Prevalence and animal level risk factors associated with Trypanosoma evansi infection in dromedary camels

Surra is a non-cyclic parasitic disease caused by Trypanosoma evansi (T. evansi) and spread by biting flies. The disease has a severe impact on camel health, productivity, and market value, posing a significant threat to food safety and the economy. In a cross-sectional study, 370 blood samples were collected from camels in three Egyptian governorates. Samples were tested using parasitological (thin blood smear (TBS)), card agglutination test for T. evansi (CATT), and PCR to estimate the prevalence of T. evansi infection. Overall, the prevalence of T. evansi among examined camels was 17.3%, 18.9% and 22.7% using TBS, CATT and PCR methods, respectively. The risk of T. evansi infection in older camels (> 10 years) is higher than that in young ones (odds ratio (OR) = 9; 95% CI: 3.5-23.1), particularly during spring (OR = 2.5; 95% CI: 1.1-5.7). Furthermore, females and poor conditioned camels were 2.6 and four times more likely to get infection than males and good conditioned camels, respectively. The level of agreement between diagnostics tests were perfect kappa (> 0.83). Moreover, CATT showed higher sensitivity (0.83; 95% CI: 0.74-0.91) than TBS (0.76; 95% CI: 0.66-0.85) and both had perfect specificity (100%). In conclusion, our findings revealed a high rate of T. evansi infection in camels from the three Egyptian governorates. The CATT is a good test for routine use in control program of trypanosomiasis in camels.