tailieunhanh - Porcine reproductive and respiratory syndrome (PRRS)

Several clinic-based programs have been evaluated with experimental designs and three (out of five) of them showed some positive impacts on reproductive health outcomes (Danielson et al., 1990; DeLameter et al., 2000; Orr et al., 1996). Those programs that showed positive impacts included one-on-one counseling and delivered a clear message about appropriate reproductive health behaviors (Kirby, 2001). School-based health centers and condom-availability programs have not had experimental evaluations, and thus cannot be included in the “what works” section of our final table. Available studies suggest that these programs show mixed associations with reproductive health outcomes. | JW i 0 fervent Porcine reproductive and respiratory syndrome PRRS virulence jumps and persistent circulation in Southeast Asia Contributors Klaas Dietze Julio Pinto Sherrilyn Wainwright Christopher Hamilton Sergei Khomenko 1. ABSTRACT 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 1. Abstract 1 2. About the virus and the disease 1 3. PRRS and the pig sector global context and regional peculiarities 3 4. Pork value chains and risks of PRRS 4 5. The global context - drivers and risks 6 6. FAO response and main recommendations 7 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 significant 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. 2. ABOUT THE VIRUS AND THE DISEASE Aetiology and pathogenesis Porcine Reproductive and Respiratory Syndrome PRRS is a highly contagious viral disease that was first recognized almost simultaneously in Western Europe and North America in the late 1980s. It is caused by the Porcine Reproductive and Respiratory Syndrome Virus PRRSV a small single-stranded non-segmented RNA virus. The virion is enveloped spherical and ranges in size from 45 to 80 nm in diameter. PRRSV is differentiated into two genetically distinct genotypes Type 1 or