Improving a Complement-fixation Test for Equine Herpesvirus Type-1 by Pretreating Sera with Potassium Periodate to Reduce Non-specific Hemolysis

Abstract

Non-specific hemolysis has often been observed during complement-fixation (CF) tests for equine herpesvirus type-1 (EHV-1), even when the sera have virus-specific CF antibodies. This phenomenon has also been reported in CF tests for various infectious diseases of swine. We found that the sera from 22 of 85 field horses (25.9%) showed non-specific hemolysis during conventional CF testing for EHV-1. Because pretreatment of swine sera with potassium periodate (KIO₄) improves the CF test for swine influenza, we applied this method to horse sera. As we expected, horse sera treated with KIO₄ did not show non-specific hemolysis in the EHV-1 CF test, and precise determination of titers was achieved.