Zoonotic Pathogens Detected in Ticks in Kenyan Game Reserves

Little is known on tick-borne pathogens and their role in disease in game reserves in Kenya. Ticks were collected by sterile forceps from restrained cattle hide and placed into labeled falcon tubes. Ticks were screened for pathogens by High Resolution Melting (HRM) analysis and sequencing of specific RT-PCR products of Anaplasma, Ehrlichia, and Rickettsia species. A total of 317 ticks (281 adult ticks and 36 nymphs) comprising seven species were collected around the Tsavo National Reserve (TNR) in Taita Taveta County with Amblyomma gemma being the most commonly collected species (n = 135, 42.6%). From near Shimba Hill game reserve (SHNR), a total of 240 adult’s ticks were sampled, representing eight species, with again Amblyomma gemma being the most sampled species (n = 156, 65%). From Tsavo, a total of three pools of Rhipicephalus appendiculatus were positive for Theileria parva, two pools of Rhipicephaline evertsi for Anaplasma platys and one pool of Amblyomma variegatum nymphs for Rickettsia africae. Rickettsia africae, which causes African tick-bite fever, was detected in two pools of Am. variegatum and one pool of Amblyomma gemma collected near Shimba Hill game reserve. Rickettsia sp. and Anaplasma sp. were detected in Am. gemma and Rh. evertsi respectively. Rickettsia aeschlimannii was detected in a pool of Am. gemma. These findings highlight the risk of transmission of zoonotic pathogens to humans in regions with high human-wildlife interfaces. Of specific importance, we provide evidence of R. aeschlimannii in A. gemma for the first time, representing a potential new R. aeschlimannii vectors.