Reduced lung lesions in pigs challenged 25 weeks after the administration of a single dose of Mycoplasma hyopneumoniae vaccine at approximately 1 week of age.
Two independent studies assessed the duration of immunity of an inactivated adjuvanted Mycoplasma hyopneumoniae vaccine against mycoplasmal pneumonia in seronegative (study A, n=52) and seropositive (study B, n=52) pigs. The pigs were allocated randomly to treatment and were then injected with a single dose of either the vaccine or a placebo at approximately 1 week of age. Twenty-five weeks after treatment administration, the pigs were challenged with a virulent strain (LI 36, Strain 232) of M. hyopneumoniae and the extent of lung lesions consistent with mycoplasmal pneumonia was assessed 4 weeks later. In study A, the geometric mean lung lesion score (expressed as least squares mean percentages of lung lesions) was significantly (P=0.0001) lower in vaccinated (0.3%, n=20) than in control pigs (5.9%, n=24) seronegative to M. hyopneumoniae at enrolment; similarly, in study B, the extent of lung lesions was significantly reduced (P=0.0385) in seropositive vaccinated pigs (2.0%, n=22) compared to controls (4.5%, n=26). At the end of the investigation period, 4 weeks after challenge, mean antibody sample-to-positive (S/P) ratios were significantly higher both in seronegative (P=0.0012) and seropositive (P=0.0001) vaccinated pigs (mean values=0.77 and 0.81, respectively) than in controls (mean values=0.51 and 0.38, respectively).
Veterinary Medicine Research and Development, Pfizer Animal Health, Sandwich CT13 9NJ, UK. sandwich-cr.ahpdinfotemp@pfizer.com
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SC
Reynolds
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St Aubin
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Sabbadini
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Kula
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Vogelaar
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Runnels
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Peters
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D005260:Female; D008168:Lung / Q000473:pathology*; D008297:Male; D045705:Mycoplasma hyopneumoniae / Q000276:immunology*; D045729:Pneumonia of Swine, Mycoplasmal / Q000097:blood / Q000276:immunology / Q000517:prevention & control*; D013552:Swine
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines