Identification of Human H1N2 and Human-Swine Reassortant H1N2 and H1N1 Influenza A Viruses among Pigs in Ontario, Canada (2003 to 2005)

Abstract

Since 2003, three novel genotypes of H1 influenza viruses have been recovered from Canadian pigs, including a wholly human H1N2 virus and human-swine reassortants. These isolates demonstrate that human-lineage H1N2 viruses are infectious for pigs and that viruses with a human PB1/swine PA/swine PB2 polymerase complex can replicate in pigs.

Vaccination with NS1-truncated H3N2 swine influenza virus primes T cells and confers cross-protection against an H1N1 heterosubtypic challenge in pigs

“…After a relatively slow evolution of classical H1N1 swine influenza virus (SIV) in the North American swine population, a new reassortant H3N2 lineage emerged and was established around 1998 [1]. Compared to the classical swine H1N1, this SIV lineage has shown a propensity for frequent gene reassortment and rapid antigenic drift [2][3][4][5]. Variants of this reassortant lineage, which have been isolated routinely in recent years, possess H3N2, H1N1, and H1N2 serotypes (reviewed by Vincent et al [6]).…”

Pandemic influenza planning: Shouldn’t swine and poultry workers be included?

“…Numerous anecdotal accounts described farmers and their families developing influenza-like illnesses after contact with ill swine and episodes where swine developed symptoms of influenza after contact with ill farmers [4]. Subsequent to the 1918 pandemic, human influenza viruses have caused considerable morbidity among swine [5] and swine influenza viruses have caused occasional morbidity among humans [6,7]. While swine influenza viruses are commonly found among domestic avian species, avian influenza viruses are only occasionally detected among swine [8].…”

Alterations in receptor-binding properties of swine influenza viruses of the H1 subtype after isolation in embryonated chicken eggs

“…Three subtypes, H1N1, H1N2 and H3N2, have been predominantly circulating in pig populations over several decades (Van Reeth, 2007). However, these subtypes have genetically distinctive characters in different geographical locations, and complicated genetic diversity has thus been demonstrated even among the same subtypes (Brown et al, 1998;Campitelli et al, 1997;Guan et al, 1996;Karasin et al, 2006;Olsen et al, 2006b;Saito et al, 2008;Takemae et al, 2008;Vincent et al, 2008;Webby et al, 2000;Yu et al, 2009). Because of the segmented nature of the genome, co-infection with more than two influenza viruses of different origins in a single host allows viruses to exchange their genes, resulting in this genetic diversity (Olsen et al, 2006a).…”