The recently identified human infections with avian influenza A(H7N9) viruses in China raise important questions regarding possible source and risk to humans. Sequence comparison with an influenza A(H7N7) outbreak in the Netherlands in 2003 and an A(H7N1) epidemic in Italy in 1999-2000 suggests that widespread circulation of A(H7N9) viruses must have occurred in China. The emergence of human adaptation marker PB2 E627K in human A(H7N9) cases parallels that of the fatal A(H7N7) human case in the Netherlands.
Department of Virology

Jonges, M, Meijer, A, Fouchier, R.A.M, Koch, G, Li, J, Pan, J.C, … Koopmans, M.P.G, D.V.M. (2013). Guiding outbreak management by the use of influenza a(H7NX) virus sequence analysis. Eurosurveillance, 18(16). Retrieved from