Quantification of porcine circovirus type 2 (PCV-2) within- and between-pen transmission in pigs Mathieu Andraud, Béatrice Grasland, Benoît Durand, Roland Cariolet, André Jestin, François Madec and Nicolas Rose Vet. Res., 39 5 (2008) 43 Published online: 17 April 2008 DOI: 10.1051/vetres:2008020