Reassortant Pandemic (H1N1) 2009 Virus in Pigs, United Kingdom

Novel triple reassortant H1N2 influenza viruses bearing six internal genes of the pandemic 2009/H1N1 influenza virus were detected in pigs in China

“…The gene constellations of the two reassortants were distinct from the previously identified reassortant H1N2 viruses from pigs in other countries [35][36][37][38][39][40]. Although it was unclear as to whether these novel viruses were transient or they had acquired pathogenicity and transmissibility in pigs, the finding that new reassortants emerged in pigs further underscores the fact that influenza virus reassortment is an ongoing process.…”

“…The M gene of the 2009/H1N1 virus plays an important role in its transmissibility [29,30], and both the PA and NS genes of 2009/H1N1 virus can make an H5N1 influenza virus highly transmissible by respiratory droplet in guinea pigs [26]. H3N2, H1N1, and H1N2 influenza viruses bearing different genes from the 2009/H1N1 virus have been detected in pigs in many countries since 2009 [31][32][33][34][35][36][37][38][39][40], and it would be of value to fully evaluate the biologic properties of these viruses.…”

Influenza A Viruses of Swine (IAV-S) in Vietnam from 2010 to 2015: Multiple Introductions of A(H1N1)pdm09 Viruses into the Pig Population and Diversifying Genetic Constellations of Enzootic IAV-S

“…To our knowledge, 9 of the 14 genotypes of reassortant IAV-S that we collected during the current study have not been reported in other countries (12,25,27,(37)(38)(39), suggesting that such reassortants had been generated in the Vietnamese pig population. In contrast, 3 of the remaining 5 genotypes (that is, genotypes 4, 12, and 13) are also found in China, but they are unlikely to have been introduced into Vietnam from China.…”

Continual Reintroduction of Human Pandemic H1N1 Influenza A Viruses into Swine in the United States, 2009 to 2014

“…Since 2009, pH1N1 viruses and pH1N1 reassortants (i.e., viruses with at least one segment of pH1N1 origin) have been identified in swine populations in the Americas (United States [20], Canada [21], Mexico [22], Argentina [6], Brazil [23], and Colombia [24]), Europe (United Kingdom [25], Germany [26], Norway [8], and Italy [27]), Asia (China [3], South Korea [28], Sri Lanka [10], Thailand [29], and Vietnam [7]), Africa (4), and Australia (5). We previously estimated that the pH1N1 virus was introduced at least 49 times from humans to swine on a global scale (9).…”