The duration of immunity after vaccination with a single dose Mycoplasma hyopneumoniae vaccine and the effect of serological status on lung lesion scores

摘要

The duration of immunity induced by a single dose Mycoplasma hyopneumoniae vaccine (StellamuneTM Once) was investigated in pigs vaccinated at approximately 3 and 5 weeks of age. Liveweight gains, coughing rates and lung lesions at post-mortem examination were compared between controls and vaccinates challenged at approximately 21 and 26 weeks of age. Three of four vaccinated groups showed significant reductions in lung lesions (55-86%) compared with their contemporary controls. In a fourth comparison, the induced lung lesion scores in the controls were relatively low and the reduction was not statistically significant in the vaccinates (4.4 vs 1.1%; P < 0.07). There were significant beneficial effects on liveweight gain and coughing rate in 2/4 vaccinated groups. In a second study, the lung lesion response to vaccination was assessed in groups of seronegative and seropositive pigs 4 weeks after challenge. Overall, there were significant reductions of 50-60% in lung lesion scores in vaccinates compared with controls ( < 0.05). The interaction between serological status and vaccination was not significant (P=0.3) showing that the effects of vaccination were not influenced by the presence of maternal antibody. It is concluded that the vaccine confers a duration of immunity of up to 23 weeks and that protection can be induced in the presence of maternally derived serum antibodies.