Together with the fact that a number of pestiviruses exhibit a broad species tropism, it became evident that taxonomic classification of pestiviruses based on the host species they were isolated from was not feasible anymore. Recently, a number of new pestiviruses were described from a large variety of species, such as atypical porcine pestivirus (APPV) ( 9) and Linda virus ( 10) in pigs, phocoena pestivirus in harbour porpoise ( 11) and, outside the order Artiodactyla, pestiviruses in rats ( 12), bats ( 13), or pangolins ( 14) ( Figure 1). In addition, several new members termed as “atypical pestiviruses” were not yet classified as species ( 3), e.g., giraffe pestivirus, HoBi-like pestiviruses ( 6), Bungowannah virus ( 7), or a pestivirus from pronghorn antelopes ( 8). Previously, the genus Pestivirus in the family Flaviviridae comprised the four species bovine viral diarrhoea virus (BVDV)-1 and−2, classical swine fever virus (CSFV) and border disease virus (BDV) from sheep ( 1, 2). Pestiviruses have gained increased attention as several new species were discovered in recent years. As a consequence of these measures, complete eradication will (hopefully) soon be achieved, and the final step will then be the continuous documentation of freedom of disease. The main challenge is to rapidly identify the source of infection in case of a positive result during antibody surveillance, and to efficiently protect the cattle population from re-infection, particularly in light of the endemic presence of the related pestivirus border disease virus (BDV) in sheep. In this review, we describe the Swiss BVD eradication scheme and the hurdles that were encountered and still remain during the implementation of the programme.
Bvd id number free#
By the end of 2020, more than 99.5% of all cattle farms in Switzerland were free of BVDV but eliminating the last remaining PI animals turned out to be a tougher nut to crack. Prevalence of calves being born PI thus diminished substantially from around 1.4% to <0.02%, which enabled broad testing for the virus to be abandoned and switching to economically more favourable serological surveillance with vaccination being prohibited. Initially, every animal was tested for PI within the first year, followed by testing for the presence of virus in all newborn calves for the next four years. The peculiar biology of pestiviruses with the birth of persistently infected (PI) animals upon in utero infection in addition to transient infection of naïve animals requires vertical and horizontal transmission to be taken into account. Switzerland started a national mandatory control programme in 2008 aiming to eradicate BVD from the Swiss cattle population. 5Federal Food Safety and Veterinary Office (FSVO), Bern, Switzerlandīovine viral diarrhoea virus (BVDV) and related ruminant pestiviruses occur worldwide and cause considerable economic losses in livestock and severely impair animal welfare.4Veterinärdienst der Urkantone, Brunnen, Switzerland.3Veterinary Office Canton Solothurn, Solothurn, Switzerland.2Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
1Institute of Virology and Immunology, Bern, Switzerland.Matthias Schweizer 1,2 * Hanspeter Stalder 1,2 Anja Haslebacher 3 Martin Grisiger 4 Heinzpeter Schwermer 5 Elena Di Labio 5
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