Isotype specific ELISAs to detect antibodies against swine vesicular disease virus and their use in epidemiology.

SUMMARY Isotype specific ELISAs to detect antibodies against swine vesicular disease, which may help to estimate the moment of infection, were developed and validated on sera from pigs experimentally infected with four dierent isolates of swine vesicular disease virus. Virus specific IgM antibodies could be detected from days 3‐49 and occasionally up to day 91 after infection. IgG " antibodies were first detected at day 8 and IgG # at day 11. IgA antibodies coincided with IgG " antibodies, but antibody titres varied widely. From the results obtained with the sera from the experimentally infected pigs, we calculated the day at which 50% of the pigs had become positive (D &! ). A D &! of 5, 4, 12, 12 and 24 days was calculated, respectively, for the appearance of antibodies in the virus neutralization test, the IgM, total IgG, IgG " and IgG # ELISA. A D &! of 49 days was calculated for the disappearance of IgM antibodies. The isotype specific ELISAs proved to be valuable tools to study the epidemiology of the disease.