Roaming cats hunt, interact with wildlife or other domestic animals, and move through environments contaminated with pathogens and toxins. (Unsplash/Oscar Fickel) Pets form an important part of many people’s lives, providing meaningful companionship. However, our pets can sometimes also be a source of unwelcome pathogens and diseases, particularly if they frequently roam outdoors. We are ecologists and a veterinarian who study wildlife health and the movement of pathogens among wildlife, domest