Prevalence of Trypanosoma evansi infection in Thai and imported beef cattle on the Thai-Myanmar border using parasitological and molecular methods.

Background and aim: Animal trypanosomiasis caused by Trypanosoma evansi is a major vector-borne disease affecting livestock productivity, especially in tropical regions. The disease has been documented in Thailand in cattle, buffaloes, and other livestock. This study aimed to estimate the prevalence of T. evansi infections in Thai and imported beef cattle along the Thai-Myanmar border using parasitological and molecular diagnostic methods.

Materials and methods: A cross-sectional study was conducted on 347 cattle, comprising 120 Thai cattle and 227 imported cattle, during December 2022 and January 2023. Blood samples were collected and tested using hematocrit centrifugation technique (HCT), buffy coat smear microscopic examination (BMIC), and polymerase chain reaction (PCR) targeting the internal transcribed spacer-2 region. Statistical analysis was performed to assess the sensitivity and specificity of diagnostic methods and evaluate risk factors such as sex, age, and breed.

Results: Trypanosomes were detected in 2.59% of samples using HCT and 0.58% using BMIC, while T. evansi was confirmed in 2.02% of samples using PCR. Among Thai cattle, T. evansi prevalence was 2.5%, compared to 1.8% in imported cattle (p = 0.64). Male cattle showed significantly higher infection rates (3.2%) compared to females (0%, p = 0.04). Younger cattle (<2 years) exhibited slightly higher prevalence than older groups. Sensitivity and specificity of HCT and BMIC were 14.28% and 97.65%, and 14.28% and 99.70%, respectively, compared to PCR.

Conclusion: The study highlights the importance of routine laboratory diagnostics, particularly PCR, to confirm T. evansi infections in livestock, especially in high-risk areas like the Thai-Myanmar border. Findings emphasize the need for integrated diagnostic approaches to improve detection and control measures. Collaborative efforts between government agencies and veterinary experts are recommended to manage trypanosomiasis and reduce its impact on livestock productivity and livelihoods.