University of British Columbia researchers discovered that outdoor pet cats carry infectious diseases at rates matching feral cats, regardless of veterinary care, regular feeding, or home shelter. The finding challenges the assumption that domesticated cats with owner support face lower disease transmission risks than wild populations.
Researchers tracked disease prevalence in both groups and found no meaningful difference in infection rates. Pet cats roaming unsupervised encounter the same pathogens and wildlife as feral cats do, exposing them to parasites, bacteria, and viruses in the environment. Even vaccination and preventive treatment cannot fully protect cats that spend time outdoors.
The study matters for public health and ecosystem protection. Outdoor cats serve as vectors for diseases that spread to other animals and potentially to humans. They also hunt wildlife, affecting local bird and small mammal populations.
The research suggests pet owners who allow cats outside accept disease risks comparable to keeping feral animals. Next steps likely involve clearer public health guidance on outdoor cat management. Some regions may strengthen policies around free-roaming cats, while veterinarians will need updated recommendations for owners unwilling to keep cats entirely indoors.