Title: Torremorell M. 1995;4:139-143. Vaccination against S suis
Headings: Vaccination against
Streptococcus suis
:
Effect on nursery mortality

Field study
Vaccination against Streptococcus suis:
Effect on nursery mortality
Montserrat Torremorell, DVM; Carlos Pijoan, DVM, PhD; Emilio Trigo, DVM, PhD
Summary
Material and methods
Herd history and clinical evaluation
Field vaccine trial
Statistical analysis
Posttrial vaccination protocols
Results
Discussion
Implications
References

Content: Pigs were vaccinated at weaning and revaccinated 10 days later. Pigs with signs of meningitis and/or arthritis were placed in the sick pen and injected with ampicillin (6-8 mg per kg) or ceftiofur sodium (3-5 mg per kg). Morbidity and mortality rate was monitored from the beginning of the trial (at weaning) until the pigs left the nursery (at 9 weeks of age). Statistical analysis
Differences in morbidity and mortality between groups were statistically analyzed using the c-square test. Groups were considered to be statistically significant at P <.05. Posttrial vaccination protocols
Following this controlled trial, the producer adopted a new vaccination protocol that was designed to boost the immune response and protect pigs with different levels of maternal immunity. Starting in late November 1995, piglets were vaccinated with the commercial bacterin IP at 5 days of age, revaccinated IP at weaning (15 days of age), and revaccinated again 10 days later IM. This program was followed in the herd for 6 months. A TGEV outbreak in March 1996 convinced the producer to begin attempts to determine the causes of nursery pig mortality. Thus, after March 1996, the herd records differentiated between total mortality data of pigs and mortality that could be directly attributed to S. suis ( i.e., pigs that exhibited obvious CNS distress, ataxia, tremors, and paddling).