What you should know about the new avian bird flu

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The death toll from a new flu strain in China has now reached six. It's not known if the virus can be transmitted from person to person, but based on what the experts are saying, it’s a development that needs to be taken very seriously.

The first report to come in that the new avian influenza, H7N9, could infect humans arrived in February of this year. Now, six deaths later, officials in China are scrambling to contain it. No less than 16 people have now been infected by it, some of them in critical condition. Of those infected, it's not known how 11 contracted it.

As of today, this is the situation among those infected:


And the apparent rate of spread:


Charts via ECDC.

In turn, Shanghai officials have closed the Hauhau agricultural market and the slaughtering of birds has begun; as of today, more than 20,000 birds have already been killed. Starting this coming April 6, Shanghai will suspend all trade of live poultry.


Situation as of April 5, 2013; via ECDC.

According to the World Health Organization, symptoms include fever, cough, and shortness of breath, leading to severe pneumonia. But in reality, precious little is known about the new strain. The virus is suspected of jumping from birds to humans, but no evidence exists that it’s transmissible from human to human. Consequently, experts are telling people to not be alarmed.


That said, scientists who have worked on the virus say a recent mutation may now allow it to move more easily from animal to animal, which could pose a heightened risk to humans. On April 4, the Center for Disease Control starting sequencing H7N9 in hopes of developing a vaccine.

Disturbingly, the new virus is harder to detect than the H5N1 virus. The new strain can infect birds without causing the disease; it produces few, if any symptoms in some birds.


One person who’s particularly worried about H7N9 is Foreign Policy’s Laurie Garrett. In particular, she’s worried that the virus is also making the rounds in the pig population.


She writes:

Influenzas are named according to the specific nature of two proteins found on the virus — the H stands for hemaggluntinin and the N for neuraminidase. These proteins play various roles in the flu-infection process, including latching onto receptors on the outside of the cells of animals to transmit the virus into their bodies. Those receptors can vary widely from one species to another, which is why most types of influenza viruses spreading now around the world are harmless to human beings. As far as any scientists know, the H7N9 forms of flu have never previously managed to infect human beings, or any mammals — it is a class of the virus found exclusively in birds. It is therefore extremely worrying to find two people killed and one barely surviving due to H7N9 infection. [Garrett wrote this prior to learning about the new deaths]

One very plausible explanation for this chain of Chinese events is that the H7N9 virus has undergone a mutation — perhaps among spring migrating birds around Lake Qinghai. The mutation rendered the virus lethal for domestic ducks and swans. Because many Chinese farmers raise both pigs and ducks, the animals can share water supplies and be in fighting proximity over food — the spread of flu from ducks to pigs, transforming avian flu into swine flu, has occurred many times. Once influenza adapts to pig cells, it is often possible for the virus to take human-transmissible form. That's precisely what happened in 2009 with the H1N1 swine flu, which spread around the world in a massive, but thankfully not terribly virulent, pandemic.

If the pigs, people, and birds have died in China from H7N9, it is imperative and urgent that the biological connection be made, and extensive research be done to determine how widespread human infection may be. Shanghai health authorities have tested dozens of people known to have been in contact with Wu and Li, none of whom have come up positive for H7N9 infection. Assuming the tests are accurate, the mystery of Li and Wu's infections only deepens. Moreover, if they are a "two of three," meaning two dead, of three known cases, the H7N9 virus is very virulent.


Hong Kong authorities are not taking any chances, and they’ve put the area on alert. Some hospitals in mainland China have also been put on high alert.

Sources: CBC, Washington Post, AP, Foreign Policy.