Original Article

Subject Category: Viruses and viral diseases

Citation: Emerging Microbes & Infections (2014) 3, e75; doi:10.1038/emi.2014.75
Published online 22 October 2014

Pathobiological features of a novel, highly pathogenic avian influenza A(H5N8) virus

Young-Il Kim1,*, Philippe Noriel Q Pascua1,*, Hyeok-Il Kwon1,*, Gyo-Jin Lim1, Eun-Ha Kim1, Sun-Woo Yoon2, Su-Jin Park1, Se Mi Kim1, Eun-Ji Choi1, Young-Jae Si1, Ok-Jun Lee1, Woo-Sub Shim1, Si-Wook Kim1, In-Pil Mo3, Yeonji Bae3, Yong Taik Lim4, Moon Hee Sung5,6, Chul-Joong Kim7, Richard J Webby8, Robert G Webster8 and Young Ki Choi1

  1. 1College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju 361-763, Korea
  2. 2Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
  3. 3College of Veterinary Medicine, Chungbuk National University, Cheongju 361-763, Korea
  4. 4SKKU Advanced Institute of Technology and Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea
  5. 5Department of Advanced Fermentation Fusion Science & Technology, Kookmin University, Seoul 136-702, Korea
  6. 6BioLeaders Corporation, Yongsandong, Yuseong-gu, Daejeon 305-500, Korea
  7. 7College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Korea
  8. 8Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA

Correspondence: YK Choi, E-mail: choiki55@chungbuk.ac.kr

*These authors contributed equally to this work.

Received 4 June 2014; Revised 4 August 2014; Accepted 19 August 2014



The endemicity of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in Asia has led to the generation of reassortant H5 strains with novel gene constellations. A newly emerged HPAI A(H5N8) virus caused poultry outbreaks in the Republic of Korea in 2014. Because newly emerging high-pathogenicity H5 viruses continue to pose public health risks, it is imperative that their pathobiological properties be examined. Here, we characterized A/mallard duck/Korea/W452/2014 (MDk/W452(H5N8)), a representative virus, and evaluated its pathogenic and pandemic potential in various animal models. We found that MDk/W452(H5N8), which originated from the reassortment of wild bird viruses harbored by migratory waterfowl in eastern China, replicated systemically and was lethal in chickens, but appeared to be attenuated, albeit efficiently transmitted, in ducks. Despite predominant attachment to avian-like virus receptors, MDk/W452(H5N8) also exhibited detectable human virus-like receptor binding and replicated in human respiratory tract tissues. In mice, MDk/W452(H5N8) was moderately pathogenic and had limited tissue tropism relative to previous HPAI A(H5N1) viruses. It also induced moderate nasal wash titers in inoculated ferrets; additionally, it was recovered in extrapulmonary tissues and one of three direct-contact ferrets seroconverted without shedding. Moreover, domesticated cats appeared to be more susceptible than dogs to virus infection. With their potential to become established in ducks, continued circulation of A(H5N8) viruses could alter the genetic evolution of pre-existing avian poultry strains. Overall, detailed virological investigation remains a necessity given the capacity of H5 viruses to evolve to cause human illness with few changes in the viral genome.


avian influenza virus; genetic evolution; HPAI A(H5N8); migratory waterfowl; reassortment