First molecular survey of animal trypanosomes in Paraguayan horses.

Despite the epidemic situation of animal trypanosomosis caused by Trypanosoma evansi, Trypanosoma equiperdum and Trypanosoma vivax in South American countries, there are no reports for the prevalence of animal trypanosomes in Paraguay. In this study, 408 blood samples were obtained from apparently healthy horses from sixteen departments of Paraguay, for routine medical check-up from August to September 2019, and a polymerase chain reaction (PCR)-based cross-sectional study was carried out to identify trypanosome prevalence. The prevalence of Trypanozoon (T. evansi and T. equiperdum) and T. vivax was 7.11% (29/408) and 26.23% (107/408), respectively. Mixed infections were detected in 4.90% (20/408) of the samples. Some of the selected trypanosome positive samples were confirmed as T. vivax and T. evansi Type A by sequence analysis of the internal transcribe spacer region and RoTat1.2 variant surface glycoprotein gene, respectively. In conclusion, we found higher prevalence of T. vivax than Trypanozoon in Paraguayan horses. However, the genotypic variation should be verified in further studies.