Research overview: trauma, disease and mortality risks of outdoor access

Free-roaming cats face elevated risks of injury, infection and death, a central consideration in the indoor-outdoor debate. This overview surveys evidence on the hazards outdoor cats encounter, including vehicle collisions as a major cause of trauma, fight wounds and abscesses, infectious diseases such as feline immunodeficiency virus and feline leukaemia virus spread through contact, parasites, poisoning and predation by larger animals. It examines studies comparing lifespan and morbidity between indoor and outdoor cats and the epidemiology of specific outdoor-associated conditions. The survey balances these risks against the behavioural benefits of outdoor access discussed elsewhere, and it informs containment recommendations by quantifying the costs to feline health and longevity that motivate keeping cats indoors or providing controlled, contained outdoor experiences.