Dr Simon Doherty, Institute for Global Food Security at Queen’s University Belfast, and Senior Vice-President of the British Veterinary Association discusses the links between COVID-19 and animal agriculture, and the importance of improving ‘One Health’.
From snakes and pangolins to farms and wet markets, our relationship with animals has come under intense scrutiny as many search for answers to the origin of the novel coronavirus outbreak.
Yet while definitive evidence remains elusive, we can be confident that our knowledge and understanding of animal health at a global level is actually more robust than ever, including within livestock farming, which has been among the scapegoats for the pandemic.
Does livestock transmit COVID-19?
Scientists have found that around six out of every 10 infectious diseases are, like COVID-19, zoonotic, or pass between animals and people. However, we also know that the vast majority of these diseases originate in wildlife rather than in pets or livestock.
Moreover, to date, there is no evidence that farmed livestock, including pigs and poultry, transmit COVID-19 and contribute to the global spread of infection.
Rather, global co-operation and advances in veterinary medicine mean that livestock diseases – whether zoonotic or not – do not usually spread internationally in the same way and with the same speed that COVID-19 has done.
This is due to the development of global systems of disease surveillance, which allow countries to share information about outbreaks, as well as mechanisms such as compartmentalisation, which allow livestock trade and movement to continue between defined areas that are demonstrably disease-free.
These measures, along with the improved availability and use of animal vaccines and medicines, have meant that even if diseases pass from wild animals to domesticated animals, outbreaks and their impact on people can be confined and managed. This is crucial in ensuring that livestock do not become a source of major global health issues.
Managing risk factors for potential outbreaks
Nevertheless, to properly understand and manage the risk factors associated with diseases like COVID-19, health authorities must treat the pandemic as part of a wider system, which includes animal, human and environmental health, or what we call ‘One Health’.
For example, many achievements in improving public health in recent years have resulted from innovations in animal agriculture that protect farmers, food handlers and consumers as well as animals.
These developments have included the preventative use of vaccines as well as measures designed to keep disease out of farms, or to contain them within the farm if a disease outbreak does occur.
Such innovations are often most effectively and rigorously applied in indoor or contained farms, where conditions can be closely managed to maintain animal health and welfare, which is critical to productivity and sustainability.
An effective vaccine for poultry widely administered across breeding farms since the mid-1990s resulted in human cases of salmonella plummeting while efforts to eradicate tuberculosis in cattle will also protect people. Vaccinating cows against leptospirosis, meanwhile, reduces the risk of exposure of dairy farmers. And even in the throes of a pandemic, veterinarians are working closely with livestock farmers to maintain animal health for safe food production and to minimise animal welfare issues that might arise through disruption caused by COVID-19 restrictions.
This has included veterinarians advising on steps to continue the safe testing of cattle for tuberculosis while observing social distancing practices where handling systems make this possible, protecting cattle and people alike from the threat of disease.
Screens and dividers have also been introduced in abattoirs and meat-packing plants to allow staff to keep processing livestock during the pandemic, providing food supplies and incomes at a crucial time.
Improving One Health is vital
Governments worldwide have identified vaccines, pharmaceuticals, and veterinary services as essential, not only in the interests of animal health but in the associated interests of human health as well.
Animal health threats may be changing as the world is changing, but there are sadly no halcyon days to which we can revert to avoid threats like COVID-19. This is why ongoing collaboration across human and animal medicine is vital. A key element of this is developing and sharing an understanding among doctors, veterinarians, and environmental experts around the identification of risks in terms of zoonotic potential.
This means assessing and understanding the critical control points in the entire farm to fork supply chain and taking action to mitigate risks, from improved genetics and breeding to hygienic farm conditions, widespread vaccination, and food safety standards. But ultimately, we need to create the ‘One Health’ systems that will maintain an appropriate balance between humans, animals, and environment.
The coronavirus pandemic has reminded everyone just how closely linked our fortunes – health, social and economic – are.
Although there is no evidence livestock or pets transmit the virus, it matters less which animal or market started the outbreak and more how we collectively respond to similar risks in the future.
Dr Simon Doherty
Institute for Global Food Security, Queen’s University
Senior Vice-President of the British Veterinary Association