Occurrence of Theileria equi in horses raised in the Jaboticabal microregion, São Paulo State, Brazil.

The study investigates the occurrence of Theileria equi, a parasitic infection, in horses located in São Paulo State, Brazil. Using multiple testing techniques, researchers found a high prevalence of infection, though disagreement occurred between different testing methods.

Sample Collection and Examination

• In this study, blood and serum samples were collected from 170 horses in the Jaboticabal microregion of São Paulo State, Brazil.
• The samples underwent various testing techniques to check for the presence of Theileria equi, a parasite that infects horses.
• The testing methods included microscopic examination of blood smears, Indirect Fluorescent Antibody Test (IFAT), and nested Polymerase Chain Reaction (nPCR).

Findings of the Study

• Through microscopic examination of blood smears, the researchers discovered parasites in 6 of the horses, which is about 3.52% of the total sample.
• Using the IFAT method, the research team found that 100% of the tested serum samples indicated the presence of anti-Theileria equi antibodies; with antibody titers ranging between 1:80 and 1:5120.
• The nPCR method based on the T. equi merozoite antigen gene (EMA-1) allowed for the detection of the parasitic species-specific amplified product in 108 horses, which approximates to 63.53% of the total sample.
• All samples that tested positive on microscopic examination also showed a positive result in the nPCR test.

Statistical Analysis and Conclusion

• A McNemar statistical test was used to analyze the association between the results from the different testing methods.
• Noticeable disagreement was found in the outcomes between IFAT and nPCR; IFAT and blood smear; and nPCR and blood smear regarding the detection of parasite carriers.
• Despite the discordant results between the testing methods, the study made it evident that Theileria equi infection is widespread among the horse population in the studied region.