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: The herd had elevated nursery mortality rates in September 1995 that reached 17%. All affected pigs showed signs of meningitis, arthritis, or a combination of these signs. Streptococcus suis serotype 2 was isolated from the brain samples of 12 necropsied pigs submitted at different times to a diagnostic laboratory. Most of the mortality occurred between 3 and 7 weeks after weaning. Clinically affected pigs were injected with ampicillin and/or ceftiofur sodium and put into a sick pen. During the course of the present study, this herd was concurrently infected with PRRSV and transmissible gastroenteritis virus (TGEV). A clinical PRRSV outbreak was observed in January 1996, but serology performed in March 1995 had already shown some seropositive pigs. A TGEV outbreak was clinically observed in March 1996 and affected mostly baby and nursery pigs, but no virus isolation was performed. Field vaccine trial
In consultation with the herd owner, a S. suis vaccination program was initiated in November 1995. Because the literature reports inconsistent findings regarding the efficacy of the S. suis vaccines, 4,5,9 we performed a concurrent controlled study in the herd with pigs from only 1 week of production.