Zoonotic diseases are infections that are transmitted from animals to humans and vice versa. For example, COVID-19 has been designated as a zoonotic disease. In fact, three-quarters of all new infectious human diseases originate in animals, making zoonotic diseases a major threat to public health. The rapid rise in intensive farming over the past 50 years has significantly increased the risk of zoonosis. For instance, the world’s chicken population has almost tripled since 1990, with most of these birds being farmed indoors in crowded conditions. Not only are these conditions stressful for the animals, but poultry farming is responsible for hundreds of human deaths caused by bird flu. Read More
To reduce the risk of zoonosis in intensive farms, protocols for using biosecurity and biocontainment have been developed around the world. However, Dr Mariëlle Stel and Janina Eggers at the University of Twente in the Netherlands, and Dr Wladimir Alonso at the Welfare Footprint Project in Brazil, argue that biosecurity and biocontainment measures are insufficient in preventing zoonotic outbreaks.
The researchers explain that even when biosecurity and biocontainment protocols are implemented, diseases can still be transmitted between indoor and outdoor environments. Bacteria, viruses and parasites can spread through water, air, waste, rodents, insects, farm workers and veterinarians, as well as during animal transportation and through the consumption of animal products.
They also show that intensive farming increases the risk of zoonosis, regardless of biosecurity and biocontainment. This is because intensive farming leads to immunosuppressed animals, due to selective breeding for fast-growth and productivity, exposure to irritants emitted from faeces, and psychological stress. The crowded conditions in such farms also facilitate the rapid spread of bacteria, viruses and parasites, increasing their chances of mutating into a zoonotic disease.
To reduce the risks of zoonoses, Stel, Eggers and Alonso advocate for a large-scale shift toward plant-based proteins. Today, high-quality substitutes for meat, eggs and dairy are increasingly available through breakthroughs in food technology.
Given the significant risks of intensive animal farming to public health, the researchers urge governments to stop subsidising this industry and start funding industries that produce plant-based and lab-grown protein instead. Governments should also encourage consumers to opt for alternative protein sources by lowering the price of high-protein vegetables and plant-based alternatives to animal products.
To further motivate a change in consumer behaviour, Stel, Eggers and Alonso recommend that people should be informed about the links between animal products and zoonotic diseases.
In addition to reducing zoonotic diseases, this protein transition would also reduce carbon emissions, pollution, habitat destruction and the suffering of farm animals, while also enhancing our future food security.
