Epidemiological Investigation And Control Of Colibacillosis Of Chickens In Hai'an County

The number of poultry in Haian county has been continuously increased to 40 million in the last 5 years, and 140,000 tons of the egg production has been reached annually. Poultry industry has been become important industry for the increasing farmer's income, however, with the development of the number and scale of the poultry farms, not only the old avian diseases have been still existed , but also the new ones increased constantly. Various diseases cause a hundreds of million dollars losses every year in Haian, especially the colibacillosis. Chicken's colibacillosis is a focus or systemic infectious disease, which is caused by E.coii ,with complicated antigens, multiple serotype and various clinical symptoms such as salpingitis, synovitis, and so on. Colibacillosis often happens together with various diseases and has been spread everywhere in Haian county in different extent.. The more and more serious economic losses to poultry industry have been existed . In the meantime, antibacterial agents,which were used widely, have led to development of multi-drug-resistani: strains, and developed vicious cycle, and, aggravated residual of drug in poultry products . So it brings latent harm to continuous development of poultry industry and human health . Therefore it is necessary to investigate and analyses the clinical cases of colibacillosis, so as to find pathogenic characteristics and to set up more reasonable preventive and remedial measures to reduce farmer losses and improve cultivation profit.Three parts have been included in this experiment: 1 , epidemiological investigation in the field ; 2, Laboratory investigation ;3, Preventive experiment. In laboratory experiment 684 E.coii strains were isolated from 856 ill and dead chickens. 22 kinds of serotype were identified from 167 strains. The primary serotypes were respectively O18 (18/167), O78(17/167;)O88(9/167) and O2(8/167),in hooping strains.O1 and O11 were all 7 strains, which occupied respectively 4.2% in them, there still lies rare serotype, such as O3, O5, O7, O9, O14, O17, O23 O29 O37, O60 O81, O87, O101, O109, O138 and O154, and soon.. Antibiotic susceptibility test showed E.coli that isolated was sensitive to some drugs, such as Cefazolin , Amikaxing, Ampicillin, and so on. Morbidity of 23600 susceptible chicken decreased from 24.78% to 1.58% after using autogenous bacterin. It is satisfactory to use autogenous bacterin with synthesized preventive measures in large poultry farm. While to small poultry farm, microbial ecological agents with synthesized preventive measures are suitable to prevent E.coli disease in the whole feeding time.