1Choi Y K, Goyal S M, Joo H S. Prevalence of swine influenza virus subtypes on swine farms in the United States [J]. Arch Virol, 2002,147(6) : 1209-1220.
2Maldonado J, van Reeth K, Riera P, et al. Evidence of the concurrent circulation of HIN2, H1N1 and H3N2 influenza A viruses in densely populated pig areas in Spain[J]. Vet J, 2006,172(2) :377-381.
3Nowotny N, Mostl K, Maderbacher R, et al. Serological studies in Austrian fattening pigs with respiratory disorders [J]. ActaVet Hung, 1994, 42(2-3):377 -379.
4Groschup M H, Brun A, Haas B. Serological studies on the potential synergism of porcine reproductive and respiratory syndrome virus and influenza-, corona- and paramyxoviruses in the induction of respiratory symptoms in swine[J]. Zentralbl Veterinarmed B, 1993 ,40(9 10):681- 689.
5Loeffen W L, Kamp E M, Stockhofe-Zurwieden N,etal. Survey of infectious agents involved in acute respiratory disease in finishing pigs[J]. Vet Rec, 1999 , 145(5):123-129.
6Jung K, Chae C. First outbreak of respiratory disease associated with swine influenza H1N2 virus in pigs in Korea[J]. J Vet Diagn Invest, 2005, 17(2) :176 -178.
7Jung T, Choi C, Chae C. Localization of swine influenza virus in naturally infected pigs[J]. Vet Pathol, 2002 ,9(1) :10-16.
8Kay R M, Done S H, Paton D J. Effect of sequential porcine reproductive and respiratory syndrome and swine influenza on the growth and performance of finishing pigs[J]. Vet Rec, 1994, 135(9):199-204.
9Elbers A R, Tielen M J, Cromwijk W A,etal. Sero epidemio logical screening of pig sera collected at the slaughterhouse to detect herds infected with Aujeszky's disease virus, porcine influenza virus and Actinobacillus (Haernophilus) pleuropneumoniae in the framework of an integrated quality control (IQC) system[J]. Vet Q, 1990, 12(4):221-230.
10Wesley R D. Exposure of sero-positive gilts to swine influenza virus may cause a few stillbirths per litter[J]. Can J Vet Res, 2004, 68(3) :215-217.