Efficacy of a Mycoplasma hyopneumoniae bacterin in pigs challenged with two contemporary pathogenic isolates of M hyopneumoniae
Erin L. Strait, DVM; Vicki J. Rapp-Gabrielson, MS, PhD; Barbara Z. Erickson, MS; Richard B. Evans, PhD; Lucas P. Taylor, MS; Therese K. Yonkers, BS; Rob L. Keich, MS; Rika Jolie, DVM, PhD, MBA; Eileen L. Thacker, DVM, PhD, Diplomate ACVM
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Objective: To evaluate the efficacy of a Mycoplasma hyopneumoniae (M hyo) bacterin against two contemporary field isolates of M hyo.
Materials and methods: Two challenge studies were performed in which pigs received two doses of either saline (nonvaccinated groups) or an M hyo bacterin (vaccinated groups), followed 3 weeks later by intratracheal inoculation of each pig with one of two M hyo field isolates. Necropsies were performed 28 or 30 days post challenge. Vaccine efficacy was determined by evaluating macroscopic lung lesions, DNA levels of M hyo in bronchial alveolar lavage fluids (BALF), M hyo-specific immunoglobulin (Ig)A and IgG antibodies, and serum antibodies measured by the Tween 20 and DAKO enzyme-linked immunosorbent assays.
Results: The percentage of macroscopic lung lesions and concentration of M hyo DNA in BALF samples post challenge with either isolate were significantly less in vaccinated than in nonvaccinated pigs (P < .05). M hyo-specific mucosal IgA and IgG antibody levels in BALF were significantly higher in the vaccinated pigs than in the nonvaccinated pigs.
Implications: Under the conditions of these studies, fewer M hyo organisms and fewer macroscopic lesions of pneumonia are observed when pigs are vaccinated with an M hyo bacterin prior to challenge with contemporary virulent M hyo field isolates. Vaccination is an effective tool to reduce pneumonia induced by M hyo, although more studies are needed to determine protection against a wide range of field isolates.
Keywords: Mycoplasma hyopneumoniae, vaccine, mycoplasmal pneumonia, lung consolidation
Cite as: Strait EL, Rapp-Gabrielson VJ, Erickson BZ, et al. Efficacy of a Mycoplasma hyopneumoniae bacterin in pigs challenged with two contemporary pathogenic isolates of M hyopneumoniae. J Swine Health Prod 2008;16(4):200-206.
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