How does the virus spread through so many farms and herds so quickly and can it establish itself permanently?
• Animals with active infection, with or without clinical signs, are the major source of continuing spread of the virus. They can produce massive amounts of virus. Having multiplied in one animal’s body the virus must find a susceptible host in order for FMD to continue to spread. The major route of spread within a herd or flock is by direct contact, e.g. infected animals breathing out virus and the animals next to them breathing it in. A major way in which the virus is spread from one farm to another is by animals which are not visibly diseased being moved. However indirect contact is also important (airborne spread between herds occurs less often). FMD can survive for some time in the environment, particularly when attached to animal debris, so long as it is not exposed to acid or alkaline conditions. In this way, FMD virus moves from the infected animal to the external environment and then on to another susceptible animal. It will then remain active in a region so long as there are
