A groundbreaking global synthesis led by researchers from the University of British Columbia has revealed startling insights into the disease risks associated with pet cats allowed to roam outdoors unsupervised. Contrary to prevailing assumptions that feral and stray cats are the primary reservoirs for zoonotic pathogens, this extensive study finds that owned outdoor cats harbor infectious diseases at rates nearly identical to their feral counterparts. This research, published ahead of print in PLOS Pathogens, compiles and analyzes data from an unprecedented global literature review comprising 604 studies and encompassing over 174,000 cats from 88 countries.
The scope of the study is vast, cataloging 124 pathogen species identified within the feline populations examined. Alarmingly, nearly 100 of these pathogens are known to infect humans, underscoring the significant zoonotic potential of cat populations that are commonly allowed unrestrained access to the outdoors. These findings challenge conventional public health paradigms which often emphasize stray and feral cats when considering disease transmission risks to humans and wildlife, inadvertently overlooking the role played by owned cats permitted to roam freely.
Dr. Amy Wilson, lead author of the study and an adjunct professor in UBC’s department of forest and conservation sciences, points out that the heightened risk associated with outdoor-access cats was somewhat anticipated due to their increased exposure to diverse disease vectors. However, the degree of similarity in infection rates between owned outdoor cats and feral cats was surprising. This parity persists despite owned cats typically benefiting from veterinary care, vaccination protocols, regular nutrition, and shelter.
Among the zoonotic pathogens identified are well-characterized agents including Toxoplasma gondii, the protozoan responsible for toxoplasmosis; a variety of parasitic roundworms; Bartonella henselae, the bacterium causing cat-scratch disease; and Leptospira species, which can induce leptospirosis in humans and animals. These pathogens pose significant health concerns due to their ability to infect multiple hosts and their environmental persistence.
Cats’ predatory behaviors result in the direct transmission of pathogens from prey to cat populations. Research indicates that cats worldwide collectively kill over 2,000 wildlife species, primarily small mammals such as rodents, which are key reservoirs for many infectious agents. Crucially, pet owners often remain unaware of the full extent of their cats’ interactions with wildlife, as only approximately 20% of prey animals killed are observed by owners, thus underestimating the exposure risk.
Dr. Wilson emphasizes the gaps in public health frameworks that narrowly focus on feral cats, noting that this perspective misses a significant part of the zoonotic disease ecology puzzle. Additionally, survey data reveals that many cat owners lack awareness about the infectious diseases that their pets can harbor and transmit, especially depending on the lifestyle and roaming habits of their companion animals.
The study highlights supervised outdoor access as a key intervention to mitigate these public health risks. Confining cats to enclosed patios, using cat-containment fencing, or employing harness-based walks can simultaneously enrich the animals’ environmental stimulation and drastically reduce direct contact with wildlife and feral animals. This approach effectively curtails the transmission pathways that lead to infection while preserving feline welfare.
It is also critical to recognize that routine veterinary care such as vaccination and deworming, while essential, alone cannot address the broad spectrum of pathogens. Many pathogens, particularly protozoal and bacterial agents, necessitate avoidance of exposure as a primary preventive measure. The public defecation of infected cats introduces environmental contamination, intensifying community health concerns well beyond individual ownership.
Drawing a parallel with canine management, Dr. Wilson notes the historical transition from free-roaming dogs to widespread leash laws and confinement for animal welfare and public safety reasons. A similar cultural and regulatory realignment appears imperative for cats globally, given the mounting evidence delineating the public health risks posed by free-roaming owned cats.
Dr. Wilson eloquently argues that unsupervised outdoor access is not a prerequisite for feline welfare or for maintaining the human-animal bond. Instead, improved management practices that prioritize containment and surveillance can protect cats themselves, safeguard vulnerable wildlife populations, and reduce zoonotic pathogen transmission risks to human communities.
The co-authorship team, comprising Dr. Peter Marra from Georgetown University, Dr. David Lapen of Agriculture and Agri-Food Canada, and Dr. Scott Wilson from Environment and Climate Change Canada and UBC, underscores the interdisciplinary nature and robustness of this research. Their collective expertise spans ecology, veterinary sciences, public health, and environmental science, lending comprehensive depth to the findings presented.
This research receives funding support from Agriculture and Agri-Food Canada’s Environmental Change One Health Observatory project, reflecting a commitment to integrative approaches that fuse environmental change science with health outcomes for animals and humans alike.
Subject of Research: Animals
Article Title: Outdoor roaming of owned cats elevates risk of zoonotic pathogen exposure: A global synthesis
News Publication Date: 29-Apr-2026
Web References: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014160
Image Credits: Dr. Amy Wilson
Keywords: Zoonoses, Animal health, Public health
Tags: cat-borne zoonotic infectionsdisease transmission from pet catsfeline pathogen diversityferal vs owned cats disease comparisonglobal feline pathogen studyglobal synthesis on cat diseasesinfectious diseases in feral catsoutdoor pet cats disease riskspet cats roaming outdoors riskspublic health and outdoor catszoonotic diseases from pet catszoonotic pathogens in cats
