Authors : Angel Lozada De Gante , E. Pablo Correa Giron , Aleyda Romero Diaz , Susana Mendoza Elvira , Maria Antonia Coba Ayala , Laura Zapata Salinas , Horacio Lara Puente , Guadalupe Socci Escatel , Jose Galaviz Rodriguez , Xochitl G. Montalvo Aguilar and Abel Ciprian Carrasco
Abstract: In 2006, a study was carried out to determine whether the attenuated live virus vaccine PAV-250 against Classical Swine Fever (CSF) interacts as a triggering factor in the presentation, pathogenesis and course of the disease caused by the virulent virus of Porcine Reproductive and Respiratory Syndrome (PRRS). Seven Groups (G) were formed and 5 SPF piglets were randomly allocated to each group: G1, negative control; G2, positive control inoculated with PRRSv; G3, vaccinated with PAV-250; G7 and G5, vaccinated with PAV-250 on days-14 and -7, respectively and inoculated with PRRSv on day 0; G8 and G6, inoculated with PRRSv on days -14 and -7, respectively and vaccinated with PAV-250 on day 0. Clinical signs, total white blood cell count by the blood count technique, antibody profile against CSF virus with the ELISA technique and identification of viral nucleic acids by nested RT-PCR were evaluated. Group 6 and 8 showed an increase in clinical signs and groups 5 and 7 did not show apparent clinical signs; body temperature following inoculation increased by 1.5°C on average during 5 days and it subsequently returned to normal (p>0.005). Group 5 and 7 showed post-vaccination leukopenia and post-inoculation leukocytosis and post-vaccination and post-inoculation leukopenia was detected in groups 6 and 8 (p<0.005). In the antibody profile against CSF in groups 5 and 7, antibody rates of 80 and 86%, respectively, were detected; group 6 and 8 had mean antibody rates of 62 and 60%, respectively (p<0.001). When, challenged with CSF virulent Ames strain, these percentages remained constant. Pigs previously vaccinated with the PAV-250 strain did not show clinical and pathological changes when they were infected with the PRRS virus, however, in pigs not vaccinated against CSF and infected with PRRS virus and subsequently with CSF pathogenic virus, the disease worsened, with a 100% mortality rate.
Angel Lozada De Gante , E. Pablo Correa Giron , Aleyda Romero Diaz , Susana Mendoza Elvira , Maria Antonia Coba Ayala , Laura Zapata Salinas , Horacio Lara Puente , Guadalupe Socci Escatel , Jose Galaviz Rodriguez , Xochitl G. Montalvo Aguilar and Abel Ciprian Carrasco , 2009. Partial Protection in Swine Challenged with Porcine Reproductive and Respiratory Syndrome Virus, Vaccinated Against Classical Swine Fever (PAV-250 Vaccine). Journal of Animal and Veterinary Advances, 8: 1052-1062.