As of Wednesday, China has reported 82 human infections of H7N9, including 17 deaths. About 40 percent of the patients had no contact with poultry or environments where birds were located, previous epidemiological studies found. It remains a mystery how they became infected, Zeng said.
China’s top health authority confirmed that a family infected by H7N9 in Shanghai might involve human-to-human transmission of H7N9 The family involves two brothers and their 87-year-old father, who died on March 4 and was reportedly China’s first human death from H7N9.
The Chinese National Health and Family Planning Commission (CNHFPC) announced that the elder son, who has recovered from the disease, was previously confirmed to have contracted the virus. However, the results of a test on the younger son were not available. The CNHFPC is now conducting an investigation to see if the cluster is indeed human-to-human transmission.
Zeng Guang, chief epidemiologist with China CDC, said people infected with H7N9 can transmit the virus within a period of time, in which they could possibly infect others.”But that’s highly rare and could be limited to within a family,” Feng said, explaining that only genetically vulnerable groups like close family members might be get infected.
Michael O’Leary, the World Health Organization’s China representative, agreed and said there is no evidence to date of sustained or efficient human-to-human transmission, which would pose a real risk of a pandemic.