The Influence of Temperature on Norovirus Inactivation by Monochloramine in Potable Waters: Testing with Murine Norovirus as a Surrogate for Human Norovirus

Human noroviral infections are generally more common during winters in temperate regions. This study used a murine norovirus (MNV) as a human norovirus surrogate to test the effect of water temperature (4 and 25°C) on virus survival and its susceptibility to the levels of monochloramine (~1.89 ppm) to terminally disinfect municipally treated potable waters. The titre of MNV remained essentially unchanged for at least 24 h in raw river water at both temperatures. The virus became undetectable in <2 h in monochloramine-containing samples held at 25°C, but its titre remained virtually unaltered at 4°C (P < 0.05) under the same conditions. These findings strongly suggest that water temperature can influence the norovirucidal activity of monochloramine and its possible impact on the seasonality of outbreaks of noroviral infections.     

Airway Reactivity to Sulfate and Sulfuric Acid Aerosols in Normal and Asthmatic Subjects

Recent epidemiologic studies have emphasized a relationship between alteration in lung function, respiratory symptoms in asthmatics, and elevated levels of sulfate air pollutants. In asthmatics, it has been reported that 1) the more acidic sulfate aerosols, sulfuric acid (H₂SO₄) and ammonium bisulfate (NH₄HSO₄), provoked the greatest changes in lung function and 2) a definite exposure-response relationship exists for H₂SO₄ inhalation. To determine if sulfate aerosol exposure caused increased reactivity to a known bronchoconstrictor, normal and asthmatic subjects inhaled subthreshold doses of carbachol after the following sulfates: H₂SO₄, NH4HSO4, and sodium bisulfate. A NaCI aerosol served as a control. Exposure times averaged 16 minutes with sulfate concentrations ranging from 100 μ/m³ to 1000 jtg/m₃. In normal subjects, prior inhalation of either 1000 yug/m₃ H₂SO₄ or NH4HSO4 significantly potentiated (P < 0.05) the bronchoconstrictor action of carbachol on airway conductance compared to NaCI and carbachol or carbachol alone by t-tests. For the asthmatic group, prior inhalation of either 1000/tg/m₃ H₂SO₄ or NH₄HSO₄ (P < 0.05), or 450 μ/m³ H₂SO₄ (P < 0.05) similarly enhanced the carbachol bronchoconstrictor effect compared to NaCI and carbachol. At the low 100 μ/m³, no sulfates altered the effects of carbachol on pulmonary function. Although mean changes between the sulfate groups did not attain significance by an analysis of variance, it was found that the bronchoconstrictor action of carbachol was potentiated by the sulfate aerosols more or less in relation to their acidity.     

Less-invasive autopsy for early pregnancy loss

Autopsy investigations provide valuable information regarding fetal death that can assist in the parental bereavement process, and influence future pregnancies, but conventional autopsy is often declined by parents because of its invasive approach. This has led to the development of less-invasive autopsy investigations based on imaging technology to provide a more accessible and acceptable choice for parents when investigating their loss. Whilst the development and use of more conventional clinical imaging techniques (radiographs, CT, MRI, US) are well described in the literature for fetuses over 20 weeks of gestational age, these investigations have limited diagnostic accuracy in imaging smaller fetuses. Techniques such as ultra-high-field MRI (>3T) and micro-focus computed tomography have been shown to have higher diagnostic accuracy whilst still being acceptable to parents. By further developing and increasing the availability of these more innovative imaging techniques, parents will be provided with a greater choice of acceptable options to investigate their loss, which may in turn increase their uptake. We provide a narrative review focussing on the development of high-resolution, non-invasive imaging techniques to evaluate early gestational pregnancy loss.