[Source: Journal of Virology, full page: (LINK). Abstract, edited.]
Highly pathogenic avian influenza H5N6 viruses exhibit enhanced affinity for human type sialic acid receptor and in-contact transmission in model ferrets
Honglei Sun a, Juan Pu a, YanDi Wei a, Yipeng Sun a, Jiao Hu b, Litao Liu a, Guanlong Xu a, Weihua Gao a, Chong Li a, Xuxiao Zhang a, Yinhua Huang a, Kin-Chow Chang c, Xiufan Liu b and Jinhua Liu a⇑
Author Affiliations: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China[a]; Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China[b]; School of Veterinary Medicine and Science, University of Nottingham Sutton Bonington Campus, Sutton Bonington, UK[c]
Since May 2014, highly pathogenic avian influenza (HPAI) H5N6 virus has been reported to cause six severe human infections three of which were fatal. The biological properties of this subtype, in particular its relative pathogenicity and transmissibility in mammals are not known. We characterized the virus receptor binding affinity, pathogenicity and transmissibility in mice and ferrets of four H5N6 isolates derived from waterfowl in China from 2013-2014. All four H5N6 viruses have acquired binding affinity for human-like SAα2,6Gal linked receptor to be able to attach to human tracheal epithelial and alveolar cells. The emergent H5N6 viruses, which share high sequence similarity with the human isolate A/Guangzhou/39715/2014 (H5N6), were fully infective and highly transmissible by direct contact in ferrets but showed less severe pathogenicity in comparison with their parental H5N1 virus. The present results highlight the threat of emergent H5N6 viruses to poultry and human health and the need to closely track their continual adaptation in humans.
Extended epizootics and panzootics of H5N1 viruses have led to the emergence of the novel 22.214.171.124 clade of H5 virus subtypes including H5N2, H5N6 and H5N8 reassortants. Avian H5N6 viruses from this clade have caused three fatalities out of six severe human infections in China since the first case in 2014. However, the biological properties of this subtype, especially the pathogenicity and transmission in mammals are not known. Here, we found that natural avian H5N6 viruses have acquired high affinity for human-type virus receptor. In comparison with parental clade 2.3.4 H5N1 virus, emergent H5N6 isolates showed less severe pathogenicity in mice and ferrets, but acquired efficient in-contact transmission in ferrets. These findings suggest that the threat of avian H5N6 viruses to humans should not be ignored.
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Keywords: Research; Abstracts; H5N6; Avian Influenza.