There is growing evidence that this is occurring to a significant degree by contact with animals in which disease has not yet been clinically recognised though they are infected. Disease may also be introduced to farms or groups of animals by vehicles, people and equipment which have been inadvertently contaminated. In cattle and pigs the signs of disease are usually readily seen. This is not always the case in sheep. There is a chance that some sheep in your flock may be infected without you realising it.
Infected animals pass the virus out in dung, urine, saliva, breath and fluid from burst blisters.
Contact does not have to be direct such as examining or lambing an infected animal. Indirect contact includes driving a vehicle over a track where infected sheep have walked or putting equipment down on straw where sheep have been bedded or lambed. A small particle of infected dung trapped in the tread of tyres or boots is a typical example of how the virus may be inadvertently moved between farms. Although the disease may not yet have been confirmed close to your farm or livestock, there is the possibility that disease may be incubating in animals almost anywhere in the country.