All of the contacts of a 2-year-old boy who tested positive for the H5N1 strain of avian influenza in Hong Kong and the Chinese mainland were either asymptomatic or tested negative for bird flu, authorities of the special administrative region and Guangdong province said, suggesting that the chance of an outbreak was slim.

The boy was still in serious condition after a week of treatment in Hong Kong.

He is being kept isolated in the pediatric intensive care unit at Princess Margaret Hospital.