Serotype Identification And Drug Sensitive Test Research On Haemophilus Parasuis Isolates

Haemophilus parasuis disease was a contact infectious respiratory disease which was prevalent inswine. It could affect all stages in pig production and presented in clinical as fibrinous polyserositis,arthritis, pericarditis and meningitis of swine. Haemophilus parasuis had15serotypes and was variousto different distinct or farms. The current serotypes which prevalent in China were serotype4,5,12,13and14. The clinical research on Hparasuis disease should include strain isolation and identification,serotyping and genotyping, drug and vaccine prevention.In this study,3serotypes were isolated from the piglets in a pig bred farm of Hubei which suspectedfibrinous polyserositis and pericarditis and finally identified to Haemophilus parasuis disease throughbacterial culture and morphological observation, biochemical identification,16S-rRNA sequencing andserotyping. The isolated strains of Haemophilus parasuis were the main epidemic of serotype2and4and serotype13, while the infected piglets all presented systemic serositis and pericarditis symptom inclinical. It suggested that pathogenic strain which parasitized in upper airway could harm visceraltissues and cause systemic infectious under specific conditions. Being a conditioned pathogenic bacteria,Haemophilus parasuis could co-infected with other pathogens as primary and secondary disease. In thisstudy, PCV2and PRRS virus were also isolated from the sick piglets which explanted its co-infectionand occurrence mechanism and provided a practical basis for clinical control.Through drug sensitivity test, several drugs which sensitive to Haemophilus parasuis such asβ-lactam antibiotics were screened for health protection and treatment. Furthermore, throughimmunizing piglets of14days age by trivalent own inactivated vaccine of the three isolated strains andadjusting swine immune procedure, the survival rate of piglets in lactation and nursing periods wereeffectively increased while the occurrence of Haemophilus parasuis were greatly decreased.