Efficacy of an attenuated European subtype 1 porcine reproductive and respiratory syndrome virus (PRRSV) vaccine in pigs upon challenge with the East European subtype 3 PRRSV strain Lena.
The efficacy of a commercial attenuated European subtype 1 PRRSV vaccine was evaluated upon challenge with the East European subtype 3 PRRSV strain Lena (83.3% nucleotide identity). Two vaccination experiments were carried out. Four- and seven-week-old pigs were vaccinated with the modified-live vaccine. Upon vaccination, virus specific IPMA antibodies were detected in all vaccinated animals with titers ranging from 10(2.8) to 10(4.6). No virus neutralizing (VN) antibodies were detected after vaccination. Eight (exp. 1) or six (exp. 2) weeks after vaccination, pigs were challenged with 10(6) (exp. 1) resp. 10(5) (exp. 2) TCID50 of the European subtype 3 PRRSV Lena. Upon challenge, non-vaccinated animals showed fever during 5.1 (exp. 1) or 7.7 (exp. 2) days. In vaccinated pigs, the duration of fever was reduced by 1.8 (exp. 1) or 3.5 (exp. 2) days. The modified-live virus vaccine reduced the mean duration of nasal shedding and viremia. In non-vaccinated pigs, virus shedding lasted 5.8 days (exp. 1), resp. 8.3 days (exp. 2). This period was reduced to 3.6 (exp. 1), resp. 3.0 (exp. 2) days in vaccinated animals. Viremia was observed during a shorter period in vaccinated (exp. 1: 7.4 days, exp. 2: 4.8 days) than in non-vaccinated groups (exp. 1: 11.8 days, exp. 2: 12.3 days). Starting from 5 days post challenge, virus titers in nasal secretions and sera were significantly lower in vaccinated animals (P<0.05). Virus-neutralizing antibodies were detected at low titers (≤ 16) after 7 days post challenge in vaccinated animals and 28 days post challenge in control animals. In conclusion, it can be stated that vaccination of pigs with an attenuated European subtype 1 vaccine provides a partial protection against a subsequent exposure to the highly pathogenic East European subtype 3 PRRSV strain Lena.
Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Electronic address: ivan.trus@ugent.be.
Ivan
I
Trus
Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Electronic address: caroline.bonckaert@ugent.be.
Caroline
C
Bonckaert
Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Electronic address: karen.vandermeulen@ugent.be.
Karen
K
van der Meulen
Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Electronic address: hans.nauwynck@ugent.be.
Hans J
HJ
Nauwynck
D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D056738:Cross Protection; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus; D034421:Sus scrofa; D013552:Swine; D014613:Vaccines, Attenuated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*; D014766:Viremia / Q000276:immunology; D017201:Virus Shedding
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines