As new cases of the bird flu H7N9 continue to pop up all over China, officals are getting more and more worried that the virus can spread between humans, or that it will soon develop the ability to spread between humans.
If it develops the ability to transfer easily from one human to another it could easily become a pandemic.
While the virus has been circulating in the bird population, and many types of birds have tested positive for it. According to the World Health organisation, researchers in China haven’t found definite evidence of how it’s transmitted to humans.
What’s the source?
There’s mounting concern about the virus’s actual origins: A number of the confirmed human cases of the new bird flu, H7N9, say they hadn’t interacted with live birds before they got sick. A Chinese official said only about 40% of the patients had tenuous connections to live birds.
Of almost 50,000 samples from poultry markets, only 39 have tested positive for the virus — a very low number according to The New York Times. They also noted that no pigs have tested positive for the virus.
It could come from birds, or from other animals, or some other environmental source, Time reports.
Will it spread between people?
There are even hints that the virus could spread from person to person, but it doesn’t seem to do it all that well yet. According to the New York Times, there are four possible instances of H7N9 spreading between people: Three families in Shanghai and one spread between two boys in Beijing.
It’s difficult to tell if family members were infected from the same original source, or if the virus passed from one to the other, WHO spokesperson Gregory Hartl told The Times.
The latest study, detailed by Reuters indicates that the virus was widespread in the animal populations (not sure which) before it made the leap to humans. The genetic diversity (small changes between individual viruses) looks like a much larger outbreak, the researchers said.
“The diversity we see in these first few samples from China is as great as the diversity we have seen with a large outbreak in the Netherlands several years ago and one in Italy,” study researcher Marion Koopmans, of the Dutch National Institute for Public Health and the Environment, told Reuters. “This means it (the H7N9 strain in China) has been spreading quite a bit and it’s important to understand where exactly that is going on.”
That’s a bad sign not just because the virus is widespread, but the greater genetic diversity gives the virus more raw materials to work with when mutating. This could make it easier for the virus to gain the ability to pass easily between humans.
A pandemic in the making?
If it can pass between people, it makes a pandemic much more likely, especially if the virus adapts to be transmitted easier. If it becomes more virulent, multiple people could be infected at once in a populated area.
They aren’t the only ones worried about human-to-human transmission of the virus. Jason Koebler of the US News and World Report talked to WHO about the possibility:
Glenn Thomas, a spokesperson for WHO, tells U.S. News that “it’s still too early to say” whether there have been human-to-human transmission, but that the team they’ve sent there will be investigating the possibility.
“There’s no evidence yet of sustained human-to-human transmission, but the team will be looking into this,” he says.
It should be pretty clear if that happens though, since epidemiologists are used to ferreting out those connections between people who have visited the same place.
An increasing threat
As of April 19, Xinuhua reports that 91 people have been diagnosed with confirmed infections with the virus. Only seven have recovered enough to be released from the hospital.
Seventeen have died, according to the World Health organisation.
There are about five new cases of infection every day. Here’s a graph from Dr. Ian M Mackay, of the University of Queensland in Australia of the number of cases in different areas of the country:
Because of the growing threat, the US centres for Disease Control have gotten a vial of the virus to start studying it, including possibly working on a vaccine, a test for the virus, and for testing new therapies.
They also warned American doctors today to be vigilant in watching out for mysterious flu viruses in the states — patients with symptoms that look like the flu but don’t show up in tests as any of the flu viruses we know are circling in the states. Doctors should send samples to the CDC, notify their local officals, and isolate the patient if they see anything weird.
The virus hasn’t been seen outside of China. Yet.
“The biggest question is just what’s going to happen,” the WHO’s top influenza scientist Keiji Fukuda told NPR’s Shots blog. “We’ve had a lot of experience in the last decade with new animal influenza viruses. But … we haven’t seen this combination before. So I think right now, anything is possible.”
Here’s a current map of confirmed H7N9 infections. See the most up to date information on this Google Map:
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