Avian influenza viruses rarely infect humans, but the recently emerged avian H7N9 influenza viruses have caused sporadic infections in humans in China, resulting in 440 confirmed cases with 122 fatalities as of 16 May 2014. In addition, epidemiologic surveys suggest that there have been asymptomatic or mild human infections with H7N9 viruses. These viruses replicate efficiently in mammals, show limited transmissibility in ferrets and guinea pigs, and possess mammalian-adapting amino acid changes that likely contribute to their ability to infect mammals. In this review, we summarize the characteristic features of the novel H7N9 viruses and assess their pandemic potential.
Tokiko Watanabe, Shinji Watanabe, Eileen A Maher, Gabriele Neumann, and Yoshihiro Kawaoka.
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 575 Science Drive, Madison, WI 53711, USA; ERATO Infection-Induced Host Responses Project, Japan Scie... more nce and Technology Agency, Saitama 332-0012, Japan; Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan. less