Often blisters may not be observed because they easily rupture, leading to erosions. Ruptured vesicles discharge either clear or cloudy fluid and leave raw, eroded areas surrounded by ragged fragments of loose tissue. Sticky, foamy, stringy saliva is produced. Consumption of feed is reduced because of painful tongue and mouth lesions. Lameness with reluctance to move is often observed.
Abortions often occur.
Milk flow of infected cows drops abruptly. Conceptions rates may be low. FMD is one of the most difficult animal infections to control. Because the disease occurs in many parts of the world, there is always a chance of its accidental introduction into the United States. Animals and animal byproducts from areas known to be infected are prohibited entry into this country.