BACKGROUND: Although previous studies have shown that meteorological factors such as temperature are related to the incidence of bacillary dysentery (BD), researches about the non-linear and interaction effect among meteorological variables remain limited. The objective of this study was to analyze the effects of temperature and other meteorological variables on BD in Beijing-Tianjin-Hebei region, which is a high-risk area for BD distribution. METHODS: Our study was based on the daily-scale data of BD cases and meteorological variables from 2014 to 2019, using generalized additive model (GAM) to explore the relationship between meteorological variables and BD cases and distributed lag non-linear model (DLNM) to analyze the lag and cumulative effects. The interaction effects and stratified analysis were developed by the GAM. RESULTS: A total of 147,001 cases were reported from 2014 to 2019. The relationship between temperature and BD was approximately liner above 0 °C, but the turning point of total temperature effect was 10 °C. Results of DLNM indicated that the effect of high temperature was significant on lag 5d and lag 6d, and the lag effect showed that each 5 °C rise caused a 3% [Relative risk (RR) = 1.03, 95% Confidence interval (CI): 1.02-1.05] increase in BD cases. The cumulative BD cases delayed by 7 days increased by 31% for each 5 °C rise in temperature above 10 °C (RR = 1.31, 95% CI: 1.30-1.33). The interaction effects and stratified analysis manifested that the incidence of BD was highest in hot and humid climates. CONCLUSIONS This study suggests that temperature can significantly affect the incidence of BD, and its effect can be enhanced by humidity and precipitation, which means that the hot and humid environment positively increases the incidence of BD.
Beijing/epidemiology* ; China/epidemiology* ; Dysentery, Bacillary/epidemiology* ; Humans ; Humidity ; Temperature

Dysentery, Bacillary ; epidemiology ; Humans ; Molecular Epidemiology ; Shigella ; genetics

To demonstrate and evaluate five different methods in the determination of temporal clustering on infectious diseases. The incidence rates of bacillary dysentery in Jinshui district, Zhengzhou city, Henan province from 2008 to 2010 were analyzed by 5 different methods-Cluster Analysis, Runs Test, Negative Binomial Distribution, Circular Distribution and Concentration Ratio. Through Cluster Analysis, data showed that the epidemic period was from May to Sept. with August as the peak. Runs Test confirmed a cluster of month-incidence in 2008 and 2009 (P < 0.05) and a random distribution in 2010. The Concentration Ratio showed a weakened seasonal incidence cluster to a certain extent by M from 2008 to 2010. The Circular Distribution demonstrated an inclining cluster of time (P < 0.01) and it was on July 11(th) and 29(th), as well on August 24(th) in 2008, 2009 and 2010. In terms of day-incidence, the Negative Binomial Distribution presented a cluster in 2008 and 2010, but with no significant difference in 2009. The five above said methods could flexibly be used in determining the temporal clustering of infectious disease at different occasions.
China ; Cluster Analysis ; Dysentery, Bacillary ; epidemiology ; Humans ; Incidence ; Time Factors

OBJECTIVETo explore the epidemic characteristics of bacterial dysentery in Jinan municipality, and to provide scientific basis for effective strategy for bacterial dysentery control.

METHODSThe epidemiological characteristics of bacillary dysentery in Jinan from 1951 to 2005 were analyzed. A total of 485,333 cases in the span of 50 years were recorded, while the population-based case distribution was less than the total cases due to the data incompleteness during the Cultural Revolution.

RESULTSThe incidence of bacillary dysentery in Jinan has been decreasing by years with average incidence rate of 283.10/100,000. The significant differences were observed among the incidence rates of various ages(chi2 = 14.99, P < 0.05). There were four epidemic peaks, and all the incidence rates were about 1000/100,000. Age of onset mainly concentrated in the 0-4 years old, 20-years old and 30-years old. In terms of occupational distribution, workers accounted for 30.31%, the living-scattered children accounted for 22.71%, and the farmers accounted for 17.90%. The incidence focus was from July to September, which accounted for 71.57%. The peak of incidence emerged in August. The highest incidence in urban was 550.94/100,000.

CONCLUSIONThrough the efforts of several generations of health workers, the incidence of bacillary dysentery in Jinan has been basically brought under control. Further step should be taken for the control of bacterial dysentery in urban areas and the management of bacterial dysentery in rural areas. Moreover, the biological characteristics of F2a should be a focus for the future study.

China ; epidemiology ; Dysentery, Bacillary ; epidemiology ; Humans ; Incidence ; Shigella dysenteriae ; Shigella flexneri ; Shigella sonnei

China ; epidemiology ; Dysentery, Bacillary ; epidemiology ; microbiology ; Humans ; Shiga Toxin ; Shigella ; classification

Shigellosis is an acute diarrheal disease caused by bacteria of the genus Shigella. Following the occurrence of a large outbreak of shigellosis as well as sporadic cases since 1998, shigellosis has been a major health problem in Korea. There have been major changes in epidemiology during the last five decades concerning shigellosis in terms of total incidence of shigellosis, prevalence of certain serogroups, selection of specific clones, and introduction of new Shigella clones. S. dysenteriae was the most prevalent species until the early twentieth century, S. flexneri was the most prevalent until the late 1980s, and S. sonnei has been the most prevalent since 1990. Diverse serotypes of S. dysenteriae (4 serotypes), S. flexneri (8 serotypes), and S. boydii (4 serotypes) were found during the Korean War and many of these Korean endemic Shigella strains circulated in the community until the late 1970s. However, the endemic strains of S. dysenteriae, S. boydii, and S. sonnei disappeared in the late 1980s. A new clone of S. sonnei that was introduced between the late 1980s and the early 1990s was responsible for a large proportion of shigellosis in recent years. S. flexneri serotype 4a was the most frequently found during the Korean War and then the incidence of S. flexneri 2a gradually increased with time. S. flexneri isolates detected from 1991 to 1997 were all serotype 2a. However, the diverse clones of S. flexneri reemerged in Korea since 1999. It has not been determined whether the S. flexneri strains from the 2000s were the descendants of the Korean endemic strains or imported new strains, but the PFGE patterns were different between S. flexneri strains from the 1980s and 2000s. The widespread of new S. sonnei strains and the persistence of S. flexneri strains are responsible for the endemicity of shigellosis in Korea.
Bacteria ; Clone Cells ; Dysentery, Bacillary* ; Epidemiology* ; Incidence ; Korea* ; Korean War ; Prevalence ; Shigella

OBJECTIVETo explore the impact of meteorological factors on the outbreak of bacillary dysentery, so as to provide suggestions for disease prevention.

METHODSBased on the Chinese medicine theory of Yunqi, the descriptive statistics, single-factor correlation analysis and back-propagation artificial neural net-work were conducted using data on five basic meteorological factors and data on incidence of bacillary dysentery in Beijing, China, for the period 1970-2004.

RESULTSThe incidence of bacillary dysentery showed significant positive correlation relationship with the precipitation, relative humidity, vapor pressure, and temperature, respectively. The incidence of bacillary dysentery showed a negatively correlated relationship with the wind speed and the change trend of average wind speed. The results of medical-meteorological forecast model showed a relatively high accuracy rate.

CONCLUSIONSThere is a close relationship between the meteorological factors and the incidence of bacillary dysentery, but the contributions of which to the onset of bacillary dysentery are different to each other.

China ; epidemiology ; Dysentery, Bacillary ; epidemiology ; Forecasting ; Humans ; Incidence ; Medicine, Chinese Traditional ; Meteorological Concepts ; Models, Theoretical ; Statistics as Topic

China ; epidemiology ; Drug Resistance, Bacterial ; Dysentery, Bacillary ; epidemiology ; microbiology ; Humans ; Serotyping ; Shigella ; classification ; drug effects ; isolation & purification

OBJECTIVETo realize the epidemiological and drug-resistance characteristics of dysentery during 1990 to 2003 in Beijing.

METHODSThe group's characteristics of dysentery were described and analysed by using descriptive study method. Drug sensitivity tests were performed with Kirby-Bauer method recommended by WHO, and data were analyzed with SPSS statistic software.

RESULTSAverage incidence rate was 222.24 /100 000 and incidence rate was high in children and in urban areas. The period of high incidence was found in July 16 to August 3. The equation of index-curve forecast model was gained as Y = e (5.816-0.5845x. It showed some value in predicting the tendency of dysentery. Shigella was sensitive to quinolones and cephalosporins, and there was no significant differences between the middle and high grade in these two kinds of antibiotics.

CONCLUSIONIt should be taken as a measurement for the period of high incidence of dysentery.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Dysentery, Bacillary ; epidemiology ; prevention & control ; Humans ; Incidence ; Microbial Sensitivity Tests ; Universal Precautions

OBJECTIVES: This study was carried out to investigate the sources of infection and modes of transmission of an outbreak of shigellosis that occurred among students of B middle and high school in Bonghwa, Korea from May 1 to 21, 1999. METHODS: We conducted questionnaires to 468 students, 38 staffs and 9 food handlers twice times (May 6, May 21) for follow up and secondary attack rate. Personal details and history of illness and exposure to particular foods were sought. And we conducted rectal swab for culture to 243 students, 33 staffs and 9 food handlers. Bacteriological examinations of water in the school were done. Cases were identified as subjects who had diarrhea (two or more loose stools in a 24-hour periods) on or after May 1. RESULTS: A total of 307 cases (attack rate: 59.6%) of 515 subjects were identified, including 50 confirmed (46 students and 4 staffs) by S. sonnei. All 9 food handlers denied illness and were had rectal swab for culture at May 6 that were negative for S. sonnei. 146 of 307 reported fever, 156 had tenesmus, 44 reported vomiting, and only 5 of 307 reported blood in the stool. The median duration of diarrhea was 4 days (range: 1-18 days). The mean incubation period until onset of diarrhea was 63 hours (range: 16-144 hours) and the secondary attack rate was 2.8% (43 cases of 1,561 family members). Risk for illness was higher among students who had eaten watered kimchi at March 30 than among those who did not [301(72.7%) of 417 versus 5(9.6%) of 52; RR=7.51; 95% CI=3.26-17.31]. CONCLUSION: The source of infection was estimated to be contaminated watered kimchi by one or two food handler who is presumed to be carrier.
Diarrhea ; Dysentery, Bacillary ; Epidemiology ; Fever ; Follow-Up Studies ; Foodborne Diseases ; Humans ; Korea ; Surveys and Questionnaires ; Shigella sonnei* ; Shigella* ; Vomiting ; Water