Avian influenza A has potential for virulence and transmissibility in humans
H7N9 attaches to the epithelium of both the upper and lower respiratory tracts, making it able to easily transmit between humans. It also has the potential to cause severe pneumonia, making it a potential pandemic.
"Abundant virus attachment to the human upper respiratory tract correlates with efficient transmissibility among humans," Thijs Kuiken, a professor at the Department of Viroscience at Erasmus University Medical Centre in Rotterdam, the Netherlands, said. "Virus attachment to Clara cells in the bronchioles and pneumocytes and macrophages in the alveoli correlates with high virulence."
The study also looked at histochemical analysis and investigated the pattern of attachment of two genetically engineered emerging H7 viruses. The investigators found that the H7N9 virus attached more strongly, and more abundantly, to the lower parts of the human respiratory tract, making it easier for the virus to spread and cause pneumonia.
"Our results indicate that based just on the pattern of virus attachment the H7N9 currently emerging in China has the potential both to cause severe pulmonary disease and to be efficiently transmitted among humans," Kuiken said.