Molecular Identifications of Hyalomma dromedarii Infecting Camels and Theileria annulata from Ticks by 18S rRNA Gene in Al Disah valley, Tabuk, Saudi Arabia

Abstract

In many places of the world, ticks and tick-borne diseases constitute a severe obstacle to camel productivity. Theileria, an obligate intracellular protozoon, is transmitted by hard ticks and induces moderate to severe diseases in vertebrate hosts. The hard ticks Hyalomma dromedarii and Hyalomma anatolicum were collected from a camel in Saudi Arabia in October 2021. A total of 140 dromedary camels were selected by a simple random selection procedure. A total of 310 two different ixodid tick species, such as H. dromedarii and H. anatolicum were identified in camels. The infection rate of H. dromedarii was 78 % (242 / 310) and that of H. anatolicum was 22% (68 / 310). To identify H. dromedarii and Theileria sp., polymerase chain reaction (PCR) using the COI gene and the 18S rRNA gene was done. The PCR-amplified 660-bplong H. dromedarii and 400-bp-long Theileria sp. genes were analyzed with phylogenetic trees. H. dromedarii had a single genotype that was completely the same as that registered for H. dromedarii. The genotype of Theileria sp. found in H. dromedarii was highly similar to T. annulata by (99.9) %. This study may contribute to understanding the epidemiology of tick-borne diseases, thus, enhancing the detection and control of the diseases in Saudi Arabia.