Evaluation of diminazene aceturate treatment efficacy in Trypanosoma spp. infected water buffaloes in Colombia: absence of drug resistance

Introduction: Hemotropic microorganisms, such as Trypanosoma spp., affect many animals, including water buffaloes. Some developing countries have reported trypanocide resistance to Diminazene Aceturate.  This study aimed to describe the presence of resistance associated with trypanocide treatment in Colombian water buffaloes. Materials and methods: In this cross-sectional study, 202 individuals were sampled from an endemic area in Colombia. The molecular technique quantitative polymerase chain reaction (qPCR) was performed targeting the 18S gene for Trypanosoma spp., and phylogenetic analysis based on the ITS1 region was performed. Results: Sixty-one animals (30.2%) were positive for Trypanosoma spp. And fifty-two sequences were completely analyzed. Of the sequences, 76.9% (40/52) were compatible with T. vivax and 23.1% (12/52) with T. theileri; the obtained results did not show homologous sequences for T. evansi. Subsequently, positive animals were treated with Diminazene Aceturate at the recommended dose (7mg/kg), and a final qPCR was performed one month after the end of the treatment. All animals were negative for Trypanosoma spp. after treatment with the drug. Discussion: Although no resistance to the drug was detected in the animals included in the study, it is necessary to implement continuous surveillance of trypanocidal drug resistance to verify the circulation of resistant strains in Colombia and endemic areas in other countries.