Rev. sci. tech. Off. int. Epiz., 2012, 31 (3), 777-787 Probability of introducing foot and mouth disease into the United States via live animal importation G.Y. Miller (1)* , J. Ming (2) , I. Williams (1) & R. Gorvett (2) 1) Department of Pathobiology, College of Veterinary Medicine, University of Illinois, 2001 S. Lincoln Ave, Urbana, IL 61802, United States of America 2) Department of Mathematics, College of Liberal Arts and Sciences, University of Illinois, 1409 W Green St, Urbana, IL 61801, United States of America *Corresponding author: gymiller@illinois.edu Summary Foot and mouth disease (FMD) continues to be a disease of major concern for the United States Department of Agriculture (USDA) and livestock industries. Foot and mouth disease virus is a high-consequence pathogen for the United States (USA). Live animal trade is a major risk factor for introduction of FMD into a country. This research estimates the probability of FMD being introduced into the USA via the legal importation of livestock. This probability is calculated by considering the potential introduction of FMD from each country from which the USA imports live animals. The total probability of introduction into the USA of FMD from imported livestock is estimated to be 0.415% per year, which is equivalent to one introduction every 241 years. In addition, to provide a basis for evaluating the significance of risk management techniques and expenditures, the sensitivity of the above result to changes in various risk parameter assumptions is determined. Keywords Foot and mouth disease – Import – Livestock – Probability – Risk – United States. Introduction Foot and mouth disease (FMD) continues to be a disease of major concern for the United States Department of Agriculture (USDA) and livestock industries. The reasons for this concern are complex and interrelated. First, FMD is a disease that occurs with regular frequency around the world. In the spring of 2011, there were 177 Member Countries of the World Organisation for Animal Health (OIE); 65 countries were ‘FMD free where vaccination is not practised’, one country was ‘FMD free where vaccination is practised’, ten countries had zones that were ‘FMD free where vaccination is not practised’, and six countries had zones that were ‘FMD free where vaccination is practised’, with the remaining countries considered to be affected by FMD (28). Second, although the USA has been free of FMD since 1929 the possibility of an outbreak is very real, and taken seriously by US officials. Planning and preparedness for the possible introduction of FMD is a continual and ongoing process. A recent evaluation of the preparedness of the USA for an FMD outbreak, carried out by veterinarians and officials who could act as ‘Incident Commanders’ in the event of such an outbreak, suggested that there is a need for improved response planning (20). The National Center for Animal Health Emergency Management (NCAHEM), which is part of the Veterinary Services at USDA, updated the response plans for FMD in 2010 and will receive public comment on the modified plans (26). Third, FMD virus is a high-consequence pathogen for the USA, mainly because of the potential economic impacts that would be associated with outbreaks. These economic impacts are tied primarily to the trade implications for countries that have the disease and the methods used to control and eradicate the disease. Industries that are not directly connected to agriculture can also suffer substantial economic losses (21). The FMD outbreak in the United Kingdom in 2001 saw a large economic impact associated with tourism losses (1). Were an outbreak of FMD to take place in the USA, two actions could generally be expected to occur simultaneously. The FMD-free segment of the world would immediately restrict imports from the USA of any live