title: Effects of challenge with a virulent genotype II strain of porcine reproductive and respiratory syndrome virus on piglets vaccinated with an attenuated genotype I strain vaccine.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is endemic in most parts of Asia, where genotype I and II strains of diverse virulence may coexist. This study evaluated the outcome of infection with a highly virulent Asian genotype II PRRSV isolate in piglets vaccinated with a genotype I vaccine. Twenty-one 3-week-old piglets were divided in three groups: Pigs in group V (n=8) were vaccinated with an attenuated genotype I commercial PRRSV vaccine, while pigs in group U (n=8) and a control group (group C; n=5) were unvaccinated; 6 weeks later, pigs in groups V and U were challenged intranasally with a highly virulent strain of genotype II PRRSV (1×10(5) 50% tissue culture infectious doses/mL), while pigs in group C received a placebo. Over a period of 21 days after challenge, vaccinated pigs had significantly lower mortality (0/8 versus 2/8), fewer days of fever, a lower frequency of catarrhal bronchopneumonia, higher weight gains (13.4 versus 6.6 kg) and lower levels of viraemia compared to unvaccinated challenged pigs. Immunisation with a genotype I attenuated PRRSV vaccine provided partial protection against challenge with a highly virulent genotype II strain.
authors.affiliation: Laboratorios Hipra S.A., Avda La Selva 135, Amer, Girona 17170, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Roca
authors.forename: M
authors.initials: M
authors.lastname: Gimeno
authors.forename: S
authors.initials: S
authors.lastname: Bruguera
authors.forename: J
authors.initials: J
authors.lastname: Segalés
authors.forename: I
authors.initials: I
authors.lastname: Díaz
authors.forename: I J
authors.initials: IJ
authors.lastname: Galindo-Cardiel
authors.forename: E
authors.initials: E
authors.lastname: Martínez
authors.forename: L
authors.initials: L
authors.lastname: Darwich
authors.forename: Y
authors.initials: Y
authors.lastname: Fang
authors.forename: J
authors.initials: J
authors.lastname: Maldonado
authors.forename: R
authors.initials: R
authors.lastname: March
authors.forename: E
authors.initials: E
authors.lastname: Mateu
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D005838:Genotype; D008171:Lung Diseases / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D016133:Polymerase Chain Reaction; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D013552:Swine; D014613:Vaccines, Attenuated / Q000276:immunology / Q000627:therapeutic use; D014765:Viral Vaccines / Q000276:immunology* / Q000627:therapeutic use; D014774:Virulence
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines