兰州市公共交通的生态足迹测算研究

以兰州市公共交通(分为公交车和出租车两种)为研究对象,运用生态足迹法,测算2010年-2014年兰州市客运交通生态足迹,并计算兰州市公共交通的生态效率和生态足迹强度.结果表明:公共交通生态足迹年均占比为7.41%;公共交通生态足迹和客运量呈同步增长态势,公共交通生态足迹年均增长1.71%;在影响公共交通生态足迹的因素中,公交车和出租车的化石能源足迹年均占比分别为76.06%和62.32%;就生态效率而言,公交车生态效率是出租车生态效率的6.24倍.     

The Effect of Heat and Free Chlorine Treatments on the Surface Properties of Murine Norovirus

Heat and free chlorine are among the most efficient and commonly used treatments to inactivate enteric viruses, but their global inactivation mechanisms have not been elucidated yet. These treatments have been shown to affect at least the capsid proteins of viruses and thus may affect the surface properties (i.e. electrostatic charge and hydrophobicity) of such particles. Our aim was to study the effects of heat and free chlorine on surface properties for a murine norovirus chosen as surrogate for human norovirus. No changes in the surface properties were observed with our methods for murine norovirus exposed to free chlorine. Only the heat treatment led to major changes in the surface properties of the virus with the expression of hydrophobic domains at the surface of the particles after exposure to a temperature of 55 °C. No modification of the expression of hydrophobic domains occurred after exposure to 60 °C, and the low hydrophobic state exhibited by infectious and inactivated particles after exposure to 60 °C appeared to be irreversible for inactivated particles only, which may provide a means to discriminate infectious from inactivated murine noroviruses. When exposed to a temperature of 72 °C or to free chlorine at a concentration of 50 mg/L, the genome became available for RNases.     

Use of ATP Readings to Predict a Successful Hygiene Intervention in the Workplace to Reduce the Spread of Viruses on Fomites

The purpose of this study was to validate the use of adenosine triphosphate (ATP) for evaluating hygiene intervention effectiveness in reducing viral dissemination in an office environment. The bacterial virus MS-2 was used to evaluate two scenarios, one where the hand of an individual was contaminated and another where a fomite was contaminated. MS-2 was selected as a model because its shape and size are similar to many human pathogenic viruses. Two separate experiments were conducted, one in which the entrance door push plate was inoculated and the other in which the hand of one selected employee was inoculated. In both scenarios, 54 selected surfaces in the office were tested to assess the dissemination of the virus within the office. Associated surface contamination was also measured employing an ATP meter. More than half of the tested hands and surfaces in the office were contaminated with MS-2 within 4 h. Next, an intervention was conducted, and each scenario was repeated. Half of the participating employees were provided hand sanitizer, facial tissues, and disinfecting wipes, and were instructed in their use. A significant (p < 0.05) reduction was observed in the number of surfaces contaminated with virus. This reduction in viral spread was evident from the results of both viral culture and the surface ATP measurements, although there was no direct correlation between ATP measurements with respect to viral concentration. Although ATP does not measure viruses, these results demonstrate that ATP measurements could be useful for evaluating the effectiveness of hygiene interventions aimed at preventing viral spread in the workplace.     

Norovirus GII.Pe Genotype: Tracking a Foodborne Outbreak on a Cruise Ship Through Molecular Epidemiology,Brazil, 2014

Norovirus (NoV) is recognized as the most common cause of foodborne outbreaks. In 2014, an outbreak of acute gastroenteritis occurred on a cruise ship in Brazil, and NoV became the suspected etiology. Here we present the molecular identification of the NoV strains and the use of sequence analysis to determine modes of virus transmission. Food (cream cheese, tuna salad, grilled fish, orange mousse, and vegetables soup) and clinical samples were analyzed by ELISA, conventional RT-PCR, qRT-PCR, and sequencing. Genogroup GII NoV was identified by ELISA and conventional RT-PCR in fecal samples from 5 of 12 patients tested (41.7%), and in the orange mousse food sample by conventional RT-PCR and qRT-PCR. Two fecal GII NoV samples and the orange mousse GII NoV sample were successfully genotyped as GII.Pe (ORF 1), revealed 98.0–98.8% identities among them, and shared phylogenetically distinct cluster. Establishing the source of a NoV outbreak can be a challenging task. In this report, the molecular analysis of the partial RdRp NoV gene provided a powerful tool for genotyping (GII.Pe) and tracking of outbreak-related samples. In addition, the same fast and simple extraction methods applied to clinical samples could be successfully used for complex food matrices, and have the potential to be introduced in routine laboratories for screening foods for presence of NoV.     

Use of Preservative Agents and Antibiotics for Increased Poliovirus Survival on Positively Charged Filters

Environmental surveillance of poliovirus (PV) and other non-enveloped viruses can help identify silent circulation and is necessary to certify eradication. The bag-mediated filtration system is an efficient method to filter large volumes of environmental waters at field sites for monitoring the presence of viruses. As filters may require long transit times to off-site laboratories for processing, viral inactivation or overgrowth of bacteria and fungi can interfere with virus detection and quantification (Miki and Jacquet in Aquatic Microb Ecol 51(2):195–208, 2008). To evaluate virus survival over time on ViroCap^? filters, the filters were seeded with PV type 1 (PV1) and/or MS2 and then dosed with preservatives or antibiotics prior to storage and elution. These filters were stored at various temperatures and time periods, and then eluted for PV1 and MS2 recovery quantification. Filters dosed with the preservative combination of 2% sodium benzoate and 0.2% calcium propionate had increased virus survival over time when stored at 25 °C, compared to samples stored at 25 °C with no preservatives. While elution within 24 h of filtration is recommended, if storage or shipping is required then this preservative mixture can help preserve sample integrity. Addition of an antibiotic cocktail containing cephapirin, gentamicin, and Proclin^? 300 increased recovery after storage at 4 and 25 °C, when compared to storage with no antibiotics. The antibiotic cocktail can aid sample preservation if access to appropriate antibiotics storage is available and sample cold chain is unreliable. This study demonstrated that the use of preservatives or antibiotics is a simple, cost-effective method to improve virus detection from ViroCap cartridge filters over time.     

DNA Heat Treatment for Improving qPCR Analysis of Human Adenovirus in Wastewater

PCR inhibitory substances in complex sample matrices can cause false negatives or under-estimation of target concentration. This study assessed DNA heat treatment for reducing inhibition during qPCR analysis of human adenovirus (HAdV) in wastewater samples. Inhibition was reduced by heat treating DNA, where mean HAdV concentration was increased by 0.71 log₁₀ GC/L (and up to 3.04 log₁₀ GC/L in one case), and replicate variability and false negatives were reduced. DNA heat treatment should be further investigated for improving reliability of HAdV concentration estimates in water, which can support more accurate assessment of health risks associated with viral pathogen exposure.