- 1 minute, 26 seconds
- Expertise article
- P. Renson, C.Fablet, M. Le Dimna, S.Mahe, F. Touzain, Y. Blanchard, F. Paboef, N. Rose, O. Bourrz
Introduction
PRRS virus (PRRSV) causes huge economic losses fot the swine industry for the swine industry worldwide. For several years highly pathogenic strains that induce even higher damages have emerged. One of this strain (Lena, geotype 1.3), isolated in Eastern Europe is threatening the Western Europe pig industry. TO prepare the possible emergence of this strain Western Europe, we evaluated and compared the protection provided by the immunization ith a French PRRSV field strain, a new genotype 1 or genotype 2 modified live virus (MLV) vaccine, upon challenge with the Lena strain.
Materials and Methods
Forty one, 4-weeks-old piglets coming from a nucleus herd were hosed in our biosecurity level-3 animal facilities. At 6 weeks of age, 7 pigs were inoculated with the genotype 1. 1 French strain 'Finistère' (Fini); 9 piglets were vaccinated with Ingelvac PRRSFLEX® EU (MLV1) and 9 piglets were vaccinated with Ingelvac PRRS MLV (MLV2). Four weeks later the 3 groups of immunized animals as well as a non-immunized group were challenged intranasally with the Lena strain. The clinical, virological and immunological parameters were followed during 5 weeks after Lena challenge.
Results
Immunization with Fini, MLV1 or MLV2 strains shortened the Lena-induced hyperthermia. In the Fini group a positive impact was also demonstrated for the growth performances. The level of Lena viremia was reduced for all the immmunized groups (significantlly for Fini and MLV2). This reduction of Lena viremia wa correlated with the level of Lena-specific IFNg-secreting cells.
Conclusion
A commercial MLV vaccine of genotype 1 or 2, as well a field strain of genotype 1. 1 could provide a partial clinical and virological protection upon a challenge with the Lena strain. The slightly higher level of protection prvided by the field strain was associated with a better cell-mediated immune response.