Waterborne Outbreak Of Gastroenteritis Research Articles

A Waterborne Gastroenteritis Outbreak Caused by a GII Norovirus in a Holiday Camp in Catalonia (Spain), 2017.

On 2 February 2017, Epidemiological Surveillance Services were notified of an outbreak of acute gastroenteritis (AGE) among schoolchildren who had taken part of a school trip from 30 January to 3 February 2017 at a holiday camp in Catalonia. A retrospective cohort study was performed to identify the causative agent, estimate the magnitude of the outbreak and identify its source, as well as to determine the route of transmission. Data collected by standardised questionnaires identified 41 episodes of AGE among 174 individuals who attended the camp. Cases had mainly symptoms of abdominal pain (73.8%), nausea (64.3%), vomiting (54.8%), diarrhoea (45.2%) and headache (42.9%). Consumption of water was associated with gastroenteritis (crude RR: 1.72, 95%CI: 1.01–2.92; adjusted RR: 1.88, 95%CI 1.03–3.56). NoV GII was detected in faeces (5 out of 13) and water samples. Additionally, faecal indicator bacteria and protozoa were detected in water samples. The outbreak showed a high attack rate and was caused by a natural water fountain not properly treated and not monitored for safety quality. There could have been a discharge of wastewater at a point close to the fountain; however, the source of contamination of the water could not be identified. Health education may be useful to eliminate risks associated with the consumption of untreated water from natural fountains.

Waterborne outbreak of gastroenteritis on the KwaZulu-Natal Coast, South Africa, December 2016/January 2017 - CORRIGENDUM.

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Waterborne outbreak of gastroenteritis on the KwaZulu-Natal Coast, South Africa, December 2016/January 2017.

An unexpected increase in gastroenteritis cases was reported by healthcare workers on the KwaZulu-Natal Coast, South Africa, January 2017 with >600 cases seen over a 3-week period. A case-control study was conducted to identify the source and risk factors associated with the outbreak so as to recommend control and prevention measures. Record review identified cases and controls and structured-telephonic interviews were conducted to obtain exposure history. Stool specimens were collected from 20 cases along with environmental samples and both screened for enteric pathogens. A total of 126 cases and 62 controls were included in the analysis. The odds of developing gastroenteritis were 6.0 times greater among holiday makers than residents (95% confidence interval (CI) 2.0-17.7). Swimming in the lagoon increased the odds of developing gastroenteritis by 3.3 times (95% CI 1.06-10.38). Lagoon water samples tested positive for norovirus (NoV) GI.6, GII.3 and GII.6, astrovirus and rotavirus. Eleven (55%) stool specimens were positive for NoV with eight genotyped as GI.1 (n = 2), GI.5 (n = 3), GI.6 (n = 2), and GI.7 (n = 1). A reported sewage contamination event impacting the lagoon was the likely source with person-to-person spread perpetuating the outbreak. Restriction to swimming in the lagoon was apparently ineffective at preventing the outbreak, possibly due to inadequate enforcement, communication and signage strategies.

Research on the contamination levels of norovirus in food facilities using groundwater in South Korea, 2015–2016

Norovirus (NoV) is a major pathogenic virus that is responsible for foodborne and waterborne gastroenteritis outbreaks. Groundwater is an important source of drinking water and is used in agriculture and food manufacturing processes. This study investigated norovirus contamination of groundwater treatment systems at 1360 sites in seven metropolitan areas and nine provinces in 2015–2016. Temperature, pH, residual chlorine, and turbidity content were assessed to analyze the water quality. In 2015, six sites were positive for the presence of NoV (0.88%) and in 2016, two sites were positive (0.29%); in total, NoV was detected in 8 of the 1360 sample sites (0.59%) investigated. Identified genotypes of NoV in groundwater included GI.5, 9 and GII.4, 6, 13, 17, and 21. GII.17 was the most prevalent genotype in treated groundwater used in the food industry. This dominance of GII.17 was corroborated by NoV infection outbreak cases and the results of a survey of coastal waters in South Korea in 2014–2015. Although a low detection rate was observed in this study, NoV is a pathogen that can spread extensively. Therefore, it is necessary to periodically monitor levels of norovirus which is responsible for food poisoning in groundwater. This is a first report to reveal epidemic genotype shift of norovirus in groundwater treatment system of food facilities in South Korea. Our results may contribute to the enhancement of public health and sanitary conditions by providing molecular epidemiological information on groundwater NoV.

A Waterborne Gastroenteritis Outbreak Caused by Norovirus GII.17 in a Hotel, Hebei, China, December 2014.

Norovirus (NoV) is responsible for an estimated 90% of all epidemic nonbacterial outbreaks of gastroenteritis worldwide. Waterborne outbreaks of NoV are commonly reported. A novel GII.17 NoV strain emerged as a major cause of gastroenteritis outbreaks in China during the winter of 2014/2015. During this time, an outbreak of gastroenteritis occurred at a hotel in a ski park in Hebei Province, China. Epidemiological investigations indicated that one water well, which had only recently been in use, was the probable source. GII.17 NoV was detected by real-time reverse-transcription polymerase chain reaction from samples taken from cases, from concentrated water samples from water well, and from the nearby sewage settling tank. Nucleotide sequences of NoV extracted from clinical and water specimens were genetically identical and had 99% homology with Beijing/CHN/2015. All epidemiological data indicated that GII.17 NoV was responsible for this outbreak. This is the first reported laboratory-confirmed waterborne outbreak caused by GII.17 NoV genotype in China. Strengthening management of well drinking water and systematica monitoring of NoV is essential for preventing future outbreaks.

A waterborne outbreak of campylobacteriosis in the South Island of New Zealand due to a failure to implement a multi-barrier approach.

Outbreaks of waterborne gastroenteritis continue to occur in developed countries. Darfield, a rural town in the South Island of New Zealand experienced an outbreak of campylobacteriosis following a transgression of Escherichia coli on 16 August 2012. A descriptive outbreak investigation was performed. As a result, 29 cases had a laboratory-confirmed diagnosis of campylobacteriosis and 138 were identified as probable cases. Heavy rains, contamination of water with animal effluent from nearby paddocks and failures in the treatment of drinking water led to pathogens being distributed through the town's water supply. A multi-barrier approach is advocated to ensure the quality of water and many countries have legislation or programmes to address this. Although legislation for water safety plans based on a multi-barrier approach is in place in New Zealand, at the time of the outbreak it was not a requirement for the Darfield water supply. In addition, despite the awareness of the importance of a multi-barrier approach, competing interests, including those from the agricultural industry and financial restraints on water suppliers, can prevent it from being implemented. Governments need to be more willing to enforce legislation and standards to protect the public from waterborne disease.

The Duration of Gastrointestinal and Joint Symptoms after a Large Waterborne Outbreak of Gastroenteritis in Finland in 2007 – A Questionnaire-Based 15-Month Follow-Up Study

An extensive drinking water-associated gastroenteritis outbreak took place in the town of Nokia in Southern Finland in 2007. 53% of the exposed came down with gastroenteritis and 7% had arthritis-like symptoms (joint swelling, redness, warmth or pain in movement) according to a population-based questionnaire study at 8 weeks after the incident. Campylobacter and norovirus were the main pathogens.A follow-up questionnaire study was carried out 15 months after the outbreak to evaluate the duration of gastrointestinal and joint symptoms. 323 residents of the original contaminated area were included. The response rate was 53%. Participants were inquired about having gastroenteritis during the outbreak and the duration of symptoms.Of those with gastroenteritis, 43% reported loose stools and abdominal pain or distension after the acute disease. The prevalence of symptoms declined promptly during the first 3 months but at 15 months, 11% reported continuing symptoms. 32% of the respondents with gastroenteritis reported subsequent arthritis-like symptoms. The disappearance of arthritis-like symptoms was more gradual and they levelled off only after 5 months. 19% showed symptoms at 15 months. Prolonged gastrointestinal symptoms correlated to prolonged arthritis-like symptoms.High proportion of respondents continued to have arthritis-like symptoms at 15 months after the epidemic. The gastrointestinal symptoms, instead, had declined to a low level.

Norovirus Variant GII.4/Sydney/2012, Bangladesh

To the Editor: Noroviruses (NoVs) are the most common cause of foodborne and waterborne outbreaks of gastroenteritis in persons from all age groups in industrialized and developing countries (1). Although NoV outbreaks occur throughout the year, activity increases in the winter months, especially in the countries with a temperate climate. As expected, during the last few months of 2012, outbreaks of NoV gastroenteritis markedly increased in Europe and the United States (2–4). These increases corresponded with the emergence of a variant of genotype GII.4, Sydney/2012, which was first reported from Australia in March 2012 and, subsequently, in the United States, Belgium, Denmark, Scotland, and Japan (2,5–7). We identified the NoV GII.4 variant Sydney/2012 through hospital surveillance on diarrhea etiology in Bangladesh in December 2011 and then throughout 2012. These strains came from 3 hospitals in Dhaka, Matlab, and Mirzapur, where ≈150,000 patients with diarrhea are treated annually. We randomly selected 795 fecal specimens from patients of all ages who sought treatment for diarrhea in these hospitals during 2010–2012 and detected NoV RNA in 90 (33.6%), 72 (27.9%), and 92 (34.2%) samples in 2010, 2011, and 2012, respectively, by performing real-time PCR (8). For characterization, we amplified and sequenced 108 samples on the basis of the capsid genes (9). Ages of diarrhea patients with NoV infection ranged from 1 month to 91 years (median 15 months; mean 11.9 years). Most (66%) NoV-positive patients were 18 years of age). NoVs were detected throughout the year, and no clear seasonal peaks were observed. Overall, GII was the most predominant genogroup (66.1%), followed by GI (18.1%) and GIV (3.9%). Mixed infections were detected in 11.8% of samples. We observed a high diversity in the GII genogroup and identified at least 11 different genotypes within the group, in which GII.4 constituted 30.1% of all GII strains. Until December 2011, the GII.4 variant NewOrleans/2009 was the most predominant strain (Figure). However, the new GII.4 variant, Sydney/2012, replaced the old variant and appeared as the dominant strain in 2012. We constructed a phylogenetic tree on the basis of 1,026 bases around the junction region of pol and cap genes, and it revealed that the newly identified variant has evolved from previous NoV GII.4 variants Apeldoorn/2007 and NewOrleans/2009 (data not shown). Figure Distribution of 108 norovirus (NoV) genotypes in Bangladesh, 2010–2012. Bar chart shows the percentage of NoV genotypes. Mixed genotypes comprise NoV GI and GII. GI comprises GI.1, GI.3, GI.4, GI.5, and GI.9. GII.others comprises GII.2, GII.3, ... NoVs, old and new, remain a substantial threat to human health, with a new variant emerging every 2–3 years. The Sydney/2012 strain appears to have replaced the previously predominant strain, but its clinical effects and epidemiology are largely unknown and warrant further investigation.

A large waterborne gastroenteritis outbreak in central Greece, March 2012: challenges for the investigation and management.

In March 2012, there was an unusual increase of gastroenteritis cases in a district with 37,264 inhabitants in central Greece. It was estimated that more than 3600 people developed symptoms. A 1:1 case-control study showed that consumption of tap water was a risk factor for acquiring infection [odds ratio (OR) 2.18, 95% confidence interval (CI) 1.11-4.28]. Descriptive data, low gastroenteritis incidence in adjacent areas with different water supply systems, and water-quality data further supported the hypothesis of a waterborne outbreak. Thirty-eight stool samples were positive for rotavirus. Bacterial indicators of recent faecal contamination were detected in samples from the water source and ice cubes from a local production enterprise. Molecular epidemiology of rotavirus strains, apart from the common strain, G3[P8], identified the unusual G/P combination G2P[8]. Water sanitation measures contributed to the control of the outbreak. This outbreak demonstrated the need for the cooperation of laboratories with different expertise and the importance of early notification of waterborne gastroenteritis outbreaks.

Outcome of reactive arthritis after an extensive Finnish waterborne gastroenteritis outbreak: a 1-year prospective follow-up study

The purpose of the study was to assess the 1-year outcome of definitive reactive arthritis (ReA) after a waterborne outbreak. A cohort of 21 patients (15 females and 6 males, median age 54 years) with ReA related to an extensive waterborne outbreak in Finland was clinically followed-up by rheumatologists with visits at baseline, at 1 month and 3, 6 and 12 months. Although the outcome was in general favourable, 1/3 of the patients had chronic course; 7 (33 %) of the 21 patients needed disease-modifying anti-rheumatic drugs (DMARDs) and even 8 (38 %) of them used glucocorticoids at 12 months. Four (19 %) were using non-steroidal anti-inflammatory drugs and nine (43 %) other analgesics. Many patients had articular pain and impaired physical function still at 12 months, even though inflammatory parameters and the number of swollen joints were low. Only one patient (5 %) was human leucocyte antigen-B27-positive. She had the most severe ReA and also additional infectious arthritis caused by Salmonella serotype enteritidis leading to osteonecrosis of her hip joint with subsequent need for arthroplasty. ReA as observed in our study was overall fairly mild, but in many individuals, postinfectious arthralgia and DMARD use continued at least up to 1 year.

Epidemiological investigation of two parallel gastroenteritis outbreaks in school settings

BackgroundTwo parallel gastroenteritis outbreaks occurred in an elementary school and a neighboring kindergarten in Kilkis, Northern Greece in 2012. The aim of the study was the investigation of these two parallel outbreaks as well as their possible source.MethodsTwo retrospective cohort studies were performed to identify the mode and the vehicle of transmission as well as the possible connection between them.ResultsElementary school and kindergarten populations of 79.9% (119/149) and 51.1% (23/45) respectively, participated in the study. Case definition was satisfied by 65 pupils from the elementary school and 14 from the kindergarten. For elementary school, 53 cases were considered primary cases of the outbreak and were included in the analysis. Based on the results of the multivariate analysis, consumption of tap water was the only statistically significant independent risk factor of gastroenteritis (RR = 2.34, 95% C.I.: 1.55-3.53).; a finding supported by the shape of the epidemic curve which referred to a common point source outbreak with secondary cases. For kindergarten, no statistically significant risk factor was identified, and the epidemic curve supported a person-to-person transmission according univariate analysis. Norovirus GI and GII and human Adenovirus were detected by Real Time PCR in stool samples from seven children of elementary school, but stool samples were not collected by children of the kindergarten.ConclusionsEven though the etiological agent of the outbreak was not verified, combined epidemiological and laboratory results were in favor of a waterborne viral gastroenteritis outbreak at the elementary school, followed by a person to person spread at the kindergarten.

Incidence of Post-Infectious Irritable Bowel Syndrome and Functional Intestinal Disorders Following a Water-Borne Viral Gastroenteritis Outbreak

Post-infectious irritable bowel syndrome (PI-IBS) may develop in 4-31% of affected patients following bacterial gastroenteritis (GE), but limited information is available on long-term outcome of viral GE. During summer 2009, a massive outbreak of viral GE associated with contamination of municipal drinking water (Norovirus) occurred in San Felice del Benaco (Lake Garda, Italy). To investigate the natural history of a community outbreak of viral GE, and to assess the incidence of PI-IBS and functional gastrointestinal disorders, we carried out a prospective population-based cohort study with a control group. Baseline questionnaires were administered to the resident community within 1 month of the outbreak. Follow-up questionnaires of the Italian version of Gastrointestinal Symptom Rating Scale (GSRS, a 15-item survey scored according to a 7-point Likert scale) were mailed to all patients responding to baseline questionnaire at 3 and 6 months, and to a cohort of unaffected controls, living in the same geographical area, at 6 months after the outbreak. The GSRS item were grouped in five dimensions: abdominal pain, reflux, indigestion, diarrhea, and constipation. At month 12, all patients and controls were interviewed by a health assistant to verify Rome III criteria of IBS. Student's t-test and χ(2)- or Fisher's exact test were used as appropriate. Baseline questionnaires were returned by 348 patients: mean age ± s.d. 45 ± 22 years, 53% female. At outbreak, nausea (scored ≥4), vomiting, and diarrhea lasting 2-3 days or more were reported by 66, 60, and 77% of patients, respectively. A total of 50% reported fever and 19% reported weight loss (mean 3 kg). Follow-up surveys were returned at month 6 by 186 patients and 198 controls: mean GSRS score was significantly higher in patients than in controls for abdominal pain, diarrhea, and constipation. At month 12, we identified 40 patients with a new diagnosis of IBS (Rome III criteria), in comparison with 3 subjects in the control cohort (P<0.0001; odds ratio 11.40; 95% confidence intervals 3.44-37.82). The 40 cases of PI-IBS were subtyped according to the predominant stool pattern as follows: 4 IBS with constipation, 7 IBS with diarrhea, 16 with mixed IBS, and 13 with unsubtyped IBS. Our study provides evidence that Norovirus GE leads to the development of PI-IBS in a substantial proportion of patients (13%), similar to that reported after bacterial GE.

Waterborne Outbreak of Gastroenteritis: Effects on Sick Leaves and Cost of Lost Workdays

BackgroundIn 2007, part of a drinking water distribution system was accidentally contaminated with waste water effluent causing a gastroenteritis outbreak in a Finnish town.We examined the acute and cumulative effects of this incidence on sick leaves among public sector employees residing in the clean and contaminated areas, and the additional costs of lost workdays due to the incidence.MethodsDaily information on sick leaves of 1789 Finnish Public Sector Study participants was obtained from employers' registers. Global Positioning System-coordinates were used for linking participants to the clean and contaminated areas. Prevalence ratios (PR) for weekly sickness absences were calculated using binomial regression analysis. Calculations for the costs were based on prior studies.ResultsAmong those living in the contaminated areas, the prevalence of participants on sick leave was 3.54 (95% confidence interval (CI) 2.97–4.22) times higher on the week following the incidence compared to the reference period. Those living and working in the clean area were basically not affected, the corresponding PR for sick leaves was 1.12, 95% CI 0.73–1.73. No cumulative effects on sick leaves were observed among the exposed. The estimated additional costs of lost workdays due to the incidence were 1.8–2.1 million euros.ConclusionsThe prevalence of sickness absences among public sector employees residing in affected areas increased shortly after drinking water distribution system was contaminated, but no long-term effects were observed. The estimated costs of lost workdays were remarkable, thus, the cost-benefits of better monitoring systems for the water distribution systems should be evaluated.

Application of Hybrid Process of Coagulation/Flocculation and Membrane Filtration for the Removal of Protozoan Parasites from Water

Among the waterborne diseases, enteric diseases are most frequent. Approximately 19% of waterborne gastroenteritis outbreaks in the United States are attributed to parasitic protozoans, particularly Giardia and Cryptosporidium species, due to their wide distribution in the environment, high incidence in the population, and resistance to conventional water treatment. These microorganisms and impurities present in water do not approach each other, it is necessary to add a coagulant. Chemical coagulants are the most used and among them the most common is aluminum sulfate, since it is cheap and easily obtained. However, chemical coagulants have certain disadvantages, as they require tight control over their residual concentration in treated water for human consumption as well as in industrial food production. Then, the objective of the present work was to evaluate the efficiency of Moringa oleifera seeds as natural coagulant in removing apparent color, turbidity, Giardia spp. cysts and Cryptosporidium spp. oocysts from water in association with microfiltration. The surface water used in the tests was collected at the Pirapó river basin, which supplies the city of Maringá, Paraná, Brazil. Samples of high and low turbidity were mixed to obtain water with different initial turbidities. Water samples with initial turbidity of 50, 150, 250, 350, and 450 NTU were used in this study. Prepared samples were artificially contaminated with 106 cysts/L of Giardia and 106 oocysts/L of Cryptosporidium obtained from the positive control (suspension of cysts and oocysts) present in the commercial kit Merifluor (Meridian Bioscience, Cincinnati, OH, USA). After being prepared, these samples were subjected to the processes of (1) coagulation/flocculation with moringa seeds (CFM), (2) coagulation/flocculation with aluminum sulfate; (3) microfiltration (MF), and (4) combined coagulation/flocculation with moringa seeds or aluminum sulfate followed by microfiltration (CFM-MF or CFM-MF). Coagulation/flocculation tests with moringa were performed in a jar test device. Each sample, with initial turbidity from 50 to 450 NTU, was subjected to 12 different concentrations.of moringa coagulant solution, ranging from 25 to 350 mg/L. Polyimide membrane with porosity of 0.40 μm was used for the MF process with an operating pressure of 1 bar. Moringa solution concentrations above 150 mg/L showed the best removal efficiency of turbidity – which varied from 3% to 97% – and color, ranging from 6.7% to 73.5%. The CFM process achieved 1.2 log removal for Giardia and 1.0 log removal for Cryptosporidium. To membrane process, color and turbidity removal ranged from 80 to 100%, and the best results were obtained with the combined CFM-MF. It was also observed that the pretreatment with moringa reduced membrane fouling (which was between 7.48 and 40.9%) and increased permeate flux (between 157 and 226 L/hm) when compared with the MF (membrane fouling from 6.13 to 56.32% and permeate flow from 157 to 187 L/hm2). It can be concluded that coagulation with moringa showed satisfactory results, reducing the number of (oo)cysts of protozoan parasites in accordance with WHO recommendations for the process of coagulation/flocculation, as well as reducing color and turbidity. Combined with MF, the proposed process removed nearly 100% of Giardia and Cryptosporidium (oo)cysts and achieved high levels of color and turbidity removal from water samples, presenting the advantage of improving the quality of filtered water and the characteristics of the MF process (reduction of fouling and increase of permeate flux).

Characterization and inhibition of norovirus proteases of genogroups I and II using a fluorescence resonance energy transfer assay

Noroviruses are the major cause of food- or water-borne gastroenteritis outbreaks in humans. The norovirus protease that cleaves a large viral polyprotein to nonstructural proteins is essential for virus replication and an attractive target for antiviral drug development. Noroviruses show high genetic diversity with at least five genogroups, GI–GV, of which GI and GII are responsible for the majority of norovirus infections in humans. We cloned and expressed proteases of Norwalk virus (GI) and MD145 virus (GII) and characterized the enzymatic activities with fluorescence resonance energy transfer substrates. We demonstrated that the GI and GII proteases cleaved the substrates derived from the naturally occurring cleavage site in the open reading frame (ORF) 1 of G1 norovirus with similar efficiency, and that enzymatic activity of both proteases was inhibited by commercial protease inhibitors including chymostatin. The interaction of chymostatin to Norwalk virus protease was validated by nuclear magnetic resonance (NMR) spectroscopy.

Presence of human noro- and adenoviruses in river and treated wastewater, a longitudinal study and method comparison

Norovirus (NoV) is one of the most common causative agents of waterborne gastroenteritis outbreaks. The main objective of the study was to determine the presence of human NoVs in river water and in treated wastewater (TW) released into the river. During a one-year survey in 2007/2008, NoVs were detected in 30.8% of river samples (20/65), and 40.5% of TW samples (17/45) with a real-time reverse transcription-PCR assay. NoVs were present in the river water in the winter and spring, coinciding with the NoV epidemiological peak in the community and the presence of NoVs in TW. Later in 2009, the concentration method used, pre-filtration with a Waterra filter combined with filtration through a negatively charged membrane, was evaluated against glass wool filtration and freeze-drying for the detection of adenoviruses in river water. The virus amounts measured varied greatly depending on the virus concentration method. The continued monitoring in the spring of 2009 also revealed that the average concentration of noro- and adenoviruses in TW was 2.64 × 10(3) and 1.29 × 10(4) pcr units per mL, respectively. No correlation between the presence of viruses and Escherichia coli was found. These results may be useful for risk assessment studies.

Joint symptoms after a large waterborne gastroenteritis outbreak—a controlled, population-based questionnaire study

Waterborne outbreaks offer an opportunity to study joint symptoms after a simultaneous exposure. In November 2007, a gastroenteritis outbreak due to faecal contamination of tap water took place in a Finnish town. The purpose of this study was to evaluate the occurrence of joint symptoms after the outbreak. The authors conducted a controlled, population-based questionnaire survey to study the occurrence of joint symptoms within 8 weeks after the exposure. The survey covered three areas: contaminated and uncontaminated parts of the town and a control town. A total of 1000 residents were randomly selected from each area, and the joint symptoms were first analysed separately and thereafter categorized as arthritis-like if joint swelling, redness, warmth or pain in movement was reported. A total of 2123 responses could be evaluated. The overall prevalence of joint symptoms was 13.9% in the contaminated group, 4.3% in the uncontaminated group and 1.5% among the control group, and the frequency of arthritis-like symptoms in the groups was 6.7, 2.1 and 0.5%, respectively. Gastrointestinal symptoms predicted joint complaints, diarrhoea and blood in faeces being the most significant. Residing in the contaminated area was associated with any joint symptom [odds ratio (OR) = 4.0, 95% CI 1.8, 9.0] and joint pain (OR = 7.3, 95% CI 2.1, 24.8) without preceding gastroenteritis. The frequency of joint symptoms was high in the contaminated group and also increased in the uncontaminated group. Furthermore, the risk of joint symptoms was increased in the contaminated group even without gastroenteritis.

Reactive arthritis in a population exposed to an extensive waterborne gastroenteritis outbreak after sewage contamination in Pirkanmaa, Finland

Objectives: To assess the occurrence, clinical picture, and triggering infections of reactive arthritis (ReA) associated with a large waterborne gastroenteritis outbreak.Methods: After an extensive sewage contamination of the water supply system, an estimated 8453 of the 30 016 inhabitants of the town of Nokia fell ill. General practitioners and occupational physicians were advised to refer any patients with suspicion of new ReA to rheumatological examination including faecal culture, human leucocyte antigen (HLA)-B27 and antibody tests for Campylobacter, Salmonella, and Yersinia.Results: Forty-five patients (33 females, 12 males) aged 16–77 years (median 53) were referred. ReA was diagnosed in 21, postinfectious arthralgia in 13, and other musculoskeletal conditions in 11 patients. HLA-B27 was positive in five out of 44 patients (11%). Of the 21 patients with ReA, possible triggering infections were observed in seven (33%), Campylobacter in four, Yersinia in three, and Salmonella in one, who also had Campylobacter infection. ReA was mild in all but one patient who presented with persistent Salmonella enterica serotype enteritidis infection.Conclusions: Taking into account the large population contaminated with potentially arthritogenic agents, the occurrence of ReA was rare and mild in character.

Incidence of functional intestinal disorders and postinfectious irritable bowel syndrome following a waterborne viral gastroenteritis outbreak

IntroductionPostinfectious irritable bowel syndrome (PI-IBS) may develop in 4–30% of patients following bacterial gastroenteritis (GE), but limited information is available on outcome of viral GE. On summer 2009 a massive...

Solution Structure Determination of Norwalk Virus 3C-Like Cysteine Protease

Noroviruses are the leading cause of acute food- or water-borne gastroenteritis outbreaks in humans with an estimated 23 million annual cases in the US alone and show high diversity with at least five genogroups (GI-GV). Norwalk virus (NV) is a prototype strain classified as GI strain. Noroviral RNA genome is composed of three open reading frames (ORFs), and the ORF1 encodes a polyprotein that is cleaved by the viral 3C-like cysteine protease (Pro) into 6 non-structural proteins, which makes the Pro as an essential component for the viral replication as well as an attractive target for antiviral drug development.