Pandemic risk posed by factory farms branded 'concerning'

Factory farms could raise the risk of a new pandemic due to contact with humans and wildlife such as rats, a new study has warned.

Intensive farming – also known as industrialised or ‘factory’ farming – is often thought to decrease the risk of diseases passing from animals to humans because the farm animals are isolated.

But the new study suggests this idea is wrong because farms exist in the real world – and this means previous studies have ignored risks such as wildlife including rats or wild birds sneaking into farms, or farm workers moving between different places.

The warning comes as a report from the UK COVID-19 inquiry found the government "failed" the public, due to “significant flaws” in preparing for the pandemic.

Why do people think factory farms are safer?

Industrialised farming is often thought to reduce the risk of zoonotic diseases – illnesses that are transmitted from animals to humans.

This is because of better control, biosecurity and separation of livestock. The idea is to separate livestock from wildlife, in theory reducing the risk of diseases spreading between livestock and wild animals.

What did the new study find?

The study found that the effects of factory farms “are at best uncertain and at worst may contribute to emerging infectious disease risk”.

Lead author Professor Steve Hinchliffe, from the University of Exeter, said: “The COVID-19 pandemic reignited interest in emerging infectious diseases, especially zoonotic viruses. The risks of emergence and transmission depend on multiple factors, including contact between humans and animals, and how we use land.

“Disease is always more than a matter of pathogen transmission, contact and contagion. The founding myth in intensive farming is that we separate livestock from wildlife and thereby shut off the risk of diseases passing between them.

“But these farms exist in the real world – so buildings and fences can get damaged, wildlife like rats or wild birds can get in, and workers move around. In short, there will always be accidents.

“Livestock farming plays a potentially significant role in those risks, shaping landscapes and providing hosts that can act as the source or amplifiers of emerging pathogens.”

“Once social, economic and political factors are taken into account, the pandemic risk posed by intensive farming is concerning.”

Why could farms become sources of disease?

Having factory farms near other kinds of farming creates ‘the worst possible world’ in terms of the risk of new diseases.

Many farms also have difficulty implementing strict ‘biosecurity’ measures to prevent disease-causing agents entering or leaving, the researchers found.

On biosecurity, the paper says some farm businesses find the costs “debilitating”, while regional variations also have an impact.

For example, European farm buildings can be old and costly to maintain, large US farms tend to be open-air concrete structures with netting (to avoid the need for air conditioning).

In subtropical areas, biosecurity is balanced against the need to reduce overheating of animals.

“The result is a far from bio-contained environment,” the authors write.

What can be done?

The researchers say that the idea that factory farming is ‘safer’ is wrong and urge debate about the risks of diseases emerging from factory farms.

They also warn about the risks of close ties between large food companies and national authorities.

The researchers say that this risks “regulatory capture… and the difficulty of decoupling interests”.

Co-author Dr Kin Wing (Ray) Chan said: “Increasing on-farm biosecurity, standardisation, and efficiency in farm animal production is not the panacea for achieving a disease-free environment.

“Rather we need to reconsider the socio-cultural impacts of intensifying farm animal production on planetary health, environmental sustainability and animal welfare issues.”