title: A study of edema disease in pigs in Vietnam with particular reference to the use of autovaccine for the prevention of disease.
abstract: Edema disease caused by Escherichia coli is one of the most common diseases in postweaning piglets throughout Vietnam. Verotoxigenic E. coli (VTEC) was isolated from 197 of 261 samples (75.5%). All isolates were confirmed by basic biochemical tests and carbohydrate fermentation characteristics. Of these, 70.1% of isolates are hemolytic, 45% isolates belonged to serotypes O149:K91, possessed the VT2e gene, and was the most predominant VTEC pathotype associated with edema disease in pigs. Serogroup O139 accounted for 30% of the isolates, followed by serogroup O138 and O141 (25%). In addition to VT2e gene, the ST (72.7%) and LT (52.7%) genes were also recognized. A total of 10 representative isolates were subjected to toxigenicity testing by intraperitoneal injection in mice and experimental infection in pigs. It was shown that 100% of the mice were killed 17-24 h post injection (p.i.). All pigs experimentally infected with challenge strains and developed typical symptoms of edema disease 36-72 h p.i. A multivalent killed whole-cells vaccine containing aluminum hydroxide was prepared from 5 VTEC strains. The vaccine was 100% safe when administered by the intramuscular route into the pigs. A field trial for over 100,000 pigs (21-90 days old) showed that vaccinated pigs were protected against edema disease at a level of 90% compared to 100% of pigs from unvaccinated groups.
authors.affiliation: Department of Bacteriology, National Institute of Veterinary Research, Dong da, 84 Hanoi, Vietnam. cuhuuphu@netnam.org.vn
authors.forename: Huu Phu
authors.initials: HP
authors.lastname: Cu
authors.forename: N N
authors.initials: NN
authors.lastname: Nguyen
authors.forename: N T
authors.initials: NT
authors.lastname: Do
authors.forename: X H
authors.initials: XH
authors.lastname: Nguyen
authors.forename: X T
authors.initials: XT
authors.lastname: Au
authors.forename: T H
authors.initials: TH
authors.lastname: Van
authors.forename: N Q
authors.initials: NQ
authors.lastname: Vu
authors.forename: T H
authors.initials: TH
authors.lastname: Dao
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology; D003967:Diarrhea / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary; D004488:Edema Disease of Swine / Q000382:microbiology* / Q000517:prevention & control*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D006461:Hemolysis; D019081:O Antigens / Q000032:analysis; D012703:Serotyping; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology / Q000517:prevention & control*; D014744:Vietnam; D014886:Weaning
chemical_list: D001428:Bacterial Vaccines; D019081:O Antigens