Infected animals exhale large amounts of the virus, which can infect other animals through the respiration or oral routes. Wind and air currents can carry the virus for long distances. All excretions and secretions from an infected animal contain the virus and the virus may be present in milk and semen for up to four days before any symptoms are present. FMD has been transmitted from cow to calf via milk and milk tankers carrying infected milk have spread the disease between farms. The FMD virus can survive in dry fecal matter for 14 days in the summer, for up to 6 months in slurry in the winter, in urine for 39 days and on and in the soil for 3 days in the summer to up to 28 days in the winter.
Transmission also occurs from contaminated clothes or footwear moving from farm to farm.
The FMD virus is sensitive to acid and alkaline pH. So, sodium hydroxide, sodium carbonate and citric or acetic acid are effective as disinfectants. The incubation period for FMD is 2 to 14 days depending on the conditions of the animal and the dose and strain of the virus. FMD has often been mis-diagnosed as Vesicular Stomatitis and other vesicular diseases and IBR, BVD, Bluetongue MCF and Contagious Ecthyma. Painful blisters then erupt on the tongue, dental pads, gums, lips, above the hoof wall and between the hooves. Blisters can also be found on teats and udders and on areas of skin subject to trauma.