The viruses most commonly associated with food-and waterborne outbreaks of gastroenteritis are the noroviruses. The lack of a culture method for noroviruses warrants the use of cultivable model viruses to gain more insight on their transmission routes and inactivation methods. We studied the inactivation of the reported enteric canine calicivirus no. 48 (CaCV) and the respiratory feline calicivirus F9 (FeCV) and correlated inactivation to reduction in PCR units of FeCV, CaCV, and a norovirus. Inactivation of suspended viruses was temperature and time dependent in the range from 0 to 100°C. UV-B radiation from 0 to 150 mJ/cm 2 caused dose-dependent inactivation, with a 3 D (D ‫؍‬ 1 log 10 ) reduction in infectivity at 34 mJ/cm 2 for both viruses. Inactivation by 70% ethanol was inefficient, with only 3 D reduction after 30 min. Sodium hypochlorite solutions were only effective at >300 ppm. FeCV showed a higher stability at pH <3 and pH >7 than CaCV. For all treatments, detection of viral RNA underestimated the reduction in viral infectivity. Norovirus was never more sensitive than the animal caliciviruses and profoundly more resistant to low and high pH. Overall, both animal viruses showed similar inactivation profiles when exposed to heat or UV-B radiation or when incubated in ethanol or hypochlorite. The low stability of CaCV at low pH suggests that this is not a typical enteric (calici-) virus. The incomplete inactivation by ethanol and the high hypochlorite concentration needed for sufficient virus inactivation point to a concern for decontamination of fomites and surfaces contaminated with noroviruses and virus-safe water.

Noroviruses (previously Norwalk-like viruses) are the most common viral agents associated with food-and waterborne outbreaks of gastroenteritis. In the absence of culture methods for noroviruses, animal caliciviruses were used as model viruses to study inactivation by nonionizing (253.7-nm-wavelength [UV]) and ionizing (gamma) radiation. Here, we studied the respiratory feline calicivirus (FeCV) and the presumed enteric canine calicivirus (CaCV) and compared them with the well-studied bacteriophage MS2. When UV irradiation was used, a 3-log 10 reduction was observed at a fluence of 120 J/m 2 in the FeCV suspension and at a fluence of 200 J/m 2 for CaCV; for the more resistant phage MS2 there was a 3-log 10 reduction at a fluence of 650 J/m 2 . Few or no differences were observed between levels of UV inactivation in high-and low-proteincontent virus stocks. In contrast, ionizing radiation could readily inactivate MS2 in water, and there was a 3-log 10 reduction at a dose of 100 Gy, although this did not occur when the phage was diluted in high-proteincontent stocks of CaCV or FeCV. The low-protein-content stocks showed 3-log 10 reductions at a dose of 500 Gy for FeCV and at a dose of 300 for CaCV. The inactivation rates for both caliciviruses with ionizing and nonionizing radiation were comparable but different from the inactivation rates for MS2. Although most FeCV and CaCV characteristics, such as overall particle and genome size and structure, are similar, the capsid sequences differ significantly, making it difficult to predict human norovirus inactivation. Adequate management of UV and gamma radiation processes for virus inactivation should limit public health risks.Human caliciviruses are the most important enteric agents of gastroenteritis in industrialized countries (13,17). Many waterborne outbreaks associated with noroviruses have been reported (1,3,5,10,15). Usually, epidemiological data prove that water was the common source for the outbreak, and in some molecular tracing studies norovirus strains were successfully identified in the source water and identical sequences were found in stools from patients (4,8,11,12,16). Virus concentrations in source water may peak with sewage overflow due to heavy rainfall or leaking septic tanks or pipes (2, 20). Breakdown or malfunctioning of water treatment plants may lead to insufficient reductions in virus concentrations in drinking water (20). Moreover, European legislation is mainly based on bacteriological quality parameters that determine fecal contamination of food and water. Viruses, however, are more resistant to treatment (9), are generally harder to detect, and exhibit lower dose-response relationships than bacteria. Therefore, water may meet microbiological safety guidelines but still pose a considerable health hazard.Irradiation treatment is being used more frequently for disinfection of food and water. Bacteriophages have been used as indicators for inactivation of viruses by ionizing and nonionizing radiation since bacteria are generally less resista...

BackgroundViral interaction in which outbreaks of influenza and other common respiratory viruses might affect each other has been postulated by several short studies. Regarding longer time periods, influenza epidemics occasionally occur very early in the season, as during the 2009 pandemic. Whether early occurrence of influenza epidemics impacts outbreaks of other common seasonal viruses is not clear.ObjectivesWe investigated whether early occurrence of influenza outbreaks coincides with shifts in the occurrence of other common viruses, including both respiratory and non‐respiratory viruses.MethodsWe investigated time trends of and the correlation between positive laboratory diagnoses of eight common viruses in the Netherlands over a 10‐year time period (2003–2012): influenza viruses types A and B, respiratory syncytial virus (RSV), rhinovirus, coronavirus, norovirus, enterovirus, and rotavirus. We compared trends in viruses between early and late influenza seasons.ResultsBetween 2003 and 2012, influenza B, RSV, and coronavirus showed shifts in their occurrence when influenza A epidemics occurred earlier than usual (before week 1). Although shifts were not always consistently of the same type, when influenza type A hit early, RSV outbreaks tended to be delayed, coronavirus outbreaks tended to be intensified, and influenza virus type B tended not to occur at all. Occurrence of rhinovirus, norovirus, rotavirus, and enterovirus did not change.ConclusionWhen influenza A epidemics occured early, timing of the epidemics of several respiratory winter viruses usually occurring close in time to influenza A was affected, while trends in rhinoviruses (occurring in autumn) and trends in enteral viruses were not.

BackgroundRisk assessment and early warning (RAEW) are essential components of any infectious disease surveillance system. In light of the International Health Regulations (IHR)(2005), this study compares the organisation of RAEW in China and the Netherlands. The respective approaches towards surveillance of arboviral disease and unexplained pneumonia were analysed to gain a better understanding of the RAEW mode of operation. This study may be used to explore options for further strengthening of global collaboration and timely detection and surveillance of infectious disease outbreaks.MethodsA qualitative study design was used, combining data retrieved from the literature and from semi-structured interviews with Chinese (5 national-level and 6 provincial-level) and Dutch (5 national-level) experts.ResultsThe results show that some differences exist such as in the use of automated electronic components of the early warning system in China (‘CIDARS’), compared to a more limited automated component in the Netherlands (‘barometer’). Moreover, RAEW units in the Netherlands focus exclusively on infectious diseases, while China has a broader ‘all hazard’ approach (including for example chemical incidents). In the Netherlands, veterinary specialists take part at the RAEW meetings, to enable a structured exchange/assessment of zoonotic signals.ConclusionDespite these differences, the main conclusion is that for the two infections studied, the early warning system in China and the Netherlands are remarkably similar considering their large differences in infectious disease history, population size and geographical setting. Our main recommendations are continued emphasis on international corporation that requires insight into national infectious disease surveillance systems, the usage of a One Health approach in infectious disease surveillance, and further exploration/strengthening of a combined syndromic and laboratory surveillance system.

Mandatory notification can be a useful tool to support infectious disease prevention and control. Guidelines are needed to help policymakers decide whether mandatory notification of an infectious disease is appropriate. We developed a decision aid, based on a range of criteria previously used in the Netherlands or in other regions to help decide whether to make a disease notifiable. Criteria were categorised as being effective, feasible and necessary with regard to the relevance of mandatory notification. Expert panels piloted the decision aid. Here we illustrate its use for three diseases (Vibrio vulnificus infection, chronic Q fever and dengue fever) for which mandatory notification was requested. For dengue fever, the expert panel advised mandatory notification; for V. vulnificus infection and chronic Q fever, the expert panel concluded that mandatory notification was not (yet) justified. Use of the decision aid led to a structured, transparent decision making process and a thorough assessment of the advantages and disadvantages of mandatory notification of these diseases. It also helped identify knowledge gaps that required further research before a decision could be made. We therefore recommend use of this aid for public health policy making.