Aseptic meningitis epidemic during a West Nile virus avian epizootic

While enteroviruses have been the most commonly identified cause of aseptic meningitis in the United States, the role of the emerging, neurotropic West Nile virus (WNV) is not clear. In summer 2001, an aseptic meningitis epidemic occurring in an area of a WNV epizootic in Baltimore, Maryland, was investigated to determine the relative contributions of WNV and enteroviruses. A total of 113 aseptic meningitis cases with onsets from June 1 to September 30, 2001, were identified at six hospitals. WNV immunoglobulin M tests were negative for 69 patients with available specimens; however, 43 (61%) of 70 patients tested enterovirus-positive by viral culture or polymerase chain reaction. Most (76%) of the serotyped enteroviruses were echoviruses 13 and 18. Enteroviruses, including previously rarely detected echoviruses, likely caused most aseptic meningitis cases in this epidemic. No WNV meningitis cases were identified. Even in areas of WNV epizootics, enteroviruses continue to be important causative agents of aseptic meningitis.     

H2 strain attenuated live hepatitis A vaccines:protective efficacy in a hepatitis A outbreak

AIM:To investigate the protective efficacy of H2 strain attenuated live hepatitis A vaccines (H2-strain vaccines) in hepatitis A (HA) outbreaks.METHODS:With the permission of their parents, 5551 pre-school and grade 1-3 primary school children were inoculated with 1 dose (10(6.5) TCID(50)) of H2 strain vaccines in a nonrandomized, controlled trial conducted in Fucheng County, Hebei Province in May 1997.Another 6485 children in the same grades and compatible in gender and age were enrolled as controls. Epidemiological and serological survey was conducted to evaluate the protective efficacy of the vaccines. ELISA was used to detect serum IgM anti-HAV.RESULTS:HA outbreak started in early May 1998, peaked in the middle of the same month, and lasted about 80 days. Overall 302 HA cases were found, 192(63.58%) were 5-9 years old. One vaccinee and 25 control cases were found to have hepatitis A, which account for 0.28% (1/356) and 5.92% (25/422) of all vaccinees and controls in the 14 villages, respectively. The protective efficacy of vaccines was 95.27% (95% CI: 85.83%-104.72%). In subjects tested for anti-HAV IgM from 13 villages, 1(0.40%) overt and 11(4.06%) asymptomatic HAV cases were found in 271 vaccinees but 21(6.69%) of overt and asymptomatic ones were found in 314 controls.CONCLUSION:H2 strain vaccines were excellent in preventing overt hepatitis A,but not so effective in preventing asymptomatic hepatitis A virus infection.A booster dose might be needed to get permanent reliable immunity.     

Association Between Human Cases and Poultry Outbreaks of Highly Pathogenic Avian Influenza in Vietnam From 2003 to 2007: A Nationwide Study

This study quantifies the spatio‐temporal association between outbreaks of highly pathogenic avian influenza H5N1 in domestic poultry (n = 3050) and human cases (n = 99) in Vietnam during 2003–2007, using rare events logisitic regression. After adjusting for the effect of known confounders, the odds of a human case being reported to authorities increased by a factor of 6.17 [95% confidence interval (CI) 3.33–11.38] and 2.48 (95% CI 1.20 – 5.13) if poultry outbreaks were reported in the same district 1 week and 4 weeks later respectively. When jointly considering poultry outbreaks in the same and neighbouring districts, occurrence of poultry outbreaks in the same week, 1‐week later, and 4 weeks later increased the odds of a human case by a factor of 2.75 (95% CI 1.43–5.30), 2.56 (95% CI 1.31–5.00) and 2.70 (95% CI 1.56–4.66) respectively. Our study found evidence of different levels of association between human cases and poultry outbreaks in the North and the South of the country. When considering the 9‐week interval extending from 4 weeks before to 4 weeks after the week of reporting a human case, in the South poultry outbreaks were recorded in 58% of cases in the same district and 83% of cases in either the same or neighbouring districts, whereas in the North the equivalent results were only 23% and 42%. The strength of the association between human and poultry cases declined over the study period. We conclude that owner reporting of clinical disease in poultry needs to be enhanced by targeted agent‐specific surveillance integrated with preventive and other measures, if human exposure is to be minimized.     

Evaluation of live attenuated S79 mumps vaccine effectiveness in mumps outbreaks: a matched case-control study

Background Mumps virus infection is a potentially serious viral infection of childhood and early adulthood. In China, live attenuated S79 mumps vaccine has been licensed for pediatric use since 1990. The objective of this study was to determine the effectiveness of live attenuated S79 mumps vaccine against clinical mumps in outbreaks. Methods Cases were selected from mumps outbreaks in schools in Guangzhou between 2004 and 2005. Each case was matched by gender, age and classroom. Vaccination information was obtained from Children＇s EPI Administrative Computerized System. Vaccine effectiveness （VE） was calculated for 1 or 2 doses of S79 vaccine with 95% confidence intervals （CI）. Results One hundred and ninety-four cases and 194 controls were enrolled into the study. VE of the S79 mumps vaccine for 1 dose versus 0 confer protection 80.4% （95% Cl, 60.0%-90.4%） and VEs against mumps in outbreaks for 1 dose of mumps vaccine are similar among those children aged 4-9 years and aged over 10 years old. Conclusion The live attenuated S79 mumps vaccine can be effective in preventing clinical mumps outbreaks.     

Fluctuations in density of an outbreak species drive diversity cascades in food webs

Patterns in food-web structure have frequently been examined in static food webs, but few studies have attempted to delineate patterns that materialize in food webs under nonequilibrium conditions. Here, using one of nature's classical nonequilibrium systems as the food-web database, we test the major assumptions of recent advances in food-web theory. We show that a complex web of interactions between insect herbivores and their natural enemies displays significant architectural flexibility over a large fluctuation in the natural abundance of the major herbivore, the spruce budworm (Choristoneura fumiferana). Importantly, this flexibility operates precisely in the manner predicted by recent foraging-based food-web theories: higher-order mobile generalists respond rapidly in time and space by converging on areas of increasing prey abundance. This "birdfeeder effect" operates such that increasing budworm densities correspond to a cascade of increasing diversity and food-web complexity. Thus, by integrating foraging theory with food-web ecology and analyzing a long-term, natural data set coupled with manipulative field experiments, we are able to show that food-web structure varies in a predictable manner. Furthermore, both recent food-web theory and longstanding foraging theory suggest that this very same food-web flexibility ought to be a potent stabilizing mechanism. Interestingly, we find that this food-web flexibility tends to be greater in heterogeneous than in homogeneous forest plots. Because our results provide a plausible mechanism for boreal forest effects on populations of forest insect pests, they have implications for forest and pest management practices.     

Concurrent Chikungunya and Dengue Virus Infections during Simultaneous Outbreaks, Gabon, 2007

An outbreak of febrile illness occurred in Gabon in 2007, with 20,000 suspected cases. Chikungunya or dengue-2 virus infections were identified in 321 patients; 8 patients had documented co-infections. Aedes albopictus was identified as the principal vector for the transmission of both viruses.     

Isolation rooms for highly infectious diseases: an inventory of capabilities in European countries

Isolation of patients with highly infectious diseases (HIDs) in hospital rooms with adequate technical facilities is essential to reduce the risk of spreading disease. The European Network for Infectious Diseases (EUNID), a project co-funded by European Commission and involving 16 European Union member states, performed an inventory of high level isolation rooms (HIRs, hospital rooms with negative pressure and anteroom). In participating countries, HIRs are available in at least 211 hospitals, with at least 1789 hospital beds. The adequacy of this number is not known and will depend on prevailing circumstances. Sporadic HID cases can be managed in the available HIRs. HIRs could also have a role in the initial phases of an influenza pandemic. However, large outbreaks due to natural or to bioterrorist events will need management strategies involving healthcare facilities other than HIRs.     

集中式供水污染致诺如病毒感染性腹泻暴发的调查

目的 了解一起感染性腹泻暴发的病因、感染来源,采取针对性措施控制疫情蔓延.方法 对涉疫的Y镇北部5个村委会的现住居民进行回顾性队列研究,用统一的调查表登记2007年11月20日以来所有有腹泻或呕吐症状之一者.对Y镇北部5个村委会的供水系统、3个自然村的环境及部分患者家庭进行现场卫生学调查.面访部分病例.用Real-time PCR和巢式PCR方法 检测患者粪便标本诺如病毒核酸.结果 2007年11月24日至12月3日,Y镇北部饮用A自备自来水的村民共发生腹泻或呕吐病例435例,发病率12.93%.病例分布在饮用A自备自来水的所有村委会,最高发病率21.23%(100/471),最低5.21%(20J/3s4),饮用A自备自来水与发病之间有关联性(RR=9246,95%C/:6.25～13.68).发病时间集中在25-27日,占85.9%(262/305).调查S2村委会某自然村年龄别发病率分别为,0岁～组20.0%(3/15)、10岁～组17.3%(9/52)、20岁～15.2%(16/105)、60岁以上23.3%(7/30),各年龄组差异无统计学意义(X2=1.15,P>0.05).病例大多病情较轻,经门诊对症治疗后痊愈,无住院和死亡病例.现场调查和水质日常监测发现水处理过程存在消毒不落实的情况.A自备自来水水质检测细菌学指标不合格.患者2份呕吐物和1份粪便未检出沙门菌、志贺菌和金黄色葡萄球菌,3份患者粪便和3份患者肛拭诺如病毒检测,Real-timePCR 3份阳性,巢式PCR 6份阳性.对供水管网进行清洗消毒后病例迅速递减.采取消毒饮用水和健康教育等综合措施后,疫情迅速得到有效控制.结论 本次疫情为一起诺如病毒感染性腹泻暴发,可能是因A自备自来水受污染而引起的暴发.