A report on tick burden and molecular detection of tick-borne pathogens in cattle blood samples collected from four regions in Saudi Arabia.

Babesiosis, theileriosis and anaplasmosis are among the most commonly reported tick-borne diseases in cattle and are associated with significant economic losses. Through the present study the researchers aimed to report the presence of various pathogens that cause babesiosis, theileriosis and anaplasmosis in cattle collected from different provinces in Saudi Arabia and to report their phylogenetic relationship. A total of 362 blood samples of cattle along with ticks that were present on the cattle were collected from four regions (Riyadh, Al-Kharj, Al-Hasa and Al-Qassim) of Saudi Arabia. Blood samples were screened by polymerase chain reaction (PCR) for the presence of various Babesia, Theileria and Anaplasma species by amplification of their 18S rRNA and/or 23S rRNA genes. A total of 541 ticks were collected and identified from the cattle. These included Hyalomma anatolicum, Hyalomma dromedarii, Hyalomma impeltatum, Hyalomma excavatum, Rhipicephalus annulatus and Rhipicephalus turanicus. Regarding tick-borne pathogens, the overall prevalence was 1.9 % (7/362) for Theileria annulata, (2/362) 0.6 % for Theileria and (21/362) 5.8 % for Anaplasma ovis. Four of the cattle were found to be co-infected with more than one pathogen (1.1 %). We did not detect any Babesia species in the blood of the studied cattle. Prevalence of the Theileria and Anaplasma species was highest in cattle that resided in Riyadh, followed by cattle from Al-Hasa and Al-Qassim. Representative amplified partial-gene sequences of T. annulata (GenBank accession numbers MK826137-39) and A. ovis (GenBank acc. no. MK 880224) were submitted to GenBank. The presence of ticks on cattle was found to be associated with a high prevalence of Theileria spp. (P = 0.02) and Anaplasma ovis (P < 0.001). We report novel genotypes of T. annulata and A. ovis from cattle in Saudi Arabia and we recommend that molecular surveys are undertaken throughout the country to address the prevalence and geographical distribution of tick-borne infections for their effective diagnosis and treatment.