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Bulletin No. 26 - Fall 2006
VirologyPMWS-PCV2-PCVD-PDNS
OPRIESSNIG T, HALBUR PG, YU S, THACKER EL, FENAUX M, MENG XJ
Effects of the timing of the administration of Mycoplasma hyopneumoniae bacterin on the development of lesions associated with porcine circovirus type 2.
Veterinary Record, 2006, Volume 158, Nš5, 149-154
Various vaccination schemes for Mycoplasma hyopneumoniae were applied to 6 groups of about 10 pigs in order to determine whether the timing of such vaccination has an impact on the pathogenesis of PCV2 infection. All vaccinated groups and an additional unvaccinated control group were inoculated with PCV2 at 8 weeks of age. All pigs were euthanized at 42 days post-inoculation.
| Age at vaccination | |||||
|---|---|---|---|---|---|
| 2 weeks | 4 weeks | 6 weeks | 8 weeks | 10 weeks | |
| Group 1 | Single dose | Single dose | |||
| Group 2 | Single dose | Single dose | |||
| Group 3 | Single dose | Single dose | |||
| Group 4 | Single dose | Single dose | |||
| Group 5 | Double dose | ||||
| Group 6 | Double dose | ||||
| Group 7 | Unvaccinated - inoculated with PCV2 at 8 weeks of age | ||||
| Group 8 | Unvaccinated - not inoculated with PCV2 | ||||
Overall, vaccination had a influence on PCV2 infection since all vaccinated animals showed more severe lesions and major quantity of PCV2 genome than those of the unvaccinated group confirming the key role of immune stimulation in the expression of lesions induced by PCV2. Moreover, the latter did depend on the timing of the administration of M. hyopneumoniae bacterin. A significantly increased quantity of PCV2 genome was notably found in groups 1, 4 and 5 when compared to group 7 at 14 days post-inoculation. Both one-shot vaccine administration protocols were associated with a particularly increased severity of the lesions induced by PCV2. Determining the approximate timing of PCV2 infection in a herd and applying the most appropriate vaccination plan for M. hyopneumoniae should be considered as a means to achieve a better control of PCV2-associated disease.
