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Norovirus gastroenteritis general outbreak associated with raw shellfish consumption in South Italy
Rosa Prato, Pier Lopalco, Maria Chironna, Giovanna Barbuti, Cinzia Germinario, Michele Quarto
BMC Infectious Diseases , 2004, DOI: 10.1186/1471-2334-4-37
Abstract: A retrospective cohort study was performed in order to assess risk factors associated with illness. All households where a case occurred were included in the study. Faecal specimens were collected from ill individuals. NV-specific RT-PCR was performed. Eleven samples of mussels were collected from fish-markets involved in the outbreak. A nested PCR was used for mussel samples.One hundred and three cases, detected by means of active surveillance, met the case definition. Raw shellfish eating was the principal risk factor for the disease, as indicated by the analytic issues (Risk Ratio: 1.50; IC 95%: 1.18 – 1.89; p < 0.001). NVs were found by means of RT-PCR of all the stool specimens from the 24 patients tested. Eleven samples of shellfish from local markets were tested for the presence or NVs; six were positive by nested PCR and genotypes were related to that found in patients' stools.This is the first community outbreak caused by NVs related to sea-food consumption described in Italy. The study confirms that the present standards for human faecal contamination do not seem to be a reliable indicator of viral contaminants in mussels.Norovirus (NV, previously "Norwalk-like viruses"), one of four genera in the Caliciviridae family, includes a group of morphologically similar but genetically different single-stranded RNA viruses. NVs represent the most important cause of non-bacterial gastroenteritis worldwide. In industrialised countries NVs may be responsible for up to 80% of all outbreaks of gastroenteritis [1]. Outbreaks may affect all age groups and generally occur in crowded communities such as restaurants, tourist resorts, hospitals, schools and nursing homes.Contaminated food or water commonly represents the main source of infection. Epidemics spread by the faecal-oral route, even if transmission may also occur through direct person-to-person contact or aerosolised viral particles.The incubation period of NV gastroenteritis is 24–48 hours and symptoms include vo
Influence of Novel Norovirus GII.4 Variants on Gastroenteritis Outbreak Dynamics in Alberta and the Northern Territories, Canada between 2000 and 2008  [PDF]
Xiaoli L. Pang,Jutta K. Preiksaitis,Sallene Wong,Vincent Li,Bonita E. Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0011599
Abstract: Norovirus GII.4 is the predominant genotype circulating worldwide over the last decade causing 80% of all norovirus outbreaks with new GII.4 variants reported in parallel with periodic epidemic waves of norovirus outbreaks. The circulating new GII.4 variants and the epidemiology of norovirus outbreaks in Alberta, Canada have not been described. Our hypothesis is that the periodic epidemic norovirus outbreak activity in Alberta was driven by new GII.4 variants evolving by genetic drift.
The Dynamics of Norovirus Outbreak Epidemics: Recent Insights  [PDF]
John A. Marshall,Leesa D. Bruggink
International Journal of Environmental Research and Public Health , 2011, DOI: 10.3390/ijerph8041141
Abstract: Noroviruses are a major cause of gastroenteritis outbreaks worldwide. Norovirus outbreaks frequently occur as epidemics which appear to be related to both genetic and environmental factors. This review considers recent progress in understanding these factors. The norovirus genome undergoes continuous change and this appears to be important in the persistence of the virus in the community. Studies on the common GII.4 genotype have shown that some norovirus outbreak epidemics involving this genotype are correlated with specific changes in the genome. In contrast to the growing understanding of the role of genetic factors in norovirus outbreak epidemics, the role of environmental factors is less well understood. Topics reviewed here include long term excretion of norovirus in some individuals, long term survivability of norovirus in the environment, the role of meteorological factors in the control of norovirus outbreaks and the possible zoonotic transmission of the virus.
A Gastroenteritis Outbreak Caused by Noroviruses in Greece  [PDF]
Apostolos Vantarakis,Kassiani Μellou,Georgia Spala,Petros Kokkinos,Yiannis Alamanos
International Journal of Environmental Research and Public Health , 2011, DOI: 10.3390/ijerph8083468
Abstract: In June 2006, an outbreak alert regarding cases of acute gastroenteritis in a region in North Eastern Greece (population 100,882 inhabitants), triggered investigations to guide control measures. The outbreak started the first days of June, and peaked in July. A descriptive epidemiological study, a virological characterization of the viral agent identified from cases as well as a phylogenetic analysis was performed. From June 5 to September 3, 2006 (weeks 23–44), 1,640 cases of gastroenteritis (45.2% male and 54.8% female, aged 3 months to 89 years) were reported. The overall attack rate for the period was 16.3 cases/1,000 inhabitants. About 57% of cases observed were under the age of 15 years. Αnalysis of faecal samples identified Norovirus GII strains. Fifteen different Norovirus GII strains were recorded, presenting a homology of 94.8% (86–97%) to GII strains obtained from GenBank. The long duration of the outbreak suggests an important role of person-to-person transmission, while the emergence of the outbreak was possibly due to contaminated potable water, although no viruses were detected in any tested water samples. This outbreak underscores the need for a national surveillance system for acute non-bacterial gastroenteritis outbreaks.
Foodborne norovirus outbreak: the role of an asymptomatic food handler
Irene Barrabeig, Ariadna Rovira, Javier Buesa, Rosa Bartolomé, Rosa Pintó, Hortènsia Prellezo, àngela Domínguez
BMC Infectious Diseases , 2010, DOI: 10.1186/1471-2334-10-269
Abstract: A retrospective cohort study was designed. Personal or telephone interview was carried out to collect demographic, clinical and microbiological data of the exposed people, as well as food consumption in the suspected lunch. Food handlers of the mentioned summer camp were interviewed.Ten stool samples were requested from symptomatic exposed residents and the three food handlers that prepared the suspected food. Stools were tested for bacteries and noroviruses. Norovirus was detected using RT-PCR and sequence analysis.Attack rate, relative risks (RR) and its 95% confidence intervals (CI) were calculated to assess the association between food consumption and disease.The global attack rate of the outbreak was 55%. The main symptoms were abdominal pain (90%), nausea (85%), vomiting (70%) and diarrhoea (42.5%). The disease remitted in 24-48 hours. Norovirus was detected in seven faecal samples, one of them was from an asymptomatic food handler who had not eaten the suspected food (round of beef), but cooked and served the lunch. Analysis of the two suspected foods isolated no pathogenic bacteria and detected no viruses. Molecular analysis showed that the viral strain was the same in ill patients and in the asymptomatic food handler (genotype GII.2 Melksham-like).In outbreaks of foodborne disease, the search for viruses in affected patients and all food handlers, even in those that are asymptomatic, is essential. Health education of food handlers with respect to hand washing should be promoted.The consumption of food contaminated by microorganisms is a common cause of gastroenteritis outbreaks in developed countries. Historically, bacteria have been the most-frequent causal agents, although the causal microorganism is not identified on many occasions [1-3].Norovirus, a member of the Caliciviridae family, is considered the major cause of acute gastroenteritis in all age groups worldwide [4]. The majority of human noroviruses can be classified into two genogroups, I (GI) and
Viral Gastroenteritis Associated with Genogroup II Norovirus among U.S. Military Personnel in Turkey, 2009  [PDF]
Salwa F. Ahmed, John D. Klena, Manal Mostafa, Jessica Dogantemur, Tracy Middleton, James Hanson, Peter J. Sebeny
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035791
Abstract: The present study demonstrates that multiple NoV genotypes belonging to genogroup II contributed to an acute gastroenteritis outbreak at a US military facility in Turkey that was associated with significant negative operational impact. Norovirus (NoV) is an important pathogen associated with acute gastroenteritis among military populations. We describe the genotypes of NoV outbreak occurred at a United States military facility in Turkey. Stool samples were collected from 37 out of 97 patients presenting to the clinic on base with acute gastroenteritis and evaluated for bacterial and viral pathogens. NoV genogroup II (GII) was identified by RT-PCR in 43% (16/37) stool samples. Phylogenetic analysis of a 260 base pair fragment of the NoV capsid gene from ten stool samples indicated the circulation of multiple and rare genotypes of GII NoV during the outbreak. We detected four GII.8 isolates, three GII.15, two GII.9 and a sole GII.10 NoV. Viral sequences could be grouped into four clusters, three of which have not been previously reported in Turkey. The fact that current NoV outbreak was caused by rare genotypes highlights the importance of norovirus strain typing. While NoV genogroup II is recognized as causative agent of outbreak, circulation of current genotypes has been rarely observed in large number of outbreaks.
An outbreak of gastroenteritis in a holiday resort in Italy: epidemiological survey, implementation and application of preventive measures  [PDF]
Giacomo Migliorati,Vincenza Prencipe,Alessandro Ripani,Cristina Di Francesco
Veterinaria Italiana , 2008,
Abstract: A major gastroenteritis outbreak was reported in a vacation resort in Central Italy in 2003. A total of 183 cases were identified. The case-control study identified a statistically significant correlation between the disease and sea bathing, use of sanitary facilities in bungalows and of common showers. Stool samples taken from people affected were found positive for Norovirus (68%, 13 of 19 samples), Rotavirus (38%, 1 of 14 samples) and Campylobacter (7%, 3 of 8 samples). Environmental investigations revealed serious faecal contamination of the groundwater and the presence of Norovirus in the seawater near the resort. The mixing of groundwater and seawater with the non-drinking water system - which was also found to be connected to the drinking water system - had a primary role in the onset and spread of infection within the village. The complete absence of any gastroenteritis epidemics among the site guests since 2006 demonstrates the effectiveness of the environmental corrective measures taken.
Electronic Outbreak Surveillance in Germany: A First Evaluation for Nosocomial Norovirus Outbreaks  [PDF]
Anja M. Hauri,Hans-Jürgen Westbrock,Herman Claus,Steffen Geis,Siegfried Giernat,Michael Forβbohm,Helmut Uphoff
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017341
Abstract: In Germany, surveillance for infectious disease outbreaks is integrated into an electronic surveillance system. For 2007, the national surveillance database contains case-based information on 201,224 norovirus cases, three-quarters of which are linked to outbreaks. We evaluated the data quality of the national database in reflecting nosocomial norovirus outbreak (NNO) data available in 19 Hessian local public health authorities (LPHAs) and the influence of differences between LPHA's follow-up procedures for laboratory notifications of Norovirus positive stool samples on outbreak underascertainment.
Food-borne norovirus-outbreak at a military base, Germany, 2009
Maria Wadl, Kathrin Scherer, Stine Nielsen, Sabine Diedrich, Lüppo Ellerbroek, Christina Frank, Renate Gatzer, Marina Hoehne, Reimar Johne, Günter Klein, Judith Koch, J?rg Schulenburg, Uta Thielbein, Klaus Stark, Helen Bernard
BMC Infectious Diseases , 2010, DOI: 10.1186/1471-2334-10-30
Abstract: During 7-9 January, 2009, 36 persons at a military base in Germany fell ill with acute gastroenteritis. Food from the military base's canteen was suspected as vehicle of infection, norovirus as the pathogen causing the illnesses. An investigation was initiated to describe the outbreak's extent, to verify the pathogen, and to identify modes of transmission and source of infection to prevent further cases.For descriptive analysis, ill persons were defined as members of the military base with acute onset of diarrhoea or vomiting between 24 December 2008, and 3 February 2009, without detection of a pathogen other than norovirus in stools. We conducted a retrospective cohort study within the headquarters company. Cases were military base members with onset of diarrhoea or vomiting during 5-9 January. We collected information on demographics, food items eaten at the canteen and contact to ill persons or vomit, using a self-administered questionnaire. We compared attack rates (AR) in exposed and unexposed persons, using bivariable and multivariable logistic regression modelling. Stool specimens of ill persons and canteen employees, canteen food served during 5-7 January and environmental swabs were investigated by laboratory analysis.Overall, 101/815 (AR 12.4%) persons fell ill between 24 December 2008 and 3 February 2009. None were canteen employees. Most persons (n = 49) had disease onset during 7-9 January. Ill persons were a median of 22 years old, 92.9% were male. The response for the cohort study was 178/274 (72.1%). Of 27 cases (AR 15.2%), 25 had eaten at the canteen and 21 had consumed salad. Salad consumption on 6 January (aOR: 8.1; 95%CI: 1.5-45.4) and 7 January (aOR: 15.7; 95%CI: 2.2-74.1) were independently associated with increased risk of disease.Norovirus was detected in 8/28 ill persons' and 4/25 canteen employees' stools, 6/55 environmental swabs and 0/33 food items. Sequences were identical in environmental and stool samples (subtype II.4 2006b), except f
An Outbreak of Gastroenteritis of Unknown Origin in Tehran, July 2003
E. Salimkhani,R. Ranjbar,N. Sadeghifard,S. Morovvati
Pakistan Journal of Biological Sciences , 2007,
Abstract: : Aim of this study was to determine the causative agent and source of a large gastroenteritis outbreak occurred in a national financial center (CBIRI) in July 2003. A patient definition was defined staff were interviewed in the clinic of the Bank and their information were collected by means of a standardized questionnaire. A total of 110 fecal specimens were collected within 48 h of symptom onset from 100 patients with symptoms of gastroenteritis and 10 restaurant staff. The specimens were processed within 12 h to detect ova and parasites by direct microscopy and common bacteria by standard methods. The outbreak started on 22 July 2003 lasted 4 days. From a total of 1300 staff. 535 persons experienced a severe gastrointestinal illness. None but one of tested fecal samples were positive for bacterial enteric pathogens. S. paratyphi B was isolated from the positive case. Definitive association between illness and isolated S. paratyphi B remained to be determined since it was isolated only from one case. There is a need, however, for increased awareness among both professionals and the public to implement appropriate prevention measures and monitoring of food and water.
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