Gastrointestinal Flu: Norovirus in Health Care and Long-Term Care Facilities
ABSTRACT Noroviruses, recognized as the leading global cause of viral gastroenteritis and a major contributor to food-borne illness, present a growing challenge in health care and long-term care facilities. The virus spreads easily and by multiple routes. A visitor to a ward might initiate an outbreak by person-to-person contact, vomiting staff members or patients can disseminate the virus by airborne means, and contaminated surfaces, such as doorknobs and computer keyboards, can sustain an epidemic. In addition, although self-limited in healthy hosts, the virus can cause increased morbidity in more-vulnerable people. The GII.4 strain of the virus now dominates in multiple recent worldwide epidemics as well as in health care and long-term care facilities. Much like the influenza virus, norovirus appears to evolve by antigenic drift and evading the immune system, causing waves of global epidemics. Previous attempts at controlling outbreaks, both in the community and in closed facilities, provide guidance about the vigilance and action required by the health care community to diminish the clinical impact of norovirus infection.
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ABSTRACT: We evaluated the virucidal efficacy of light-activated fluorinated TiO2 surface coatings on human norovirus and several surrogates (bacteriophage MS2, feline calicivirus (FCV), and murine norovirus (MNV)). Inactivation of viruses on surfaces exposed to a common fluorescent lamp was monitored and the effects of UVA intensity, temperature, and fluoride content were assessed. Destruction of RNA and capsid oxidation were evaluated for human norovirus inocula on the F-TiO2 surfaces, while contact with the F-TiO2 surface and exposure to residual UVA radiation of 10μWcm(-2) for 60min resulted in infectivity reductions for the norovirus surrogates of 2-3 log10. Infectivity reductions on pristine TiO2 surfaces in identical conditions were over 2 orders of magnitude lower. Under realistic room lighting conditions, MS2 infectivity declined below the lower detection limit after 12h. Reductions in RNA were generally low, with the exception of GII.4, while capsid protein oxidation likely played a larger role in infectivity loss. Inactivation of norovirus surrogates occurred significantly faster on F-TiO2 compared to pristine TiO2 surfaces. The material demonstrated antiviral action against human norovirus surrogates and was shown to effectively inhibit MS2 when exposed to residual UVA present in fluorescent room lighting conditions in a laboratory setting.Journal of Photochemistry and Photobiology B Biology 08/2014; 140C:315-320. DOI:10.1016/j.jphotobiol.2014.08.009 · 2.80 Impact Factor
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ABSTRACT: To investigate the antiviral efficacy of oregano oil and its primary active component, carvacrol, against the nonenveloped murine norovirus (MNV), a human norovirus surrogate. Along with an observed loss in cell culture infectivity, the antiviral mechanisms of action were determined in side-by-side experiments including a cell-binding assay, an RNase I protection assay and transmission electron microscopy (TEM). Both antimicrobials produced statistically significant reductions (P ≤ 0·05) in virus infectivity within 15 min of exposure (c. 1·0-log10 ). Despite this, the MNV infectivity remained stable with increasing time exposure to oregano oil (1·07-log10 after 24 h), while carvacrol was far more effective, producing up to 3·87-log10 reductions within 1 h. Based on the RNase I protection assay, both antimicrobials appeared to act directly upon the virus capsid and subsequently the RNA. Under TEM, the capsids enlarged from ≤35 nm in diameter to up to 75 nm following treatment with oregano oil and up to 800 nm with carvacrol; with greater expansion, capsid disintegration could be observed. Virus adsorption to host cells did not appear to be affected by either antimicrobial. Our results demonstrate that carvacrol is effective in inactivating MNV within 1 h of exposure by acting directly on the viral capsid and subsequently the RNA. This study provides novel findings on the antiviral properties of oregano oil and carvacrol against MNV and demonstrates the potential of carvacrol as a natural food and surface (fomite) sanitizer to control human norovirus.Journal of Applied Microbiology 05/2014; 116(5):1149-1163. DOI:10.1111/jam.12453 · 2.39 Impact Factor
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ABSTRACT: Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. However, the presence of above-mentioned indicators do not always suggest the presence of human enteric viruses. It is important to study human enteric viruses in water. Human enteric viruses can tolerate fluctuating environmental conditions and survive in the environment for long periods of time becoming causal agents of diarrhoeal diseases. Therefore, the potential of human pathogenic viruses as significant indicators of water quality is emerging. Human Adenoviruses and other viruses have been proposed as suitable indices for the effective identification of such organisms of human origin contaminating water systems. This article reports on the recent developments in the management of water quality specifically focusing on human enteric viruses as indicators.International Journal of Environmental Health Research 02/2013; DOI:10.1080/09603123.2013.769201 · 1.51 Impact Factor