Scientific opinion on the possible risks posed by the influenza A(H3N2v) virus for animal health and its potential spread and implications for animal and human health
The likelihood of the swine-origin influenza A(H3N2)v appearing in the EU is low. Nevertheless, it is important to reinforce the monitoring of influenza strains circulating in pigs and link this to surveillance of influenza viruses in humans concludes the joint scientific opinion of three EU agencies, European Food Safety Authority, European Medicines Agency and European Centre for Disease Prevention and Control. The opinion assesses and advises on the possible risks posed by influenza A(H3N2)v virus for animal health and the potential implications for animal and human health. Pigs are an important host in influenza virus ecology since they are susceptible to infections with both avian and human influenza A viruses and can play a role in interspecies transmission. This can lead to co-infection and genetic reassortment of viruses of swine, human or avian origin. In 2011, the United States of America reported a cluster of cases of human infection with a swine-origin influenza A(H3N2) variant virus H3N2v. In 2012, 309 influenza H3N2v virus infections in humans were identified in the US and 12 cases so far in 2013. The joint scientific opinion assesses the following: - risk of introduction of H3N2v in EU - diagnostic capabilities to early detect H3N2v incursion in EU - implications and consequences of the possible evolution of H3N2v virus on pig health - the use of vaccines in relation to the possible evolution of variants of influenza viruses posing a risk to public and animal health - factors to be monitored that would suggest a risk for the emergence of a new pandemic influenza strain from the influenza A(H3N2v) virus The joint opinion concludes that it is recommended to reinforce the monitoring of influenza strains circulating in pigs in EU because it is not possible to predict nor monitor changes to the H3N2v virus that might enable it to develop pandemic properties.