Porcine reproductive and respiratory syndrome ( PRRS ) virulence jumps and persistent circulation in Southeast Asia

Since 2006, the pig sectors of China, Viet Nam, the Philippines and Thailand, have been continuously hit by atypical highly virulent strains of Porcine Reproductive and Respiratory Syndrome (PRRS). In 2010, the disease affected additional countries in Southeast Asia, including Lao People’s Democratic Republic and Cambodia, while causing a higher than expected epidemic wave in Thailand, underlining the regional burden PRRS represents today. Clinical symptoms of PRRS include reproductive failure in breeding stock and respiratory tract illness in young pigs. The signifi cant economic losses to swine producers comprise an overall estimated fatality rate of approximately 20% (up to 100% in single production units) for the newly emerged virulent strains. For East and Southeast Asia, with the highest pig densities worldwide, the persistence of this disease poses a growing socioeconomic concern. Given the structure of the production sector, additional virulent pathogens may soon follow.