HANGZHOU, May 7 -- A human blood protein has been found to be associated with the H7N9 fatality rate, according to a study by Chinese medical scientists.

The study, published in Nature Communications on Tuesday, showed that blood plasma levels of angiotensin II are higher in H7N9 patients and could be used to predict their physical deterioration.

Angiotensin II is a human protein contained in plasma, the vascular wall, heart and kidney to regulate blood pressure. It is closely linked to acute lung injury.

H7N9 patients with higher levels of angiotensin II carry more viral load, said Li Lanjuan, researcher at the Chinese Academy of Engineering and a specialist in H7N9 prevention.

"It is particularly obvious in the second week of human infection. The angiotensin II level of patients in critical condition keeps going up, while that of mild cases tends to drop," Li said.

Li added the new finding could help in clinical practice. Medical personnel could adopt more effective and reliable treatment measures for patients suffering different conditions.

"This study will provide a new perspective to H7N9 pathology and potential treatment for future cases," said Ed Gerstner, executive editor of Nature Communications.

The study was led by researchers of the First Affiliated Hospital of Zhejiang University, Chinese Academy of Medical Sciences and Chinese Center for Disease Control and Prevention.

They collected plasma from 47 H7N9 patients in cities of Hangzhou, Shanghai and Nanjing and analyzed the correlation between angiotensin II and viral load.

H7N9 was first reported in China in March 2013. The virus causes severe disease in humans, including acute and often lethal respiratory failure.The country has reported more than 200 human H7N9 cases.