Beaudeau et al. Acta Veterinaria Scandinavica 2010, 52:33 http://www.actavetscand.com/content/52/1/33 R E S E A R C H Open Access RSepseaarcthial patterns of Bovine Corona Virus and Bovine Respiratory Syncytial Virus in the Swedish beef cattle population Francois Beaudeau*1,2,3,4, Camilla Björkman4, Stefan Alenius4 and Jenny Frössling5 Abstract Background: Both bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) infections are currently wide-spread in the Swedish dairy cattle population. Surveys of antibody levels in bulk tank milk have shown very high nationwide prevalences of both BCV and BRSV, with large variations between regions. In the Swedish beef cattle population however, no investigations have yet been performed regarding the prevalence and geographical distribution of BCV and BRSV. A cross-sectional serological survey for BCV and BRSV was carried out in Swedish beef cattle to explore any geographical patterns of these infections. Methods: Blood samples were collected from 2,763 animals located in 2,137 herds and analyzed for presence of antibodies to BCV and BRSV. Moran's I was calculated to assess spatial autocorrelation, and identification of geographical cluster was performed using spatial scan statistics. Results: Animals detected positive to BCV or BRSV were predominately located in the central-western and some southern parts of Sweden. Moran's I indicated global spatial autocorrelation. BCV and BRSV appeared to be spatially related: two areas in southern Sweden (Skaraborg and Skåne) had a significantly higher prevalence of BCV (72.5 and 65.5% respectively); almost the same two areas were identified as being high-prevalence clusters for BRSV (69.2 and 66.8% respectively). An area in south-east Sweden (Kronoberg-Blekinge) had lower prevalences for both infections than expected (23.8 and 20.7% for BCV and BRSV respectively). Another area in middle-west Sweden (Värmland- Dalarna) had also a lower prevalence for BRSV (7.9%). Areas with beef herd density > 10 per 100 km2 were found to be at significantly higher risk of being part of high-prevalence clusters. Conclusion: These results form a basis for further investigations of between-herds dynamics and risk factors for these infections in order to design effective control strategies. Background Bovine coronavirus (BCV) and bovine respiratory syncy- tial virus (BRSV) are frequently involved in the respira- tory and enteric disease complexes of cattle [1,2]. BCV is causing winter dysentery in adults [3,4], calf diarrhoea [5] and also respiratory disease of young stock [6]. BRSV is recognized as one of the most important causes of respi- ratory tract disease in beef and dairy cattle, especially in young animals [7-9]. * Correspondence: francois.beaudeau@oniris-nantes.fr 1 ONIRIS, UMR 1300 Bioagression, Epidémiologie et Analyse de Risque, BP 40706, F-44307, Nantes, France Full list of author information is available at the end of the article Presence of antibodies to BCV [10-15] and to BRSV [9,10,12,16,17] has been reported worldwide in both dairy and beef cattle. Both BCV infection and BRSV infection are considered relatively contagious and are currently wide-spread in the Swedish dairy cattle population. Surveys of antibody lev- els in bulk tank milk have shown very high nationwide prevalences of both BCV [13] and BRSV [9], with large variations between regions. The highest herd-preva- lences (90 to 100%) were found in the southern parts of the country. It was suggested that a reason for the higher BCV prevalence in the south could be the high dairy-herd density, associated with an increased risk of spread between herds through infected animals, vectors and air- © 2010 Beaudeau et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.