Inter-laboratory ring trials to evaluate serological methods for dourine diagnosis.

This research paper examines the reproducibility of specific serological methods for diagnosing dourine, a sexually transmitted disease in equines, across multiple laboratories. The study identifies potential improvements in the process, such as standardizing critical reagents.

Research Overview

• This study involved two inter-laboratory ring trials that aimed to assess the reliability and reproducability of routine serological methods for detecting Trypanosoma equiperdum antibodies in equine sera. Trypanosoma equiperdum is the causative agent of dourine, a sexually transmitted disease in horses.
• The research involved 26 reference laboratories across Europe and other parts of the world that handle dourine.
• Two types of serological methods were evaluated – the Complement Fixation Test (CFT) that was applied by 25 laboratories and the Indirect Fluorescent Antibody Test (IFAT) used by 4 laboratories. Three of these labs used both methods.

Experimentation and Findings

• The tests were performed using panels of equine sera that were either negative, positive, or suspected for dourine. One of the negative samples was from a donkey naturally infected with Trypanosoma evansi.
• The results confirmed the reliability of the CFT and its reproducibility across labs for positively identifying known T. equiperdum positive and negative serums. The reproducibility was not as high for serums positive for T. evansi or of unknown status.
• Nine out of twenty-two laboratories reported a false positive using the T. evansi-positive serum.

Suggestions for Improvement

• The study suggested that the specificity of dourine serodiagnosis could be improved by streamlining the critical reagents, including the antigens, and outlining a standard T. equiperdum serum for cross-calibrating tests across multiple labs.
• The trial data identified one of the three horses as seropositive for dourine. The general use of a viably low-titer serum control derived from a standard serum was proposed for standardizing the detection limit of the method.