Comparison of haemagglutination inhibition and indirect fluorescent antibody tests to detect certain flavivirus antibodies in equines.

Formalinized goose erythrocytes were used in haemagglutination inhibition (HI) and indirect fluorescent-antibody (IFA) tests to detect antibodies to Japanese encephalitis (JE) and West Nile (WN) viruses in equines. Paired serum samples from 31 cases having clinical symptoms of flaviviral infections (JE and WN viruses) and 45 controls were examined. For HI test, formalinized goose erythrocytes were used as such, whereas in IFA test, formalinized goose erythrocytes were first coated with respective viral antigens separately and later used to detect antibodies. By employing HI and IFA tests, paired samples having a titre same or less than two fold rise over the control sera were considered normal for both the viruses. IFA test was found to be a method of choice, due to its sensitivity over HI test.