A new strain of bird flu killed two people among at least seven infected in eastern China, prompting officials in Shanghai and Hong Kong to issue alerts and the World Health Organization to investigate whether the virus could spread more widely.
The two deaths were in Shanghai, and five people in Anhui and Jiangsu provinces are in critical condition after being infected with the H7N9 strain, according to China’s official Xinhua News Agency and Jiangsu’s provincial government website.
No link between the cases has been identified, and no further infections have been found among 88 contacts of the first three patients, according to the Geneva-based WHO, suggesting the virus isn’t easily transmitted from person to person. One of the other cases is a 45-year-old woman who slaughters poultry in Nanjing city, Xinhua reported.
“This is of concern,” Gregory Hartl, a WHO spokesman, said by phone yesterday. “These are the first cases we’ve seen in human beings. We’re watching this very closely.”
The virus is genetically an avian flu virus, and hasn’t mixed with human or pig pathogens, Hartl said. The WHO is looking into whether H7N9 has evolved to become more of a threat to humans, he said.
The flu pandemics of the past century, including the 1918 Spanish flu that killed as many as 50 million people, have all been triggered by the mixing of human and animal flu viruses to create new pathogens to which people have no pre-existing immunity.
Shanghai issued a level-3 flu alert yesterday, the second-lowest stage of four levels, following the deaths of the two men, ages 87 and 27, in China’s financial hub last month. Municipal authorities will strengthen monitoring of influenza and will require daily reporting of pneumonia cases where the causes are unknown, Xu Jianguang, head of Shanghai’s health and family planning commission, said at a briefing yesterday.
Investigations still haven’t uncovered how the two men contracted the virus, and tests have yet to prove whether it can be transmitted among humans, said Wu Fan, head of the city’s disease control center.
There’s also no evidence that the virus is related to dead pigs found in a Shanghai river last month, according to Wu. More than 11,000 hog carcasses were pulled from the Huangpu river, which supplies about 22 percent of the city’s water, and thousands more were found in neighboring Zhejiang province.
Concerns about the spread of infections among poultry led soybean meal futures traded in the Chinese city of Dalian to fall by as much as 2.6 percent today, Alice Xuan, analyst at Shanghai JC Intelligence Co., said by telephone. Soybean meal is a primary ingredient in chicken feed.
Shares of Beijing Dabeinong Technology Group Co., which makes animal feed, sank to a more than three-month low in trading on the Shenzhen Stock Exchange.
The discovery of the new virus has prompted other cities in the region to intensify checks. Beijing, the Chinese capital, started monitoring for H7N9 influenza, Xinhua reported, while Taiwan’s Central News Agency said March 31 the island is on the alert for the bug. Officials in Hong Kong activated the alert response level, the lowest of three in the island’s pandemic preparedness plan, and advised people to avoid direct contact with birds.
“Although there is no evidence to show human-to-human transmission, the mutation potential of the virus is high,” Leung Ting-hung, controller of Hong Kong’s Centre for Health Protection, said in an e-mailed statement.
More than 600 people have been infected with the H5N1 bird flu strain since 2003, and almost 60 percent have died, according to the WHO. Most had direct contact with infected poultry, and the virus hasn’t acquired the ability to spread easily between people.
The H1N1 virus responsible for the 2009 swine flu pandemic originated in pigs, then mixed with human and avian viruses, touching off the first global flu outbreak in more than 40 years and killing about 284,500 people, according to the U.S. Centers for Disease Control and Prevention.