The president of one of Beijing's top hospitals has said that improper medical treatment has caused a severe increase of A/H1N1 cases.

An overuse of hormone therapies to treat A/H1N1 has weakened patients' immune systems, making them more susceptible to the illness, Li Ning, president of Beijing You'an Hospital, said at an H1N1 flu control and prevention meeting.

As one of Beijing's leading infectious disease centers, You'an Hospital has been responsible for the treatment of critically ill swine flu patients. It has diagnosed more than 400 infected with the virus, 80 of who were diagnosed with severe cases.

There have been 15 deaths from A/H1N1 at You'an.

"All the cases that have been transferred [to You'an] from other hospitals received hormone therapy doses ranging from 320 mg to 800 mg," Li said. "A patient from Daxing Hospital was even given 1,500 mg."

A 1,000 mg dose of hormones can cause an adult to lose immune system activity for 72 hours, Li said.

Li did not specify the exact nature of the hormone therapies.

Some patients from other hospitals were not immediately administered Oseltamivir, an antiviral drug sold under the name Tamiflu, when they came for treatment, he said.

"Oseltamivir should be used for A/H1N1 patients within 48 hours," Li said. "The severe patients who came to our hospital were given the drug three to four days after they started running fever."

Li said his team is still researching whether delayed use of Tamiflu worsens the effect of the virus.

"A/H1N1 was not as normal as we expected," Li said, noting the virus was also traced in urine. "Actually it is more dangerous than SARS."

A deadly outbreak of Severe Acute Respiratory Syndrom, or SARS, sickened more than 8,000 people, killing nearly 800, in China in 2003.

H1N1 flu has also been found in patients' excrement, said Cao Wuchun, a microbiological expert.

"It means the virus can no longer be classified just as a respiratory illness," he said.