EVALUATION OF PROTECTION CONFERRED BY PASSIVE IMMUNITY AGAINST STREPTOCOCCUS SUIS TYPE

摘要

Streptococcus suis (S. suis) infection in swine is associated with meningitis, polyarthritis and bronchopneumonia. It is considered a bacteria to be present everywhere where there is swine. Outbreaks usually occur in weaned pigs causing arthritis, endocarditis and meningitis. Overcrowding, poor ventilation and mixing of pigs from different litters are predisposing factors in a herd. S. suis is the most important meningitis-causing agent observed in swine high health herds. There has been an apparentincrease in prevalence in the last years, with nursery mortalities commonly ranging between 4 and 14% in infected herds. It has been shown that pigs inoculated with live fully pathogenic, weakly pathogenic or formalin-killed S. suis type 2 were completely resistant to challenge. Protection was transferred passively to susceptible pigs by the intravenous inoculation of sera from protected pigs. The objectives of the work presented here were: to produce hyperimmune sera against a field pathogenic isolateof S. suis; to evaluate antibody decline after administration of hyperimmune serum to newborn piglets. As well as to evaluate protection against challend conferred by hyperimmune sera administered either orally at birth or subcutaneously at approximately 30 days of age.