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.

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.

Clostridium difficile is not associated with outbreaks of viral gastroenteritis in the elderly in the Netherlands

The coincidental increase in norovirus outbreaks and Clostridium difficile infection (CDI) raised the question of whether these events could be related, e.g. by enhancing spread by diarrhoeal disease outbreaks. Therefore, we studied the prevalence of C. difficile in outbreaks of viral gastroenteritis in nursing homes for the elderly and characterised enzyme immunoassay (EIA)-positive stool samples. Stool samples from nursing home residents (n = 752) in 137 outbreaks of viral aetiology were investigated by EIA for the presence of C. difficile toxins. Positive samples were further tested by a cell neutralisation cytotoxicity test, a second EIA and culture. Cultured isolates were tested for the presence of toxin genes, the production of toxins and characterised by 16S rRNA polymerase chain reaction (PCR) and sequencing. Twenty-four samples (3.2%) tested positive in the EIA. Of these 24 positive samples, only two were positive by cytotoxicity and three by a second EIA. Bacterial culture of 21 available stool samples yielded a toxinogenic C. difficile PCR ribotype 001 in one patient sample only. In conclusion, we found no evidence in this retrospective study for an association between viral gastroenteritis outbreaks and C. difficile. The high rate of false-positive EIA samples emphasises the need for second confirmation tests to diagnose CDI.

Import of norovirus infections in the Netherlands and Ireland following pilgrimages to Lourdes, 2008--preliminary report

Between mid-September and 19 October 2008, nine clusters of norovirus infection involving around 90 primary cases and over a hundred secondary cases were identified in patients from the Netherlands, Ireland, Italy and France, linked to pilgrimage to Lourdes, France.

Import of norovirus infections in the Netherlands and Ireland following pilgrimages to Lourdes, 2008 – preliminary report

Between mid-September and 19 October 2008, nine clusters of norovirus infection involving around 90 primary cases and over a hundred secondary cases were identified in patients from the Netherlands, Ireland, Italy and France, linked to pilgrimage to Lourdes, France.

Multiple exposures during a norovirus outbreak on a river-cruise sailing through Europe, 2006

In the summer of 2006, several cruise-related viral gastroenteritis outbreaks were reported in Europe. One report came from a river-cruise, belonging to a ship-owner who had two other ships with outbreaks. This situation warranted onsite investigation in order to identify a potential common source of infection. A retrospective cohort study was performed among 137 people on board. Epidemiological questionnaire data were analysed using logistic regression. Stool, food, water and surface samples were collected for norovirus detection. Norovirus GGII.4-2006b was responsible for 48 gastroenteritis cases on this ship as confirmed in six patients. Identical norovirus sequences were detected in stool samples, on surfaces and in tap water. Epidemiological and microbiological data indicated multiple exposures contributing to the outbreak. Microbiological results demonstrated person-to-person transmission to be clearly present. Epidemiological results indicated that consuming tap water was a risk factor; however, this could not be concluded definitively on the basis of the available data. A common source for all cruise-related outbreaks was unlikely. The ongoing outbreaks on this ship demonstrated that evidence based guidelines on effective disinfection strategies are needed.

Multiple exposures during a norovirus outbreak on a river-cruise sailing through Europe, 2006

In the summer of 2006, several cruise-related viral gastroenteritis outbreaks were reported in Europe. One report came from a river-cruise, belonging to a ship-owner who had two other ships with outbreaks. This situation warranted onsite investigation in order to identify a potential common source of infection. A retrospective cohort study was performed among 137 people on board. Epidemiological questionnaire data were analysed using logistic regression. Stool, food, water and surface samples were collected for norovirus detection. Norovirus GGII.4-2006b was responsible for 48 gastroenteritis cases on this ship as confirmed in six patients. Identical norovirus sequences were detected in stool samples, on surfaces and in tap water. Epidemiological and microbiological data indicated multiple exposures contributing to the outbreak. Microbiological results demonstrated person-to-person transmission to be clearly present. Epidemiological results indicated that consuming tap water was a risk factor; however, this could not be concluded definitively on the basis of the available data. A common source for all cruise-related outbreaks was unlikely. The ongoing outbreaks on this ship demonstrated that evidence based guidelines on effective disinfection strategies are needed.

Typing database for noroviruses

The FBVE (Food-borne Viruses in Europe) network was initiated during a research project funded by the European Commission (contract QLK1-1999-00594). The aim of the network is to establish a framework for rapid, (pre-publication) exchange of epidemiological, virological and molecular diagnostic data on outbreaks of viral gastroenteritis and acute hepatitis due to hepatitis A and E viruses for both surveillance and research purposes.

Food-borne viruses in Europe network report: the norovirus GII.4 2006b (for US named Minerva-like, for Japan Kobe034-like, for UK V6) variant now dominant in early seasonal surveillance

Binary file ES_Abstracts_Final_ECDC.txt matches

Data quality of 5 years of central norovirus outbreak reporting in the European Network for food-borne viruses

BACKGROUND

The food-borne viruses in Europe (FBVE) network database was established in 1999 to monitor trends in outbreaks of gastroenteritis due to noroviruses (NoVs), to identify major transmission routes of NoV infections within and between participating countries and to detect diffuse international food-borne outbreaks.

METHODS

We reviewed the total of 9430 NoV outbreak reports from 13 countries with date of onset between 1 January 2002 and 1 January 2007 for representativeness, completeness and timeliness against these objectives.

RESULTS

Rates of reporting ranged from a yearly average of 1.8 in 2003 to 11.6 in 2006. Completeness of reporting of an agreed minimum dataset improved over the years, both for epidemiological and virological data. For the 10 countries that provided integrated (epidemiological AND virological) reporting over the 5-year period, the completeness of the minimum dataset rose from 15% in 2003 to 48% in 2006. Two countries have not been able to combine both data types due to the structure of the national surveillance system (England and Wales and Germany). Timeliness of reporting (median days between the onset of an outbreak and the date of reporting to the FBVE database) differed greatly between countries, but gradually improved to 47 days in 2006.

CONCLUSION

The outbreaks reported to the FBVE reflect the lack of standardization of surveillance systems across Europe, making direct comparison of data between countries difficult. However, trends in reported outbreaks per country, distribution of NoV genotypes, and detection of diffuse international outbreaks were used as background data in acute questions about NoV illness and the changing genotype distribution during the 5-year period, shown to be of added value. Integrated reporting is essential for these objectives, but could be limited to sentinel countries with surveillance systems that allow this integration. For successful intervention in case of diffuse international outbreaks, completeness and timeliness of reporting would need to be improved and expanded to countries that presently do not participate.

Use of serological assays for diagnosis of hepatitis E virus genotype 1 and 3 infections in a setting of low endemicity

Because of the occurrence of genotype 3 hepatitis E virus (HEV) in regions of low endemicity, it is important to validate the currently used serological assays for diagnosing infections with viruses belonging to this lineage, since these assays only use antigens derived from genotype 1 and 2 viruses. We evaluated the Genelabs enzyme-linked immunosorbent assay (ELISA) and the RecomBlot from Mikrogen for the detection of HEV-specific immunoglobulin M (IgM) and IgG under conditions of low endemicity. We compared test results of 16 patients with locally acquired genotype 3 HEV, 8 genotype 1 patients, 167 healthy controls from the general population, and 101 cases with hepatitis due to other viral causes. The measured specificities of the ELISA (98%) and the RecomBlot (97%) were comparable to those given by the manufacturer for IgM but were significantly lower for IgG (93% by ELISA and 66% by immunoblotting, versus reported values of 98% for ELISA and 95% for blotting). Antibody levels detected following infections with genotype 3 were lower than those following genotype 1 infections except for those measured in the IgM ELISA. Reactivity to the four antigens used in the immunoblot assay were analyzed and showed differences in the IgM immunoblot reactions between genotype 1 patients and genotype 3 patients. The ORF3 antigen was the most specific antigen. The specificity could be improved by a combined testing regimen with confirmation by immunoblotting of all positive ELISA results and by raising the cutoff of the IgG immunoblot assay without loss of sensitivity. We conclude that a combination of ELISA and immunoblotting is needed for acceptable specificity and sensitivity of HEV assays under conditions of low endemicity.

Swine-like hepatitis E viruses are a cause of unexplained hepatitis in the Netherlands

Hepatitis E virus (HEV) infections in developed countries are recognized as an imported disease related to travel to endemic regions. However, increasing evidence suggests that HEV infection may also occur in the developed countries and that swine may act as a possible reservoir. To investigate the indigenous transmission of HEV in the Netherlands, sera from 50 blood donors and 1027 sera from patients with acute hepatitis were screened with an ELISA for HEV-specific IgG and IgM. Because the Netherlands is considered a nonendemic region, all positive ELISA results were confirmed by immunoblot to exclude false-positive results. Evidence of recent HEV infection was detected in 0% of the blood donors and 4.4% of the cases, based on combined positive IgM and IgG responses. The serodiagnosis was confirmed by a positive polymerase chain reaction (PCR) in 24 patients with hepatitis (2.3% overall, 51% of confirmed IgM+/IgG+ cases). IgG antibodies alone were detected in 4.2% of patients. We found related sequences to virus strains detected in Dutch pigs (genotype 3, 91-97% homology) in 89% of PCR-confirmed HEV patients. The detection of unique swine-like HEV sequences in 16 indigenous hepatitis patients without a recent travel history suggests that HEV is endemic in the Netherlands. We recommend including HEV tests in unexplained acute hepatitis patients, despite their travel history.

Detection of hepatitis E virus-specific immunoglobulin a in patients infected with hepatitis E virus genotype 1 or 3

Currently, diagnosis of acute hepatitis E virus (HEV) in patients is primarily based on anti-HEV immunoglobulin M (IgM) detection. However, several investigations suggest the use of HEV-specific IgA for diagnosing acute HEV infections. We evaluated two commercially available assays, an IgA enzyme-linked immunosorbent assay (ELISA) (Diacheck) and an adapted immunoblot protocol (Mikrogen) for IgA detection and compared the performance in genotype 1- and 3-infected patients. The specificity of the IgA assays was high, with no positive reactions in a control group of 18 acute hepatitis patients who were negative for HEV. The sensitivity calculated in nine PCR-positive type 1-infected patients was 100% in both assays but was clearly lower in genotype 3-infected patients (n = 14), with sensitivities of only 67% and 57% for the ELISA and immunoblot assay, respectively. The lower IgA responses detected in genotype 3-infected patients could be caused by the use of only the genotype 1 and 2 antigens in the serological assays. Interestingly in two patients with possible infection through blood transfusion no response or intermediate IgA responses were detected, and this might confirm the parenteral route of transmission. In both the type 1- and type 3-infected patients both the IgA and IgM responses disappeared simultaneously. We conclude that IgA detection is of limited value for the serodiagnosis of acute HEV cases, particularly with genotype 3.

Molecular epidemiology of human enteric caliciviruses in The Netherlands

Caliciviruses are among the most common causes of gastroenteritis in people of all age groups. These antigenetically and genetically diverse viruses have been grouped into two genera within the family Caliciviridae, designated Norwalk-like viruses (NLV) and Sapporo-like viruses (SLV). To gain more insight in their epidemiology, we have developed a tentative genotyping scheme, which was used to differentiate the viruses detected in a set of epidemiological studies. NLVs and SLVs were detected by generic RT-PCR in stool specimens from 5.1% and 2.4% of cases with acute gastroenteritis for which a general practitioner was consulted, and in 16.5% and 6.3% of community cases of gastroenteritis. In addition, NLVs were associated with more than 80% of reported outbreaks of gastroenteritis from 1994-1999. Typically, several genotypes of NLV co-circulate in the community. Occasionally, however, several consecutive outbreaks were caused by essentially the same virus, although an epidemiological link had not previously been noted. This was most pronounced in 1995/1996, when a Lordsdale-like variant was detected that subsequently was found worldwide. This epidemic spread suggests differences in virulence or mode of transmission. In addition, we found that related NLVs are highly prevalent in calves in The Netherlands, raising questions about their potential for zoonotic transmission.

Effects of cadmium chloride on the paracellular barrier function of intestinal epithelial cell lines

In the present study we characterized the functional and structural disruption of the paracellular barrier of intestinal epithelium in vitro in relation to cytotoxicity after apical Cd2+ exposure. For that purpose filter-grown Caco-2 and IEC-18 cells were apically exposed to 5 to 100 microM CdCl2 for 4 or 14 h. It was found that the effects of Cd2+ on the epithelial barrier were concentration- and time-dependent. The first detected effects of Cd2+ in Caco-2 cells after 4 h exposure were a decrease in transepithelial electrical resistance, increased permeabilities of mannitol and PEG-4000, and changes in intercellular localization of ZO-1, occludin, and e-cadherin. The effects were far more pronounced after prolonged exposure. The disruption of the paracellular barrier by 5 to 30 microM Cd2+ was detected without a significant loss of viability of the Caco-2 cells. In the IEC-18 cells, Cd2+ concentrations affecting the barrier (50 and 100 microM) also affected cell viability. In both cell lines the effects on the cell layers continued to develop after removal of extracellular Cd2+. This correlated with the cellular retention of Cd2+, which was high for the 12 h following 4 h accumulation. This study showed that the decreased epithelial barrier function of intestinal epithelial cells is accompanied by tight junction disruption. It is concluded that Cd2+ causes increased paracellular permeability by disruption of junctional function and structure. The initial junctional effects of Cd2+ suggest that Cd2+ increases its own bioavailability by causing disruption of the intestinal paracellular barrier.

Absorption enhancement, structural changes in tight junctions and cytotoxicity caused by palmitoyl carnitine in Caco-2 and IEC-18 cells

Palmitoyl carnitine chloride (PCC) has been shown to be an effective enhancer of intestinal transport of hydrophilic molecules. The exact mechanism by which the epithelial barrier function is decreased is not clear. In an attempt to elucidate the mechanism of action of PCC, we studied the relationship among absorption enhancement, cell viability and tight junction protein localization in the human colonic Caco-2 cell line and the rat small intestinal cell line IEC-18. Filter-grown cells were exposed to 0 to 1 mM PCC for 30 min, and the efficacy of PCC treatment was determined by assessing the transepithelial electrical resistance and the apparent permeability for mannitol and PEG-4000. Membrane lysis and cytotoxicity were assessed by measurement of lactate dehydrogenase leakage and uptake of propidium iodide and neutral red. The immunolocalization of the tight junctional protein ZO-1 was quantified using CSLM and image-processing software. In both cell lines, PCC caused a dose-dependent decrease in transepithelial electrical resistance and a concomitant increase in the permeability for mannitol and PEG-4000. The transport enhancement was accompanied by an increase in apical membrane permeability and a reduction in cell viability. At higher PCC concentrations (>/=0.4 mM), the distribution of the tight junctional protein ZO-1 was changed and cells were unable to recover viability. PCC is effective as an absorption enhancer for hydrophilic macromolecules. However, lytic effects on the cell membrane and reduced cell viability were concomitant with transport enhancement.

Cytochrome P450-mediated oxidation of pentafluorophenol to tetrafluorobenzoquinone as the primary reaction product

In the present study the oxidative dehalogenation of a para-halogenated phenol was studied using pentafluorophenol and its non-para-halogenated analogue 2,3,5,6-tetrafluorophenol as model compounds. 19F NMR was used to characterize the metabolite patterns. In order to study the primary oxidation products of the microsomal cytochrome P450-catalyzed conversion, the alternative oxygen donors cumene hydroperoxide (CumOOH) and iodosobenzene (IOB) were used in addition to the use of NADPH and molecular oxygen. In a NADPH/oxygen-driven reaction, but also in a CumOOH- or IOB-driven cytochrome P450 reaction, tetrafluorophenol was converted to tetrafluorohydroquinone. However, for pentafluorophenol, the formation of tetrafluorohydroquinone as a product of its cytochrome P450-mediated conversion was only observed in the NADPH-driven system. Addition of reducing equivalents such as NADH to the CumOOH or IOB incubations resulted in the formation of tetrafluorohydroquinone. From these data it was concluded that the primary reaction product of the cytochrome P450-catalyzed conversion of pentafluorophenol is a reactive species that can be reduced to tetrafluorohydroquinone by NAD(P)H and, thus, must be tetrafluorobenzoquinone. Additional experiments with tetrafluorobenzoquinone, incubated in vitro with either microsomal protein or glutathione in the presence or absence of reducing equivalents, demonstrated that the tetrafluorobenzoquinone ends up bound to proteins, losing its fluorine atoms as fluoride anions. Thus, while cytochrome P450-mediated conversion of the 2,3,5,6-tetrafluorophenol results in the formation of tetrafluorohydroquinone as the primary reaction product, monooxygenation at a fluorinated para position, such as in pentafluorophenol, results in the formation of the reactive tetrafluorobenzoquinone derivative as the primary reaction product.(ABSTRACT TRUNCATED AT 250 WORDS)