Trend analysis suggested a change in subspecies among  isolated from pigs in Belgium, 1967-2013., Soetaert, Karine, Duytschaever L, Denoël J, Roupie Virginie, Smeets F, Bruffaerts Nicolas, Huygen K, Fretin David, Diels M, Rigouts L, et al. , Vet Rec, 2017 May 06, Volume 180, Issue 18, p.449, (2017)