Associate professor Ben Cowling, of HKU's Li Ka Shing Faculty of Medicine, said there was no evidence that H7N9 could spread from human to human. Yet he advised that people pay attention to their hygiene.
Last week, several cases of H7N9 human infection were reported on the mainland, including Shanghai, Nanjing and Suzhou. Until yesterday, 24 people had been infected. Seven of them died.
Cowling said that locals should not worry because, even if infected people came here, they would still not be able to pass on the virus. However, he noted that avian flu was particularly dangerous because almost half of the people who got it died. The death rate of severe acute respiratory syndrome, or Sars, in 2003, was about 10 per cent.
"The big danger is the virus will continually mutate with small changes," Cowling said.
To be able to pass from human to human, the virus would need to evolve through a process called the assortment. It could do so by combining with another virus, which can pass among people.
Cowling said that pig farms could be breeding grounds for viruses. Pigs can be infected by both avian flu and the seasonal flu, which allows the assortment to take place.
The virus has only one strand of RNA, which makes it easy for the virus to mutate.
He said mainland officials are reportedly working hard to stamp out H7N9. In some cities, they have already started culling poultry.
He suggested that Hong Kong officials keep a close watch on local poultry for signs of disease.