A strain of bird flu previously unseen in humans has killed two men and made one woman seriously ill in China. Health officials are not sure how the three became infected, but they believe it is unlikely the strain could spread easily from person to person.
The two men, ages 27 and 87, became infected with H7N9 bird flu in February, according to China's National Health and Family Planning Commission. They died in early March. Both lived in Shanghai, but authorities have not disclosed the professions of any of the patients.
The 35-year-old woman, who became ill on Mar. 9, remains in serious condition in the eastern city of Chuzhou.
Xinhua reported that the patients initially experienced fever and coughing that escalated to pneumonia and trouble breathing. Experts assigned by the health commission have not discovered how the three contracted the virus, but the ruled out the possibility that they infected each other. 88 people who were in close contact with the patients did not contract H7N9. However, two sons of one of the Shanghai men also suffered acute pneumonia, the health experts noted.
"We don't know yet the causes of illness in the two sons, but naturally, if three people in one family acquire severe pneumonia in a short period of time, it raises a lot of concern," said Michael O’Leary, the World Health Organization's China representative, at a briefing on Monday.
"It's really important to understand where this virus is coming from," professor at Hong Kong University's School of Public Health Malik Peiris said.
Peiris said that H7N9, known to infect wild birds, was probably contracted by humans through handling poultry.
Farmers in densely populated areas of China live closely with livestock, which can be a petri dish for infectious diseases that transmit from animals to humans.
Experts must trace the virus in order to understand if this H7N9 has evolved to become more dangerous to humans or not.
"I would guess that given the severity of the human disease it is likely that these particular viruses have undergone the change to become highly pathogenic but obviously that remains to be ascertained," Peiris said. "The crucial question is the source of this virus, where is it."