Enzyme-linked immunosorbent assay (ELISA) for detection of anti-Trypanosoma evansi equine antibodies.

This research study standardizes the use of the Enzyme-linked Immunosorbent Assay (ELISA) test in detecting anti-Trypanosoma evansi antibodies in horses. Both naturally and experimentally infected subjects were included in the study. High sensitivity and specificity were achieved in the ELISA test results, which were validated against results from an Immunofluorescence Assay (IFA). The study also investigated antibody production in experimentally infected horses and examined the prevalence of the disease in different equine populations.

Standardizing ELISA for T. evansi Detection

• The study aims to develop standardization for a diagnostic test known as ELISA in detecting antibodies against Trypanosoma evansi in horses. This protozoan parasite causes surra, a serious disease in horses.
• Horses were both naturally and experimentally infected with the parasite. The ELISA technique was used to detect the presence of these anti-Trypanosoma evansi antibodies in the horses.
• The correct cutoff to distinguish between positive and negative sera was established using Bayesian analysis.

Evaluating the Accuracy of ELISA Test

• The effectiveness and precision of the ELISA test were evaluated by comparing the results with those achieved using an Immunofluorescence Assay (IFA). IFA serves as the reference method in the study.
• According to the results, the ELISA test exhibited a relative sensitivity of 98.39%, meaning it accurately identified infection in 98.39% of the cases. It also showed a specificity of 95.12%, indicating it accurately identified non-infected cases in 95.12% of the instances.
• The predictive value of the test was 96.83%, implying high reliability of the test results.

Application of Standardized ELISA Test

• The standardized ELISA was utilized to examine the antibody production against the trypanosome parasite in an experimentally infected horse. The study reports that the horse sera showed conversion 15 days following infection.
• Further application of the ELISA test was done to study the prevalence of T. evansi infection in two different groups of horses: workhorses and stable horses. The resulting prevalence was 81.7% in workhorses and 57.14% in stable horses.
• This discrepancy shows that the prevalence of infection can vary significantly depending on the population, potentially due to differences in exposure risks.