Molecular Detection of Theileria annulata among Dairy Cattle and Vector Ticks in the Herat Area, Afghanistan

Theileriosis is one of the most important diseases in tropical and subtropical regions and leads to annual economic losses, such as the reduction of dairy products and casualties. Although the clinical form of bovine theileriosis has been observed in Afghanistan, to the best of our knowledge, no comprehensive study has been conducted on this issue. This molecular survey was performed to identify Theileria annulata and tick vectors in dairy cattle in the Herat area, Afghanistan, from June ۲۰۱۵-September ۲۰۱۶. A total of ۱۰۰ dairy cattle were clinically examined and their blood smears, EDTA blood samples, and ixodid ticks were collected. The blood samples were transported to the laboratory, followed by the preparation of the blood smears and staining with the Giemsa method. The collected ticks were identified at the species (spp) level using the identification key and were then separated into ۷۰ tick pools according to their species. Subsequently, the salivary glands were dissected out in ۰.۸۵% saline under a stereomicroscope. The DNA of blood and salivary glands was extracted using a commercial kit and analyzed by polymerase chain reaction (PCR). The ring form of Theileria spp infection was observed in ۲۲ (۲۲%) of blood smears, while ۷۴% of blood samples were T. annulata positive using PCR. Among the collected ticks, the numbers of male and female ticks were obtained at ۲۱۹ and ۱۳۰ ticks, respectively. The frequency of tick spp was rated in descending order as Hyalomma annatolicum (۷۳.۹%), Hyalomma excavatum (۲۲.۳%), Hyalomma nymph spp (۱۲%), Hyalomma marginatum (۱.۷%), Hyalomma asiaticum (۱.۱%), and Hyalomma rufipes (۰.۷۵%). The PCR results showed that seven pools belonging to salivary glands of H. anatolicum were infected with T. annulata. Based on the obtained results, it can be concluded that T. annulata had a high frequency in dairy cattle and H. anatoloicum was also identified, such as the vectors of T. annulata in the Herat area, Afghanistan.

Keywords:

Theileria annulata , PCR , Cattle , Ixodid tick , Afghanistan