Although the disease is not known to be transmissible to humans, it is highly contagious among deer, elk and related animals, which can shed infectious misfolded prion proteins in their saliva, urine and faeces. Animals infected with CWD have been found in more than 20 states in the United States and 2 provinces in Canada. The disease has also been detected in captive animals in South Korea, which imported CWD with a shipment of live elk brought into the country for farming in the late 1990s.