China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

[JimO]

Re: China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

If this is the case, then it has acquired the ability to infect humans quite rapidly.

Top Chinese lab reveals H7N9 source [ http://news.xinhuanet.com/english/ch..._132299005.htm ]

According to the researchers, the genetic reassortment is likely to have occurred in east China's Yangtze River Delta areas covering Shanghai, Zhejiang and Jiangsu.

The lab's research shows the H7 and N9 gene segments in H7N9 are similar to those in avian influenza samples collected from wild birds from east Asia, while the other six genes are traceable to chickens in China's Shanghai, Zhejiang and Jiangsu.

As to why the H7N9 is less harmful to the animals than to humans, researchers said it's because of viral mutation, adding that they had monitored the mutation of the N9 genes.

[jflorida]

Re: China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

PB2 changes I guess they saw.

Viruses can change so fast a increased mutation rate isnt necessarily a good thing for them - I dont know if the 8 x is a max "in theory" kinda thing or what.

Mutation rates among RNA viruses - 1999 [ http://www.pnas.org/content/96/24/13910.full ]

[NS1]

Re: China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

post incomplete.

More later.

[Shiloh]

Re: China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

Source: http://www.newscientist.com/article/...-pandemic.html

China bird flu may be two mutations from a pandemic
17:21 10 April 2013 by Debora MacKenzie
F
In China, nine people have died and more than 20 are seriously ill in the latest outbreak of bird flu, H7N9. And there are fears that the death toll could rise much higher because the virus already has three of the five mutations that we know could allow another bird flu, H5N1, to spread between mammals...

[jflorida]

Re: China: Researchers in Hong Kong suggest that "H7N9 bird flu may mutate 8 times faster than regular flu"

Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests [ http://www.bloomberg.com/news/2013-0...rug-tests.html ]

A gene mutation known to help influenza resist Tamiflu was found in the first of three H7N9 bird-flu patient specimens in China, sequence data show.

The flu virus from the patient in Shanghai has a mutation known as R292K that causes high-level resistance to the Roche Holding AG (ROG) pill and reduced sensitivity to a related drug from GlaxoSmithKline Plc (GSK) called Relenza, genetic sequence information posted on the website of the Global Initiative on Sharing Avian Influenza Data show. Subsequent H7N9 specimens from a patient in Shanghai and one in Anhui province don’t show the mutation.

Preliminary tests so far show no evidence that the new flu strain, which has sickened at least 33 people, killing nine, in eastern China, has developed resistance to the neuraminidase inhibitor drugs Tamiflu and Relenza, the World Health Organization said in a statement yesterday.
“When you look at the raw data and compare the three strains of the virus, there’s a signal from one strain that it’s less sensitive to both of the neuraminidase inhibitors,”


Neuraminidase Inhibitors May Work When Tamiflu Doesn't February 21, 2013 [ http://cen.acs.org/articles/91/i8/Ne...lu-Doesnt.html ]

The new agents, devised by a University of British Columbia-based team, inhibit the flu virus enzyme neuraminidase. They halt the spread of flu viruses in cell culture and animal tests, including strains resistant to the commercial flu drug Tamiflu, which also inhibits neuraminidase. The compounds could therefore lead to a Tamiflu backup drug.

neuraminidase catalyzes sialic acid cleavage by a mechanism involving a covalent intermediate. They determined the structure of the intermediate and designed sialic acid analogs that bond covalently to the viral neuraminidase active site but release very slowly, thus disabling it, and do not inhibit human neuraminidase. The compounds may evade viral resistance more effectively than Tamiflu because their structures more closely resemble that of sialic acid. Also, covalent bonding permanently inactivates the neuraminidase active site; Tamiflu and the three other inhibitors bind noncovalently.


Mechanism-Based Covalent Neuraminidase Inhibitors with Broad-Spectrum Influenza Antiviral Activity [ http://www.sciencemag.org/content/340/6128/71 ]


First H7N9 patient discharged from hospital, more recovering [ http://news.xinhuanet.com/english/ch..._132298381.htm ]

Lu Hongzhou, a professor with the Shanghai Public Health Clinic Center, said clinical observations have found that if a H7N9 patient can be given treatment no later than five days after he or she shows flu symptoms, China's current therapeutic methods can be effective in treating the disease.

"Over five days, the patient's visceral organs can be damaged, and the medicines like oseltamivir will have little effect on the patient," Lu said.

Doctors with the Pediatric Hospital affiliated to Fudan University, one of Shanghai's designated hospitals for taking H7N9 patients, said they did not use a large dose of antiviral drugs on the boy in order to minimize the side effects.



Note: Oseltamivir is marketed under the trade name Tamiflu.