Scientific Opinion on Swine Vesicular Disease and Vesicular Stomatitis

Abstract

SVD is a disease of pigs caused by a virus of the family Picornaviridae. All isolates are classified in a single serotype. The disease has been reported mainly in Italy. Due to the pen disease characteristics of SVD, its negligible mortality, low morbidity and negligible production losses, the significance and the impact of SVD are considered low. The between farm spread of SVD is mainly related to movements of infected animals and/or contaminated trucks, but also to the introduction of contaminated material or persons. When applying SVD estimates of transmission, the modelled spread within farms was limited. The modelled spread of SVD between farms is at least similar to CSF if all transportation procedures of CSF contribute. Under the assumption that between-farm transmission of SVD is as low as between-animal transmission the modelled spread halved. Therefore, the impact of SVD has to be assessed on the level of infected farms and not on the level of the spread within livestock populations. VS is a disease of mainly horses, cattle and pigs caused by a virus of the family Rhabdoviridae. Two distinct immunological groups of VS virus have been recognised. There is seasonal variation in the occurrence of VS. Humans are susceptible to VSV but with limited signs of infection. VSV has been isolated from insects but no natural transmission through these vectors has been observed. VS is limited mainly to the Americas. When VS is introduced to a naïve population, the infection can lead to wide range of clinical signs from mild to severe both in cattle and horses. The mortality of VS is negligible, the morbidity is low, but the production losses in cattle can be higher yet the data are limited. For this reason, the significance and overall impact of VS are difficult to estimate. In comparison to CSFV, the modelled spread of VSV was less predictable due to several susceptible species, assuming insect vectors resulted in a VSV spread worse than CSFV. Depending on the testing system and the VSV prevalence in the subpopulation destined for export and considering that 4000 susceptible animals are imported per year, it likely will take between 14 and 100 years to import an infected animal. It is unlikely that animal products will contribute to between farm spread of SVDV and VSV.