The average incubation period for FMD is between three and eight days, but can be up to two weeks in some cases. The disease is rarely fatal but may kill very young animals. Animals that survive are often debilitated and experience severe loss in milk or meat production. It also can infect animals through contaminated hay or feedstuffs and if susceptible animals drink from a common water source. The virus can harbor in the human nasal passages for as long as 28 hours.
Wind also can spread the virus through the air.
If FMD were to occur in the U.S., the degree of economic impact would depend on how quickly the disease was identified and effective control measures put in place. If it was controlled quickly and eradicated, as was the case with the last outbreak in the U.S. in 1929, the damage might be small. However, if the disease became widespread, the economic loss could easily be many billions of dollars. The most serious effects would result from the necessity of destroying animals in order to eradicate the disease. In addition, countries with FMD experience restricted exports.