Agricultural authorities in south China's Guangdong Province tightened inspection over trading markets for domestic poultry after an 82-day-old baby girl was diagnosed in Hong Kong with bird flu.

No further infections were detected in the province, the provincial agricultural department announced on Wednesday.

The girl, surnamed Chen, was born in Hong Kong. She had been living in Xiabaishi Village, Nanshan District of Shenzhen, Guangdong Province, with her grandmother while her parents were working in Hong Kong.

The baby fell ill last Monday and was diagnosed as having the H9N2 bird flu strain on Tuesday in a Hong Kong hospital.

Experts from Shenzhen city's health bureau and disease control center went to the village to investigate. They collected blood samples from the baby's grandmother and eight staff members in a local hospital who had contact with the baby. No virus was detected in those samples.

Experts also investigated a restaurant near the patient's home that kept live chickens. No virus was found in blood samples from four staff members of the restaurant.

The disease control center has sterilized the area around the baby's home and the hospital where she sought treatment.

The provincial agricultural department instructed its Shenzhen bureau to step up efforts to prevent and control the pathogenic avian flu in a bid to stem an outbreak of the disease in the city.

All poultry in Shenzhen have been vaccinated.

The provincial agricultural department sent staff to inspect markets together with staff from the Guangzhou city bureau.

It also sent five extra teams to other areas of the province to inspect bird flu prevention and control measures. There have been no reports of a bird flu outbreak.

Experts said the H9N2 bird flu strain is less pathogenic than the H5N1 strain.