Limited airborne transmission of influenza A/H7N9 virus between ferrets

The research group of Ron Fouchier of Viroscience lab Erasmus MC has published in the renowned journal Nature.
Since the end of March 2013, a novel avian origin influenza A H7N9 virus is responsible for 133 laboratory confirmed cases of infection in humans, resulting in 37 fatalities in China.
Fortunately, this H7N9 virus does not have the ability to spread efficiently between humans.

Transmission via respiratory droplets and aerosols (airborne transmission) is the main route for efficient transmission between humans, hence it is important to gain insight on airborne transmission of the A/H7N9 virus.
In this research we used the ferret model to investigate whether this virus has the ability to spread via the airborne route. The ferret is a widely used animal model to study influenza A virus virulence and ability to spread.

We showed that, although A/Anhui/1/2013 A/H7N9 virus harbours determinants associated with human adaptation and transmissibility between mammals, its airborne transmissibility in ferrets was limited, intermediate between that of typical human and avian influenza viruses.  Multiple A/H7N9 virus genetic variants were transmitted. Upon ferret passage, variants with higher avian receptor binding, higher pH of fusion, and lower thermostability were selected, potentially resulting in reduced transmissibility.

This A/H7N9 virus outbreak highlights the need for increased understanding of determinants of efficient airborne transmission of avian influenza viruses between mammals.

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