Current intensive farming techniques involving overuse of antibiotics, high numbers of animals, and low genetic diversity are hotbeds for pathogens to spread, scientists have said.
A team of researchers led by the University of Sheffield and Bath studied the way a bacteria commonly carried by chickens and cattle behaved and spread between different species.
The bacteria, known as Campylobacter jejuni, are resistant to antibiotics due to the use of drugs in farming, and can be transferred to humans if they eat undercooked meat and poultry, causing gastroenteritis or food poisoning.
Gastroenteritis is the inflammation of the stomach and small intestine, and can lead to diarrhoea and vomiting, according the NHS.
A cattle-specific strain of the bacteria emerged in the 20th century when livestock farming grew exponentially across the world. According to agricultural data by the House of Commons Library, the number of cattle on UK farms increased from six million to 15.2 million between 1875 to 1974.
Currently, there are an estimated 1.5 billion cattle on Earth, said Professor Sam Sheppard of the University of Bath. If around 20 per cent of these cattle are carriers of the bacteria, “that amounts to a huge potential public health risk”, he said.
“Over the past few decades, there have been several viruses and pathogenic bacteria that have switches species from wild animals to humans: HIV started in monkeys, H5N1 came from birds, now Covid-19 is suspected to have come from bats.
“I think this is a wake-up call to be more responsible about farming methods, so we can reduce the risk of outbreaks of problematic pathogens in the future,” added Prof Sheppard.