Virus was recovered from pharyngeal/tonsillar samples and from rectal swabs for periods up to 11 days from pigs infected with the Italy 1/66 strain of swine vesicular disease virus. Attempts to recover virus from the faeces of convalescent pigs 5 to 9 weeks after infection were unsuccessful. Pigs suffering from, or exposed to, clinical disease developed high levels of neutralizing antibody which were maintained for at least 4 months. In an experiment in which inoculated pips acquired a subclinical infection virus excretion was not detected and the pigs developed much lower antibody levels which declined fairly quickly.