title: Schmallenberg Virus beyond Latitude 65°N.
abstract: Extensive and rapid spread of Schmallenberg virus (SBV) in Sweden was detected by consecutive serological bulk milk surveys conducted before and after the vector season of 2012. Whereas <0.2% of cattle herds tested positive in a first survey in spring 2012, SBV-specific antibodies were detected in almost 75% of 723 bulk milk samples randomly collected all over the country 6 months later, beyond the 65th northern latitude, and with an observed spatial distribution suggesting multiple introductions of the virus. Circulation of virus was later confirmed by the detection of SBV in malformed lambs and calves starting from November 2012 and January 2013, respectively. These observations suggest SBV circulation starting from July 2012, with a peak in transmission between August and October. A local heterogeneity of within-herd seroprevalence was found, indicating that SBV-naïve animals remain also in highly infected areas enabling the re-emergence of the infection in the coming vector season.
authors: National Veterinary Institute, Uppsala, Sweden.
authors: E
authors: E
authors: Chenais
authors: National Veterinary Institute, Uppsala, Sweden.
authors: K
authors: K
authors: Ståhl
authors: National Veterinary Institute, Uppsala, Sweden.
authors: J
authors: J
authors: Frössling
authors: National Veterinary Institute, Uppsala, Sweden.
authors: G
authors: G
authors: Blomqvist
authors: National Veterinary Institute, Uppsala, Sweden.
authors: K
authors: K
authors: Näslund
authors: National Veterinary Institute, Uppsala, Sweden.
authors: L
authors: L
authors: Svensson
authors: National Veterinary Institute, Uppsala, Sweden.
authors: L
authors: L
authors: Renström
authors: Swedish Board of Agriculture, Jönköping, Sweden.
authors: K
authors: K
authors: Mieziewska
authors: National Veterinary Institute, Uppsala, Sweden.
authors: M
authors: M
authors: Elvander
authors: National Veterinary Institute, Uppsala, Sweden.
authors: J F
authors: JF
authors: Valarcher
mesh_terms: D000818:Animals; D002044:Bunyaviridae Infections / Q000453:epidemiology* / Q000662:veterinary* / Q000821:virology; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology*; D062306:Geography, Medical; D008892:Milk / Q000821:virology; D016851:Orthobunyavirus / Q000276:immunology / Q000302:isolation & purification*; D012621:Seasons; D016036:Seroepidemiologic Studies; D012756:Sheep; D012757:Sheep Diseases / Q000821:virology*; D013548:Sweden
keywords: Schmallenberg virus; bulk milk; emerging; surveillance; vectorborne infection