda and the western
counties of Kenya, with one fatal case of Crimean-Congo haemorrhagic
fever (CCHF) reported in 2000 in western Kenya. Recent reports of CCHF
in Uganda have highlighted the risk of cross-border disease translocation
and the importance of establishing inter-epidemic, early warning systems
to detect possible outbreaks. We therefore carried out surveillance of
tick-borne zoonotic pathogens at livestock markets and slaughterhouses
in three counties of Western Kenya that neighbour Uganda. Ticks and
other ectoparasites were collected from livestock and identified using
morphological keys. The two most frequently sampled tick species were Rhipicephalus decoloratus (35%) and Amblyomma variegatum (30%), and Ctenocephalides felis fleas and Haematopinus
suis lice were also present. In total 486 ticks, lice, and fleas were
screened for pathogen presence using established molecular workflows
incorporating high-resolution melting analysis and identified through
PCR-sequencing of PCR products. We detected CCHF virus in Rh.
decoloratus and Rhipicephalus sp. cattle ticks and 82 of 96
pools of Am. variegatum were positive for Rickettsia
africae. Apicomplexan protozoa and bacteria of veterinary importance,
such as Theileria parva, Babesia bigemina, and Anaplasma marginale, were primarily detected in rhipicephaline
ticks. Our findings show the presence of several pathogens of public
health and veterinary importance in ticks from livestock at livestock
markets and slaughterhouses in estern Kenya. Confirmation of CCHF
virus, a Nairovirus that causes haemorrhagic fever with a high
case fatality rate in humans, highlights the risk of under-diagnosed
zoonotic diseases and calls for continuous surveillance and the development of preventative measures.
Keywords: Emerging infectious disease, Zoonoses, Nairovirus, Rickettsia, Rhipicephalus, East Africa.