Validation of a monoclonal antibody-based ELISA to detect antibodies directed against swine vesicular disease virus.

A simple, rapid and sensitive competitive monoclonal antibody-based ELISA for the detection of antibodies directed against swine vesicular disease virus (SVDV) was developed. The ELISA was validated using field sera originating from SVDV-infected and non-infected Dutch pig herds, reference sera obtained from the Community Reference Laboratory for Swine Vesicular Disease at the Institute for Animal Health, Pirbright Laboratory, UK, and sera from animals infected experimentally. When testing 4277 sera originating from non-infected Dutch pig herds and collected as part of the national screening program, this ELISA had only 0.6% false positive results, whereas approximately 2% of false positive results were obtained with a conventional blocking ELISA used until recently. A sensitivity relative to the virus neutralisation test of > 97% was achieved when testing sera collected from Dutch pig farms where an outbreak of SVDV had occurred. All international reference sera scored consistently correct. Sera collected sequentially from pigs experimentally infected with SVDV isolates representing all currently recognized antigenic groups, were scored positive slightly earlier by the ELISA compared to the virus neutralisation test. This monoclonal antibody-based competitive ELISA for SVDV antibodies designated the Ceditest ELISA for SVDV-Ab, is as sensitive but more specific than the ELISA used until recently. Because sera are tested at a single dilution (1:5), incubations are carried out at room temperature and test results are available within 3 h, this ELISA is simple, easy to automate and therefore very suitable for screening large numbers of serum samples.

[Swine vesicular disease: threat or challenge for Dutch pig farming?]. / Vesiculaire varkensziekte: bedreiging of uitdaging voor de Nederlandse varkenshouderij?

Swine vesicular disease (SVD) caused problems in 1993 when it was detected in Dutch pigs in Italy. As a result, the EC took measures against the export of live pigs. In all cases the animals had been retained at an Italian abattoir or farm for three days or more, which is longer than the minimum incubation time. Extensive clinical inspections and serological testing on the farms from where the pigs originated revealed no evidence of SVD infection. Serological testing for SVD of over 1.5 million blood samples collected from herds within the framework of export- and herd certification, and the testing of slaughter sows and slaughter boars (EC directive), was negative as well. In view of these results it has to be assumed that the Dutch pig population is free from SVD and that the pigs were infected in Italy. However, a complaint from Italy in 1994 led to the detection of two SVD virus-contaminated export collection centres. If the existing regulations on the cleansing and disinfection of the transport chains are stringently enforced and implementation of the rules is continuously supervised, then it may be expected that the problems have been overcome.