... Health experts have been sounding the alarm about the potential pandemic threat posed by bird flu, which has been showing signs of mutating as it spreads among cows and infects people in the United States.
There is no guarantee that bird flu will ever begin transmitting between humans, and US health authorities have emphasised that the risk to the general public remains low.
The deadly bird flu variant H5N1 first emerged in China in 1996, but over the last four years it has spread more widely than ever before, reaching previously untouched regions such as penguin-haven Antarctica.
More than 300 million poultry birds have been killed or culled since October 2021, while 315 different species of wild birds have died across 79 countries, the World Organisation for Animal Health told AFP.
h5n1 virus particles
Mammals that ate the infected birds, such as seals, have also experienced mass-die offs.
The situation changed again in March, when the virus began spreading among dairy cows across the United States in another first.
Fifty-eight people have tested positive for bird flu in the US this year, including two who had no known exposure to infected animals, according to the Centers for Disease Control and Prevention.
There are also fears that some human cases are going undetected. Researchers said last month that eight out of 115 dairy workers tested in Michigan and Colorado had antibodies for bird flu, suggesting an infection rate of seven percent. ...
