Bird flu strain has died down but experts say it is likely to return

The deadly H7N9 strain of bird flu that broke out on the mainland in February appears to have died down in recent weeks but could strike again in the autumn if it follows the pattern of the H5N1 virus, University of Hong Kong researchers warn.

They called for vigilance to be maintained.

There have been 131 reported cases of the virus on the mainland and in Taiwan but researchers believe this is just a fraction of the real number. Of the reported cases, 123 were admitted to hospital and 39 died.

But there have been no new cases reported since last month.

"It seems that the epidemic has ended in the past month," said Professor Gabriel Leung, director of the university's Public Health Research Centre. "In the next few months it will be important to work on preventing and preparing for its return in autumn or winter.

"Killing of chickens and market closures may still be needed when the epidemic reappears. I believe these measures should not be relaxed."

The researchers looked at cases of H5N1 - another deadly strain that broke out in 2003 - over the past decade. They found that infections never occurred from July to September.