Practices of livestock farming are a global health issue

There has been an understandable rush to see the coronavirus pandemic as a reason to rethink aspects of modern life. Working from home has been touted as a solution to long commutes and cycle lanes to the problem of urban traffic.

Environmentalists have pointed out that swift collective action, similar to that against Covid-19, could be effectively applied to the problem of climate change. If we focus specifically on the issue of containing infectious disease, however, then we ought to be having a very stark look at our relationship with the other animals on the planet.

SARS CoV 2 is believed to be a zoonotic disease (one spread from animals to humans), only one among the many that emerge each year. Scientists have just identified another swine flu strain that they believe has potential to cause a pandemic. If we think back to the feared pandemics of the recent past most of them can be traced to animals. More importantly, they can be traced to human relationships with other animals.

For example, it is now generally accepted that HIV/AIDs (arguably the last pandemic to cause a similar global panic as SARS CoV 2) moved from chimpanzees into humans. Both the emergence and the subsequent spread of the disease were enabled by economic factors (including imperialism) that brought people into denser groups and encouraged game hunting. This allowed many more opportunities for disease exchange between humans and between humans and chimpanzees.

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Domestic animals

Expansion of human habitats has often exposed us to new diseases from wild animals, but equally important are livestock farming practices. In fact many historians believe that Europeans experienced higher rates of disease than indigenous peoples in the Americas because of close association with domestic animals rather than close association with other humans.

The SARS CoV 2 pandemic is a reminder that food animals can give us much more than nourishment. How we manage livestock may have a direct bearing on whether we can avoid future pandemics of zoonotic diseases.

A significant shift in how Ireland and much of the western world raised food animals occurred during the 19th century. Diseases like rinderpest, tuberculosis and pleuropneumonia threatened supplies of cattle and had the potential to sicken the people who ate them. Rinderpest and pleuropneumonia do not pass to humans, but that was not known at the time.

City governments sought to eliminate sick animals from the food chain, and they demanded centralised abattoirs where they could more effectively inspect the meat. One was constructed in Dublin in 1882, just outside of the North Circular Road near to the former cattle market. The idea was to prevent butchers from slaughtering in their own yards and thus remove an environmental hazard while improving meat inspection.

Since the 19th century many aspects of livestock farming have gone in the same direction: towards larger farms, larger herds, larger killing facilities and larger markets. This has created efficiencies and enabled an improved human diet (which in and of itself is one protection against disease). And the changes worked to reduce problems with tuberculosis and other diseases transmitted by food.

But that solution has created a new problem. Public health officials of the 19th and 20th centuries worried about the crowding of people into tenements where disease might spread easily. They worried about these people bringing animals into those environments, believing that their presence made habitations and yards even dirtier and more of a risk. Now, however, we often crowd those animals together in conditions far worse than a 19th century tenement building.

Public health

Those who sought public health reform in the past believed that if they could only separate dense human populations from animals then they would reduce the risk of disease. And for a while and in some places it did.

But we need a much more drastic reimagination of our relationship with the animals we raise to eat. Practices of livestock farming are a global health issue, not just a climate change issue. Human health cannot be crudely separated from animal health.

We can do little about farming practices in China, but we can learn from this disaster. If we continue to crowd animals together in large numbers to feed ourselves we maintain a high risk from emergent zoonotic disease.

Dr Juliana Adelman lectures in history at Dublin City University