Zoonotic Pathogens in Ticks Collected from Livestock in Kenya

Ticks are reservoirs of a variety of pathogens including bacteria, viruses and protozoa. We used PCR to detect pathogens of public health importance in ticks collected from diverse regions of Kenya. 503 tick pools were collected from 982 cattle, 300 sheep and 379 goats that were presented for slaughter at major abattoirs in Nairobi and Mombasa. Tick DNA was screened by qPCR optimized for single-plex detection of Babesia microti, two-plex Coxiella burnetii/Ehrlichia chaffeensis or Bartonella henselae/Borrelia recurrentis or three-plex for the non-human Babesia spp/Anaplasma phagocytophylum/Borrelia burgdorferi. Pathogen prevalence was calculated against tick type and the geographical origin. Computational analysis was performed with Graphpad prism 5. Out of 503 tick analyzed, 21% (106) were positive for at least one pathogen. C. burnetii was the most abundant at 70% (74/106), followed by non-human Babesia at 17% (18/106), 5% (5/106) for B. burgdorferi, 7% (7/106) for other Borrelia species and <1% (1/106) for E. chaffeensis and A. phagocytophylum. B. henselae and the human infective B. microti were not detected. Rh. pulchellus was the most promiscuous one in carrying pathogens: C. burnetti, Babesia, B. burgdorferi, E. chaffeensis and A. phagocytophylum. Non-human infective Babesia were detected in all ticks except Amblyomma. Four counties had 70% of the infected ticks: Marsabit 25% (n = 26/106), Kajiado 17% (18/106), Wajir 16% (17/106) and Narok 11% (12/106). This study identified a number of tick-borne pathogens that cause febrile infections often confused with malaria. Follow-up research will be needed to determine prevalence in humans.