A Chinese expert on respiratory diseases says the H5N1 bird flu virus has shown signs of mutation and urged vigilance at a time when seasonal human influenza is at a peak, newspapers reported on Tuesday.

“When avian flu is around and human flu appears, this will raise the chances of avian flu turning into a human flu. We have to be very alert and careful in March,” Zhong Nanshan was quoted by the Ming Pao newspaper as saying.

“People who were killed by bird flu last year and this year were too poor to seek treatment. If you happen to have high fever and pneumonia, you must seek treatment fast,” said Zhong, director of the Guangzhou Institute of Respiratory Diseases in China’s southern Guangdong province.

Experts are worried about seasonal flu, because it could get mixed up with a deadly novel strain, such as the H5N1 bird flu virus. Such a hybrid would not only become easily transmissible between people, but packed with great killing power.

“The bird flu virus has shown signs of mutation. If infected people don’t get treatment in a timely manner, they can die easily,” Zhong was quoted as telling reporters on the sidelines of the Chinese parliament’s annual meeting.

Three Chinese have died this year of H5N1 bird flu and they were infected probably through contact with sick poultry. The World Health Organisation said there was no evidence of transmission between humans in all three cases.

In Hong Kong, the government shut a primary school early ahead of the Easter holidays after one of its students, a 7-year-old boy, died at noon on Tuesday. The boy was admitted to hospital last week with flu-like symptoms and authorities are still trying to determine the cause of his illness.

Thomas Tsang, controller of the Centre for Health Protection, said five other pupils at the school have been admitted to hospital for respiratory infection and their conditions were stable. Three samples have tested positive for influenza A, Tsang said, without specifying the strain.

“The school will close early for Easter from tomorrow ... to facilitate disinfection,” Tsang told a news conference. But he said there was no reason to close all schools in Hong Kong, although they would monitor the situation closely.

Hong Kong, which lies at the south of China, is in the grip of a seasonal flu peak, with outbreaks reported in a growing number of schools.

A 3-year-old girl died last week of human H3N2 flu and authorities have ordered schools to conduct fever checks and advise those who are unwell to stay home.

Although the H5N1 virus has infected only 368 people around the world since 2003, its mortality rate has been high, killing 234 of them.

HONG KONG (Reuters)