No between-pen transmission of foot-and-mouth disease virus in vaccinated pigs.

Many studies have shown transmission of foot-and-mouth disease virus (FMDV) within groups of pigs, even when vaccinated, but only limited information is available on transmission between pens. Three new experiments were carried out in two replicates, which consisted of infectious pigs housed in a central pen surrounded by four separate pens. First, all pigs were non-vaccinated and pens were separated by a walkway of 40-70 cm. Second, all pigs were non-vaccinated again but pens were adjacent. Third, this was repeated with all pigs vaccinated. From the experiments it is concluded that a single pen wall of solid wood between adjacent pens reduces the FMDV transmission 10- to 20-fold compared to within-pen transmission, for both non-vaccinated and for vaccinated pigs. Vaccination of pigs reduces the pen-to-adjacent pen R to values significantly below 1, whereas previous studies showed that it does not reduce the within-pen R(0) to values below 1.