Investigation On Epidemiology Of Piglets Yellow And White Scour Pathgeons In Jilin Area And The Preparation Of Inactivated Vaccines

The purpose of this study was to investigate the incidence rate, death rate and fatality rate of piglets yellow and white scour in Jilin area, as well as the influence of environmental factors on yellow and white scour of piglets through the observation on the clinical features, pathological changes and the preliminary checks of the 1 to 30-day-old piglets from 13 households specialized in animal husbandry and 8 large-scale pig farms in 5 main counties/cities of Jilin area. The results of the investigation showed that the yellow and white scour of piglets was widely spread in Jilin area with high incidence rate and fatality rate every year. It can be reduced through feeding complete diet, supplementing iron in time after birth, starting feed during the early stage of weaning, strict disinfection on sows before and after delivery.Seventy-one suspected samples were collected from 13 households specialized in animal husbandry and 8 large-scale pig farms in 5 main counties/cities of Jilin area. From these samples, a total of 43 strains pathogenic Escherichia coli were isolated and their serotypes were determined with single factor serum of Escherichia coli (E.coli) O-antigen serotype. The results showed that the serotypes of 35 strains E.coil were determined, and they belongs to 8 serotypes which were O149,O20,O141,O8,O137,O147,O64,O87. Among them, O149,O20,O141,O8,O137,and O64 are the dominant serotypes, the strains of these 6 serotypes occupied 92% of the identified strains. In addition, serotypes of 8 strains E.coli were unidentified, occupying 18.6% of the isolated strains.The dominant serotypes pathogenic E.coli isolated from piglets infected by yellow and white scour in the local pig farms of Jilin area were selected for preparing the inactivated vaccines. The inactivated vaccines were proved to be qualified through sterility test and security test. The gravid sows and 12 to 14-day-old piglets were vaccinated with the prepared vaccines. At the same time, sows with the similar ages, parities and date of delivery and piglets with the similar ages and nutrition conditions were vaccinated with K88K99, a kind of genetic engineering vaccine, and salt solution respectively. Results showed that the incidences of disease in piglets respectively vaccinated with the prepared vaccines, K88K99 and salt solution were 9.48%, 19.37% and 36.57%, and the fatality rates were 2.18%, 10.67% and 28.36% respectively. These results indicated that the prepared vaccines had very well immunological effects...