Diagnosis Of Main Pathogens Of Diarrhea Piglets In A Scale Pig Farm Of Shihezi

During the period from2012January to June,some farms surrounding Shihezi,2-7daysold piglets have been incidents of severe diarrhea.More than800piglets were died of thedisease successively.The incidence rate was90%,The death rate was80%.Sick pigletsshowned depression, loss of appetite,discharge yellow watery feces.The course of the diseasewas3-5days. Pathological anatomy showned: mesenteric severe congestion, enlargementmesenteric lymph nodes,intestinal mucosal thinning, cut the small intestinal contents wasyellow and containing a large number of undigested curd. According to the epidemiologicaland pathological changes of clinical symptoms, the initial diagnosis due to Escherichia coli;In order to diagnosis the disease for further, we used molecular biology diagnosis separation,pathogens and biochemical identification, pathogenic factors and virulence identification,pathogen, the results are as follows:1Sterile to mortality in piglets contents, mesenteric lymph nodes and other pathologicaltissue, smear staining, microscopy, take the diseased inoculated on LB broth culture at thesame time, the isolated bacterias were inoculated on Makanke medium and rabbit blood agarplate, we employed biochemical test, molecular identification, drug sensitivity test to theisolated bacterias. The results showed that: the strains on Makanke medium appeared redcolonies; the mice died within8h; The results of biochemical identification and PCRidentification are Escherichia coli; The Escherichia coli was sensitive to cepHalosporins andbeta lactam drugs.2Through PCR and MRHA in test the pili adhesin types, the rabbit ileum test heat-labileentero-toxin LT, detected by using injection experiment rat stomach heat-sta-ble enterotoxinSTa. PCR and MRHA results show that the virulence factors of Escherichia coli isolated inthis experiment is987P, rabbit ileum test dose not detect LT, rat intragastric injectionexperiment dose not detected STa. The pathogenic Escherichia coli cultured at100℃for30min,0.5mL injected rats, mice died within8h, showed that isolates of pathogenicEscherichia coli may have other types of heat stable enterotoxin.3RT-PCR was used to detect Transmissible gastroenteritis virus (TGEV) and porcineepidemic diarrhea virus (PEDV); only detected PEDV, M gene and N gene of PEDV aredifferent from other PEDV strains which were compared and analyzed, The homologybetween this experiment detected PEDV M gene and other published PEDV strain M gene is97.9-99.7%, N gene is95.1%-96.4%; M gene and domestic separation test of detection ofPEDV CH-SC2-2012lie in the same branch; N gene and the separation of PEDV YT12-4liein the same branch. Laboratory diagnosis of the pig farm in the major cause of carrying987Ppili of pathogenic Escherichia coli and hybrid porcine epidemic diarrhea virus infection.