Mycoplasma hyopneumoniae (Mhyo) causes mycoplasmal pneumonia, an economically important disease of swine. Serodiagnosis of Mhyo is based on the current available commercial enzyme immunoassays for detection of swine antibodies against Mhyo, which are the indirect enzyme-linked immunosorbent assay (ELISA) and the blocking ELISA (B-ELISA). Because of the limited information available for these ELISAs, these 2 assays were compared by testing 347 serum samples collected from vaccinated pigs at 0, 13, 28, 43, and 62 days postimmunization (DPI), 50 samples from nonvaccinated pigs, and 1,013 field serum samples. The results of comparison study showed that the specificity for both ELISAs was 99.2% generated from 139 non-vaccinated negative samples. The sensitivities for indirect ELISA generated from samples collected from animals that received the vaccine at DPI 13, 28, 43, and 62 were 0%, 95.7%, 88.4%, and 92.6%, respectively, whereas the sensitivities for B-ELISA were 0%, 98%, 100%, and 97%, respectively. The overall agreement of 96.7% and 80.3% was generated between 2 ELISAs from negative and vaccinated pigs and from field samples, respectively.

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Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), is a disease of great economic importance for the swine industry worldwide. PRRSV is a member of the family Arteriviridae in the order Nidovirales. PRRSV is an enveloped positive single-stranded RNA virus, which encodes an approximately 4,000-aminoacid large replicase polyprotein (open reading frame [ORF] 1 a and 1 b) and six structural proteins of 130 to 265 amino acids (ORFs 2 to 7). Three of these structural proteins have been identified as envelope (25 kDa), matrix (19 kDa), and nucleocapsid (15 kDa) proteins, i.e. GP5, M, and N proteins, respectively. PRRSV infection poses a challenge to current serodiagnostic and vaccination strategies. A better understanding of the mechanisms that regulate immunity to this virus will aid in the development of more effective vaccines, as well as serodiagnostic CHAPTER 3. Swine Auto-anti-Idiotypic Antibody Specific for Antibodies Against GPS Antigen of Porcine Reproductive and Respiratory Syndrome Virus Elicits Specific