Foot-and-Mouth Disease Situation worldwide and major epidemiological events in 2005-2006

Foot-and-mouth disease (FMD) is the most contagious transboundary animal disease (TAD) affecting cloven hoofed animals. Significant economic losses are produced by its high morbidity and the export trade restrictions imposed on affected countries. There are seven recognised serotypes of FMD (O, A, C, Asia , SAT , SAT 2 and SAT 3), which differ in distribution across the world. Serotypes A and O have the widest distribution, occurring in Africa, Asia and South America. Types SAT , 2 and 3 are currently restricted to Africa only and Asia to Asia; the capacity to invade free areas is common to all types and periodically SATs are introduced into the Near East, and Asiainto western and eastern parts of Eurasia. Infection or vaccination against one serotype does not provide protection against the other serotypes. Since surveillance intensity and reporting is less in the least developed regions, traditional mapping of FMD outbreaks underestimates the presence and incidence of the disease, especially in the most heavily affected locations. Therefore FAO has used an approach based on expert opinion over the last 5 years, and on global livestock distributions, to map the expected FMD incidence and prevalence for the major species. For cattle, the assessment suggests that the highest FMD challenge is in sub-Saharan Africa and in south Asia (Figure ). These areas can provide a long term reservoir for neighbouring regions, as can be seen from epidemiological events in recent years. The years 2005-2006 have seen some dramatic, in places devastating events in FMD epidemiology in the Near East, Far East and Africa. Since these each occurred in areas not considered officially free (by the OIE) of FMD, international attention has been limited compared to the epidemic in north-west Europe in 200 . In the same period, three incursions of FMD were reported in countries or zones declared officially free by the OIE in Argentina (type O in february 2006), Brazil (type O in september and october 2005) and Botswana (type SAT 2 in april 2006). The unstable epidemiological situation in endemic regions is highlighted by this review, which analyses the distribution of the FMD serotypes in 2004-2006, and assesses the risks posed by FMD in specific regions, including the emergence and spread of a serotype A virus in the Near East; the resurgence of FMD different lineages of type Asia in Asia (China and Vietnam) and part of Russia and Mongolia; the introduction of type A into Egypt from sub-Saharan areas and the increased distribution of outbreaks caused by type O in the Great Lakes region of Africa. The situation of FMD in infected areas indicates that FMD types continually spread within endemic regions, and periodically and unpredictably give rise to virus types that “break immunity” and cause regional epidemics. Prevention of FMD epidemics requires a good understanding of the virus types within a country or region and sufficient surveillance to identify emergent infections before regional spread occurs.