Zoonotic diseases transmit between animals and humans, and many originate in factory farming and wildlife trade conditions that also cause significant animal welfare harm.
The connection between animal welfare and zoonotic disease risk is both scientifically well-established and underutilized in public health advocacy. Overcrowded, stressful farm conditions that compromise animal immune function create environments where diseases evolve and spread. Wildlife markets that keep stressed, immunocompromised animals in close proximity enable viral spillover between species. The pandemic potential of these conditions represents a public health argument for animal welfare improvements that complements and strengthens the ethical animal welfare argument. COVID-19 and successive influenza pandemics share origins in conditions that are also welfare failures - the interests of animals and humans align around the need for better standards in both farming and wildlife trade.