| ObjectiveEnteroheamorrhagic E.coli. EHEC belongs to E. coli, which can causes human Hemorrhagic colitis(HC), Hemolytic uemic syndrom(HUS) and Thrombotic thromobocytopenic porpura(TTP). Besides its main serum type of O157:H7, there are still some types including O26:H11, O111:H8, O125:NM, etc. It is one of newly found main infectious diseases to be infected by Enteroheamorrhagic E. coli. In summer 2000, an epidemic caused by Enteroheamorrhagic E. coli was first found in Suixian County, Shangqiu City, Henan Province. Several steps were taken for this study in order to find the regularity of the disease as well as the influence factors so that effective strategies can be made for its control. It concludes understanding the distribution feature of the infection to diarrhea cases, and domestic animals and fouls so as to find the main animal host of EHEC O157:H7 and the dominate types of strains in the district; seeing the relationship between HC or/and HUS, and carriers of EHEC O157:H7 among domestic animals and fouls; understanding the gene type of shiga toxin of the epidemic strains, setting up lab techniques for molecular typing of EHEC and determination of toxicion so as to find infectious sources.Methods1. An epidemiological survey on this epidemic was taken from every May to September in 2000-2002. The epidemiological investigations were made not only among the infected but also among their close contacted. The epidemiological investigations also includs the infection among domestic animals and fouls, food and the environment.2. Collection of samples: The samples were collected from diarrhea cases, their close contacted and domestic animals and fouls as well as food suspected for infection based on same standard. Isolation of EHEC from samples of diarrhea cases, suspected cases, domestic animals and fouls, and food., Toxin genes and subtype of shiga toxin genes were tested with melocular biology technique, in order to find composition of toxin genes, and the character of shiga toxin genes etc.ResultsBy surveillance lasting 3 years, EHEC O157:H7 strains were isolated from samples of diarrhea case, and samples of domestic animal and domestic fowl as well as meet food, flies and Dung Beetles. 47 strains of O157:H7 were isolated from 884 diarrhea cases and 217 strains were isolated from 2547 samples of domestic animals and fouls. 12 strains of O157:H7 were isolated from 333 food samples. The carrying rate of Boer goat was as high as 15.09%. Of the 81strains with shiga toxin genes 51strains of EHEC O157:H7 were found, which made up 62.96% of the toxin-producing strains. 30strains of non O157EHECwere foundwhich made up 37.04%.The strains with sï¿¡t2and/or stx2 all have the Vero toxicity.Conclusions1.There are such diarrhea cases infected with EHEC in Shangqiu City. The outbreak of diarrhea with acute renal failure was caused by infection of E.Coli O157:H7.2. Some of domestic animals and fouls in epidemic areas were carrying pathogens. The ship who was infected seriously was the main host of EHEC in this district. Boar goat might be the infectious source of the epidemic.3. Currently shiga toxin genotype of EHECO157:H7 strains is stx2. |
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