Isolation And Identification Of Haemophilus Parasuis In Dezhou County And Study On Protective Efficiency Of Inactivated Vaccine Against Glasser's Disease

Haempohilus Parasusi(HPs) is the etiological agent of Porcine Glsser's Disease, which can invade and cause severe systemic disease, characterized by fibrinous polyserositis, arthritis and meningitis. HPs is a kind of NAD-dependent, non-motion, Grma-negative, rod-shaped baeterium, which belongs to the family of Pastteuerllaeeae, the genus Haemophilus. The higher prevalence of HPs in intensive pig farms has become the main reason for the high mortality of young pigs and led to the huge economic losses.Three Parts have been ineluded in this experiment:1. The operation of pure culture, dye and observation, and biochemical experiment of 20 isolates of HPs from 32 pig farms of Dezhou county were investigated. The results showed that the cultural characteristics, patterns of structure and basic biological characteristics of the 20 strains are basically consistent with the published information of HPs. 16s rRNA-based PCR confirmed the isolates and demonstrated that the bacteria are assigned to HPs. The results indicated that HPs is prevalent in Dezhou county of Shandong Province.2. The result of AST showed that the 20 isolates of HPs are insusceptible for Terramycin, Streptomycin, Tetracycline and Lincomycin, but susceptible for Ceftazidim, Ceftiofur, Ofloxacin, Doxycycline and Ciprofloxacin.3. Study on grouth curve of DZ02 isolate showed that the number of Haemophilus parasuis would achieve to maximum when it grown in the liquid culture medium Typtic Soy Broth for 13 to 15 hours. 4. The inactived vaccine made from DZ02 isolate possessed good safety, high stability and enough protective efficiency. At 14 days after the second vaccination with the optimal dose of Haemophilus parasuis inactivated vaccine with 8×10~8CFU per pig, the vaccined piglets were protected from lethal challenge. At five large scale pig farms in Dezhou couty, the incidence of Porcine Glsser's Disease of vaccined piglets was dropped to 1.9% from 10.9% of unvaccined piglets, and the incidence of the disease in every vaccined pig farm was under 2.5%.