Bird flu fears in the US are being fueled by sick minks. Reasons why
As bird flu hits more and varied animals, scientists fear is that the virus could evolve to spread more easily between people, and potentially trigger a pandemic.
Concerns about the virus spreading to more people have been rekindled by a recent incident of avian flu at a mink farm.
This bird flu virus has been studied by scientists since the 1950s, but it wasn't considered a threat to people until a 1997 outbreak in Hong Kong among people who visited live chicken markets.
As bird flu hits more and varied animals, like at the mink farm, the fear is that the virus could evolve to spread more easily between people, and potentially trigger a pandemic.
Scientists say another kind of bird flu was likely behind the devastating 1918-1919 flu pandemic, and avian viruses played roles in other flu pandemics in 1957, 1968, and 2009.
Still, the risk to the general public now is low, says Dr. Tim Uyeki of the U.S. Centers for Disease Control and Prevention.
A look at the bird flu virus and why it is getting renewed attention:
What is bird flu?
Some flu viruses mainly affect people, but some others chiefly occur in animals. For example, there are flus that occur in dogs, plus pig– or swine– flu viruses. And then there are avian viruses that spread naturally in wild aquatic birds like ducks and geese, and then to chickens and other domesticated poultry.
The bird flu virus drawing attention today –Type A H5N1– was first identified in 1959, by investigators looking into a flu outbreak in chickens in Scotland. Like other viruses, it has evolved over time, spawning newer versions of itself.
By 2007, the virus was found in more than 60 countries. In the U.S., it has recently been detected in wild birds in every state, as well as in commercial poultry operations or backyard flocks in 47 states. Since the beginning of last year, tens of millions of chickens have died of the virus or been killed to stop outbreaks from spreading, one of the reasons cited for soaring egg prices.