The samples were sent to the State's laboratory for further examination, according to a press release from Guangdong provincial department of agriculture.

"More than 40 samples collected from poultry in local meat and vegetable bazaars have been examined since the beginning of the month, and all the samples were negative," said the press release.

The Guangdong provincial department of agriculture has also issued a notice to relevant cities and departments, asking them to expand examination and stress sterilization work on local live poultry booths and bazaars to prevent the outbreak of bird flu in the province, which borders the Hong Kong and Macao special administrative regions.

The notice was issued after a 2-year-old boy who had visited a poultry bazaar in Guangzhou's Haizhu district tested positive for the deadly H5N1 strain of avian influenza in Hong Kong earlier this month.

The boy is still in hospital in Hong Kong, but all 22 contacts he had were examined and found to be negative for the H5N1 virus, according to sources with Guangdong provincial department of health.

In another development, He Jianfeng, director of Guangdong Provincial Institute of Infectious Disease Control and Prevention, said Guangdong is now experiencing a high incidence of flu.

"The spread of flu has entered into the peak period in Guangdong, with many outbreaks having been reported in schools and kindergartens in previous months," Mr Jianfeng told local media.

And 92.2 per cent of the flu is type A, caused by H3N2 virus, while 7.8 per cent is type B, said Mr Jianfeng.

He predicted that the number of flu patients will continue to grow in the province in the coming months, reaching a peak in July.

And the cities of Guangzhou, Shenzhen, Zhuhai, Foshan, Dongguan and Zhanjiang have been hardest hit, he said.

Guangdong has been on the warning list for flu, meaning that flu patients have made up more than 5 per cent of the province's total number of outpatients since March, he added.

Mr Jianfeng urged experts and doctors from Guangdong, Hong Kong and Macao to expand co-operation in preventing and curing the disease.

Luo Xuequn, a professor from the Paediatrics Department of Zhongshan No 1 Hospital affiliated to Sun Yatsen University, said the number of children coming to his hospital because of flu has doubled in the past two months.

"Paediatricians are seeing more than 500 children a day," he said.

Zhong Shijie, a doctor from Guangdong Provincial Hospital of Traditional Chinese Medicines, said the number of flu patients in his hospital has grown by 20 to 30 per cent since May.

"The hospital now has to cope with more than 3,000 flu patients a day, accounting for more than 15 per cent of outpatients," Dr Shijie said.

He added that the hospital has opened a special clinic to treat flu patients.

Further Reading You can visit the Avian Flu page by clicking here.