Bird flu has been evolving and migrating for 30 years. It is a far more deadly virus that has now arrived in Australia

Experts say the H5N1 bird flu virus’s risk to humans is low, but fear an impeding decimation of seal populations after tens of thousands of deaths in South America and Antarctica Get our breaking news email, free app or daily news podcast In 1996, geese in poultry farms in the Guangdong province of southern China started to get sick with a virus causing “bleeding and neurological dysfunction” and then death. A strain of avian influenza had likely arrived as a relatively harmless virus in migrating wild birds but had morphed into something “highly pathogenic”, killing about 40% of infected geese. Now, after appearing and disappearing, evolving and mutating and traversing the planet – leaving millions of dead birds and mammals in its wake – a descendant of that same H5N1 virus is, 30 years later, killing wild birds in Australia. “Right from the beginning there was great concern about the emergence of this virus,” says Dr Frank Wong, a virologist and avian influenza expert at the CSIRO’s Australian Centre for Disease Preparedness. Many avian influenza viruses are known as “low pathogenicity” because they cause only mild symptoms, or none at all. High pathogenicity viruses cause seriou