Direct agglutination test for the detection of antibodies to Sarcocystis neurona in experimentally infected animals.

The research study developed a direct agglutination test (SAT), proving effective in the detection of antibodies to the protozoan (Sarcocystis neurona) associated with equine protozoal myeloencephalitis disease in horses, using infected mice for experimental purposes.

Development of the Detection Tool

• The apicomplexan protozoan, Sarcocystis neurona, has been identified as the main cause for equine protozoal myeloencephalitis (EPM), a severe neurological syndrome in horses across the Americas. To detect the presence of antibodies to this protozoan, the research group developed a direct agglutination test (SAT).
• The test employs merozoites of the SN6 strain of S. neurona as an antigen. These merozoites were collected from cultivated cells.
• To focus on the detection of IgG antibodies, 2-mercaptoethanol, a chemical reducing agent, was introduced into the antigen suspension. The addition of 2-mercaptoethanol allowed for the breakdown of IgM antibodies during the test phase with the test sera.

Experimental Testing on Animals

• The SAT was experimentally verified through its application to mice who were fed with sporocysts of Sarcocystis species namely, S. speeri and S. falcatula, obtained from opossums.
• Interesting to note, none of the mice in these groups displayed any evidence of a response to the SAT, also known as seroconversion.

Sensitivity and Specificity of the Test

• Through experimental testing, the team was able to discern that the SAT produced a sensitivity rate at 100%. Sensitivity refers to the test’s ability to correctly identify those with the disease.
• Additionally, it was found that the specificity of the SAT was tabulated at 90%. In testing terms, specificity is the ability of the test to rightly identify those without the disease.

Inference

• As such, it can be inferred that this SAT demonstrates high efficacy in the detection of S. neurona infections, proven by its high sensitivity and specificity ratings. However, further evaluations and research would be advantageous to corroborate and bolster these findings.