Introduction of the disease to such areas is thought to have resulted initially from the free movement of infected animals from warmer, higher incidence areas. (priory.com)
The virus can be easily spread through contact with infected animals in boarding kennels, dog parks, doggie daycare, rescues, and anywhere dogs interact. (petpantrylc.org)
It is transmitted by bites or saliva from infected animals. (arkvet.vet)