title: Experimental infection of a US spike-insertion deletion porcine epidemic diarrhea virus in conventional nursing piglets and cross-protection to the original US PEDV infection.
abstract: Although the original US porcine epidemic diarrhea virus (PEDV) was confirmed as highly virulent by multiple studies, the virulence of spike-insertion deletion (S-INDEL) PEDV strains is undefined. In this study, 3-4 day-old conventional suckling piglets were inoculated with S-INDEL PEDV Iowa106 (4 pig litters) to study its virulence. Two litters of age-matched piglets were inoculated with either the original US PEDV PC21A or mock as positive and negative controls, respectively. Subsequently, all pigs were challenged with the original US PEDV PC21A on 21-29 days post-inoculation (dpi) to assess cross-protection. All S-INDEL Iowa106- and the original US PC21A-inoculated piglets developed diarrhea. However, the severity of clinical signs, mortality (0-75%) and fecal PEDV RNA shedding titers varied among the four S-INDEL Iowa106-inoculated litters. Compared with the original PC21A, piglets euthanized/died acutely from S-INDEL Iowa106 infection had relatively milder villous atrophy, lower antigen scores and more limited intestinal infection. Two of four S-INDEL Iowa106-infected sows and the original PC21A-infected sow showed anorexia and watery diarrhea for 1-4 days. After the original PC21A challenge, a subset (13/16) of S-INDEL Iowa106-inoculated piglets developed diarrhea, whereas all (5/5) and no (0/4) pigs in the mock and original PC21A-inoculated pigs had diarrhea, respectively. Our results suggest that the virulence of S-INDEL PEDV Iowa106 was less than the original US PEDV PC21A in suckling pigs, with 100% morbidity and 18% (6/33) overall (0-75%) mortality in suckling pigs depending on factors such as the sow's health and lactation and the piglets' birth weight. Prior infection by S-INDEL Iowa106 provided partial cross-protection to piglets against the original PC21A challenge at 21-29 dpi.
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. lin.1903@osu.edu.
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Lin
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. annamalai.5@osu.edu.
authors.forename: Thavamathi
authors.initials: T
authors.lastname: Annamalai
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. liuxinsheng@caas.cn.|State Key Laboratory of Veterinary Etiological Biology, OIE/National Foot-and-Mouth Disease Reference Laboratory of China, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China. liuxinsheng@caas.cn.
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Liu
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. gao.898@osu.edu.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. lu.608@buckeyemail.osu.edu.
authors.forename: Zhongyan
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. tholothvirol@mans.edu.eg.|Department of Virology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt. tholothvirol@mans.edu.eg.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Tholoth
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. hu.1092@osu.edu.
authors.forename: Hui
authors.initials: H
authors.lastname: Hu
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. saif.2@osu.edu.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Saif
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA. wang.655@osu.edu.
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000818:Animals; D018352:Coronavirus Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D056738:Cross Protection; D003967:Diarrhea / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D005243:Feces / Q000821:virology; D054643:INDEL Mutation; D053485:Porcine epidemic diarrhea virus / Q000472:pathogenicity* / Q000502:physiology*; D017422:Sequence Analysis, DNA / Q000662:veterinary; D064370:Spike Glycoprotein, Coronavirus / Q000235:genetics* / Q000378:metabolism; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000821:virology; D014774:Virulence
chemical_list: D064370:Spike Glycoprotein, Coronavirus