Prevalence and Risk Factors Associated With Natural Infection by Trypanosoma evansi in Campeiro Horses.
Authors: Golombieski Lisiane, Bassi das Neves Gabriela, Casa Mariana da Silva, Costa Gabriela Campos de Souza, Miletti Luiz C, Saito Mere E, Fonteque Joandes H
Journal: Journal of equine veterinary science
Summary
# Trypanosoma evansi in Campeiro Horses: Prevalence and Clinical Significance Surra, the parasitic disease caused by *Trypanosoma evansi*, represents a significant but largely undocumented threat to the endangered Campeiro horse breed of southern Brazil, prompting this first comprehensive prevalence study across 214 animals from Santa Catarina, Rio Grande do Sul, and Paraná. Using polymerase chain reaction (PCR) and immunofluorescence antibody testing alongside full haematological and biochemical profiling, researchers identified active infection in 14% of horses and serological evidence in 59%—indicating substantial exposure across the breed population. Infected animals demonstrated a complex haematological picture including elevated hematocrit and basophils but decreased plasma fibrinogen, alongside altered enzymatic markers (elevated creatine phosphokinase and creatinine, depressed liver enzymes and urea), though the clinical significance of these changes relative to infection remains uncertain. Surprisingly, epidemiological questionnaires failed to identify consistent management or environmental risk factors, suggesting either that transmission dynamics differ from other regions or that current risk assessment tools are inadequate for this population. For practitioners working with Campeiro horses or managing endemic herds in southern Brazil, this data underscores the need for serological screening protocols and heightened vigilance for surra-associated clinical signs, particularly given the breed's conservation status and the potential for unrecognised subclinical disease to compromise both individual welfare and genetic preservation efforts.
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Practical Takeaways
- •Campeiro horse owners and veterinarians in southern Brazil should screen for T. evansi infection given the 14-59% prevalence range depending on test methodology
- •Hematological and biochemical changes may indicate T. evansi infection; unexplained anemia or altered liver/kidney enzymes warrant serological testing in this region
- •No specific management or husbandry practices were identified to prevent infection, suggesting vector control or other biosecurity measures should be investigated
Key Findings
- •14% of Campeiro horses tested positive for T. evansi by PCR and 59% by immunofluorescence antibody test
- •Infected animals showed increased hematocrit, basophils, creatine phosphokinase, and creatinine with decreased fibrinogen and aminotransferase activity
- •T. evansi is present in South Brazil with high prevalence in the Campeiro breed
- •Epidemiological questionnaires identified no significant risk factors associated with infection