Generally, outbreaks occur in settings where susceptible dogs are in close contact and where there is a high turnover of dogs in and out of facilities such as shelters, dog day care centers, boarding and training facilities, grooming shops, pet supply stores, dog parks, veterinary hospitals and dog shows. The disease is spread by direct contact with infected dogs via airborne particles generated from coughing and sneezing. The virus also contaminates kennel surfaces — walls, floors — food and water bowls, leashes and collars, and the clothing and hands of people who care for infected dogs. According to the AVMA, the virus can remain alive and be able to infect surfaces for up to 48 hours, clothing for 24 hours, and hands for 12 hours. The incubation period is usually two to four days from exposure to onset of symptoms, and dogs are highly contagious during this time when they do not show signs of illness.