Prevalence and molecular characterization of Theileria sp. from endangered Arabian gazelles in Saudi Arabia

Wildlife conservation in Saudi Arabia is gaining much attention from the authorities. Habitat destruction, climate change, and human encroachment, as well as disease outbreaks, negatively impact conservation efforts. Hemoparasites among endangered Saudi wildlife have not been studied before. This study aims to investigate the prevalence of hemoparasites among two endangered gazelle species, Gazella marica (Reem) and Gazella arabica (Idmi), raised at King Khalid Wildlife Research Center (KKWRC) for breeding and reintroduction purposes. A total of 233 blood samples were collected from the jugular veins of gazelles and examined microscopically for the detection of piroplasm or any relevant blood parasites. Ticks were collected from some gazelles at KKWRC to identify them and see their potential role in the transmission of hemoparasites. DNA was extracted from the collected blood and ticks for the detection of hemoparasites and amplified, targeting the partial 18S rRNA gene. The prevalence of intraerythrocytic bodies suggestive of Theileria sp. was detected in 41 (17.9%) gazelles of both species, whereas PCR products of Theileria sp. DNA was detected in 65 (27.9%) gazelles. The sensitivity of the molecular technique compared to the direct microscopy was 76.74%, whereas the specificity was 83.16%. Ticks were morphologically identified as Hyalomma impeltatum and confirmed with molecular techniques. Sequences obtained from Theileria sp. from both Reem and Idmi gazelles were identical, except for a single mutation (transition) at position 140: a T in Reem sequences, whereas it was a C in all Idmi sequences. Phylogenetic studies indicated that sequences obtained from gazelles in the present study group were related to Theileria sp., which was isolated from the Chinkara gazelle from Pakistan and related to isolates from the dama gazelle. Theileria sp. DNA was amplified from two ticks collected from Reem gazelles and found to be identical to the Theileria sp. sequences obtained from Reem gazelles. This finding suggested that H. impeltatum may carry Theileria DNA; however, vector competence requires further investigations. The prevalence of Theileria infection in gazelles at KKWRC in Saudi Arabia was reported for the first time. The possible vector responsible for the transmission was also identified.