Emergence of an exotic strain of serotype O foot-and-mouth disease virus O/ME-SA/Ind-2001d in South-East Asia in 2015.

The O/Middle East-South Asia (ME-SA)/Ind-2001 lineage of foot-and-mouth disease virus (FMDV) is endemic in the Indian subcontinent and has been reported in the Middle East and North Africa, but it had not been detected in South-East Asia (SEA) before 2015. This study reports the recent incursions of this viral lineage into SEA, which caused outbreaks in Vientiane Capital of Lao People's Democratic Republic (PDR) in April 2015, in Dak Nong, Dak Lak and Ninh Thuan Provinces of Vietnam from May to October 2015, and in Rakhine State of Myanmar in October 2015. Disease investigations were conducted during the outbreaks and followed up after laboratory results confirmed the involvement of FMDV O/ME-SA/Ind-2001 sublineage d (O/ME-SA/Ind-2001d). Affected host species included cattle, buffalo and pig, and all the outbreaks resolved within 2 months. Animals with clinical signs were separated, and affected premises were disinfected. However, strict movement restrictions were not enforced, and emergency vaccinations were only implemented in Vientiane Capital of Lao PDR and Dak Nong and Ninh Thuan Provinces of Vietnam. Clinical samples were collected from each outbreak and examined by nucleotide sequencing of the FMDV viral protein 1 coding region. Sequence analysis revealed that the O/ME-SA/Ind-2001d isolates from Lao PDR and Vietnam were closely related to each other and similar to viruses previously circulating in India in 2013. Viruses collected from Myanmar were divergent from viruses of the same sublineage recovered from Lao PDR and Vietnam but were closely related to viruses present in Bangladesh in 2015. These findings imply that at least two independent introductions of O/ME-SA/Ind-2001d into SEA have occurred. Our study highlights the transboundary nature of foot-and-mouth disease (FMD) and reinforces the importance of improved FMD surveillance and promotion of safer cross-border trade in SEA to control the risk of introduction and spread of exotic FMDV strains.

The dynamics and impact of foot and mouth disease in smallholder farming systems in South-East Asia: a case study in Laos.

There is a general lack of data on the different patterns of dynamics and impact of foot and mouth disease (FMD) in South-East Asia and the impact the disease has on different sectors, in particular the smallholder sector in which livestock play such an important role. A pilot study was conducted of a recent outbreak of FMD that swept across the southern part of Laos during the second half of 1999. The main objectives of the study were to investigate the possible routes of transmission of the disease and the impact of FMD on the predominantly smallholder rice/livestock production system of Savannakhet Province. The study was performed by group interviews of farmers in ten villages, located in five districts across the width of the Province, and of district and provincial veterinary officials. Results suggested that the infection had probably been introduced from the eastern border and had spread rapidly west, along a principal trading route of pigs, cattle and buffalo. In the process, many villages adjacent to this trading route became infected and the disease spread rapidly within infected villages. The disease had a significant impact on the agricultural system, but the impact would have been much greater had the epidemic occurred during the season of paddy field preparation. Mortality was observed in young buffalo, cattle and pigs, and long periods of morbidity were observed in buffalo, often requiring extended treatment. The sale of livestock for cash was severely restricted, creating additional repercussions on that sector. It was concluded that the most appropriate approach to FMD control would be to prevent infected animals from entering the principal trading routes for pigs, cattle and buffalo. This will require the involvement of all the stakeholders of the livestock industry, including traders and veterinary authorities. A further tactic to be considered would be to protect livestock systems adjacent to these trading routes by vaccination. An economic study of the market incentives of both traders and smallholders is recommended and this approach is advocated in other parts of South-East Asia where livestock trading routes present the major risk of FMD outbreaks.