Each time H5N1 infects a mammal, it has a chance to develop mutations that make it more transmissible
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It has been detected in birds on every continent except Australia, seals in South America, foxes in Canada, as well as poultry, dairy cows and dozens of farm workers who have had contact with them in the United States—and now the highly contagious H5N1 bird flu virus has jumped to a pig in USA for the first time.
This development is undoubtedly worrying. It gives the virus one of its best opportunities yet to evolve…