Limited Antigenic Diversity in Contemporary H7 Avian-Origin Influenza A Viruses from North America

Authors

Yifei Xu, Mississippi State University
Elizabeth Bailey, Mississippi State University
Erica Spackman, USDA-ARSFollow
Tao Li, Viral Diseases Branch, Walter Reed Army Institute of Research
Hui Wang, Mississippi State University
Li-Ping Long, Mississippi State University
John A. Baroch, USDA National Wildlife Research Center
Fred L. Cunningham, 5Follow
Xiaoxu Lin, Viral Diseases Branch, Walter Reed Army Institute of Research
Richard G. Jarman, Viral Diseases Branch, Walter Reed Army Institute of Research
Thomas J. DeLiberto, USDA National Wildlife Research CenterFollow
Xiu-Feng Wan, Mississippi State UniversityFollow

Document Type

Article

Date of this Version

2016

Citation

Xu, Y. et al. Limited Antigenic Diversity in Contemporary H7 Avian-Origin Influenza A Viruses from North America. Sci. Rep. 6, 20688; doi: 10.1038/srep20688 (2016).

Comments

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Subtype H7 avian–origin influenza A viruses (AIVs) have caused at least 500 confirmed human infections since 2003 and culling of >75 million birds in recent years. Here we antigenically and genetically characterized 93 AIV isolates from North America (85 from migratory waterfowl [1976–2010], 7 from domestic poultry [1971–2012], and 1 from a seal [1980]). The hemagglutinin gene of these H7 viruses are separated from those from Eurasia. Gradual accumulation of nucleotide and amino acid substitutions was observed in the hemagglutinin of H7 AIVs from waterfowl and domestic poultry. Genotype characterization suggested that H7 AIVs in wild birds form diverse and transient internal gene constellations. Serologic analyses showed that the 93 isolates cross-reacted with each other to different extents. Antigenic cartography showed that the average antigenic distance among them was 1.14 units (standard deviation [SD], 0.57 unit) and that antigenic diversity among the H7 isolates we tested was limited. Our results suggest that the continuous genetic evolution has not led to significant antigenic diversity for H7 AIVs from North America. These findings add to our understanding of the natural history of IAVs and will inform public health decision-making regarding the threat these viruses pose to humans and poultry.