Insights into equine piroplasmosis in Venezuelan sport horses: Molecular diagnosis, clinical, and cardiovascular findings.

Equine piroplasmosis (EP), a tick-borne infectious disease common in tropical and subtropical regions like Venezuela, was observed in sport horses in this study. The researchers analyzed 33 horses and used diagnostic tests and observations to understand how the disease impacts these animals, including its effect on heart rate variability.

Research Methodology

• The research team conducted an observational survey and case-control study on 33 sport horses under regular training activities from endemic regions of north-central Venezuela.
• They used a conventional PCR assay that targets the SSU rRNA gene to confirm the presence of EP etiologic agents in the horses.
• The researchers then confirmed the infections caused by Babesia caballi or Theileria equi by DNA sequencing and BLASTN analyses.
• Further, a phylogenetic analysis of SSU rRNA gene sequences was carried out.
• Clinical signs and heart rate variability frequency domain analysis were also observed to check the effect on health of infected animals.

Research Findings

• Out of 33 horses, 13 (~ 39.4%) were found to be infected with EP.
• Out of these 13 EP-positive samples, 9 were infected with either Babesia caballi (6/9 = 66.7%) or Theileria equi (3/9 = 33.3%).
• The phylogenetic analysis revealed that these sequences clustered within the worldwide distributed phylogenetic genotype A.
• There were no horses with acute cases of EP observed, however, six horses displayed mild clinical signs associated with EP, including mild leukocytosis.
• Heart rate variability analysis of four infected animals pointed towards a sympathovagal imbalance suggesting an ongoing infection.

Conclusions

• The research suggests potential risks for sport horses stemming from intense training programs and sport-related activities. These activities could upset the host-parasite equilibrium present in endemic regions, leading to increased chances of infection reactivation and transmission.
• The researchers emphasized the need for better health programs for sport horses in endemic regions, including the use of molecular diagnostic tests for EP detection based on the presence of parasite DNA in equine blood samples.