SHANGHAI, April 1 (UPI) -- A rare strain of avian flu was blamed for the deaths of two men in Shanghai while a woman remained in critical condition from the virus, Chinese officials said.
The two men, ages 27 and 87, died in March after being infected with H7N9, the first such cases of infection of humans from this strain, the official China Daily reported the National Health and Family Planning Commission said Sunday.
The woman, a 35-year-old from Chuzhou in eastern China's Anhui province, remained in intensive care in Nanjing in neighboring eastern coastal Jiangsu province.
The newspaper said it is the first time a human infection from H7N9 has been detected and that there are no vaccines as scant research has been done on the relatively unknown bird flu.
The report also said it was not clear how the three got infected. Commission experts said there were no signs they contracted the disease from one another nor were there any signs of any infected person being in close contact with any of them.
Initial symptoms included fever, cough and difficulties in breathing.
The commission said the World Health Organization in Hong Kong and "related countries" had been informed.
The New York Times reported the H7N9 strain had not been previously found in humans. However, another strain of avian flu, H5N1, has led to hundreds of deaths since 2003 and has killed millions of birds, the report said.