Molecular and serological survey on Theileria equi and Babesia caballi infecting Arabian horses in the northern provinces of Syria.

BACKGROUND

Equine babesiosis is one of the prevalent diseases in horses worldwide, but its presence in Syria generally and in the northern region specifically is not known. In Syria, the civil war has severely disrupted veterinary services, hence disease control measures, creating a fertile ground for the spread of tick-borne diseases.

AIM: This study aimed to conduct a comprehensive molecular and serological survey of Theileria. equi and Babesia. caballi in Arabian horses from the northern provinces of Syria, regions heavily impacted by the war.

METHODS

A total of 110 Arabian horses, aged between 2 and 10 years, were included in the study. Each horse underwent a thorough clinical examination and blood analysis. The blood sample was taken from each animal for hematological and immunological analysis, including competitive enzyme-linked immunosorbent assay (cELISA) and polymerase chain reaction (PCR).

RESULTS

Clinical signs of piroplasmosis, such as fever, jaundice, anorexia, and lethargy, were observed in only a small fraction of the horses (4/110). Hematological analysis of these symptomatic horses revealed a significant decrease in lymphocyte, hematocrit, and platelet counts compared to their healthy counterparts. The cELISA detected antibodies against T. equi in 47% (52/110) of the horses, while no antibodies for B. caballi were detected. In the T. equi-positive group, a significant increase in eosinophil percentage and a decrease in red blood cell distribution width were noted. Molecular diagnosis using a nested PCR approach targeting the EMA-1 gene completes the presence of T. equi Deoxyribonucleic Acid (DNA) in 9 out of 10 samples that were initially positive in a screening PCR, as evidenced by the expected specific amplicon at 274 bp. In contrast, no B. caballi DNA was detected in any examined sample, as no specific 566 bp fragment corresponding to the RAP-1 gene was observed. The PCR-positive horses also showed a significant increase in eosinophil percentage and a decrease in platelet counts.

CONCLUSION

The current results confirm the widespread exposure of horses in Northern Syria to T. equi but not B. caballi, which should be taken into account when planning effective control measures in the post-war time.