Farmed carnivores may become disease reservoirs posing human health risk

Carnivorous animals lack key genes needed to detect and respond to infection by pathogens, a study has found. Farming large numbers of carnivores, like mink, could allow the formation of undetected 'disease reservoirs', in which a pathogen could spread to many animals and mutate to become a risk to human health.

Research led by the University of Cambridge has discovered that carnivores have a defective immune system, which makes them likely to be asymptomatic carriers of disease-causing pathogens.

Three key genes in carnivores that are critical for gut health were found to have lost their function. If these genes were working, they would produce protein complexes called inflammasomes to activate inflammatory responses and fight off pathogens.

The researchers say that the carnivorous diet, which is high in protein, is thought to have antimicrobial properties that could compensate for the loss of these immune pathways in carnivores – any gut infection is expelled by the production of diarrhea. But the immune deficiency means that other pathogens can reside undetected elsewhere in these animals.

Zoonotic pathogens are those that live in animal hosts before jumping to infect humans. The COVID-19 pandemic, thought to originate in a wild animal, has shown the enormous damage that can be wrought by a novel human disease. Carnivores include mink, dogs, and cats, and are the biggest carriers of zoonotic pathogens.