Overuse of antibiotics, high animal numbers and low genetic diversity caused by intensive farming techniques increase the likelihood of pathogens becoming a major public health risk, according to new research led by UK scientists.
An international team of researchers led by the Universities of Bath and Sheffield, investigated the evolution of Campylobacter jejuni, a bacterium carried by cattle which is the leading cause of gastroenteritis in high income countries.
The authors of the study suggest that changes in cattle diet, anatomy and physiology triggered gene transfer between general and cattle-specific strains with significant gene gain and loss. This helped the bacterium to cross the species barrier and infect humans, triggering a major public health problem. Combine this with the increased movement of animals globally, intensive farming practices have provided the perfect environment in which to spread globally through trade networks.
Professor Sam Sheppard from the Milner Centre for Evolution at the University of Bath, said: "Over the past few decades, there have been several viruses and pathogenic bacteria that have switched species from wild animals to humans: HIV started in monkeys; H5N1 came from birds; now Covid-19 is suspected to have come from bats".
"Our work shows that environmental change and increased contact with farm animals has caused bacterial infections to cross over to humans too."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."
Take a look at that last quote from Prof Sam Sheppard. What do you think it means to be "more responsible about farming methods"? To some it might mean abolishing intensive farming, to others it might raise concerns related to what is widely known as "animal-rights".
IAL advocates that it's time for law's duty of care to be extended so that there is a "responsibility" not just to prevent animals from unnecessary suffering, but also a "responsibility" to provide animals with opportunities to experience positive states (e.g. comfort, interest, pleasure).
In a world where there is an inseparable relationship between people and animals, the reality is that by raising the bar of responsibility to give animals a better life, there are enormous economic, environmental and social benefits to people as well.