Intensive farming could increase the risk of new pandemics, researchers warn

Industrialized agriculture is often thought to reduce the risk of zoonotic diseases (those transmitted from animals to humans) due to better control, biosecurity and segregation of livestock.

A study, led by the University of Exeter, examines the effect of social and economic factors – which are often overlooked in traditional assessments. The paper, published in the journal Royal Society for Open Sciencetitled “Understanding the Roles of Economy and Society in the Relative Risks of Zoonotic Emergence from Livestock.”

It finds that the effects of agricultural intensification “are at best uncertain and at worst may contribute to the risk of EID (emerging infectious diseases).

Lead author Professor Steve Hinchliffe, from the University of Exeter, said, “The COVID-19 pandemic has revived interest in EIDs, particularly zoonotic viruses.

“The risks of emergence and transmission depend on many factors, including contact between humans and animals and how we use the land.

“Livestock play a potentially important role in those risks, shaping landscapes and providing refuges that can act as a source or amplifier of emerging pathogens.”

While such risks are usually assessed in terms of microbiological, ecological and veterinary sciences, the new study highlights the need to consider social, economic and political factors.

“Disease is always more than a matter of pathogen transmission, contact and contagion,” Professor Hinchliffe said.

“The founding myth in intensive farming is that we separate livestock from wild animals and thereby close the risk of disease passing between them.

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

“Once social, economic and political factors are taken into account, the pandemic risk from intensive agriculture is worrisome.

The paper highlights the expansion of intensive agriculture and the resulting environmental degradation as factors that may increase the risks of EID.

It also says that intensification leads to a “mixed landscape” – with a variety of farming practices and types – that creates “the worst of all possible worlds in terms of EID risk”.

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

For example, European farm buildings can be old and expensive to maintain, large American farms tend to be open-air concrete structures with mesh (to avoid the need for air conditioning), and in areas subtropical biosecurity is balanced against the need to reduce animal overheating.

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

They also note the close ties between big food companies and national authorities – which suggest “regulatory entrapment… and the difficulty of disentangling interests”.

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

“Instead, we need to re-examine the socio-cultural impacts of intensification of farm animal production on planetary health, environmental sustainability and animal welfare issues.”

The research team included Tufts University, the Royal Agricultural University, the University of Wollongong, Clark University, the Cambridge Conservation Initiative and the Institute of Development Studies.