The Epidemiological Investigations And Prevention Of Infectious Bronchitis At Scale Poultry Farms In Henan

Abstract:Infectious Bronchitis is an infectious disease caused by avian infectious bronchitis virus (IBV).The features of IBV that easy variation, serotype and tissue tropism of many diverse features, often leads to the failure of IB clinical prevention, which is causing serious economic losses. In view of this, for better prevention and control of IB in poultry production, this study conducted in Henan IB epidemiological investigation, and a typical case for virus isolation, using their own methods for preparing a comprehensive prevention and control of vaccines, the results reported as follows:Add up the clinical cases in Henan Province from2012.1to2013.12and335patients with suspected material were collected for molecular epidemiology in large-scale poultry farmsfrom at21urban municipalities. The Epidemiology were expanded by RT-PCR methods for epidemiological investigations conservative IBV N gene. The total positive rate was17.91%(95%CI14.0-22.40), and which in2012was18.09%(95%CI12.9-24.3),2013was17.69%(95%CI11.9-24.8). IBV infection occurs in most cities of Henan Province in varying degrees and the stocking density is relatively large area, the higher positive rate is generally than in other regions.2012mainly concentrated in the7-9month;2013mainly concentrated in1-6months. IBV infections are concentrated in the0-60day-old chicks in2012-2013,and the infection rate was30.15%(95%CI22.6-38.6),and the infection rate was16.18%(95%CI8.4-27.1) between60to120days, and the120days or more laying hens overall infection rate was6.11%(95%CI2.7-11.7) Infectious Bronchitis is still one important common diseases of poultry, and should strengthen the prevention and control of avian infectious bronchitis.To order to understand the IBV genetic variation in the gene level of Henan Province, the study use the laboratory preservation primer to amplificate the S1gene sequences of positive allantoic fluid IBV,obtaining three strains, namely HN LH strains, HN XYHL and HN LY. The another two strains cK/CH/HN/1205and Jin-13were preserved by laboratory reference strains. The IBV S1genes were analysised on nucleotide and amino acid homology and phylogenetic tree constructed from different regions at home and abroad. By comparison with the market, the HN LY strain was homology with the respiratory vaccine strain,such as H120, H52and W93and so on,which was between99.5and99.6%, closely genetic relationship,which may be caused by infection vaccine strain variation; Jin-13strain and Shandong isolates SDA lines close genetic relationship,which may be because the two provinces are likely to be farmed in the province and is closely linked geographically, poultry and their products,so the trade is frequent and extensive exchanges with each other; cK/CH/HN/1205strain, HN LH strain and HN XYHL strain in the same branch, and they were a close genetic relationshipon with LX4the behalf of the domestic kidney isolates,whose the homology was between94.9and97.2percent.The above results show that at the genetic level, there are different evolution branches of IBV strains in Henan and its surrounding areas,which show the field IBV strains polymorphism popular variations. Among HN LH strain and HN XYHL kinship were the closer homology of97.2%. Understanding the specificity of the IBV strains in Henan Province, which provides a scientific reference of prevention and treatment of the Infectious BronchitisBased on the above findings, the author select a representative preparation of oil emulsion vaccine strains HN XYHL to preparate the inactivated oil emulsion vaccine strains. After the quality inspection,to immun the chickens of Xingyang farm, and the first immunization was for8days, staring the second immunization after two weeks. While improve the rearing environment, adjust the immunization program, with drug care and control secondary infection and so on.These prevention and control measures, such as comprehensive, well controlled occurrence of the disease with the hemagglutination test and neutralizing antibody assay results, combined with the production index flock based oil emulsion vaccine for immunization to assess the effect, and ultimately better prevention and control the disease. Oil emulsion vaccine strains in the application of a good solution to problem it,which the current IB is difficult to prevention, which provide a scientific basis to prevente and control the epidemic strains of Henan.