LIVESTOCK TICKS IN THE UAE: PREVALENCE, DISTRIBUTION, POPULATION DYNAMICS, AND ASSOCIATED MICROORGANISMS

Ticks are important vectors of an array of viral, bacterial, and protozoan pathogens resulting in a wide range of animal and human diseases in the Middle East and North Africa (MENA). In this study, ticks were collected from camels, cows, sheep, and goats in Abu Dhabi, Dubai, and Sharjah in the United Arab Emirates (UAE). The objectives of the study were to (1) identify tick species of livestock through taxonomic keys and using molecular markers, and determine their prevalence and distribution in the UAE, (2) assess Hyalomma dromedarii seasonal population fluctuation over a year under common camel breeding and management practices, (3) determine bacterial communities’ composition and diversity in camel tick, H. dromedarii using Next-Generation Sequencing, and (4) detect tick-borne microbes and their prevalence in Hyalomma ticks collected from livestock. In the UAE, information on the ticks on camels and other livestock is limited, which is essential for designing and instigating effective tick control strategies in the country. In this study, four aspects of ticks and tick-borne diseases of livestock have been investigated in the UAE. First, four tick species, H. dromedarii, Hyalomma anatolicum, Amblyomma lepidum, and Rhipicephalus sanguineus were identified from livestock including camel, cow, sheep, and goat. These tick species were morphologically identified by using taxonomic keys and confirmed through molecular characterization. This study provided the first DNA molecular record of H. anatolicum, A. lepidum, and R. sanguineus from the UAE. Second, the population fluctuation of H. dromedarii was evaluated over one year. Ticks were collected monthly from camels in Al-Ain, UAE, over 12 months (March 2019 to February 2020). Further, H. dromedarii sex ratio was calculated and parasitological indicators were measured. Results showed that the infestation prevalence was very high (94.33%) during the whole study period. The maximum infestation intensity occurred in June, while the minimum occurred in November. Overall, H. dromedarii ticks were found on camels during the entire year despite monthly applications of an acaricide. Third, the composition and diversity of bacterial communities associated with H. dromedarii collected from camels in Al-Ain, UAE, were determined. A total of 100 partially engorged female ticks were taken from tick samples and subjected to DNA extraction and Next-Generation Sequencing. The 16S rRNA gene was amplified from genomic DNA and sequenced using the Illumina MiSeq platform to reveal the bacterial communities. Principal Coordinates Analysis (PCoA) was conducted to determine patterns of diversity in bacterial communities. Twenty-five bacterial families with high relative abundance were identified. Francisellaceae and Enterobacteriaceae coexisted in H. dromedarii. The dominant bacterial genus was Francisella. Fourth, the presence and prevalence of tick-borne Francisella sp., Rickettsia sp., and piroplasmids were determined in Hyalomma ticks infesting livestock. A total of 562 tick samples were collected from camels, cows, sheep, and goats from 24 locations. DNA was extracted from ticks and Polymerase Chain Reactions (PCRs) were performed. Hyalomma dromedarii ticks collected from camels were infected with Francisella-Like Endosymbionts (FLE) (5.81%) and Candidatus Rickettsia andeanae (1.36%). Hyalomma anatolicum ticks collected from cows were found positive with Theileria annulata (4.55%) whereas H. anatolicum ticks collected from goats were positive with Theileria ovis (10%). Theileria ovis was detected for the first time in the UAE. Therefore, further investigations on tick species and tick-borne microbes are required to understand ticks’ biology, ecology, and microbes’ interaction and their role in tick-borne diseases epidemiology in the UAE.