Efficacy of immunoprophylaxis in control of swine losses due to Streptococcus suis type 2 infections

Laboratory investigations confirm that the etiological cause of streptococc i in pigs are alpha and beta hemolytic Streptococcus suis (Strep, suis) cap sular type 2, group D, subgroup R. These pathogens are responsible for all kinds of symptoms like: meningitis, arthritis, pericarditis, serosities, peritonitis, septicemia and pneumonia . The aim of this study was to estimate the usefulness of prophylaxis of Stre ptococcus suis infections in swine, using a non-activated autogenous vaccin e. One dose of autogenous vaccine contains no less then 2-5x10(9) non-activate d cells of Strep. suis type 2 - isolated from lungs and brains of pigs dead due to streptococci - supplemented with two adjuvants: aluminum hydroxide and mineral oil. The vaccine was administrated intramuscularly twice in a 2 mi dose to piglets before weaning (24 day of age) and 2 weeks later (38 da y of age). The experiment was performed on a large farm with 30 000 fatteners produced per year Apart from Strep. suis infections the farm was also infected with PRRS virus. Clinical signs of this disease occurred in the farm mainly 7 d ays after birth, but significant problems were observed in 6-7 week old pig s, which demonstrated clinical signs associated with changes in the central nervous system. Losses due to streptococci were almost 5%. The vaccine was used to immunize pigs from 6 different groups tin total 216 8). Two other groups (727 pigs in total) were used as controls. The paramet ers of production in every experimental group were compared with the result s in two control groups in order to estimate the efficacy of the vaccine. T he following criteria was evaluated: percentage of weaned piglets with clin ical signs of infection, body weight on the day of the first vaccination, n umber and percentage of pigs which died due to streptococci, mean body weig ht gains during the period of weaning until the final stage of production, average weight of weaned pigs before moving to the finishing house. The analyzed results indicated a significant reduction in the average numbe r of pigs with typical central nervous signs of infection (5.62% in experim ental groups and 9.62% in a control groups). Similarly, a lower mortality r ate in vaccinated pigs was observed. The average death rate for control gro ups was 4.67% and for experimental groups 2.30%. The mean body-weight gains for experimental pigs were more than 1.00 kg higher compared to the nonvac cinated control group. To summarize, applying autogenous vaccine against Strep. suis ensures a sig nificant reduction of losses caused by this disease.