Egyptian H5N1 Influenza Viruses—Cause for Concern?

Gabriele Neumann,Ron A M Fouchier,Catherine A Macken,Yoshihiro Kawaoka,Alexander I Karasin

doi:10.1371/journal.ppat.1002932

Abstract

Highly pathogenic avian H5N1 influenza viruses are now enzootic in parts of Southeast Asia and the Middle East. Occasionally, these viruses transmit to humans and cause severe respiratory disease and fatalities. Currently, these viruses are not efficiently transmitted from person to person, although limited human-to-human transmission may have occurred [1]–[4]. A major determinant of influenza virus host range is the viral hemagglutinin (HA) protein: avian virus HA binds preferentially to sialic acid linked to the penultimate galactose residue by an α2,3-linkage (Siaα2,3Gal) [5]–[7], as found for sialic acid–containing receptors of the epithelial cells in duck intestine [8], the site of avian influenza virus replication. By contrast, human virus HA has higher affinity for Siaα2,6Gal [5]–[7], the main sialyloligosaccharide on the epithelial cells of the human upper respiratory tract [9], [10].

Highlights

Pathogenic avian H5N1 influenza viruses are enzootic in parts of Southeast Asia and the Middle East
The transmissible virus identified by Imai et al [12] possesses a mutant HA gene of an avian H5N1 virus and the remaining seven viral genes of a prototypic pandemic 2009 (H1N1) virus
Since lack of the HA154–156 glycosylation site appears to be critical for H5 virus transmission in mammals, we inspected avian H5N1 viruses for this feature

Summary

Introduction

Pathogenic avian H5N1 influenza viruses are enzootic in parts of Southeast Asia and the Middle East. Herfst et al [11] and Imai et al [12] identified H5 HA-possessing viruses that transmit via respiratory droplets among ferrets, an established animal model for influenza virus transmission studies.

Results

Conclusion