After infection with Foot-and-mouth disease virus, there is an incubation period which usually lasts a few days, but occasionally up to two weeks.
Then there is a fever associated with general illness and in cows with a marked decline in milk production.
Soon after, blisters appear on the feet and in the mouth. Blistering in the mouth may cause stringy or foamy saliva and drooling, while foot blisters may cause lameness. Blisters rupture to form erosions that heal over a period of weeks.
Disease severity varies according to species, breed and pre-existing immunity.
Subclinical infection is common in small ruminants.
Myocarditis is possible in young animals and this can be associated with sudden death.