Molecular Assay Proves the Presence of Theileria annulata Infection in Camels in Al-Diwaniyah Province, Iraq

BACKGROUND: Theileria camelensis and T. dromedarii are parasitic protozoans reported by several studies as specific species that infect the one-humped camel (Camelus dromedarius). However, other findings casted significant doubts on the true identity of the causative species of theileriosis in camels. Therefore, the present study was conducted to investigate of T. camelensis and T. dromedarii in one humped camels in Iraq during Apr-Oct 2017. METHODS: Blood samples for DNA extraction were obtained from 181 slaughtered camels. Molecular investigation was performed following the amplification of 18S rRNA gene by conventional PCR technique. DNA sequencing was then utilized only for the positive samples to confirm the infection with the Theileria species. RESULTS: Nine (4.97%) out of 181 examined samples showed a positive result to infection with Theileria spp., and all these appeared as a T. annulata when subjected to DNA amplification and sequencing techniques. There was a complete absence of any new sequence outside the known species. CONCLUSION: Most of Theileria infection in camels in the study area is caused by T. annulata and no other causative agents like T. camelensis or T. dromedarii.