Swine vesicular disease: continuing serological surveys of pigs presented for slaughter in the United Kingdom.

Following the first serum survey for swine vesicular disease [SVD] in Great Britain in 1974 (Watson and Hedger 1974), three further surveys have been carried out. In these four surveys an overall total of 9760 sera have been examined, involving pigs from 958 premises in the first three surveys and an unknown number of premises in the fourth survey taken on a national basis. Forty-three farms were visited as sources of origin or possible sources of origin of the pigs from which positive or inconclusive results were obtained. Subsequent to the one clinical case of disease already reported with the results of the first survey, no further clinical cases of SVD have been confirmed, although lesions suggestive of the disease were found in some pigs on four of the premises visited. SVD quarantine restrictions on these four farms were removed subsequent to further serological sampling and when there was no indication that a spreading vesicular condition existed.