Emergency Epidemiological Investigation on an Entry Porcine Reproductive and Respiratory Syndrome Outbreak
Since June 4,2023,piglets introduced to a pig contract farm in Jintang County of Sichuan Province had abnormally died one after another.In order to find out the cause of the disease,analyze its source and to evaluate possible risk of transmission,an emergency epidemiological investigation was conducted at the site.A total of 2 200 piglets were introduced to the farm in 4 batches from May 20,2023 to May 30,2023,of which 222 piglets were diseased including 124 died as of July 14,with an attack rate of 10.09%and a mortality rate of 55.86%.Based on field clinical diagnosis,pathological dissection of dead pigs,laboratory test and corroboration by intervention treatment effect,it was comprehensively determined that the abnormal death was caused by infection with porcine reproductive and respiratory syndrome virus(PRRSV).It was investigated and traced that no live pig was transported out of the infected farm,and no similar outbreak was found in other farms epidemiologically linked to the farm,so the risk of disease transmission was determined to be low.Traceability investigation results revealed that porcine reproductive and respiratory syndrome(PRRS)outbreak had occurred on the origin genetic farm from where the infected piglets were introduced,formal production and management was applied on the infected farm as investigated at field level,and no any abnormal death was found on its surrounding farms,the outbreak was therefore determined to be caused by the virus carried by introduced piglets.Such entry outbreak should be avoided as much as possible through identifying disease status on genetic farms prior to introduction by target farms and strengthening introduction quarantine.
emergency epidemiological investigationPRRSpigletsudden death
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