Potential for Low-Pathogenic Avian H7 Influenza A Viruses To Replicate and Cause Disease in a Mammalian Model

Zanin M., KOÇER Z. A., Poulson R. L., Gabbard J. D., Howerth E. W., Jones C. A., ...More

JOURNAL OF VIROLOGY, vol.91, no.3, 2017 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 91 Issue: 3
  • Publication Date: 2017
  • Doi Number: 10.1128/jvi.01934-16
  • Journal Name: JOURNAL OF VIROLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: H7, influenza, avian viruses, viral pathogenesis, RECEPTOR-BINDING, TRANSMISSION, FERRETS, VACCINE, BIRDS
  • Dokuz Eylül University Affiliated: Yes

Abstract

H7 subtype influenza A viruses are widely distributed and have been responsible for human infections and numerous outbreaks in poultry with significant impact. Despite this, the disease-causing potential of the precursor low-pathogenic (LP) H7 viruses from the wild bird reservoir has not been investigated. Our objective was to assess the disease-causing potential of 30 LP H7 viruses isolated from wild avian species in the United States and Canada using the DBA/2J mouse model. Without prior mammalian adaptation, the majority of viruses, 27 (90%), caused mortality in mice. Of these, 17 (56.7%) caused 100% mortality and 24 were of pathogenicity similar to that of A/Anhui/1/2013 (H7N9), which is highly pathogenic in mice. Viruses of duck origin were more pathogenic than those of shorebird origin, as 13 of 18 (72.2%) duck origin viruses caused 100% mortality while 4 of 12 (33.3%) shorebird origin viruses caused 100% mortality, despite there being no difference in mean lung viral titers between the groups. Replication beyond the respiratory tract was also evident, particularly in the heart and brain. Of the 16 viruses studied for fecal shedding, 11 were detected in fecal samples. These viruses exhibited a strong preference for avian-type alpha 2,3-linked sialic acids; however, binding to mammalian-type alpha 2,6-linked sialic acids was also detected. These findings indicate that LP avian H7 influenza A viruses are able to infect and cause disease in mammals without prior adaptation and therefore pose a potential public health risk.