Tiny genetic change lets bird flu leap to humans


Poultry, ChinaImage copyrightGETTY IMAGES
Image captionAt least six provinces have reported human cases of H7N9 influenza this year, according to Chinese state media

A change in just a single genetic “letter” of the flu virus allows bird flu to pass to humans, according to scientists.

Monitoring birds for viruses that carry the change could provide early warning of risk to people, they say.

Researchers at the University of Hong Kong studied a strain of bird flu that has caused human cases in China for several years.

Birds carry many flu viruses, but only a few strains can cause human disease.

H7N9 is a strain of bird flu that has caused more than 1,000 infections in people in China, according to the World Health Organization.

Most cases are linked to contact with infected poultry or live poultry markets.

The change in a single nucleotide (a building block of RNA) allows the H7N9 virus to infect human cells as well as birds, say Prof Honglin Chen and colleagues.

They say there is “strong interest in understanding the mechanism underpinning the ability of this virus to cause human infections and identification of residues that support replication in mammalians cells is important for surveillance of circulating strains.”


Dr Derek Gatherer, an expert on viruses at Lancaster University, UK, says more surveillance of bird flu viruses is needed.

“The recent flare-up of H7N9 bird flu in China has been the cause of some concern this winter, and the demonstration that the new replicative efficiency mutation is present in this strain is not good news,” he told BBC News.

“Also, the observation that this mutation has been present in other bird flu subtypes like H9N2 and spreading slowly for over 15 years shows that H7N9 isn’t the only kind of bird flu that is potentially a pandemic risk for humans.

“We need to maintain a broader surveillance of bird flu to identify which strains have this mutation.”

The research, published in the journal, Nature Communications, will help scientists understand more about how bird flu viruses adapt to infect humans.

10 thoughts on “Tiny genetic change lets bird flu leap to humans

  1. Well, that obviously calls for emergeny vaccines and anti-virals for human beings. Then after the usual massacre of the innocent infected birds, business can go on as usual.

  2. This seems like a good place for words of wisdom by George Carlin:

    “Whar makes me happy in the midst of all this is that ultimately animals get even. The major killers of humanity throughout history–smallpox, influenza, tuberculosis, malaria, bubonic plague, measles, cholera, and AIDS–are all infectious diseases that arose from the dideases of animals. I pray that mad cow disease will come to this country and completely wipe out the hamburger criminals.”
    From “Brain Droppings,” page 239

    If he were here today, I’m sure he would add bird flu to the list.

    • I’d edit that to say that many diseases, such as TB, did not emerge for animal diseases, but are mankind’s alone – TB was introduced to cattle by man. The ‘human strain’ follows mankind’s history very closely – you know, our war and conquering and spreading our genes far and wide history. They also arose from our own squalor living habits when we didn’t know about hygiene. (Yes, I’ve been watching Game of Thrones). Of course, the biggest disease to threaten the planet, and even ourselves, is ourselves. Mother Nature is no fool, and she will have the last laugh.

      • oops, that should read ‘did not emerge ‘from’ animal diseases. So, maybe globalism will have a positive side, in the end. 😉

  3. Yes, we’re the biggest threat to the planet with our continued overbreeding and the consequent destruction of all other lives for our benefit and their deaths as collateral damage from our folly.

    The Mycobacterium has a long and complicated history and occurs in many species. With population pressure and the resulting poverty and squalor, we’re setting up the conditions for Nature’s last laugh. And it may come from the lowly microbe instead of a nuclear disaster or ciimate catastrophe.

    • Yes, and you know I don’t mean to be too harsh when I said I wanted to ‘edit’ the comment (I meant George Carlin’s words). And you are all right about the sarcasm – we all get it, and it is cathartic many times with all of the awfulness we observe done by our own kind. 🙂

      • I didn’t notice anything harsh. Carlin was pretty outspoken at a time when speaking up for animals would have been considered more shocking than it is now. I’m sure he wouldn’t have given a rip if anyone didn’t like it anyway.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s