Changing pattern of human listeriosis, England and Wales, 2001-2004

Microbiologic and epidemiologic data on 1,933 cases of human listeriosis reported in England and Wales from 1990 to 2004 were reviewed. A substantial increase in incidence occurred from 2001 to 2004. Ten clusters (60 cases), likely to represent common-source outbreaks, were detected. However, these clusters did not account for the upsurge in incidence, which occurred sporadically, predominantly in patients > or =60 years of age with bacteremia and which was independent of sex; regional, seasonal, ethnic, or socioeconomic differences; underlying conditions; or Listeria monocytogenes subtype. The reasons for the increase are not known, but since multiple L. monocytogenes strains were responsible, this upsurge is unlikely to be due to a common-source outbreak. In the absence of risk factors for listeriosis in this emerging at-risk sector of the population, dietary advice on avoiding high-risk foods should be provided routinely to the elderly and immunocompromised, not just to pregnant women.     

Transmission potential of primary pneumonic plague: time inhomogeneous evaluation based on historical documents of the transmission network

BACKGROUND: The transmission potential of primary pneumonic plague, caused by Yersinia pestis, is one of the key epidemiological determinants of a potential biological weapon, and requires clarification and time dependent interpretation. Method: This study estimated the reproduction number and its time dependent change through investigations of outbreaks in Mukden, China (1946), and Madagascar (1957). Reconstruction of an epidemic tree, which shows who infected whom, from the observed dates of onset was performed using the serial interval. Furthermore, a likelihood based approach was used for the time inhomogeneous evaluation of the outbreaks for which there was scarcity of cases. RESULTS: According to the estimates, the basic reproduction number, R(0), was on the order of 2.8 to 3.5, which is higher than previous estimates. The lower 95% confidence intervals of R(0) exceeded unity. The effective reproduction number declined below unity after control measures were introduced in Mukden, and before the official implementation in Madagascar. CONCLUSION: While the time course of the latter outbreak could be explained by intrinsic factors and stochasticity in this remote and scarcely populated area, the former in Mukden suggests the possible continued chains of transmission in highly populated areas. Using the proposed methods, the who infected whom information permitted the evaluation of the time inhomogeneous transmission potential in relation to public health measures. The study also tackles the problem of statistical estimation of R(0) based on similar information, which was previously performed simply by counting the number of secondary transmissions regardless of time.     

Dual infection with hepatitis A and E viruses in outbreaks and in sporadic clinical cases: Cuba 1998-2003

Viral hepatitis ranks as the fifth cause of morbidity for infectious diseases in Cuba. Epidemics are observed frequently in the population, the hepatitis A virus being the main agent responsible for such epidemics. Previous reports also confirmed the circulation of the hepatitis E virus. From 1998 to 2003, 258 serum samples were collected by the Reference Laboratory on Viral Hepatitis during 33 outbreaks of acute viral hepatitis as well as from 39 sporadic clinical cases. Sera were tested for anti-HAV and anti-HEV IgM by EIA. Overall of the 33 outbreaks studied sera from 12 (36.4%) were positive for anti-HAV IgM only, from 7 (21.2%) were positive for anti-HEV IgM only, and from 14 (42.4%) were positive for antibodies to both viruses. Individually of the 258 sera collected, 137 (53.1%) were positives for anti-HAV IgM, 20 (7.8%) were positives for anti-HEV IgM, 33 (12.8%) were positives for both markers and 68 (26.4%) were negative to both. Of the clinical cases, 4 (10.3%) were positives for anti-HAV IgM, 13 (33.3%) were positives for anti-HEV IgM and 5 (12.8%) were positives for both markers. Seventeen (43.6%) sera were negatives for all viral hepatitis markers available (A-E). A high positivity for HEV was found in outbreaks tested with the kit produced by CIGB. In particular HEV seems to infect individuals of all ages. The results demonstrate the co-circulation of and co-infection with two enterically transmitted viruses; however a higher positivity was observed for anti-HAV than to anti-HEV (53.1% vs. 7.8%) in outbreaks.     

肾综合征出血热流行预警指标体系研究

目的 用德尔菲(Delphi)法征求专家意见,构建肾综合征出血热流行的预警指标体系.方法 通过文献检索和专家会议法初步拟定该病流行预警指标的初始框架和预警指标,对来自全国14个省(市)、自治区的25名专家进行两轮咨询,根据指标重要性的均值大小筛选指标,权重得分的均值大小确定其权重,并用权重法确定指标的相对重要程度.结果 专家从事肾综合征出血热防控工作的平均年限为(23.80±11.70)年,两轮咨询专家的积极系数分别为100%和72%.两轮咨询Kendall协调系数分别为0.50(x2R=148.95,P＜0.01)和0.54(x2R=212.63,P＜0.01),具有统计学意义,可认为全部专家对整个评价指标意见趋于一致,咨询已经满足预测的要求;肾综合征出血热预警指标体系共包括4个一级指标(宿主动物、高危人群、社会环境和病例指标)和14个二级指标,4个一级指标的权重系数分别是0.28、0.23、0.23和0.26.结论 初步建立了肾综合征出血热流行预警指标体系,可对该病的预测、预警工作提供参考.

Abstract：

Objective To establish an early-warning indicator system on outbreak of hemorrhagic fever with renal syndrome by Delphi method seeking expert advices. Methods Firstly,the literature review and the experts meeting method were used to formulate the initiatory frame work and indicators. A two-round consultation was used to filter indicators, discuss the boundary of indicators and determine the weighting coefficient among 25 experts from 14 provinces, municipalities and autonomous regions. The relative weightiness of indicators was determined by the weight coefficients method. Results The experts' average length of service in prevention and control of hemorrhagic fever with renal syndrome was (23.80 ± 11.70) years. The positivity coefficients of the two-round experts were 100% and 72%. Kendall's coefficients of the two-round consultation were 0. 50 ( x2R = 148.95, P ＜ 0. 01 ) and 0. 54 ( x2R = 212. 63, P ＜ 0. 01 ) andopinions among experts became consistent and the consultation had achieved the need of forecast. Four firstclgss indicators (host animals, risk population, social environment and case-related indicators) and 14 second-class indicators were filtered to develop the indicators system. The weight coefficients of the first-class indicators were 0. 28,0. 23,0. 23 and 0. 26. Conclusion The early-warning index system of hemorrhagic fever with renal syndrome has been established and it could provide a reference for the forest and warning of HFRS outbreak.     

1起水源性诺如病毒腹泻暴发疫情的现场流行病学调查

目的探讨某工厂1起感染性腹泻暴发疫情的病原体和传播媒介及其防制对策。方法按照病例定义开展病例搜索,采用描述性流行病学方法进行分析,并选择罹患率最高的1个车间,采用回顾性队列研究方法,对调查对象的病例接触史、饮水习惯、就餐习惯等情况进行调查,分析可能的暴露因素。采集部分病例的粪便和肛拭子及蓄水池、直饮机、厕所洗手水等水样进行诺如病毒核酸检测。结果 2009年9月21日至10月3日,该工厂共发生病例634例,总罹患率为4.39%(634/14 439),其中男性罹患率为5.35%(411/7 677),女性罹患率为3.30%(223/6 762),男性高于女性(P<0.01)。A12栋检修科罹患率最高为21.15%(11/52),其次为A23栋总务科20.00%(4/20),第3为A15栋厨房19.57%(27/138)。回顾性队列研究共调查315人,结果显示,接触病例(RR=6.069,5%CI为3.35～10.97)和饮直饮水(RR=2.87,95%CI为1.46～5.65)是危险因素。无论是上班时还是下班时饮直饮水,直饮水饮用量与发病之间均存在剂量反应关系,饮用量越大罹患率越高(P<0.01)。共检测3份粪便1、0份肛拭子样本及13份水样,其中8份病例肛拭子样本和4份水样(2份蓄水池、1份直饮机及1份厕所洗手水的水样)中检测到诺如病毒核酸。结论该起疫情为水源性诺如病毒感染性腹泻暴发疫情。建议由市政水直接提供厂区一切生活饮用水。     

Water-related diseases outbreaks reported in Italy

Water related disease outbreak (WRDO) statistics in Italy from 1998 to 2005 have been discussed in this paper. The true incidence of WRDO is not reflected in the National Surveillance System (NSS), although this study has provided information on pathogens associated to different water sources, incidence in Regions and inadequacy of regulations. 192 outbreaks and 2546 cases of WRD were reported to the NSS, an average of 318 cases per year. Cases were associated to shellfish (58.79%), drinking water (39.94%) and agricultural products (1.25%). WRDs have been detected in 76% of Regions: central and southern Regions showed lower percentage of cases (35.4%) due to under-reporting. Most of WRD cases in the North were related to drinking water; WRDs in marine coastal Regions were mostly related to shellfish. 49% of Districts (Province) notified WRDs, including only 101 Municipalities. Pathogenic microorganisms were identified in a few cases from clinical investigations. They included enteric viruses, Norwalk viruses, Salmonella, Shigella, Giardia and Campylobacter. There is the need to improve the existing NSS in relation to WRDs. An adequate WRDs Surveillance System should be based on connection between health and environmental authorities, priority pathogens and critical areas identification, response capability and contingency plans.     

Characterization of toxigenic Vibrio cholerae from Haiti, 2010-2011

In October 2010, the US Centers for Disease Control and Prevention received reports of cases of severe watery diarrhea in Haiti. The cause was confirmed to be toxigenic Vibrio cholerae, serogroup O1, serotype Ogawa, biotype El Tor. We characterized 122 isolates from Haiti and compared them with isolates from other countries. Antimicrobial drug susceptibility was tested by disk diffusion and broth microdilution. Analyses included identification of rstR and VC2346 genes, sequencing of ctxAB and tcpA genes, and pulsed-field gel electrophoresis with SfiI and NotI enzymes. All isolates were susceptible to doxycycline and azithromycin. One pulsed-field gel electrophoresis pattern predominated, and ctxB sequence of all isolates matched the B-7 allele. We identified the tcpETCIRS allele, which is also present in Bangladesh strain CIRS 101. These data show that the isolates from Haiti are clonally and genetically similar to isolates originating in Africa and southern Asia and that ctxB-7 and tcpET(CIRS) alleles are undergoing global dissemination.