First record of a spotted fever group Rickettsia sp. and Theileria annulata in Hyalomma dromedarii (Acari: Ixodidae) ticks in the United Arab Emirates

Rickettsiosis and theileriosis can cause mortalities in camel populations. This study was conducted to achieve 2 objectives: (1) to detect the presence of SFG Rickettsia sp. and Theileria sp. in Hyalomma dromedarii Koch, 1844 (Acari: Ixodidae) ticks and (2) to determine their prevalence in the tick population on the sampled camel farms in Al-Ain, United Arab Emirates (UAE). Camel ticks (H. dromedarii) were collected from a total of 625 one-humped camels (Camelus dromedarius) in 22 sampling locations in Al-Ain, UAE. Tick samples were analyzed by Polymerase Chain Reaction (PCR). An SFG Rickettsia sp., which was 99% similar to Candidatus 'Rickettsia andeanae' and Rickettsia endosymbionts, was detected only in 2011 and its prevalence in the sampled ticks was 1.12%, while Theileria annulata was detected in both years with a prevalence of 2.3% and 1.60%, respectively. Additionally, T. annulata was present in all of the sampling zones (east, west, north, and south) of the study area, whereas SFG Rickettsia sp. was limited to 2 zones only (east and south). The geographic distributions of SFG Rickettsia sp. and T. annulata showed no overlap throughout the entire study area except in one location in which both of the disease agents were present. This study is the first published record on the presence of SFG Rickettsia sp. and T. annulata in camel ticks in the UAE. In addition, the current study should serve as a foundation for more studies leading to a better understanding of the reservoir potential of camels and the risk posed by these 2 disease agents to camels and other livestock.