Free-Roaming Cats Can Bring Many Pathogens Home

A comprehensive study, supported by Canada's Department of Agriculture and Agri-Food, reveals that allowing pet cats to roam freely dramatically increases their risk of carrying and transmitting diseases to humans. The research, which synthesized data from over 400 global scientific works, found that outdoor-access cats are 3 to 5 times more likely to harbor pathogens compared to their indoor-only counterparts.

The risk profile for free-roaming cats closely mirrors that of feral cats. Scientists have identified nearly 100 pathogens transmissible from cats to humans. These include viruses like rabies, and parasites such as *Toxoplasma gondii*, as well as bacteria like *Salmonella*. These infections are often acquired when cats hunt small animals like rodents, birds, or bats, which can be carriers of various diseases. Exposure to natural environments, wildlife, and other domestic animals further facilitates the spread of these pathogens.

Researchers noted that many owners underestimate their pets' hunting behaviors, with actual prey capture rates potentially 80% higher than observed. Globally, domestic cats have been documented preying on over 2,000 different wildlife species. The problem extends beyond direct contact; cat feces, often deposited in gardens, parks, and public spaces, can contain hundreds to hundreds of thousands of parasite eggs. These eggs can persist in soil and water for months or even years, posing a risk of infection to humans and other animals through contact with contaminated environments.

To address these risks, experts strongly advise against unsupervised outdoor access for cats. Instead of complete confinement, owners can create secure, enclosed outdoor play areas, use leashes, or provide direct supervision during outdoor activities. Essential preventative measures include maintaining up-to-date vaccinations, particularly for rabies, and regular deworming. Ultimately, managing a cat's exposure to the outside world is identified as the most effective strategy to reduce disease transmission, promoting both pet health and public safety.