Ticks and Tick-Borne Pathogens Associated with Dromedary Camels (Camelus dromedarius) in Northern Kenya.

Dennis Getange,Eric M Fèvre,Lesley Bell-Sakyi,Mario Younan,Tatenda Chiuya,Jandouwe Villinger,Boku Bodha,Esther Kanduma,Naftaly Githaka,Marisol Collins,Joel L Bargul,Diba Denge

doi:10.3390/microorganisms9071414

Abstract

Ticks and tick-borne pathogens (TBPs) are major constraints to camel health and production, yet epidemiological data on their diversity and impact on dromedary camels remain limited. We surveyed the diversity of ticks and TBPs associated with camels and co-grazing sheep at 12 sites in Marsabit County, northern Kenya. We screened blood and ticks (858 pools) from 296 camels and 77 sheep for bacterial and protozoan TBPs by high-resolution melting analysis and sequencing of PCR products. Hyalomma (75.7%), Amblyomma (17.6%) and Rhipicephalus (6.7%) spp. ticks were morphologically identified and confirmed by molecular analyses. We detected TBP DNA in 80.1% of blood samples from 296 healthy camels. “Candidatus Anaplasma camelii”, “Candidatus Ehrlichia regneryi” and Coxiella burnetii were detected in both camels and associated ticks, and Ehrlichia chaffeensis, Rickettsia africae, Rickettsia aeschlimannii and Coxiella endosymbionts were detected in camel ticks. We also detected Ehrlichia ruminantium, which is responsible for heartwater disease in ruminants, in Amblyomma ticks infesting camels and sheep and in sheep blood, indicating its endemicity in Marsabit. Our findings also suggest that camels and/or the ticks infesting them are disease reservoirs of zoonotic Q fever (C. burnetii), ehrlichiosis (E. chaffeensis) and rickettsiosis (R. africae), which pose public health threats to pastoralist communities.

Highlights

We report for the first time that Hy. impeltatum ticks parasitise camels in Kenya
We identified four tick-borne pathogens (TBPs), R. africae, E. ruminantium, E. chaffeensis and C. burnetii, that are of major economic, animal health and/or human health importance [11,13,43]
Our findings show that E. ruminantium, E. chaffeensis, “Ca. E. regneryi”, C. burnetii, “Ca. A. camelii”, A. ovis and T. ovis are circulating among ticks from camels and sheep in the study area

Summary

Introduction

Kenya is home to over 3 million camels, representing about 6% of Africa’s camel population [1,2]. In the northern parts of Kenya and the Horn of Africa, camel production is a major source of livelihood [1,3]. Since the 1960s, camel populations in this region have continued to increase despite numerous challenges brought about by climate change [2]. In response to increasingly frequent droughts, pastoralist communities that did not previously keep camels have started rearing them to supplement or replace income from cattle production [1]. In comparison with other ruminant livestock, camels are biologically and Microorganisms 2021, 9, 1414.

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Discussion

Conclusion