A Survery Of Epidemiologic And Prevention Of Newcastle Disease In Breeder In Qingdao District Of Shandong Province

Through the investigation of epizotiology in more then eighteen Parents Broiler Breeder farms with Newcastle disease in Qingdao area of Shan Dong province. In this investigation, 48 flocks, and a total 2,740,000 set of Parents Broiler Breeder were investigated. Twenty-eight virus strains were isolated from outbreaks flocks using specific pathogen free (SPF) chick embryos. Twenty-three virus strains of them were characterized as Newcastle disease virus (NDV) by hemagglutination (HA)/hemagglutination-in hibition (HI) test. The biological characteristics of these viruses were determined by measuring the mean death time of chick embroys(MDT), the intracerebral pathogenicity index in day-old chicks(ICPI)and the intravenous pathogenicity index in 6-week old chickens(IVPI) at the virulence of NDV. The results indicated that these isolatesof Newcastle disease virus were high virulent Newcastle disease virus. 30-day-old unimmunized chicks were inoculated with these isolates Newcastle disease virus. As a result, all the tested chicks show a 100%morbility and a 70%-100% mortality respectively.The epidemiological results showed the Newcastle disease outbreaks in Jiaonan, Jiaozhou, Pingdu, Jimo, Laixi ect, of Qingdao area, Newcastle disease could infect different ages and species chick in all seasons, but it was most poupular in winter and in 20-40 or 200-350day old chicks The level of Newcastle disease antibody can not prevevt the NDV infect the flock of Broiler Breeder, the higher antibody level may control the mortality of one flock, but can't control the drop of produce performance actively. The immunity of Newcastle disease needs the lood serum antybody, and also needs catarrh antybody,. Therefore, we should attach importance to the method of vaccaination, such as IO, IN, SP, ect, the catarrh vaccination of chicken in the processing of control Newcastle disease is the most important.Broiler Breeder in production period can't protect themselves very well after immunized vaccine virus that was made from high virulent Newcastle disease viruses which were seprated from one farm of Qingdao area. The experiment result indicated the vaccine we use now in priduction can't protect Broiler Breeder completely to exempt the attack of epizootiology Newcastle disease virus. This may be the main reason that Newcastle disease still can be outbreak in Broiler Breeder flock that have high antybody level. We suggest we should immune epizootiology Newcastle disease virus vaccine after immune tradition Newcastle disease virus vaccine, this can enhances the immunity effect, and reduces the rate. of Newcastle diseaseThe cause of Newcastle disease outbreaking in eighteen Parents Broiler Breeder farms and twenty-three flocks were analysed and a integrated measure of biosecurity against were made The integrated measure was applied in 10 farms, and abtained a satisfying result. The reduction rates was 81.25%. The results indicated that the integrated measure for Broiler Breeder was applicable, it is worth application.