As individual countries suffer outbreaks of avian influenza (bird flu), the worldwide impact of the virus on birds, mammals and humans is often overlooked.
The numbers have been pulled together by London’s The Guardian newspaper, which calls bird flu “the forgotten epidemic”. More than 280 million poultry birds have died or been culled since October 2021, it says, based on data from the World Animal Health Information System.
The highly infectious H5N1 strain of avian flu has “devastated poultry and caused the biggest sudden drop of the world’s wild bird population in decades,” the newspaper reported.
“The millions of wild birds killed includes tens of thousands of endangered and endemic species – and tens of thousands of mammals have died too.”
The article tracks the spread of bird flu from China in 1996 to Antarctica this year. The virus has reached the world’s southernmost tip, with new data published in Nature Communications.
The highly pathogenic (disease causing) H5N1 bird flu strain was first found at a goose farm in China in 1996. Since then it has spread to every region in the world, including, most recently, Australia. New Zealand is so far unaffected, but is preparing for outbreaks
After devastating outbreaks in Europe, bird flu reached North America in November 2021 and South America in October 2022, spreading down the 6 000 km length of the continent in less than six months.
In South America, bird flu caused mass die-offs of mammals such as sea lions and elephant seals, the Guardian reported. In March this year it started spreading among US cattle, with more than 100 herds affected.
What is the risk to humans?
As the virus evolves, it could become more of a threat to people, according to a recent report by the US Centers for Disease Control and Prevention (CDC). There have been nine cases of H5N1 in humans in the US (although symptoms have been relatively mild) and officials said they expected to see more.
The UN health agency’s chief scientist has also said the risk of bird flu spreading to humans is an “enormous concern”.
“So far, there is no evidence that H5N1 is spreading between humans. But in the hundreds of cases where humans have been infected through contact with animals over the past 20 years the mortality rate is above 50%,” The Guardian reported.
