Seroprevalence, risk factors and haematology of Trypanosoma evansi in dromedary camels in northern Oman

Trypanosoma evansi is a blood parasite that is mechanically transmitted by hematophagous flies and causes a serious disease in most mammals in the tropics and subtropics. This study aimed to investigate the seroprevalence of Trypanosoma evansi and the associated risk factors in dromedary camels from the northern region of Oman. Serum samples were collected from 388 dromedary camels and examined using a card agglutination test (CATT/T. evansi). Haematological parameters were also assessed using EDTA blood samples. Binary logistic regression was used to examine the association of T. evansi seroprevalence with potential risk factors, including location, age, sex, mixing with other animals, deworming, tick presence, prophylaxis usage, vector control and abortions in she camels. The overall seroprevalence of T. evansi detected by the CATT/T. evansi test was 26.3% (102/388, CI: 21.9-30.9%). There was a significant relationship between T. evansi seroprevalence and the location (x²=11.99, p=0.017). Camels younger than four years of age were 3.79 times more likely to have circulating antibodies against T. evansi than camels between four to ten years of age. The mean MCV and eosinophil count in the seropositive camels were significantly lower than in non-infected ones. Further research is needed to investigate the active infection of T. evansi in other animal species and locations in the country.