ABSTRACT
<p><b>OBJECTIVE</b>To carry out epidemiological study on an outbreak caused by E. coli O157:H7 infection in Jiangsu province in 1999.</p><p><b>METHODS</b>Epidemiological, microbiological and moleculebiological methods were used to find out the source, route of transmission and risk factors.</p><p><b>RESULTS</b>95 severe O157:H7 infected patients with acute renal failure in 9 counties and districts of 2 municipalities were reported in Jiangsu province, 1999 while 83 of the patients died with a death rate of 87.37%. Most patients were seen in mid or late June. The ratio of male to female was 1 to 1.44 and 88.42% of the patients were over 50 years old. 38 patients occurred in 2000 with 34 deaths. Major factors contributing to the outbreak would include without drinking tap water, eating leftover food, poor sanitary status in kitchen, not washing hands before meal and after bowl movement. 2 strain of O157:H7 was isolated from severe patients and 3 from diarrhea cases. Carrier rate among animals was up to 9.62% and 99.41% of the strains carried toxic gene. Strains isolated from feces of patients and animals belonged to the same colonies.</p><p><b>CONCLUSION</b>This outbreak was severe which caused by O157:H7 and was first seen in China, which was closely related to the high carrier rate of O157:H7 in animals and to the positive rate of high toxic gene of the strains. There were various routes of transmission and the main factors of infection would include poor personal health habits and poor sanitation of the household.</p>
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Acute Kidney Injury , Epidemiology , Antibodies, Bacterial , Allergy and Immunology , Case-Control Studies , China , Epidemiology , Diarrhea , Epidemiology , Microbiology , Disease Outbreaks , Escherichia coli Infections , Epidemiology , Escherichia coli O157 , Escherichia coli Proteins , Allergy and Immunology , Hemolysin Proteins , Allergy and Immunology , Seroepidemiologic StudiesABSTRACT
<p><b>OBJECTIVE</b>To analyze the incidence rate, animal hosts, and human inapparent infection rate from surveillance data collected in Jiangsu province from 1996 to 2000 and the risk factors of hemorrhagic fever with renal syndrome (HFRS).</p><p><b>METHODS</b>Data on the incidence rate was collected from the whole province to describe the epidemiologic characteristics of HFRS. Data on the density of rats, proportion of rats with virus, index of rats with virus and the human inapparent infection rate were collected in special areas according to the standardised protocol in the project.</p><p><b>RESULTS</b>The incidence rate of HFRS reduced continuously in Jiangsu province, with a 42.17% reduction from 1996 to 2000. The ratio between the incidence rate of autumn-winter peak and spring peak had also reduced. The main host in spring was Rattus norvegicus (with a density of 3.07%), while that in autumn was Apodemus agrarius (with a density of 4.64%). The density of main hosts and mixed species of rats had all reduced during the five years of observation. The proportions of Rattus norvegicus, Apodemus agrarius, Mus musculus with virus were relatively high in spring and autumn. The index of Rattus norvegicus and Mus musculus with virus in spring were 0.025 5 and 0.028 4 respectively, while that of Apodemus agrarius with virus in autumn was 0.030 2. The average human inapparent infection rate was 4.73% in the five years.</p><p><b>CONCLUSION</b>The incidence rate of HFRS in Jiangsu reduced significantly from 1996 to 2000, but the risk factors still widely existed. Suggesting that the surveillance program needs to be carried out steadily in Jiangsu.</p>