A review of the status of foot and mouth disease in South-East Asia and approaches to control and eradication.
The author presents reports of foot and mouth disease (FMD) submitted between 1996 and 2001 to the Office International des Epizooties (OIE: World organisation for animal health) Sub-Commission for FMD in South-East Asia. Of the ten countries in South-East Asia, FMD is endemic in seven (Cambodia, Laos, Malaysia, Myanmar, the Philippines, Thailand and Vietnam) and three are free of the disease (Brunei, Indonesia and Singapore). Part of the Philippines is also recognised internationally as being free of FMD. From 1996 to 2001, serotype O viruses caused outbreaks in all seven of the endemically infected countries. On the mainland, three different type O lineages have been recorded, namely: the South-East Asian (SEA) topotype, the pig-adapted or Cathay topotype and the pan-Asian topotype. Prior to 1999, one group of SEA topotype viruses occurred in the eastern part of the region and another group in the western part. However, in 1999, the pan-Asian lineage was introduced to the region and has become widespread. The Cathay topotype was reported from Vietnam in 1997 and is the only FMD virus currently endemic in the Philippines. Type Asia 1 has never been reported from the Philippines but was reported from all countries on the mainland except Vietnam between 1996 and 2001. Type A virus has not been reported from east of the Mekong River in the past six years and seems to be mainly confined to Thailand with occasional spillover into Malaysia. The distribution and movement of FMD viruses in the region is a reflection of the trade-driven movement of livestock. There is great disparity across the region in the strength and resources of the animal health services and this has a direct impact on FMD control. Regulatory environments are not well developed and enforcement of regulations can be ineffectual. The management of animal movement is quite variable across the region and much market-driven transboundary movement of livestock is unregulated. Formal quarantine approaches are generally not supported by traders or are not available. Vaccination is not used widely as a control tool because of the expense. However, it is applied by the Veterinary Services in Malaysia to control incursions of the disease and there is a mass vaccination programme for large ruminants in Thailand where the Government produces and distributes vaccine. Vaccination is also used by the commercial pig sector, particularly in the Philippines and Thailand.