Epidemiological Investigation Of Layer Newcastle Disease And Infectious Bursal Disease In Changchun Area

New castle disease and infectious bursal disease of layers has been the main diseases ofbreeding production, and causes great economic losses to poultry industry every year. Theexperiments, examined new castle disease and infectious bursal disease epidemiology of95layer and specialized households of Changchun surrounding areas (Dehui、Nongan、Yushu、Jiutai、Shuangyang) between2010and2012years. Specifically studies are as follows:15NDV strains were isolated from20suspected ND fowl groups through separation andidentification of NDV from dead layers. There were3virulent strains,4moderately strains and8low virulent strains in15NDV strains by virulence detecting.30day-old non-immunized fowlswere inoculated by15isolated NDV strains respectively, and set up a control group meanwhile.The experimental groups attack rate were100%, case fatality were30%-100%. The controlgroup was all normal. The eliminated toxic material chickens were diseased from day1to day3,and begin to die from day4to day6. The clinical symptoms, pathological changes the same asnaturally infected fowls.Separated and identificated the IBDV from15suspected IBD fowl groups.12IBDV strainswere isolated through viral isolation and identification, agar gel precipitation test, medianembryo lethal dose test and animal regression experiment.4weeks non-immunized fowls wereinoculated by12isolated IBDV strains respectively, and set up a control group meanwhile. Theexperimental groups attack rate were100%, case fatality were20%-100%. The control groupwas all normal.Survey results showed that: New castle disease of layers have been different popularity inChangchun surrounding areas. Egg laying hens were usually happened in four seasons of ayear, most commonly occurred in spring and winter. All days old layers can be infected, mostcommonly occurred between30-50and180-260fowl groups,10days old chickens can also beinfected ND, and the death rate can up to60%. Egg production decreased significantly afteronset, ranging from10%-50%, and the mortality rate is not high, mostly between2%-5%. Theonset seasons of layer groups IBD have all-year trend, but fastigium was among the5-9monthsin a year. The amplitude of infected layers days old expanded. Immured layer groups can also beinfected, the complaint appeared complication and atypism changes. By analyzing the mainaetiological agent of new castle disease and infectious bursal disease of layers, thecomprehensiveness prevention and control measures were established.