Transmission of SARS and MERS coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination

Viruses with pandemic potential including H1N1, H5N1, and H5N7 influenza viruses, and severe acute respiratory syndrome (SARS)/Middle East respiratory syndrome (MERS) coronaviruses (CoV) have emerged in recent years. SARS-CoV, MERS-CoV, and influenza virus can survive on surfaces for extended periods, sometimes up to months. Factors influencing the survival of these viruses on surfaces include: strain variation, titre, surface type, suspending medium, mode of deposition, temperature and relative humidity, and the method used to determine the viability of the virus. Environmental sampling has identified contamination in field-settings with SARS-CoV and influenza virus, although the frequent use of molecular detection methods may not necessarily represent the presence of viable virus. The importance of indirect contact transmission (involving contamination of inanimate surfaces) is uncertain compared with other transmission routes, principally direct contact transmission (independent of surface contamination), droplet, and airborne routes. However, influenza virus and SARS-CoV may be shed into the environment and be transferred from environmental surfaces to hands of patients and healthcare providers. Emerging data suggest that MERS-CoV also shares these properties. Once contaminated from the environment, hands can then initiate self-inoculation of mucous membranes of the nose, eyes or mouth. Mathematical and animal models, and intervention studies suggest that contact transmission is the most important route in some scenarios. Infection prevention and control implications include the need for hand hygiene and personal protective equipment to minimize self-contamination and to protect against inoculation of mucosal surfaces and the respiratory tract, and enhanced surface cleaning and disinfection in healthcare settings

Playa lake chains: the example of the Yenyening lakes of the upper Avon river catchment of western Australia

The term “playa” or “pan” applies to individual arid zone basins of varying size and origin that are subject to ephemeral surface water flows (Shaw and Thomas, 1989) such that lakes may occur within playas as permanent or ephemeral features. Playas in Australia are often geologically young (Quaternary) features developed in arid environments and are often dry due to evaporation (Boggs et al., 2006). Although playas are a response to tectonics, climate change, and eolian and fluvial processes, the majority of the scientific literature considers either their origin within a regional context, or the development dynamics of individual playas (e.g., Bettenay, 1962). However, where playas are developed within paleodrainage channels, they may exist as isolated features, but more often they exhibit a degree of hydrological interconnectivity with other playas to form "playa chains” such that the development history of an individual playa cannot be addressedwithout consideration of its neighbors

Late Wolstonian and Ipswichian (MIS 6/5e) sediment fill in a limestone sinkhole, Askham Fell, northern England

In 2019 a sinkhole (doline) occurred in Late Devensian till above fissured limestone in northern England. Most sediment plugging the fissure was evacuated down into a karstic drainage system. The residual sedimentary fill comprises three main lithofacies, dated using optically stimulated luminescence to between 170.7ka ± 40.0ka and 56.1 ± 13.5ka. The earliest date demonstrates fissures were present in the limestone pavement at the time of Marine Isotope Stage (MIS) 6, or shortly thereafter. The fissure filled with fine sand and silt due to surface runoff and aeolian processes most likely at the MIS 6 to MIS 5e transition after Wolstonian glacial ice had retreated. The deposits then collapsed into the karst system. Further fine sand and silt deposition occurred during MIS 3; this deposit filled the central cavity surrounded by residual MIS 6/5e deposits. The sequence was capped by till as Late Devensian (MIS 2) ice transgressed the area. Solution fissures in the karst surfaces of northern England may pre-date the Late Devensian glaciation. Moreover, fissures are repositories of pre-Devensian sediment deposits which survived the Late Devensian glaciation and the Ipswichian interglacial. Such sites should provide information on the nature and timing of pre-Devensian glacial-interglacial events and shed light on basal ice conditions and glaciokarst drainage behaviour