浅谈我国海洋环境中人类肠病毒的污染监管

介水传染病是当今世界主要环境问题之一,其中人类肠病毒通过污染水体导致人类感染的胃肠道等疾病是主要传染病之一。本文以人类肠病毒经过污水处理厂排放为起点,分析其进入海洋环境后通过海水或海产品等途径给人体健康带来的风险;综述了国内外关于海洋环境中病原微生物的监测与评价技术体系的最新进展,指出目前我国海洋环境微生物监测指标和评价方法还不能满足指示人类肠病毒污染的问题。基于此,本文提出为更好地保护公众健康,我国迫切需要制定切实可行的海洋环境中人类肠病毒的风险监管措施,包括构建科学的海洋环境中人类肠病毒监测技术体系,构建全国相关的监测网络体系,构建海洋环境中人类肠病毒风险评价和预警体系,制定加强我国海洋环境中人类肠病毒的污染监管办法等。     

A 1-Year Study on the Detection of Human Enteric Viruses in New Caledonia

Human enteric viruses occur in high concentrations in wastewater and can contaminate receiving environmental waters. Due to the lack of data on the prevalence of enteric viruses in New Caledonia, the presence and the concentrations of enteric viruses in wastewater and seawater were determined. Untreated wastewater and seawater samples were collected monthly for 1 year from a wastewater treatment plant (WWTP) and from the WWTP’s outlet, located directly on a popular recreational beach. Samples were tested for norovirus genogroups I and II (NoV GI and GII), astroviruses (AsV), sapoviruses (SaV), enteroviruses (EV), hepatitis A viruses (HAV), rotaviruses (RoV), human adenoviruses (HAdV) and human polyomaviruses (HPyV). To support these data, faecal samples from cases of gastroenteritis were tested for the first time for NoV and detected in the population. NoV GI, NoV GII, EV, SaV, HAdV and HPyV were detected in all wastewaters, RoV in 75 % and AsV in 67 %. HAV were not detected in wastewater. Overall, 92 % of seawater samples were positive for at least one virus. HPyV were detected most frequently in 92 % of samples and at concentrations up to 7.7 × 10³ genome copies/L. NoV GI, NoV GII, EV, SaV, RoV and HAdV were found in 33, 66, 41, 33, 16 and 66 % of seawater samples, respectively. AsV were not detected in seawater. This study reports for the first time the presence of NoV and other enteric viruses in New Caledonia and highlights the year-round presence of enteric viruses in the seawater of a popular beach.     

Rethinking the Significance of Reovirus in Water and Wastewater

The genus Orthoreovirus contains nonenveloped viruses with double-stranded gene segments encased in a double-layered icosahedral capsid shell. These features constitute major determinants of virion stability in the environment and virion resistance against physical and chemical agents. Reovirus (ReoV) is the general term most commonly used for all virus strains that infect humans and nonhuman animals. Several studies have demonstrated the frequent occurrence of ReoV in wastewaters and natural waters, including surface and ground waters from different geographical areas. Most of these studies have reported higher concentrations of ReoV than any other enteric virus analyzed. They are more commonly isolated in chlorine-disinfected wastewaters than other enteric viruses, and appear to survive longer in water. The ability of ReoV to form large aggregates, even with different types of enteric viruses (e.g., poliovirus) and their ability to undergo mechanisms of gene segment reassortment among different serotypes may also explain their greater stability. Different approaches have been applied for concentration of ReoV from water; however, the recovery efficiency of the filtration methods has not been fully evaluated. Recently, molecular methods for identification of ReoV strains and quantification of virus genome have been developed. Studies have shown that the overall detection sensitivity of ReoV RNA is enhanced through initial replication of infectious virions in cell culture. More studies are needed to specifically address unresolved issues about the fate and distribution of ReoV in the environment since this virus is not commonly included in virological investigations.     

Human Enteric Viruses in Groundwater

Waterborne outbreaks of enteric viruses are a major public health concern. The present study has been carried out to assess the presence of enteric viruses responsible for human acute gastroenteritis (AGE) in groundwater intended for drinking and produce washing. In total, 62 samples from groundwater for drinking and produce washing collected from Dec 2007 to Dec 2008 in Seoul were tested for enteric viruses using conventional RT–PCR, ELISA, and real-time RT–PCR. Our results showed that enteric viruses were detected in 7 (8.8%) groundwater samples. Rotaviruses were detected in 3 (4.8%) of the samples by ELISA; human adenoviruses were detected in 2 (3.2%) of the samples by ELISA; and nested RT–PCR detected noroviruses in 2 (3.2%) of the samples. In one of the groundwater sample, the norovirus RNA was detected by conventional RT–PCR which was confirmed positive by real-time RT–PCR. Additionally, real-time RT–PCR successfully detected norovirus RNA in five out of 62 water samples (8.1%). The data demonstrate that real-time RT–PCR will be useful as a rapid and sensitive method for detecting norovirus in water samples. Phylogenetic analysis revealed that the noroviruses detected in two of the groundwater samples belonged to GII-4. These studies can provide important information for the prevalence of enteric viruses in Korean groundwater.     

Viral Interference as a Factor of False-Negative in the Infectious Adenovirus Detection Using Integrated Cell Culture-PCR with a BGM Cell Line

Food and Environmental Virology - This study investigated the influence of viral interference on the detection of enteric viruses using the integrated cell culture (ICC)-PCR with a BGM cell line....     

Reduction of Human Enteric and Indicator Viruses at a Wastewater Treatment Plant in Southern Louisiana,USA

This study assessed wastewater quality through the quantification of four human enteric viruses and the applicability of pepper mild mottle virus (PMMoV) a     

Male-Specific and Somatic Coliphage Profiles from Major Aquaculture Areas in Republic of Korea

Human and animal feces are important sources of various types of microbial contamination in water. Especially, enteric viruses, the major agents of waterbo     

中国动物源CH_4排放空间分布和时间变化研究

将IPCC国家温室气体清单指南（2006）用于估算动物源CH4排放的方法2和GIS空间化数据库技术结合,以2004年全国各县级行政单位的畜牧统计数据和1 km×1 km土地利用栅格数据为主要数据源,系统地估算了中国大陆当年动物源CH4排放量（包括消化道CH4排放和粪便管理系统CH4排放两部分）,并分析了其空间分布和季节...     

Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment

Viruses are a significant cause of morbidity and mortality around the world. Determining the minimum dose of virus particles that can initiate infection, termed the minimum infective dose (MID), is important for the development of risk assessment models in the fields of food and water treatment and the implementation of appropriate infection control strategies in healthcare settings. Both respiratory and enteric viruses can be shed at high titers from infected individuals even when the infection is asymptomatic. Presence of pre-existing antibodies has been shown to affect the infectious dose and to be protective against reinfection for many, but not all viruses. Most respiratory viruses appear to be as infective in humans as in tissue culture. Doses of <1 TCID₅₀ of influenza virus, rhinovirus, and adenovirus were reported to infect 50% of the tested population. Similarly, low doses of the enteric viruses, norovirus, rotavirus, echovirus, poliovirus, and hepatitis A virus, caused infection in at least some of the volunteers tested. A number of factors may influence viruses’ infectivity in experimentally infected human volunteers. These include host and pathogen factors as well as the experimental methodology. As a result, the reported infective doses of human viruses have to be interpreted with caution.     

Development of the Pasture Simulation Model for assessing livestock production under climate change

To simulate climate change impacts on pastures and domestic herbivores as well as feedbacks to the atmosphere in terms of greenhouse gas emissions, we have improved a process-based biogeochemical pasture model, PaSim. The overall aim was to simulate the meat and milk production of cattle (suckler cows with their calves, dairy cows and heifers) in response to climate and management, as well as feedbacks to the atmosphere through enteric methane emissions. Herbage intake at grazing was calculated from animal characteristics, herbage availability, diet digestibility and air temperature. With suckler cows, milk production and changes in daily liveweight and body condition were calculated from net energy balance. The net energy intake of dairy cows and their body reserves at turnout to pasture were used to simulate milk production at pasture, daily liveweight and body condition changes, taking into account cow energy requirements and intake capacity. Heifer growth was determined from heifer net energy intake and liveweight. Net energy intake was used to assess enteric methane production through a conversion factor, which depends both on the energy level of the diet and on the herbivore type. The model was assessed against experimental data for animal performance and methane emissions at grazing. Predictions show good agreement with observations. On average, the root mean square error was 6.5, 4 and 2.5% for the liveweights of suckler cows, suckler calves and heifers, respectively, 18% for dairy milk production and 12% for enteric methane emissions. By comparing this new version of the PaSim model to the previous version, we show that a greater accuracy in animal performance modelling improves the sensitivity of the model to interannual climate variability. However, long term (30 years) projections of climate change impacts on grasslands and of radiative feedbacks to the atmosphere are not significantly modified. The originality and the validity domain of the model are discussed.     

The Impact of the Extreme Amazonian Flood Season on the Incidence of Viral Gastroenteritis Cases

During the Amazonian flood season in 2012, the Negro River reached its highest level in 110 years, submerging residential and commercial areas which appeared associated with an elevation in the observed gastroenteritis cases in the city of Manaus. The aim of this study was to evaluate the microbiological water quality of the Negro River basin during this extreme flood to investigate this apparent association between the illness cases and the population exposed to the contaminated waters. Forty water samples were collected and analysed for classic and emerging enteric viruses. Human adenoviruses, group A rotaviruses and genogroup II noroviruses were detected in 100, 77.5 and 27.5% of the samples, respectively, in concentrations of 10³–10⁶ GC/L. All samples were compliant with local bacteriological standards. HAdV2 and 41 and RVA G2, P[6], and P[8] were characterised. Astroviruses, sapoviruses, genogroup IV noroviruses, klasseviruses, bocaviruses and aichiviruses were not detected. Statistical analyses showed correlations between river stage level and reported gastroenteritis cases and, also, significant differences between virus concentrations during this extreme event when compared with normal dry seasons and previous flood seasons of the Negro River. These findings suggest an association between the extreme flood experienced and gastrointestinal cases in the affected areas providing circumstantial evidence of causality between the elevations in enteric viruses in surface waters and reported illness.     

Bioaccumulation Dynamic by Crassostrea gigas Oysters of Viruses That Are Proposed as Surrogates for Enteric Virus Contamination in Environmental Samples

Food and Environmental Virology - Oysters are filter-feeders and retain sewage-derived pathogens in their organs or tissues. Since most enteric viruses involved in outbreaks cannot grow in cell...     

First Occurrence of Saffold Virus in Sewage and River Water Samples in Karaj,Iran

Food and Environmental Virology - Saffold virus as a newly discovered virus, which seems to be related to acute gastroenteritis as with other enteric viruses and to human airway diseases in...     

The Effect of Heat on the Physicochemical Properties of Bacteriophage MS2

The differences in physicochemical characteristics between infectious and non-infectious viral particles are poorly known. Even for heat, which is known as one of the most efficient treatments to inactivate enteric viruses, the global inactivation mechanisms have not been described yet. Such knowledge would help distinguish between both types of particles and therefore clarify the interpretation of the presence of viral genomes in food after heat treatment. In this study, we examined in particular the differences in electrostatic charge and hydrophobicity between the two particle types. MS2 phage, a common surrogate for enteric viruses, was used as a model virus. The heat-induced inactivation process of the infectious phages caused hydrophobic domains to be transiently exposed and their charge to become less negative. The particles also became progressively permeable to small molecules such as SYPRO Orange dye. The presence of non-infectious phage particles in which the genome was not accessible to RNases has been clearly demonstrated. These observations were done for MS2 phages exposed to a temperature of 60 °C. When exposed to a temperature higher than their critical temperature (72 °C), the particles were disrupted and the genome became available for RNases. At lower temperatures, 60 °C in this study, the transient expression of hydrophobic domains of remaining infectious phages appeared as an interesting parameter for improving their specific detection.     

Identification of Enteric Viruses in Foods from Mexico City

Foodborne viruses are a common and, probably, the most under-recognized cause of outbreaks of gastroenteritis. Among the main foods involved in the transmission of human enteric viruses are mollusks, and fruits and vegetables irrigated with wastewater and/or washed with non-potable water or contaminated by contact with surfaces or hands of the infected personnel during its preparation. In this study, 134 food samples were analyzed for the detection of Norovirus, Rotavirus, and Hepatitis A virus (HAV) by amplification of conserved regions of these viruses. From the 134 analyzed samples, 14 were positive for HAV, 6 for Norovirus, and 11 for Rotavirus. This is the first report in Mexico where emphasis is given to the presence of HAV and Norovirus on perishable foods and food from fisheries, as well as Rotavirus on frozen vegetables, confirming the role of vegetables and bivalve mollusks as transmitting vehicles of enteric viruses.     

The Detection Rate of Enteric Viruses and <Emphasis Type="Italic">Clostridium difficile</Emphasis> in a Waste Water Treatment Plant Effluent

Waste water treatment plant (WWTP) is considered as an important source of surface water contamination by enteric pathogens. In this study, we describe the occurrence of enteric viruses (group A rotaviruses, noroviruses, astroviruses, sapoviruses, hepatitis A virus, and hepatitis E virus) and Clostridium difficile in the effluent of a wastewater treatment plant during a 1-year period. Enteric viruses were simultaneously and efficiently concentrated in a single step using methacrylate monolithic chromatographic support. Rotaviruses, noroviruses (genogroup I and II), and sapoviruses were detected in all 12 concentrated samples, whereas astroviruses were not detected in August and September and hepatitis A and E viruses were not detected at all. Clostridium difficile was detected in all samples and altogether 121 strains were isolated and grouped into 32 different ribotypes of which 014/020 and 010 were most prevalent. Pathogens detected in WWTP effluent partially reflect the epidemiological situation of enteric viruses and C. difficile in human population and open the discussion on implementation of possible techniques for virus and bacteria removal from WWTP effluent prior to release into the surface water system.     

Development and Evaluation of a Multiplexed Real-Time TaqMan RT-PCR Assay with a Sample Process Control for Detection of F-specific RNA Coliphage Genogroups I and IV

There are increasing concerns of zoonotic transmission of some animal enteric viruses, such as calicivirus, hepatitis E virus, and rotavirus, which are closely related to human pathogenic strains. Most enteric viruses are detected by molecular techniques because they cannot be cultured. Surrogates such as F-RNA coliphages are cultivable but few molecular methods exist. Individual real-time TaqMan RT-PCR assays for the replicase gene of F-RNA coliphage genogroups I and IV were developed and multiplexed with a real-time TaqMan RT-PCR assay for feline calicivirus as a sample process control for the simultaneous detection and enumeration of genogroup I and IV F-RNA coliphages. Genogroup IV were successfully detected with the multiplexed assay in 80% of fecal samples that contained F-RNA coliphage levels ≥3.2 log plaque forming units (pfu). F-RNA coliphage were at or below the limit of detection in most fecal samples when levels were ≤4 log pfu/g.     

Detection of Human Enteric Viruses in Freshwater from European Countries

The transmission of water-borne pathogens typically occurs by a faecal–oral route, through inhalation of aerosols, or by direct or indirect contact with contaminated water. Previous molecular-based studies have identified viral particles of zoonotic and human nature in surface waters. Contaminated water can lead to human health issues, and the development of rapid methods for the detection of pathogenic microorganisms is a valuable tool for the prevention of their spread. The aims of this work were to determine the presence and identity of representative human pathogenic enteric viruses in water samples from six European countries by quantitative polymerase chain reaction (q-PCR) and to develop two quantitative PCR methods for Adenovirus 41 and Mammalian Orthoreoviruses. A 2-year survey showed that Norovirus, Mammalian Orthoreovirus and Adenoviruses were the most frequently identified enteric viruses in the sampled surface waters. Although it was not possible to establish viability and infectivity of the viruses considered, the detectable presence of pathogenic viruses may represent a potential risk for human health. The methodology developed may aid in rapid detection of these pathogens for monitoring quality of surface waters.     

Detection and Molecular Characterization of Aichivirus 1 in Wastewater Samples from Uruguay

Aichivirus 1 (AiV-1) is an enteric virus with 30 nm in diameter, belonging to the genus Kobuvirus in the Picornaviridae family being a causative agent of gastroenteritis in humans. The transmission is via the fecal-oral route, through person to person contact, recreation in contaminated waters, or through the consumption of contaminated food or water. The aim of this study was to determine the frequency and the molecular characterization of AiV-1 in wastewater from Uruguay. Biweekly collections from March 2011 to February 2012 were performed in the cities of Bella Unión, Salto, Paysandú, and Fray Bentos, northwestern region of Uruguay. A total of 96 samples were collected; viruses were concentrated by ultracentrifugation, and AiV-1 was detected by using a nested PCR with primers directed to a conserved region (3CD junction) of the viral genome. A high frequency of AiV-1 (n = 54) was observed at all the cities analyzed mainly in the colder months of the year. AiV-1 was not evidenced as an appropriate viral fecal indicator since when compared with other previously detected enteric viruses, no correlation was observed. All 13 characterized AiV-1 belonged to the genotype B after the phylogenetic analysis performed with the sequences obtained from the first round PCR amplicon. This study demonstrates that AiV-1 is a frequently detected enteric viruses present in wastewater and excreted by infected persons in the northwestern region of Uruguay.