原文：
Repeat PEDv outbreak confirmed at Indiana farm
Date: 2014-05-29
Second outbreak at farm disproves theory that pigs develop immunity to PEDv after infection
Porcine epidemic diarrhea (PED) virus has proven more difficult to contain than veterinarians earlier thought, as one Indiana farm confirmed a second outbreak of PED virus. The farm did not want to be publicly identified, but authorized its veterinarian, Matt Ackerman, to speak on its behalf.
The state and federal effort to stamp out PED virus had operated on an assumption that a pig, once infected, develops immunity and will not be afflicted by the disease again for at least a few years, according to a Reuters report. Likewise, farms that had endured the disease were not known to suffer secondary outbreaks. The Indiana farm is the first to publicly confirm a repeat outbreak.
In the Indiana case, genetic sequencing showed the "exact same strain" of PED virus hit pigs at the farm in May 2013 and again in March 2014, said Ackerman, who collected samples from the farm. Piglets born to sows that were infected for a second time have a death rate of about 30 percent, compared with a nearly 100 percent death rate among newborn piglets during the first outbreak, he said.
Ackerman did not know why the sows on the Indiana farm were re-infected after being exposed to the virus during the original outbreak last year. At the time, they were about six months to a year old. The sows are having piglets and passing limited immunity on to their offspring, he said. Ackerman added that the farm does an “excellent job of sanitation,” making it more puzzling as to how a repeat outbreak of PED virus could occur.
IP卡
狗仔卡
[信息未更新]
發表於 2014-6-2 16:13:57
提升卡
置頂卡
沉默卡
喧囂卡
變色卡
搶沙發
千斤頂
顯身卡
發表於 2014-6-2 17:22:13
樓主
