Lactogenic immunity and vaccines for porcine epidemic diarrhea virus (PEDV): Revisiting transmissible gastroenteritis virus (TGEV) vaccine concepts

摘要

The alphacoronavirus PEDV emerged in the US in April 2013 as a new, devastating diarrheal disease in swine. It spread rapidly throughout the US, infecting swine of all ages and causing major economic losses to the swine industry.1 It also spread to Canada and Mexico. Although the origin of US PEDV strains is unknown, genetically they resemble recent highly virulent strains from China (China AH2012 and CH/ZMZDY/11). In the 1970s PED first occurred in fattening pigs in European swine herds.5 No vaccines were used and PED has largely disappeared in Europe with only sporadic outbreaks. PED outbreaks occurred in Asian swine herds in the 1980s, spread widely, and then became endemic.6 Since 2010, severe PEDV outbreaks with increasingly virulent PEDV strains have been reported throughout Asia. For unknown reasons, vaccines based on European and other historic PEDV strains failed to control the recent virulent PEDV outbreaks in Asia.