Epidemiological Surveillance Of Porcine Contagious Pleuropneumonia And Integrated Control In Henan

Porcine contagious pleuropneumonia(PCP)is a highly contagious respiratory disease caused by Actinobacillus pleuropneumoniae(APP).With the introduction of frequent and large scale aquaculture introduced from abroad in recent years,the PCP outbreak in Henan Province has occurred from time to time,bringing huge economic losses to the pig industry in Henan Province.The purpose of this experiment is to identify the prevalence of PCP in Henan Province,isolate and identify APP predominant serotype strains,monitor the resistance of APP and prepare multivalent inactivated vaccines for PCP,providing the basis for the prevention and control of Henan PCP.1.Epidemiological survey of swine infectious pleuropneumonia in HenanIn order to understand the dynamic changes of epidemic porcine contagious pleuropneumonia in Henan Province,on the one hand,through the collection of three years of case diagnosis records of the Animal Epidemic Disease Surveillance and Diagnosis Center of Henan Agricultural University,to analyze the prevalence and seasonality of contagious pleuropneumonia in Henan in recent years.And the epidemic in the area;on the other hand,139 samples from different regions of Henan Province were collected for total DNA extraction,and nested PCR was used to monitor the infection rate of APP.A total of 1,714 case records were collected in this study.It was found that the incidence of contagious pleuropneumonia in pigs has been on an upward trend in the past three years.The main onset season is in March-May and September-November each year,and the onset regions mainly focus on northern Henan and Henan provinces.In the east and west of Henan,mixed infections are more serious.From the etiological monitoring of 139 samples,64 positive samples were detected,with a positive rate of 46% and a positive rate of 72.6%.Through clinical epidemiological investigation and etiological monitoring results,the prevention and control of porcine infectious pleuropneumonia in Henan Province is facing severe challenges.2.Isolation,identification,genotyping and drug susceptibility testing of Actinobacillus pleuropneumoniae strains in HenanIn order to investigate the predominant serotype of Actinobacillus pleuropneumoniae currently circulating in Henan Province,40 isolates of suspected porcine contagious pleuropneumoniae from Henan Province were isolated and cultured,and the isolates were identified using molecular biological methods.The Actinobacillus pleuropneumoniae was genotyped using multiplex PCR combined with evolutionary analysis.In this study,7 strains of Actinobacillus pleuropneumoniae were isolated from 40 samples.Multiplex PCR genotyping results showed that 4 strains amplified the expected gene fragment that was consistent with serum type 1,and 3 strains were consistent with serum 15 strains.Sequence and phylogenetic analysis were consistent with multiplex PCR results.The results showed that the most prevalent serotypes of Proteus pleuropneumonia in Henan Province are serum type 1 and type 15.3.Development of a bivalent inactivated vaccine for Actinobacillus pleuropneumoniaeIn order to develop an APP vaccine suitable for local use in Henan Province to prevent and control the occurrence of PCP,this trial tested the virulence of 4 strains of serum type 1 and 3 strains of type 15 APP isolated from samples submitted in various regions of Henan Province.Immune protection trials were conducted to screen out candidate vaccine strains,make APP divalent inactivated vaccines,and conduct immune challenge protection experiments.Finally,based on the pathogenicity test results of APP,the APP-ZMD-1 and APP-DF-1 strains with strong virulence and good immunogenicity were screened from the serum type 1 and type 15 isolates,respectively.Divalent inactivated vaccine.After mice were immunized with APP bivalent inactivated vaccine,mice were challenged with the minimum lethal dose and the mice had better protective effects.In this study,epidemiological investigation of porcine contagious pleuropneumonia,isolation and identification of Actinobacillus pleuropneumoniae strains in Henan,classification drug susceptibility testing,and development of a bivalent inactivated vaccine for porcine contagious pleuropneumonia were studied.Knowing the current predominant APP serotypes in Henan,screening drugs that are sensitive to APP,and preparing a whole-cell bivalent inactivated vaccine with the same serotype as the local epidemic strain,and understanding the PCP in Henan in recent years Epidemics,high seasons and high incidence areas can be used to develop reasonable vaccine immunization procedures and medications to reduce the losses caused by PCP.This research provides a reference for the prevention and control of PCP in Henan through systematic investigation and research.