After being treated in the Donghu Hospital for 50 days, the patient, surnamed Jiang, 31, a truck driver from Shenzhen, had recovered sufficiently to leave, the Shenzhen municipal health department said.

On June 15, the Ministry of Health confirmed that Jiang had contracted the H5N1 strain of avian influenza, bringing China's total human infections to 19.

Jiang had been to a local market where live poultry was sold several times before developing symptoms of fever and pneumonia on June 3.

He was critically ill when he got to hospital, according to Zhou Boping, head of the hospital.

Many internal organs showed signs of failure and his lungs were severely infected by different kinds of anti-drug virus, according to Zhou.

Several treatment methods were used, including some "innovative technology", said a source with the department.

Jiang's condition was the most serious of all the bird-flu patients who have recovered in China, according to the department.

He has been doing well since late June. Examinations showed the avian influenza virus was no longer in his system by June 22. By July 5, he was able to breathe without the use of a respirator.

Health workers will monitor his physical condition after he leaves hospital, the department said.

Since appearing on Asian poultry farms in late 2003, bird flu has killed 12 people in China.