**5. Epidemiology of the FMDV**

The epidemiology of FMDV includes the source of infection and the route of transmission. Foot-and-mouth disease (FMD) has the epidemiological characteristics of rapid epidemic, wide spread, and acute onset. The main source of infection is sick animals and the incubation period of animals, the incubation period 1–7 days, the average 2-4 days. Foot-and-mouth disease mainly affects artiodactyls, mainly cattle, especially calves, followed by pigs, camels, sheep, goats, and wild animals. In addition, the virus was found in blisters, milk, urine, saliva, tears, and feces of sick animals. The transmission route is extensive, which can be transmitted to susceptible animals either by direct contact or by indirect contact (e.g., secretions, feces, animal products, contaminated air, feed, etc.). Foot-and-mouth disease occurs frequently in the spring and fall. Clinical features are blister rash in the oral mucosa, hoof, and breast skin. This disease has broken out in the world several times, causing huge political and economic losses.
