Kennel cough, also known as canine infectious respiratory disease, formerly canine infectious tracheobronchitis, is an upper respiratory infection affecting dogs. There are multiple causative agents, the most common being the bacterium "Bordetella bronchiseptica" (found in 78.7% of cases in Southern Germany), followed by canine parainfluenza virus (37.7% of cases), and to a lesser extent canine coronavirus (9.8% of cases). It is highly contagious; however adult dogs may display immunity to reinfection even under constant exposure. Kennel cough is so named because the infection can spread quickly among dogs in the close quarters of a kennel or animal shelter.