Select The Inactivated Vaccine Strains Of Haemophilus Suis Disease

Objective;Virulent strains of Haemophilus were separated from our popular domestic serum4,5,12,13,14type, to provide basis of our popular domestic serotype inactivated vaccine for further study. Methods and Results;The study of five popular serotypes of HPS in our country include cell morphology, growth rate, NAD-dependent biochemical tests, susceptibility testing, PCR and test animals (mice piglets), the biological characteristics of the virulence and immunogenicity. The strain identification results show that the16bacteria stains were compliance with the basic biological characteristics of HPS, PCR identification was HPS positive and serotyping serum of these stains were identified HPS type4(4strains), type5(4strains), type12(3strains), type13(2strains) and type14(3strains) by the KRG agar diffusion.16strains were gram-negative bacteria, and dependent on NAD. With the exception of the S4S3of4serotype4strains, all of the HPS strains with the same serotype have the similar morphology each other. There are significant differences in the bacterial morphology among the HPS strains with the different serotypes. That’s to say, bacterial morphology is type-specific in these5serotypes of HPS. Five serotype strains cultured under solid conditions to arrive at the average growth rate from fast to slow:type13, type4, type5, type14, type12. The results of the biochemical reactions of the presence were significant differences, even between different strains of the same serotype. Mouse virulence test results show that the virulence strength followed by serum of type12, type14, type5, type4and type13. The S4S1strain of serotype4, S5S3strain of serotype5and S12S3strain of serum12may be preparation of inactivated vaccines and test of Haemophilus by piglets virulence testing. The immunogenicity of the vaccine were confirmed through a piglet immunity test. Conclusion; According to epidemiological study of the vice pig Haemophilus, clinical data, the results of animal experiments screened strains of virulent, the better immunogenicity of S4S1strains of serotype4, S5S3strains of serotype5and S12S3strain of serotype12as a vaccine candidate strains, the stability of the virulence and immunogenicity stability results show that these three strains were fit related conditions as preparation of inactivated vaccines and inspection of Haemophilus parasuis.