Research overview: stress, immunity and upper respiratory disease in shelter cats

Feline upper respiratory disease is the most common illness in shelters, and a body of research connects its incidence to stress-related immunosuppression as much as to pathogen exposure. This overview surveys evidence that stressed cats shed and succumb to respiratory viruses more readily, that improving welfare through reduced stress, positive handling and better housing lowers disease rates, and the role of mucosal immunity markers such as secretory IgA. It discusses how crowding, frequent moves and barren housing increase disease, while hiding, predictability, gentle interaction and single-room or low-stress housing protect health. The synthesis frames respiratory disease control as inseparable from welfare, arguing that stress reduction is a practical infection-control as well as an ethical priority.