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　　US - The Swine Health Information Center urges continued biosecurity as immunity to PED resulting from exposure dissipates, writes Bruce Cochrane.Although the level of Porcine Epidemic Diarrhea in the US is low, there is still virus circulating.Dr Paul Sundberg, the Executive Director of the Swine Health Information Center, says improved biosecurity and a buildup of natural immunity as herds have been exposed have helped reduce the level of PED but that natural immunity may be short lived.

　　布魯斯·科克倫(Bruce Cochrane)寫道，由于豬流行性腹瀉的免疫露餡消散，生豬健康信息中央敦促持久的生物安全。盡管豬流行性腹瀉病在美國嚴重程度較低，但仍有病毒傳播。生豬健康信息中央的執(zhí)行理事保羅桑德博格(Paul Sundberg)博士說，“由于自然免疫十分暫時，提高生物安全和積累自然免疫能幫助露餡在戶外的豬群減少豬流行性腹瀉這種程度疾病的危害”。