志贺菌痢暴发菌株的分子流行病学分析

目的 探讨4种基因分型方法在一起F2a志贺菌痢暴发的流行病学研究中的意义。方法 对43株从患粪便和食物中分离菌株进行质粒图谱分析、质粒DNA酶切图谱分析、随机PCR分析、setl／set2毒力基因PCR分析。结果 随机PCR将43株F2a志贺菌分为2个不同的谱型，质粒图谱、setl／set2毒力基因PCR分为3个不同的谱型。而质粒：DNA酶切图谱分为4个不同的谱型。其中基因型完全相同的菌株35株，为引起本次菌痢暴发的流行株。7株基因型不同的菌株是本次暴发期间同时存在的散发病例。从食物中分离的菌株基因型与流行株相同，证明此次暴发是通过污染的食物而引起传播的。食堂炊事员粪便中虽然分离出了F2a志贺菌，但基因型与流行株不同，不是本次暴发的传染源。结论 DNA水平上的分型方法能更为准确、深入地揭示菌痢暴发过程中各分离株之间的流行病学联系。     

Changes in the trend of shigellosis in Dhaka: family study on secondary infection, clinical manifestation and sensitivity pattern: 1980

The incidence of shigellosis and the death rate have increased and the resistance of shigellae to antibiotics has changed in Dhaka during our experiences. In 1980, we investigated the secondary infection and case rates, infection to case ratio, duration of illness, excretion of shigellae and antibiotic sensitivity pattern in 100 families with cases of shigellosis, culturing rectal swabs obtained by home visits for a 10-day period. Standard methods were used for culture and sensitivity tests. The over-all secondary infection rate in contacts was 27.3% and the case rate 10.7%. The rates were higher for Shigella flexneri than for Sh. dysenteriae. When the index cases were nought to four years old the secondary infection and case rates were higher than when index cases were older. Contacts aged nought to four years had highest attack rates. The average duration of excretion of Sh. flexneri was 4.5 and Sh. dysenteriae 2.6 days. Illness was one day longer for Sh. dysenteriae than for Sh. flexneri. Cases of shigellosis in hospital had higher rates of fever and blood in stool than those who were not in-patients. 40% of Sh. dysenteriae and 14% of Sh. flexneri were sensitive to tetracycline, 0 to 5% to streptomycin and 100% to sulphamethoxazole, trimethoprim and gentamicin. Incidence of Sh. flexneri had increased in 1980 but that of Sh. dysenteriae remained the same as in 1973 although Sh. dysenteriae type 1 appeared to be less infective in 1980 than in 1973.     

Geographic analysis of shigellosis in Vietnam

Geographic and ecological analysis may provide investigators useful ecological information for the control of shigellosis. This paper provides distribution of individual Shigella species in space, and ecological covariates for shigellosis in Nha Trang, Vietnam. Data on shigellosis in neighborhoods were used to identify ecological covariates. A Bayesian hierarchical model was used to obtain joint posterior distribution of model parameters and to construct smoothed risk maps for shigellosis. Neighborhoods with a high proportion of worshippers of traditional religion, close proximity to hospital, or close proximity to the river had increased risk for shigellosis. The ecological covariates associated with Shigella flexneri differed from the covariates for Shigella sonnei. In contrast the spatial distribution of the two species was similar. The disease maps can help identify high-risk areas of shigellosis that can be targeted for interventions. This approach may be useful for the selection of populations and the analysis of vaccine trials.     

Risk factors for carotid artery stenosis: an epidemiological study of men aged 69 years

Four hundred and seventy-eight men born in 1914 and residing in the city of Malm?, Sweden, underwent ultrasonic Doppler examination of the carotid arteries in 1982/83. The known risk factors for vascular disease--blood pressure, lipids, glucose, hematocrit, alcohol consumption and Body Mass Index were also measured. A moderate stenosis (diameter reduction 30-59%) of the internal carotid artery was found in 95 men (20%); 15 men (3%) had a greater than or equal to 60% stenosis of the internal carotid artery, while 7 (1.5%) had complete unilateral occlusion. Smoking was found to be significantly related to severe carotid artery disease. There was also a significant correlation between maximum flow velocity in the internal carotid artery and triglycerides. Those quitting smoking before the age of 50 had the same incidence of internal carotid artery disease as non-smokers, while those quitting later in life had a slightly higher incidence than life-long smokers.     

Path analysis: application in an epidemiological study of echinococcosis in New Zealand.

The method of path analysis is described in detail. Application of this analyogical systems is demonstrated using data from an epidemiological study of echinococcosis in New Zealand. The results identified the major causal pathways determining Echinococcus granulosus prevalence in dogs, based on multiple regression analysis of a linear causal model constructed from prior biological and epidemiological knowledge. Only ethnic and sheep husbandry variables had important direct effect on prevalence in the North Island of New Zealand, with some climate factors (maximum temperature and relative humidity) and soil porosity acting indirectly through animal husbandry practices. It is suggested that path analysis, by permitting interaction between epidemiological theory and statistical analysis, provides a valuable additional tool to epidemiologists for the study of causal relationships among variables in multivariates systems.     

Epidemic Reiter's syndrome following an outbreak of shigellosis

We prospectively studied the occurrence of Reiter's syndrome (RS) or reactive arthritis (ReA) in 205 of 349 cruise-ship passengers who attended a buffet ashore and developed Shigella flexneri 2a enteritis. Five passengers probably had RS/ReA and 16 were possible or doubtful cases of RS/ReA. HLA-B27 was identified in 4 of 5 probable RS cases, but was not present in any of the 16 possible or doubtful cases nor in any of 20 passengers (controls) without any symptoms of RS/ReA. There was no statistically significant difference in the frequency of B7-Creg antigens in persons with possible or doubtful RS/ReA (9/16) compared to controls (8/20).currently with Center for Vaccine Development University of Maryland, Baltimore, MD.Corresponding author.     

福建省2005-2009年流行性乙型脑炎流行病学分析

目的了解福建省2005-2009年流行性乙型脑炎（乙脑）流行病学特征,为制定福建省乙脑监测及控制策略提供依据。方法对2005-2009年福建省乙脑疫情报告资料进行回顾性分析。结果福建省2005-2009年共报告174例乙脑病例,年均发病率0.0980/10万。历年发病率均低于全国同期水平。174例病例发生在除厦门市外的8个地市、57个县。7月份为发病高峰,占总病例的64.94%,其次为6月和8月。83.33%的病例集中在15岁以下儿童,在131例有调查资料的病例中,50.38%无免疫史。结论福建省自2004年将乙脑疫苗纳入儿童计划免疫后,乙脑发病率处于低发水平,控制效果较为显著。在乙脑高发地区必须进一步制定强有力的措施提高乙脑疫苗接种的及时率和全程接种率。     

An epidemic of cholera due to Vibrio cholerae O139 in Dhaka, Bangladesh: clinical and epidemiological features.

We describe the disease spectrum and socio-demographic and epidemiological features of an epidemic of cholera due to a new pathogen, Vibrio cholerae O139, in patients attending a very large hospital in the metropolitan city of Dhaka, Bangladesh. This hospital treats 70,000-90,000 patients a year with diarrhoeal diseases. A 4% systematic sample of 1854 patients attending from January to April 1993 were studied. Five hundred and two (27%) of the 1854 patients were culture positive for V. cholerae O139 and 63 (3%) were culture positive for V. cholerae O1 biotype El Tor. Patients with V. cholerae O139 were mainly adults with a short history of watery diarrhoea. Eight-three percent of patients had moderate to severe dehydration. All recovered except one 80-year-old man with compromised renal function who died. Seventy-eight percent of patients required initial intravenous rehydration followed by oral rehydration therapy with rice ORS; they also received tetracycline to reduce diarrhoea severity. Most patients were from urban slums with inadequate sanitation facilities and hygiene practices. The newly recognized V. cholerae O139 infection produced an epidemic of severe dehydrating diarrhoea indistinguishable from clinical cholera in a population which experiences two epidemic peaks of cholera in a year due to V. cholerae O1. Infection with the latter does not appear to confer any cross-protection from V. cholerae O139. The new pathogen suppressed, albeit temporarily, V. cholerae O1. Unlike other non-O1 serogroups of V. cholerae this new serogroup appears to have epidemic potential.     

Expected epidemiological impacts of introducing an HIV vaccine in Thailand: a model-based analysis

Background

The RV144 trial conducted in Thailand was the first to demonstrate modest protective efficacy of an HIV vaccine. Its estimated initial efficacy was ∼74%, but this waned considerably over time.

Methods

We developed a mathematical model to reflect historical and current HIV trends across different at-risk populations in Thailand. The model was used to estimate the expected number of infections that would be averted if a vaccine with outcome characteristics similar to the RV144 vaccine was implemented in Thailand at varying levels of coverage.

Results

In the absence of a vaccine, we projected roughly 65,000 new HIV infections among adults during the period between 2011 and 2021. Due to the waning efficacy of the vaccine, vaccination campaigns were found to have modest long-term public health benefit unless re-vaccination occurred. We forecast that an RV144-like vaccine with coverage of 30% of the population would lead to a 3% reduction in HIV incidence during the next 10 years. In comparison, 30% coverage of annual or biennial re-vaccination with the vaccine was found to result in 23% and 14% reductions in incidence, respectively. Coverage of 60% without re-vaccination resulted in a 7% reduction. Epidemiological outcomes were found to depend primarily on three factors: vaccination coverage, vaccine efficacy, and the duration of protection the vaccine provided.

Discussion

Due to the short duration of protection the vaccine provides without re-vaccination, our model predicts modest benefit from a vaccination campaign with an RV144-like HIV vaccine in Thailand. Annual or biannual re-vaccination is predicted to greatly increase the long-term public health benefits of a vaccination campaign. The feasibility of vaccine implementation, as well as its economic viability, remains to be determined.     

Restaurant-associated outbreak of Salmonella typhi in Nauru: an epidemiological and cost analysis.

Typhoid fever is endemic in the South Pacific. We investigated an outbreak in Nauru. Through interviews and medical records, we identified 50 persons with onset between 1 October 1998 and 10 May 1999, of fever lasting > or = 3 days and one other symptom. Salmonella Typhi was isolated from 19 (38%) cases. Thirty-two (64%) patients were school-aged children, and 17 (34%) were in four households. Case-control studies of (a) culture-confirmed cases and age- and neighbourhood-matched controls; and (b) household index cases and randomly selected age-matched controls implicated two restaurants: Restaurant M (matched OR [MOR] = 11, 95% confidence interval [CI] = 1.3-96) and Restaurant I (MOR = 5.8, 95% CI = 1.2-29). Food-handlers at both restaurants had elevated anti-Vi antibody titres indicative of carrier state. The annual incidence was 5.0/1000 persons. Outbreak-associated costs were $46,000. Routine or emergency immunization campaigns targeting school-aged children may help prevent or control outbreaks of typhoid fever in endemic disease areas.     

Rotavirus infections and climate variability in Dhaka, Bangladesh: a time-series analysis

Attempts to explain the clear seasonality of rotavirus infections have been made by relating disease incidence to climate factors; however, few studies have disentangled the effects of weather from other factors that might cause seasonality. We investigated the relationships between hospital visits for rotavirus diarrhoea and temperature, humidity and river level, in Dhaka, Bangladesh, using time-series analysis adjusting for other confounding seasonal factors. There was strong evidence for an increase in rotavirus diarrhoea at high temperatures, by 40.2% for each 1 degrees C increase above a threshold (29 degrees C). Relative humidity had a linear inverse relationship with the number of cases of rotavirus diarrhoea. River level, above a threshold (4.8 m), was associated with an increase in cases of rotavirus diarrhoea, by 5.5% per 10-cm river-level rise. Our findings provide evidence that factors associated with high temperature, low humidity and high river-level increase the incidence of rotavirus diarrhoea in Dhaka.     

The analysis of recurrence risk as an epidemiological tool

Recurrence risk provides information on the heterogeneity of risk in the population, and thus is useful for aetiological studies. While recurrence risk is observable in many areas of epidemiology, it is particularly accessible in the study of perinatal events. High recurrence rates of pregnancy problems suggest genetic causes, but can also reflect the presence of persistent environmental causes. Specific patterns of recurrence risk can provide further clues about the relative importance of genetic vs. environmental factors, for example through comparisons of recurring pregnancy problems in women who change their male partner and women who keep the same partner. Interpretation of recurrence risk is subject to confusion from bias and confounding, and some examples are discussed. In addition to providing information on causality, recurrence risk offers a means for more efficient design of aetiological studies.     

Suicide in Canada: an epidemiological assessment

Suicide rates in Canada rapidly increased during the 1960s and 1970s. More recent analysis of these trends indicates that in males suicide rates have stabilized and in females a notable decrease has been identified. The greatest changes in suicide rates have occurred among the youngest age groups (15 to 19), while little change has occurred in suicide mortality rates for males aged 50 years and over. The age-specific death rates in 1986 are uniformly distributed in males above age 20, while in females an inverted "U" curve is demonstrated with the peak at age 45-50. Males continue to have higher rates and the difference between males and females is expanding. A birth cohort analysis indicates that the contribution of the birth cohort to explaining suicide rates has diminished and been replaced by a more recent period effect. Suicide remains the second most important cause of death of persons between 15 and 34 years of age. Provincial variation is discussed through geographic variation, cause-specific rankings and potential years of life lost. In contrast to national trends, suicide mortality in Alberta, Quebec and New Brunswick continues to increase. An atlas is provided to display Canadian census divisions that exhibit elevated rates of suicide.     

Measles in Europe: an epidemiological assessment

Measles in Europe: an epidemiological assessment .
Muscat M. , Bang H. , Wohlfahrt J. , Glismann S. & Mølbak K. , for the EUVAC.NET Group . ( 2009 ) The Lancet , 373 , 383 – 389 .     

An outbreak of shigellosis at an outdoor music festival

In August 1988, an estimated 3,175 women who attended a 5-day outdoor music festival in Michigan became ill with gastroenteritis caused by Shigella sonnei. Onset of illness peaked 2 days after the festival ended, and patients were spread throughout the United States by the time the outbreak was recognized. An uncooked tofu salad served on the last day was implicated as the outbreak vehicle (odds ratio = 3.4, p less than 0.0001). Over 2,000 volunteer food handlers prepared the communal meals served during the festival. This large foodborne outbreak had been heralded by a smaller outbreak of shigellosis among staff shortly before the festival began and by continued transmission of shigellosis from staff to attendees during the festival. S. sonnei isolated from women who became ill before, during, and after the festival had identical antimicrobial susceptibility patterns and plasmid profiles. Limited access to soap and running water for handwashing was one of the few sanitary deficits noted at this gathering. This investigation demonstrates the need for surveillance and prompt public health intervention when Shigella infections are recognized in persons attending mass outdoor gatherings, the singular importance of handwashing in reducing secondary transmission of shigellosis, and the potential for explosive outbreaks when communal meals are prepared by large numbers of food handlers.     

Guidelines for regional mortality analysis: an epidemiological approach to health planning

In view of the epidemiological responsibility that the new Swedish health legislation gives to the local county councils, it has been increasingly necessary to identify and monitor the health status of the local population, eg the commune. As part of a large-scale collaborative project this paper focuses on problems of analysing regional mortality data and presents an attempt to deal with them by means of a systematic procedure.