Noroviruses in healthcare settings: a challenging problem

Ozone efficacy for the control of airborne viruses: Bacteriophage and norovirus models

This study was designed to test the efficacy of an air treatment using ozone and relative humidity (RH) for the inactivation of airborne viruses. Four phages (φX174, PR772, MS2 and φ6) and one eukaryotic virus (murine norovirus MNV-1) were exposed to low ozone concentrations (1.23 ppm for phages and 0.23 ppm for MNV-1) and various levels of RH for 10 to 70 minutes. The inactivation of these viruses was then assessed to determine which of the tested conditions provided the greatest reduction in virus infectivity. An inactivation of at least two orders of magnitude for φX174, MS2 and MNV-1 was achieved with an ozone exposure of 40 minutes at 85% RH. For PR772 and φ6, exposure to the reference condition at 20% RH for 10 minutes yielded the same results. These findings suggest that ozone used at a low concentration is a powerful disinfectant for airborne viruses when combined with a high RH. Air treatment could therefore be implemented inside hospital rooms ventilated naturally.

Recombinase polymerase amplification: a promising point-of-care detection method for enteric viruses

Viral enteric disease imposes a considerable public health and economic burden globally in both humans and livestock. Because enteric viruses are highly transmissible and resistant to numerous control strategies, making early in-field or point-of-care detection is important. There are problems with ligand-based detection strategies (e.g., sensitivity, false positive/negatives) for virus detection. Traditional amplification-based strategies are sensitive, but not as portable or rapid. Recombinase polymerase amplification is a new isothermal technique that utilizes bacterial genome repair enzymes to rapidly amplify target sequences. This report reviews the use of recombinase polymerase amplification for virus detection, showing that the method has favorable fundamental properties supporting its promise for rapid point-of-care detection of enteric viruses.

Effects of operational decisions on the diffusion of epidemic disease: A system dynamics modeling of the MERS-CoV outbreak in South Korea

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Development of a macro-level health system dynamics model.

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Performance measurements of epidemic disease diffusion and patient-care performance from an operational perspective.

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Comparison of economic and optimal patient room design performance under different infectivity scenarios.

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Comparison of secondary infection outcomes under different ER occupancy circumstances.

We evaluated the nosocomial outbreak of Middle East Respiratory Syndrome (MERS) Coronavirus (CoV) in the Republic of Korea, 2015, from a healthcare operations management perspective. Establishment of healthcare policy in South Korea provides patients’ freedom to select and visit multiple hospitals. Current policy enforces hospitals preference for multi-patient rooms to single-patient rooms, to lower financial burden. Existing healthcare systems tragically contributed to 186 MERS outbreak cases, starting from single “index patient” into three generations of secondary infections. By developing a macro-level health system dynamics model, we provide empirical knowledge to examining the case from both operational and financial perspectives. In our simulation, under base infectivity scenario, high emergency room occupancy circumstance contributed to an estimated average of 101 (917%) more infected patients, compared to when in low occupancy circumstance. Economic patient room design showed an estimated 702% increase in the number of infected patients, despite the overall 98% savings in total expected costs compared to optimal room design. This study provides first time, system dynamics model, performance measurements from an operational perspective. Importantly, the intent of this study was to provide evidence to motivate public, private, and government healthcare administrators’ recognition of current shortcomings, to optimize performance as a whole system, rather than mere individual aspects.

A large common-source outbreak of norovirus gastroenteritis in a hotel in Singapore, 2012

An outbreak of gastroenteritis affected 453 attendees (attack rate 28·5%) of six separate events held at a hotel in Singapore. Active case detection, case-control studies, hygiene inspections and microbial analysis of food, environmental and stool samples were conducted to determine the aetiology of the outbreak and the modes of transmission. The only commonality was the food, crockery and cutlery provided and/or handled by the hotel's Chinese banquet kitchen. Stool specimens from 34 cases and 15 food handlers were positive for norovirus genogroup II. The putative index case was one of eight norovirus-positive food handlers who had worked while they were symptomatic. Several food samples and remnants tested positive for Escherichia coli or high faecal coliforms, aerobic plate counts and/or total coliforms, indicating poor food hygiene. This large common-source outbreak of norovirus gastroenteritis was caused by the consumption of contaminated food and/or contact with contaminated crockery or cutlery provided or handled by the hotel's Chinese banquet kitchen.

A Multi-Site Study of Norovirus Molecular Epidemiology in Australia and New Zealand, 2013-2014

Background

Norovirus (NoV) is the major cause of acute gastroenteritis across all age groups. In particular, variants of genogroup II, genotype 4 (GII.4) have been associated with epidemics globally, occurring approximately every three years. The pandemic GII.4 variant, Sydney 2012, was first reported in early 2012 and soon became the predominant circulating NoV strain globally. Despite its broad impact, both clinically and economically, our understanding of the fundamental diversity and mechanisms by which new NoV strains emerge remains limited. In this study, we describe the molecular epidemiological trends of NoV-associated acute gastroenteritis in Australia and New Zealand between January 2013 and June 2014.

Methodology

Overall, 647 NoV-positive clinical faecal samples from 409 outbreaks and 238 unlinked cases of acute gastroenteritis were examined by RT-PCR and sequencing. Phylogenetic analysis was then performed to identify NoV capsid genotypes and to establish the temporal dominance of circulating pandemic GII.4 variants. Recombinant viruses were also identified based on analysis of the ORF1/2 overlapping region.

Findings

Peaks in NoV activity were observed, however the timing of these epidemics varied between different regions. Overall, GII.4 NoVs were the dominant cause of both outbreaks and cases of NoV-associated acute gastroenteritis (63.1%, n = 408/647), with Sydney 2012 being the most common GII.4 variant identified (98.8%, n = 403/408). Of the 409 reported NoV outbreaks, aged-care facilities were the most common setting in both Western Australia (87%, n = 20/23) and New Zealand (58.1%, n = 200/344) while most of the NoV outbreaks were reported from hospitals (38%, n = 16/42) in New South Wales, Australia. An analysis of a subset of non-GII.4 viruses from all locations (125/239) showed the majority (56.8%, n = 71/125) were inter-genotype recombinants. These recombinants were surprisingly diverse and could be classified into 18 distinct recombinant types, with GII.P16/GII.13 (24% of recombinants) the most common.

Conclusion

This study revealed that following its emergence in 2012, GII.4 Sydney 2012 variant continued to be the predominant cause of NoV-associated acute gastroenteritis in Australia and New Zealand between 2013 and 2014.

Test and validation of methods to sample and detect human virus from environmental surfaces using norovirus as a model virus

BACKGROUND

Viruses cause a major proportion of human infections, especially gastroenteritis and respiratory infections in children and adults. Indirect transmission between humans via environmental surfaces may play a role in infections, but methods to investigate this have been sparse.

AIM

To validate and test efficient and reliable procedures to detect multiple human pathogenic viruses on surfaces.

METHODS

The study was divided into two parts. In Part A, six combinations of three different swabs (consisting of cotton, foamed cotton, or polyester head) and two different elution methods (direct lysis or immersion in alkaline glycine buffer before lysis) were tested for efficient recovery of human norovirus GII.7 and mengovirus from artificially contaminated surfaces. In Part B we determined the detection limit for norovirus GI.1 and GII.3 using the best procedure found in Part A linked with a commercial multiplex real-time quantitative polymerase chain reaction detection assay.

FINDINGS

Combining the polyester swab with direct lysis allowed recovery down to 100 and 10 genome copies/cm(2) of norovirus GI.1 and GII.3, respectively. This procedure resulted in the significant highest recovery of both norovirus and mengovirus, whereas no differences in amplification efficiencies were observed between the different procedures.

CONCLUSION

The results indicate that it is possible to detect low concentrations of virus on environmental surfaces. We therefore suggest that a polyester swab, followed by direct lysis, combined with a multiplex qPCR detection assay is an efficient screening tool that merits study of different respiratory and gastrointestinal viruses on environment surfaces.

Inactivation Kinetics and Mechanism of a Human Norovirus Surrogate on Stainless Steel Coupons via Chlorine Dioxide Gas

Acute gastroenteritis caused by human norovirus is a significant public health issue. Fresh produce and seafood are examples of high-risk foods associated with norovirus outbreaks. Food contact surfaces also have the potential to harbor noroviruses if exposed to fecal contamination, aerosolized vomitus, or infected food handlers. Currently, there is no effective measure to decontaminate norovirus on food contact surfaces. Chlorine dioxide (ClO2) gas is a strong oxidizer and is used as a decontaminating agent in food processing plants. The objective of this study was to determine the kinetics and mechanism of ClO2 gas inactivation of a norovirus surrogate, murine norovirus 1 (MNV-1), on stainless steel (SS) coupons. MNV-1 was inoculated on SS coupons at the concentration of 10(7) PFU/coupon. The samples were treated with ClO2 gas at 1, 1.5, 2, 2.5, and 4 mg/liter for up to 5 min at 25°C and a relative humidity of 85%, and virus survival was determined by plaque assay. Treatment of the SS coupons with ClO2 gas at 2 mg/liter for 5 min and 2.5 mg/liter for 2 min resulted in at least a 3-log reduction in MNV-1, while no infectious virus was recovered at a concentration of 4 mg/liter even within 1 min of treatment. Furthermore, it was found that the mechanism of ClO2 gas inactivation included degradation of viral protein, disruption of viral structure, and degradation of viral genomic RNA. In conclusion, treatment with ClO2 gas can serve as an effective method to inactivate a human norovirus surrogate on SS contact surfaces.

Noroviruses: epidemiology, immunity and prospects for prevention

In recent years, noroviruses have become recognized as an important cause of both sporadic and epidemic acute gastroenteritis (AGE), largely due to the improved availability of broadly reactive real-time RT-PCR (TaqMan-based RT-PCR) assays. While there is substantial diversity among noroviruses, one specific genotype, GII.4, is the most common etiology in sporadic and epidemic AGE. Outbreaks of norovirus AGE most commonly occur in healthcare facilities and restaurants and result in significant morbidity and mortality and substantial healthcare costs. Norovirus vaccine development is progressing, and Phase I and II human trials have shown proof-of-principle that norovirus vaccines can reduce illness and infection.

Reducing viral contamination from finger pads: handwashing is more effective than alcohol-based hand disinfectants

BACKGROUND

Hand hygiene is important for interrupting transmission of viruses through hands. Effectiveness of alcohol-based hand disinfectant has been shown for bacteria but their effectiveness in reducing transmission of viruses is ambiguous.

AIM

To test efficacy of alcohol hand disinfectant against human enteric and respiratory viruses and to compare efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against norovirus.

METHODS

Efficacies of a propanol and an ethanol-based hand disinfectant against human enteric and respiratory viruses were tested in carrier tests. Efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against noroviruses GI.4, GII.4, and MNV1 were tested using finger pad tests.

FINDINGS

The alcohol-based hand disinfectant reduced the infectivity of rotavirus and influenza A virus completely within 30s whereas poliovirus Sabin 1, adenovirus type 5, parechovirus 1, and MNV1 infectivity were reduced <3 log10 within 3 min. MNV1 infectivity reduction by washing hands with soap and water for 30s (>3.0 ± 0.4 log10) was significantly higher than treating hands with alcohol (2.8 ± 1.5 log10). Washing with soap and water for 30s removed genomic copies of MNV1 (>5 log10), noroviruses GI.4 (>6 log10), and GII.4 (4 log10) completely from all finger pads. Treating hands with propanol-based hand disinfectant showed little or no reduction to complete reduction with mean genomic copy reduction of noroviruses GI.4, GII.4, and MNV1 being >2.6, >3.3, and >1.2 log10 polymerase chain reaction units respectively.

CONCLUSIONS

Washing hands with soap and water is better than using alcohol-based hand disinfectants in removing noroviruses from hands.

Surveillance for outbreaks of gastroenteritis in elderly long-term care facilities in France, November 2010 to May 2012

This article describes outbreaks of gastroenteritis in elderly long-term care facilities (LTCF) in France from November 2010 to May 2012 reported through the surveillance system for gastroenteritis outbreaks in LTCF. A total of 1,072 outbreaks were reported, causing 26,551 episodes of illness and 60 deaths. The median attack rate (AR) among residents was 32%. Norovirus and person-to-person transmission were the most frequently reported aetiology and mode of transmission. Control measures were implemented in 1,054 (98%) outbreaks and for 928 outbreaks, the timing of such measures could be inferred. Of these, 799 (86%) had put control measures into effect within three days of the occurrence of the first case. Outbreaks of gastroenteritis in LTCF cause substantial morbidity and mortality among elderly people in France. LTCF are encouraged to develop infection prevention and control plans and to notify any gastroenteritis outbreak to health authorities to ensure rapid control.

Detecting the norovirus season in Sweden using search engine data--meeting the needs of hospital infection control teams

Norovirus outbreaks severely disrupt healthcare systems. We evaluated whether Websök, an internet-based surveillance system using search engine data, improved norovirus surveillance and response in Sweden. We compared Websök users' characteristics with the general population, cross-correlated weekly Websök searches with laboratory notifications between 2006 and 2013, compared the time Websök and laboratory data crossed the epidemic threshold and surveyed infection control teams about their perception and use of Websök. Users of Websök were not representative of the general population. Websök correlated with laboratory data (b = 0.88-0.89) and gave an earlier signal to the onset of the norovirus season compared with laboratory-based surveillance. 17/21 (81%) infection control teams answered the survey, of which 11 (65%) believed Websök could help with infection control plans. Websök is a low-resource, easily replicable system that detects the norovirus season as reliably as laboratory data, but earlier. Using Websök in routine surveillance can help infection control teams prepare for the yearly norovirus season.

Transfer of noroviruses between fingers and fomites and food products

Human norovirus (NoV) contaminated hands are important routes for transmission. Quantitative data on transfer during contact with surfaces and food are scarce but necessary for a quantitative risk assessment. Therefore, transfer of MNV1 and human NoVs GI.4 and GII.4 was studied by artificially contaminating human finger pads, followed by pressing on stainless steel and Trespa® surfaces and also on whole tomatoes and cucumber slices. In addition, clean finger pads were pressed on artificially contaminated stainless steel and Trespa® surfaces. The transfers were performed at a pressure of 0.8-1.9 kg/cm(2) for approximately 2s up to 7 sequential transfers either to carriers or to food products. MNV1 infectivity transfer from finger pads to stainless steel ranged from 13 ± 16% on the first to 0.003 ± 0.009% on the sixth transfer on immediate transfer. After 10 min of drying, transfer was reduced to 0.1 ± 0.2% on the first transfer to 0.013 ± 0.023% on the fifth transfer. MNV1 infectivity transfer from stainless steel and Trespa® to finger pads after 40 min of drying was 2.0 ± 2.0% and 4.0 ± 5.0% respectively. MNV1 infectivity was transferred 7 ± 8% to cucumber slices and 0.3 ± 0.5% to tomatoes after 10 min of drying, where the higher transfer to cucumber was probably due to the higher moisture content of the cucumber slices. Similar results were found for NoVs GI.4 and GII.4 transfers measured in PCR units. The results indicate that transfer of the virus is possible even after the virus is dried on the surface of hands or carriers. Furthermore, the role of fingers in transmission of NoVs was quantified and these data can be useful in risk assessment models and to establish target levels for efficacy of transmission intervention methods.

Rapid detection of a norovirus pseudo-outbreak by using real-time sequence based information

BACKGROUND

Sequence based information is increasingly used to study the epidemiology of viruses, not only to provide insight in viral evolution, but also to understand transmission patterns during outbreaks. However, sequence analysis is not yet routinely performed by diagnostic laboratories, limiting its use in clinical practice.

OBJECTIVES

To describe the added value of sequence based information available within 3 days after the detection of norovirus in fecal samples of patients and personnel during a suspected outbreak on a hospital ward. Results were used to guide the implementation of appropriate infection control measures, in particular closure of the ward.

STUDY DESIGN

Observational study.

RESULTS

Norovirus infection was detected in seven patients and two health care workers on an oncology ward of the children's hospital. Six of seven patients had a hospital acquired infection defined as a first day of illness more than two days after admission. After notification of the first two patients, supplementary infection control measures were taken to prevent further spread. Despite these measures, three additional patients with norovirus infection were identified. Characterization of the noroviruses of 5 out of 7 patients was available within 7 days after the notification of the first patient. Four different genotypes were detected, providing evidence for multiple introductions of different norovirus strains with only a few secondary cases rather than ongoing nosocomial transmission. Therefore, we maintained the already implemented infection control interventions without closure of the ward.

CONCLUSIONS

Sequence based information available in real-time is helpful for understanding norovirus transmission in the hospital and facilitates appropriate infection control measures during an outbreak.

Emergence of a new norovirus GII.4 variant and changes in the historical biennial pattern of norovirus outbreak activity in Alberta, Canada, from 2008 to 2013

The public health impact of the emergence of new norovirus (NoV) strains is uncertain. A biennial pattern of alternating quiescent and epidemic levels of NoV outbreak activity associated with the emergence of new GII.4 variants was observed in Alberta, Canada, between July 2000 and June 2008. In this study, NoV genogroup I (GI) and GII strains isolated from 710 outbreak specimens in Alberta between July 2008 and January 2013 were characterized to update historical data. The seasonality and annual variation in NoV outbreak burden were analyzed over a 10-year period (July 2002 to June 2012). We found that GII.4-2006b had persisted as the predominant variant over three observation periods (July 2006 to June 2009) during which the biennial NoV outbreak pattern continued. The emergence of GII.4-2010 (winter 2009) was not associated with increased outbreak activity, and outbreak activity between July 2009 and June 2012 when GII.4-2010 predominated (67.5 to 97.7%) did not follow a biennial pattern. GII.4-2012 first emerged in Alberta in September 2011 and became predominant in observation period July 2012 to June 2013. NoV GI, relatively rare in past years, had a higher activity level (37.3%) as represented by GI.6 and GI.7 in the winter of 2012 to 2013. A higher proportion of GI outbreaks occurred in non-health care facility settings compared to GII. Our study suggests that factors other than new variants emergence contribute to the levels of NoV outbreak activity in Alberta.

A review of known and hypothetical transmission routes for noroviruses

Human noroviruses (NoVs) are considered a worldwide leading cause of acute non-bacterial gastroenteritis. Due to a combination of prolonged shedding of high virus levels in feces, virus particle shedding during asymptomatic infections, and a high environmental persistence, NoVs are easily transmitted pathogens. Norovirus (NoV) outbreaks have often been reported and tend to affect a lot of people. NoV is spread via feces and vomit, but this NoV spread can occur through several transmission routes. While person-to-person transmission is without a doubt the dominant transmission route, human infective NoV outbreaks are often initiated by contaminated food or water. Zoonotic transmission of NoV has been investigated, but has thus far not been demonstrated. The presented review aims to give an overview of these NoV transmission routes. Regarding NoV person-to-person transmission, the NoV GII.4 genotype is discussed in the current review as it has been very successful for several decades but reasons for its success have only recently been suggested. Both pre-harvest and post-harvest contamination of food products can lead to NoV food borne illness. Pre-harvest contamination of food products mainly occurs via contact with polluted irrigation water in case of fresh produce or with contaminated harvesting water in case of bivalve molluscan shellfish. On the other hand, an infected food handler is considered as a major cause of post-harvest contamination of food products. Both transmission routes are reviewed by a summary of described NoV food borne outbreaks between 2000 and 2010. A third NoV transmission route occurs via water and the spread of NoV via river water, ground water, and surface water is reviewed. Finally, although zoonotic transmission remains hypothetical, a summary on the bovine and porcine NoV presence observed in animals is given and the presence of human infective NoV in animals is discussed.

Evaluation of 4 immunochromatographic tests for rapid detection of norovirus in faecal samples

BACKGROUND

The rapid detection of noroviruses is essential to implement measures to reduce the rapid spread of gastroenteritis infections they cause, notably in institutions.

OBJECTIVES

To evaluate 4 rapid immunochromatographic tests: RIDA(®)QUICK Norovirus, ImmunoCardSTAT!(®) Norovirus, NOROTOP(®) and SD BIOLINE NOROVIRUS by determining their sensitivity and specificity on a large panel of samples representing 11 genotypes of norovirus genogroup I and 14 of genogroup II, and their cross-reactivity with other enteric viruses.

STUDY DESIGN

Thawed stool samples containing norovirus genogroup I or II or other enteric viruses, and negative samples, were tested by the 4 assays and compared to the reference standard RT-PCR. Fresh stool samples were also tested by RIDA(®)QUICK.

RESULTS

The sensitivity of RIDA(®)QUICK, ImmunoCardSTAT!(®), NOROTOP(®) and SD BIOLINE for the detection of norovirus genogroup I on thawed samples was 17%, 26%, 52% and 23%, respectively. For genogroup II, the sensitivity was 64%, 39%, 50% and 54%, respectively. For GII.4, the main circulating genotype, the sensitivity was 78%, 59%, 61% and 67%, respectively. For all tests, the specificity was 100% and no cross-reactivity with other enteric viruses was observed. The sensitivity of RIDA(®)QUICK on fresh stool samples positive for GII.4 was 71%.

CONCLUSIONS

Knowing that most gastroenteritis cases are due to GII.4, the immunochromatographic tests may be useful for preliminary screening, notably in outbreaks. However, negative samples need to be tested using RT-PCR methods.

Fighting nosocomial infections with biocidal non-intrusive hard and soft surfaces

Approximately 7 million people worldwide acquire a healthcare associated infection each year. Despite aggressive monitoring, hand washing campaigns and other infection control measures, nosocomial infections (NI) rates, especially those caused by antibiotic resistant pathogens, are unacceptably high worldwide. Additional ways to fight these infections need to be developed. A potential overlooked and neglected source of nosocomial pathogens are those found in non-intrusive soft and hard surfaces located in clinical settings. Soft surfaces, such as patient pyjamas and beddings, can be an excellent substrate for bacterial and fungal growth under appropriate temperature and humidity conditions as those present between patients and the bed. Bed making in hospitals releases large quantities of microorganisms into the air, which contaminate the immediate and non-immediate surroundings. Microbes can survive on hard surfaces, such as metal trays, bed rails and door knobs, for very prolonged periods of time. Thus soft and hard surfaces that are in direct or indirect contact with the patients can serve as a source of nosocomial pathogens. Recently it has been demonstrated that copper surfaces and copper oxide containing textiles have potent intrinsic biocidal properties. This manuscript reviews the recent laboratory and clinical studies, which demonstrate that biocidal surfaces made of copper or containing copper can reduce the microbiological burden and the NI rates.

Unrecognized norovirus infections in health care institutions and their clinical impact

Noroviruses (NoVs) have emerged as the leading cause of acute viral gastroenteritis (GE) in humans. Although diagnostic facilities have greatly improved, significant underdiagnosis of NoV in hospitals may still occur, thereby increasing clinical burden and nosocomial spread. We evaluated the underdiagnosis of sporadic NoV infections in a tertiary care hospital and estimated its clinical impact. From December 2008 until July 2009, fecal samples specifically referred for bacterial but not viral examination were retrospectively tested for NoV by real-time PCR. The clinical and virological data from patients with undiagnosed NoV infection (missed patients) were evaluated and compared with those from patients with recognized NoV. During the study period, 45 patients with undiagnosed NoV were detected, whereas 50 patients were regularly diagnosed. The missed NoV cases were more frequently adults than children (80% versus 46%; P < 0.001). The viral load levels did not differ between the diagnosed and missed patients, but missed patients more frequently presented without diarrhea (20% versus 4%; P < 0.07). The newly admitted missed NoV cases with GE underwent more diagnostic imaging (24% versus 4%; P < 0.01) and tended to be hospitalized longer. When missed-NoV patients were included, the number of nosocomial clusters doubled and missed patients were index cases in 5 of the 6 clusters. These data indicate that NoV infections are frequently missed despite routine laboratory testing and demonstrate that underdiagnosis of NoV patients is associated with costly abdominal imaging and nosocomial clustering. Awareness of NoV infection in adult patients and education about the importance of viral GE should be increased.

Thermal stability of structurally different viruses with proven or potential relevance to food safety

Aims:  To collect comparative data on thermal stability of structurally different viruses with proven or potential relevance to food safety.

Methods and Results:  Suspensions with poliovirus Sabin1, adenovirus type5, parechovirus1, human norovirus (NoV) GII.4, murine NoV (MNV1) and human influenza A (H1N1) viruses were heated at 56 and 73°C. Infectivity was tested by culture assay for all but human NoV GII.4 that cannot be cultivated in vitro. Time to first log₁₀ reduction (TFL‐value) was calculated based on best fit using the monophasic, biphasic or Weibull models. The Weibull model provided the best fit at 56°C for all viruses except influenza virus. The TFL at 56°C varied between a high of 27 min (parechovirus) to a low of 10 s (adenovirus) and ranked parechovirus > influenza > MNV1 > poliovirus > adenovirus. The monophasic model best described the behaviour of the viruses at 73°C, in which case the TFL was MNV1(62s) > influenza > adenovirus > parechovirus > poliovirus(14s).

Conclusions:  Viruses do not follow log‐linear thermal inactivation kinetics and the thermostability of parechovirus and influenza virus is similar to that of proven foodborne viruses.

Significance and Impact of the Study:  Resistant fractions of viruses may remain infectious in thermal inactivation processes and inactivation of newly discovered or enveloped viruses in thermal food preparation processes should not be assumed without further testing.

Assessment of a rapid immunochromatographic test for the diagnosis of norovirus gastroenteritis

Noroviruses are the leading cause of acute gastroenteritis in people of all ages. Since the viruses are highly infectious, rapid and early diagnosis is important to prevent and control the disease. The present study aimed to evaluate the commercial immunochromatographic test RIDA® QUICK Norovirus for the detection of norovirus in stool samples from patients with acute gastroenteritis in Thailand. As compared with reference RT-PCR results, the RIDA® QUICK Norovirus assay provided a sensitivity of 48.2 and 83.3% with a specificity of 87.5%. False positive results were observed in 12.5% of norovirus-negative stool samples. Based on commercial quantitative real-time RT-PCR, the RIDA® QUICK Norovirus assay revealed a highly significant association, p-value <0.001, and good agreement (kappa = 0.6). The assay could detect norovirus in stool samples ranging from 3.22 × 10(6) to 3.26 × 10(8) copies/ml. False negative results occurred in the stool samples containing 5.9 × 10(6) copies/ml of norovirus GI or 1.85 × 10(4) - 4.28 × 10(5) copies/ml of GII. The immunochromatographic RIDA® QUICK Norovirus assay may be useful for rapid screening of norovirus infections in patients with acute gastroenteritis in both developed and developing countries where the RT-PCR method has not been established for routine diagnosis.

High level of gastrointestinal nosocomial infections in the german surveillance system, 2002-2008

OBJECTIVE

Surveillance of nosocomial infections (NIs) is well established in many countries but often does not include gastrointestinal infections. We sought to determine the proportion of NIs among all hospitalized cases for the 4 most prevalent types of gastrointestinal infections in Germany.

METHODS

We analyzed all notifications of laboratory-confirmed or epidemiologically linked gastrointestinal infections due to norovirus, rotavirus, Salmonella species, and Campylobacter species reported to the Robert Koch Institute in Berlin, Germany, from 2002 through 2008. Infections were considered nosocomial if disease onset was more than 2 days after hospitalization for norovirus, rotavirus, and Salmonella infection and more than 5 days after hospitalization for Campylobacter infection.

RESULTS

  During the study period, 710,725 norovirus, 394,500 rotavirus, 395,736 Salmonella, and 405,234 Campylobacter gastrointestinal infections were reported. Excluding cases for which nosocomial status could not be determined, we identified 39,424 (49%) of 80,650 norovirus, 11,592 (14%) of 83,451 rotavirus, 3,432 (8%) of 43,348 Salmonella, and 645 (2%) of 33,503 Campylobacter gastrointestinal infections as definite nosocomial cases. Multivariate analysis confirmed higher risk of gastrointestinal NIs for patients aged more than 70 years (relative risk [RR], 7.0 [95% confidence interval {CI}, 6.7-7.2]; [Formula: see text]) and residents of western states (RR, 1.3 [95% CI, 1.2-1.3]; [Formula: see text]) and lower risk for female patients (RR, 0.9 [95% CI, 0.9-0.9; [Formula: see text]). Yearly NI proportions remained stable except for norovirus.

CONCLUSIONS

The investigated gastrointestinal NIs in Germany do not show a clear trend, but they are at high level, revealing potential for public health action and improvement of hospital infection control mainly among older patients. National prevalence studies on gastrointestinal NIs would be of additional value to give more insight on how and where to improve hospital infection control.

Norovirus infections in children under 5 years of age hospitalized due to the acute viral gastroenteritis in northeastern Poland

The primary aim of this study was to evaluate the frequency and seasonality of norovirus infection in hospitalized Polish children under 5 years of age, and a secondary aim was to compare the clinical severity of norovirus and rotavirus disease. The prospective surveillance study was carried out from July 2009 through June 2010. Stool samples from 242 children hospitalized due to acute viral gastroenteritis were tested for rotavirus group A and adenovirus with commercial immunochromatographic test and for norovirus with EIA assay. Single norovirus infection was found in 35/242 (14.5%) patients and in a further 5 (2.1%) children as co-infection with rotavirus. Overall, norovirus was detected in 16.5% of stool specimens. Norovirus infections tended to peak from October to November and again from February to March. In autumn months and in February, the proportion of norovirus gastroenteritis cases was equal or even surpassed those of rotavirus origin. Both norovirus and rotavirus infections most commonly affected children between 12 and 23 months of age. The low-grade or no fever was significantly more common in children infected with norovirus (94.3%) compared to rotavirus cases (52.9%). Overall, norovirus gastroenteritis was less severe than rotavirus disease with regard to 20-point severity scale (p < 0.05). Noroviruses have emerged as a relevant cause of acute gastroenteritis in Polish children. There is a great need for introducing routine norovirus testing of hospitalized children with gastroenteritis.

Novel norovirus recombinants and of GII.4 sub-lineages associated with outbreaks between 2006 and 2010 in Belgium

BACKGROUND

Noroviruses (NoVs) are an important cause of acute gastroenteritis in humans worldwide. To gain insight into the epidemiologic patterns of NoV outbreaks and to determine the genetic variation of NoVs strains circulating in Belgium, stool samples originating from patients infected with NoVs in foodborne outbreak investigations were analysed between December 2006 and December 2010.

RESULTS

NoVs were found responsible of 11.8% of all suspected foodborne outbreaks reported in the last 4 years and the number of NoV outbreaks reported increased along the years representing more than 30% of all foodborne outbreaks in 2010. Genogroup II outbreaks largely predominated and represented more than 90% of all outbreaks. Phylogenetic analyses were performed with 63 NoV-positive samples for the partial polymerase (N = 45) and/or capsid gene (N = 35) sequences. For 12 samples, sequences covering the ORF1-ORF2 junction were obtained. A variety of genotypes was found among genogroups I and II; GII.4 was predominant followed in order of importance by GII.2, GII.7, GII.13, GI.4 and GI.7. In the study period, GII.4 NoVs variants 2006a, 2006b, 2007, 2008 and 2010 were identified. Moreover, phylogenetic analyses identified different recombinant NoV strains that were further characterised as intergenotype (GII.e/GII.4 2007, GII.e/GII.3 and GII.g/GII.1) and intersub-genotype (GII.4 2006b/GII.4 2007 and GII.4 2010/GII.4 2010b) recombinants.

CONCLUSIONS

NoVs circulating in the last 4 years in Belgium showed remarkable genetic diversity either by small-scale mutations or genetic recombination. In this period, GII.4 2006b was successfully displaced by the GII.4 2010 subtype, and previously reported epidemic GII.b recombinants seemed to have been superseded by GII.e recombinants in 2009 and GII.g recombinants in 2010. This study showed that the emergence of novel GII.4 variants together with novel GII recombinants could lead to an explosion in NoV outbreaks, likewise to what was observed in 2008 and 2010. Among recombinants detected in this study, two hitherto unreported strains GII.e/GII.3 and GII.g/GII.1 were characterised. Surveillance will remain important to monitor contemporaneously circulating strains in order to adapt preventive and curative strategies.

Year-round prevalence of norovirus in the environment of catering companies without a recently reported outbreak of gastroenteritis

Food handlers play an important role in the transmission of norovirus (NoV) in food-borne outbreaks of gastroenteritis (GE). In a year-round prevalence study, the prevalence of NoV in catering companies without recently reported outbreaks of GE was investigated and compared to the observed prevalence in catering companies with recently reported outbreaks. Swab samples were collected from surfaces in the kitchens and (staff) bathrooms in 832 randomly chosen companies and analyzed for the presence of NoV RNA. In total, 42 (1.7%) out of 2,496 environmental swabs from 35 (4.2%) catering companies tested positive. In contrast, NoV was detected in 147 (39.7%) of the 370 samples for 44 (61.1%) of the 72 establishments associated with outbreaks of gastroenteritis. NoV-positive swabs were more frequently found in winter, in specific types of companies (elderly homes and lunchrooms), and in establishments with separate bathrooms for staff. We found a borderline association with population density but no relation to the number of employees. Sequence analysis showed that environmental strains were interspersed with strains found in outbreaks of illness in humans. Thus, the presence of NoV in catering companies seemed to mirror the presence in the population but was strongly increased when associated with food-borne GE. Swabs may therefore serve as a valuable tool in outbreak investigations for the identification of the causative agent, although results should be interpreted with care, taking into account all other epidemiological data.

In vivo comparison of two human norovirus surrogates for testing ethanol-based handrubs: the mouse chasing the cat!

Human noroviruses (HuNoV), a major cause of acute gastroenteritis worldwide, cannot be readily cultured in the lab. Therefore, a feline calicivirus (FCV) is often used as its surrogate to, among other things, test alcohol-based handrubs (ABHR). The more recent laboratory culture of a mouse norovirus (MNV) provides an alternative. While MNV is closer to HuNoV in several respects, to date, no comparative testing of FCV and MNV survival and inactivation on human hands has been performed. This study was designed to address the knowledge gap. The rates of loss in viability during drying on hands were -1.91 and -1.65% per minute for FCV and MNV, respectively. When the contaminated skin was exposed for 20 s to either a commercial ABHR with 62% (v/v) ethanol or to 75% (v/v) ethanol in water, FCV infectivity was reduced by <1 log₁₀ while that of MNV by nearly 2.8 log₁₀. Extending the contact time to 30 s reduced the FCV titer by almost 2 log₁₀ by both test substances and that of MNV by >3.5 log₁₀ by the commercial ABHR while 75% ethanol did not show any noticeable improvement in activity as compared to the 20 s contact. An 80% (v/v) aqueous solution of ethanol gave only a 1.75 log₁₀ reduction in MNV activity after 20 s. The results show significant differences in the ethanol susceptibility of FCV and MNV in contact times relevant to field use of ABHR and also that 62% ethanol was a more effective virucide than either 75% or 80% ethanol. These findings indicate the need for a review of the continuing use of FCV as a surrogate for HuNoV.

[Nosocomial diarrhea]

Hospital acquired or nosocomial diarrhea affects up to one third of hospitalized patients. It increases mortality rates as well as length and costs of the hospital stay. Drug side effects are the predominant cause of nosocomial diarrhea whilst clostridium difficile is the most common infectious agent, whose development is closely linked to antibiotic usage. The causal therapy of mild clostridium difficile infections is controversially discussed. Nevertheless, the use of Metronidazol for mild cases and of vancomycin for severe forms of the disease is recommended. Diarrhea outbreaks might be caused by viruses and less often by Salmonella and Listeria. Norovirus infections are of outstanding importance. Rehydration and isolation to prevent the spread of this highly contagious virus are the only reasonable options as we still lack a proper therapy.

Norovirus as a foodborne disease hazard

Norovirus (NoV) is the most common cause of infectious gastroenteritis in the world. Gastroenteritis caused by bacterial and parasitic pathogens is commonly linked to food sources, but the link between NoV and contaminated foods has been more difficult to establish. Even when epidemiological information indicates that an outbreak originated with food, the presence of NoV in the suspect product may not be confirmed. If food is found to contain a common strain of NoV that circulates widely in the community, it is not possible to use strain typing to link the contamination to patient cases. Although food is certainly implicated in NoV spread, there are additional person-to-person and fomite transmission routes that have been shown to be important. NoV has an extremely low infectious dose, is stable in the environment, and resists disinfection. Cell culture methods are not available, so viability cannot be determined. Finally, many NoV outbreaks originate with when an infected food handler contaminates ready-to-eat food, which can be interpreted as foodborne or person-to-person transmission. This review will discuss both the physical characteristics of NoVs and the available epidemiological information with particular reference to the role of foods in NoV transmission.

Twenty-four-hour observational study of hospital hand hygiene compliance

This observational study measured healthcare workers' (HCWs'), patients' and visitors' hand hygiene compliance over a 24h period in two hospital wards using the 'five moments of hand hygiene' observation tool. Hand hygiene is considered to be the most effective measure in reducing healthcare-associated infections but studies have reported suboptimal levels of compliance. Most studies have used random observational time-periods for data collection and this has been criticised. We monitored a total of 823 hand hygiene opportunities (HCWs, N=659; patients and visitors, N=164). Among HCWs, compliance was 47% for doctors, 75% for nurses, 78% for allied health professionals, and 59% for ancillary and other staff (P<0.001). There was no difference in compliance between patients and visitors (56% vs 57%, P=0.87). Hand hygiene compliance varied depending on which of the five moments of hygiene HCWs had undertaken (P<0.001), with compliance before an aseptic task being 100% (3/3); after body fluid exposure 93% (86/93); after patient contact 80% (114/142); before patient contact 68% (196/290); and after contact with surroundings 50% (65/129). Lower levels of compliance were found for HCWs working during the early shift (P<0.001). For patients and visitors there was no evidence of an association between moments of hygiene and compliance. Levels of compliance were higher compared with previous reported estimates. Medical staff had the lowest level of compliance and this continues to be a concern which warrants specific future interventions.