THE TELEGRAPH – Fears are growing that the H5N1 outbreak among cattle in the United States could have been caused by contaminated animal feed.
In contrast to Britain and Europe, American farmers are still allowed to feed cattle and other farm animals ground-up waste from other animals including birds.
Dairy cows across six US states – and at least one farm worker – have become infected with the highly pathogenic virus, which has already killed millions of animals across the globe since 2021.
The farm worker, who is thought to have been exposed via infected cattle in Texas, is only the second recorded human H5N1 case in the US. Since February, the US has investigated and discounted a further 8,000 possible exposures, according to Dr Joshua Mott, WHO senior advisor on influenza.
The development is of concern because it allows the virus, which has killed millions of birds and wild mammals around the world, more opportunities to mutate.
Experts fear that H5N1, which was only first detected in cows a few weeks ago, may have been transmitted through a type of cattle feed called “poultry litter” – a mix of poultry excreta, spilled feed, feathers, and other waste scraped from the floors of industrial chicken and turkey production plants.
In the UK and EU, feeding cows proteins from other animals has been tightly regulated since the outbreak of BSE – or ‘mad cow disease’ – 30 years ago.
Experts are unsure but fear it could be the poultry litter feed used in the US that has passed the virus to cattle.
“In the US, the feeding of poultry litter to beef cows is a known factor in the cause of botulism in cattle, and is a risk in the case of H5N1,” said Dr Steve Van Winden, Associate Professor in Population Medicine at the Royal Veterinary College.
Dr Tom Peacock, a virologist and fellow at the Pirbright Institute agreed: “This latest case wouldn’t be the first time there have been concerns H5N1 could be moving through different mammals via contaminated feed … ”
