21.10.2017

Cell Host & Microbe 22, 1–12 November 8, 2017

U.S. and Japanese researchers studied a sample of a new highly pathogenic strain H7N9 to see how effectively it spread among mammals, including ferrets, which are considered the best animal model for testing the transmissibility of influenza in humans.
In the study published in Cell Host & Microbe, flu expert Yoshihiro Kawaoka of the University of Wisconsin and colleagues tested an isolate of the new H7N9 strain taken from a person who died from the infection last spring.
They found that the virus replicated efficiently in mice, ferrets and non-human primates, and that it caused even more severe disease in mice and ferrets than a low pathogenic strain of the same virus that does not cause illness in birds.
To test transmissibility, the team placed healthy ferrets next to infected animals and found the virus spread easily from cage to cage, suggesting the virus can be transmitted by respiratory droplets such as those produced by coughing and sneezing.
Two out of three healthy ferrets infected in this way died, which is “extremely unusual,” suggesting that even a small amount of virus can cause severe disease.