Animals carrying the virus are introduced into susceptible herds. Contaminated facilities are used to hold susceptible animals. Contaminated vehicles are used to move susceptible animals. Raw or improperly cooked garbage containing infected meat or animal products is fed to susceptible animals. Susceptible animals are exposed to materials such as hay, feedstuffs, hides or biologics contaminated with the virus.
Susceptible animals drink contaminated water.
A susceptible cow is inseminated with material from an infected bull.