| Porcine proliferative enteritis(PPE), also known as ileitis, which growing and occurring in pigs is an important infectious intestinal diseases. It is an infectious intestinal disease caused by Lawsonia intracellularis (LI). Pig ileum is the primary infection site, LI can cause the thickening of the intestinal mucosa, thereby cause the slow growth of pigs, decrease the feed conversion ratio. Lawsonia intracellularis is a membrane structure consisting of three wavy,it breed itself in the second division in the ileal epithelial cells replicate, usually curved, comma-shaped or S-shaped, Gram-negative, strictly intracellular parasite. At present, the clinical infection related research reports little, so it is necessary to conduct further research. Now this study are outlined below:1 The establishment and application of IPMA assay for the detection of Lawsonia intracellularisIn this experiment, we established an IPMA assay to detect the antibody of Lawsonia intracellularis, explored the method’s best HRP-Protein A concentration at work was 1:2000, optimal incubation time was 1 h, and the the best time to substrate color was 15 min. This method has a good specificity with strong sensitivity, easy operation and be proved suitable for Lawsonia intracellularis antibody detection. The technical method is good for evaluating the LI vaccine’s immunization effect, epidemiological investigation and related quarantine.2 A reliminary exploration on the infection of porcine proliferative enteritis in the large-scale pig farms in ShanghaiIn this study, the infection of porcine proliferative enteritis (PPE) was examined in the large-scale pig farms in Shanghai.225 swabs samples collected from stool, ileum and anus were subjected to PCR test to detect the lawsonia intracelluaris(LI), meanwhile,504 serum samples were subjected to IPMA to detect the antibody against LI. In results,36 swabs samples were infected with LI (14.1%), and 56 serum samples were positive (11.1%). The results indicated pigs were ubiquitous infected in shanghai. Moreover, it showed that the infection of PPE in Jiading is relatively high followed by Songjiang and Fengxian and the infection in Chongming as the bottom level, which may be due to the geographical advantages of surrounding waters in Chongming. The results showed that compared with the infection of finishing pigs, the positive rate of the sows pigs was slightly higher, which may be due to the use of antibotic medicines. And summer has a higher infection compared to the other seasons. Comparison of two methods, clinical testing can choose different methods to detect according to the need in the future.3 The duplication of Lawsonia intracellularis bacteria from Pigs inoculated in MiceThrough this experiment, we successfully inoculate Lawson intracellularis from pigs in mice, indicates that Lawson intracellularis in porcine cells can be bred in rodents because of mice’s naturally infection by direct contact with faeces of porcine infected, which certificates faeces is the important source of infection of LI. Infected mice were not died, which certificates that Lawson intracellularis in porcine cells has no lethality in spite of pathogenicity. The weight of mice had no evident change that shows fodder has no big effection on mice with infected porcine cells. Pathogenic part is mainly at ileum and duodenum, because LI cannot survive in another organs. After intruding into mice, for 6 days, the host began to excrete, and the sequence of time may be in relation to animal individual biological differences and the quantity of bacteria on the conditions of initial contact. After 30 days persistent infection, LI was still detected from faeces, which indicates the lenghth of bacteria excretion can be above 30 day once LI is duplicated in mice. |
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