First molecular survey of animal trypanosomes in Paraguayan horses.

This study, for the first time, investigated the occurrence of diseases caused by Trypanosoma parasites in Paraguayan horses, detailing the prevalence and identifying the specific trypanosome species causing the infections using polymerase chain reaction (PCR) tests.

Background and Objectives

• The researchers aimed to examine the prevalence of Trypanosoma evansi, Trypanosoma equiperdum, and Trypanosoma vivax in horses in Paraguay, where no previous reports on these parasites existed. These organisms cause animal trypanosomosis, a disease with significant impacts in many South American countries.

Methodology

• The study utilized a polymerase chain reaction (PCR)-based cross-sectional survey, conducted from August to September 2019.
• A total of 408 blood samples were obtained from apparently healthy horses from sixteen different Paraguayan regions.
• The research team used PCR to identify the presence of Trypanozoon (T. evansi and T. equiperdum) and T. vivax in the samples.

Results

• The prevalence of Trypanozoon and T. vivax was 7.11% (29/408) and 26.23% (107/408), respectively, identifying both diseases in a significant number of Paraguayan horses.
• Mixed infections, involving more than one type of parasite, were detected in 4.90% (20/408) of the samples.
• Some of the positive trypanosome samples were confirmed as T. vivax and T. evansi Type A through sequence analysis of their respective genes—internal transcribe spacer region and RoTat1.2 variant surface glycoprotein.

Conclusions

• The study concluded that there was a higher prevalence of T. vivax than Trypanozoon in Paraguayan horses, which was an unexpected finding.
• However, the authors advocate for further studies to authenticate genotypic variation since the study’s data might not provide a comprehensive representation of the situation across the entire horse population of Paraguay.