A third man in China has died from the H7N9 virus, a strain of avian flu not previously detected in humans, the Zhejiang provincial department of health said Wednesday, according to state-run media outlet Xinhua.
Scientists taking a first look at the genetics of the bird flu strain said Wednesday that the virus could be harder to track than its better-known cousin H5N1 because it might be able to spread silently among poultry without notice, according to CBC News.
“We speculate that when this virus is maintained in poultry the disease will not appear, and similar in pigs, if they are infected, so nobody recognizes the infection in animals around them, then the transmission from animal to human may occur,” said Dr. Masato Tashiro, director of the World Health Organization’s influenza research centre in Tokyo and one of the specialists who studied the genetic data. “In terms of this phenomenon, it’s more problematic.”
This behavior is unlike the virus’s more established relative, the virulent H5N1 strain, which set off warnings when it began ravaging poultry across Asia in 2003. H5N1 has since killed 360 people worldwide, mostly after close contact with infected birds.
The World Health Organization (WHO), which is monitoring the cases in cooperation with Chinese authorities, said the strain was not transmittable from human to human. China’s state newswire Xinhua reported that almost 200 people who came into contact with infected patients had tested negative for the virus.
Two people in Shanghai died of the disease last month, according to Xinhua: an 87-year-old surnamed Li and 27 year-old pork butcher Wu Liangliang. The former’s two sons, aged 69 and 55, were admitted to hospital with flu-like symptoms over a 10-day span in mid-February, according to the Shanghai Daily newspaper. Both have tested negative for avian flu.
“He was a perfectly healthy man who walked into hospital unaided and came out a dead body,” said Wu’s uncle, also surnamed Wu. Though Wu died on 10 March, for 20 days afterwards his family understood the cause was pneumonia until they saw the news on television. “We were not notified about the bird flu virus from the start to the finish, and didn’t understand how a small cold could be fatal,” said the uncle, who declined to give his full name when he was interviewed by the Guardian at Shanghai’s Jingchuan vegetable market.
In a more calming note, a professor of virology at Britain’s University of Reading told Reuters news agency there was no cause for alarm at this stage. “At the moment I don’t think it’s anything more than an unusual set of isolated cases,” Ian Jones said.
“Of course we need to take account of these cases and follow up the contacts and so on, but I think that’s where it rests at the moment,” Jones said. “It’s far too soon to assume this is the start of something.”
“In that sense, if this continues to spread throughout China and beyond China, it would be an even bigger problem than with H5N1 in some sense, because with H5N1 you can see evidence of poultry dying, but here you can see this would be more or less a silent virus in poultry species that will occasionally infect humans,” said University of Hong Kong microbiologist Malik Peiris to CBC News, who also examined the information.
Scientists closely monitor bird flu viruses, fearing they may change and become easier to spread among humans, possibly sparking a pandemic. There’s no evidence of that happening in China.
Peiris praised Chinese health authorities for being forthcoming with data and information, but said animal health agencies needed to step up and act quickly. He urged China to widely test healthy birds in live animal markets in the parts of the country where the human infections have been reported to find out what bird species might be hosting the virus and stop the spread.
- 4 more human cases of unusual strain of bird flu (cnn.com)
- Two men die of bird flu in China (bbc.co.uk)
- 2 dead from unusual bird flu strain (cnn.com)
- 2 dead in China from unusual bird flu strain (edition.cnn.com)
- Report: Third man in China dies from unusual bird flu strain (fox6now.com)
- China reports 4 more human cases of unusual strain of bird flu (fox4kc.com)