Impact of a porcine epidemic diarrhea outbreak on swine productivity in Japan: a retrospective cohort study

YAMANE, Itsuro; YAMAZAKI, Hisanori; ISHIZEKI, Sayoko; WATANABE, Yugo; OKUMURA, Hanako; OKUBO, Mitsuharu; KURE, Katsumasa; HAYAKAWA, Yuiko; FURUKAWA, Makoto; OOI, Munetaka; MIZUKAMI, Yoshihiro; ITO, Mitsugu

Porcine epidemic diarrhea (PED) was first reported in the United Kingdom in 1971 [16] . The clinical signs of PED are acute diarrhea, vomiting, dehydration and high mortality in neonatal piglets, resulting in significant economic losses [5] . Outbreaks of PED continued in Europe during the 1980s and 1990s [5] . In October 2010, a severe outbreak of PED occurred in >10 provinces in southern China, and >1,000,000 piglets died [13] . PED outbreaks were subsequently reported in other Asian countries, including Korea [6] , Taiwan [7] and Thailand [11] , and were then reported in European countries, including Germany in 2014 [4] and Belgium in 2015 [15] . PED was identified in the United States for the first time in May 2013 [12] and spread rapidly to approximately 50% of the US swine breeding herds from July 2013 to July 2014 [3] . The PED isolates collected in the United States were genetically similar to those obtained in Asian [2, 6, 7, 10] and European countries [4, 15] , indicating potential trans-continental transmission.