Location: Foreign Animal Disease Research
Title: Foot-and-mouth disease Authors
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: October 18, 2009
Publication Date: September 23, 2010
Citation: Grubman, M.J., Rodriguez, L.L., De Los Santos, T.B. 2010. Foot-and-mouth disease. In: Ehrenfeld, E., Domingo, E., Roos, R.P., editors. The Picornaviruses. Washington, DC: ASM Press. p. 397-410. Technical Abstract: Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals. An outbreak of FMD can have a significant economic impact because of the restrictions on international trade of susceptible animals and their products with FMD-free countries. In this chapter we discuss various aspects of the disease, the virus, and its interaction with the host. The viral agent FMD virus (FMDV), a member of the Picornaviridae, has a single-stranded positive-sense RNA genome encapsidated in an icosahedral particle containing 60 copies each of 4 structural proteins. We discuss the genome organization and describe its unique features as compared to other picornaviruses. Natural infection can occur by direct contact or indirectly by aerosol or contaminated material. The virus initially infects the respiratory system and rapidly replicates and spreads through the bloodstream 1-3 days postinfection causing vesicular lesions in the mouth, feet, and teats by 2-5 days. The virus enters cells by interaction with cellular integrins, is internalized in acidic endosomes, and virion RNA is released to begin the replication cycle. Infection results in lymphopenia and immune suppression, but a rapid neutralizing antibody response is induced and virus is cleared from the blood by 5-7 days and lesions heal within 1-2 weeks. Nevertheless, ruminants can become persistently infected for months to years and these animals are a potential source of transmission of the disease. We discuss studies examining the interaction of FMDV with cells of the host immune system and the role of various viral nonstructural proteins in inhibiting both the innate and adaptive immune response. We finally suggest areas of future research that we believe will lead us to a better understanding of viral pathogenesis and hopefully develop new improved disease control strategies.