Health experts are sounding the alarm about the potential pandemic threat posed by bird flu. Bird flu is spreading among cattle in the United States and is showing signs of mutating as it infects people.
There is no guarantee that bird flu will begin to spread between humans, and U.S. health officials stress that the risk to the general public remains low.
The deadly H5N1 avian influenza variant first appeared in China in 1996, but in the past four years it has spread more widely than ever before, reaching previously unreached areas such as penguin paradise Antarctica. reached.
The World Animal Health Organization told AFP that more than 300 million poultry have been killed or culled since October 2021, and 315 species of wild birds have died in 79 countries.
Seals and other mammals that have eaten infected birds have also experienced mass mortality.
The situation changed again in March, when the virus began to spread among dairy cows across the United States. This was also my first time.
Fifty-eight people have tested positive for bird flu in the United States this year, two of whom had unknown contact with infected animals, according to the Centers for Disease Control and Prevention.
There are also concerns that some human cases may remain undetected. Researchers announced last month that eight of 115 dairy workers tested in Michigan and Colorado had antibodies for bird flu, suggesting an infection rate of 7%. did.
Meg Schaefer, an epidemiologist at the US-based SAS Institute, told AFP that factors suggest “avian influenza is knocking on our door and a new pandemic could start at any time.” He said there are several.
“The bird flu pandemic will be one of the most foreseeable catastrophes in history,” read the headline of an opinion piece in the New York Times late last month.
Done in “simple steps”
There are still barriers to preventing the H5N1 virus from easily transmitting between people. These include the need for the virus to mutate to make it more infectious to human lungs.
However, in a study published in a journal, science On Thursday, it was demonstrated that a version of the bird flu that infects cattle in the United States is close to being able to spread more effectively among humans with just one mutation.
Ed Hutchinson, a virologist at the University of Glasgow, said this suggested a “simple step” before the H5N1 virus became “even more dangerous to us”.
And last month, the genetic sequence of a Canadian teenager who became seriously ill with bird flu “suggests that the virus has begun to evolve to find ways to bind more effectively to cells in the body. Hutchinson said.
“We still don’t know whether the H5N1 influenza virus will evolve to cause human disease,” Hutchinson stressed, adding that other hurdles remain.
But the more animals and different species a virus can infect, “the more likely it is that it will adapt to become more transmissible,” Schaefer said.
And if a bird flu pandemic were to occur, it would be “very serious” because humans have no built-up immunity, she added.
Infections among U.S. farmworkers have so far been relatively mild. But of the 904 human H5N1 infections recorded since 2003, nearly half have died, according to the World Health Organization.
Raw milk: “Terrible idea”
Tom Peacock, a virologist at Imperial College London, told AFP there were several reasons to be “less pessimistic about the potential for a pandemic”.
Antiviral treatments and vaccines are already available for avian influenza, which is a big difference from the 2020 coronavirus, he noted.
To avoid the worst-case scenario, many health researchers are calling on the U.S. government to ramp up testing and ensure information is shared across agencies and countries.
The U.S. Department of Agriculture announced Friday plans to test the nation’s milk supply for avian influenza.
Of particular concern is raw or unpasteurized milk, which has repeatedly been found to be contaminated with avian influenza.
© Agence France-Presse
