Potential Approaches to Assess the Infectivity of Hepatitis E Virus in Pork Products: A Review

The zoonotic transmission of hepatitis E, caused by the hepatitis E virus (HEV), is an emerging issue. HEV appears common in pigs (although infected pigs do not show clinical signs), and evidence suggests that a number of hepatitis E cases have been associated with the consumption of undercooked pork meat and products. Little information is available on whether cooking can eliminate HEV, since there is currently no robust method for measuring its infectivity. HEV infectivity can be clearly demonstrated by monitoring for signs of infection (e.g., shedding of virus) in an animal model. However, this approach has several disadvantages, such as lack of reproducibility and unsuitability for performing large numbers of tests, high costs, and not least ethical considerations. Growth in cell culture can unambiguously show that a virus is infectious and has the potential for replication, without the disadvantages of using animals. Large numbers of tests can also be performed, which can make the results more amenable to statistical interpretation. However, no HEV cell culture system has been shown to be applicable to all HEV strains, none has been standardized, and few studies have demonstrated their use for measurement of HEV infectivity in food samples. Nonetheless, cell culture remains the most promising approach, and the main recommendation of this review is that there should be an extensive research effort to develop and validate a cell culture-based method for assessing HEV infectivity in pork products. Systems comprising promising cell lines and HEV strains which can grow well in cell culture should be tested to select an assay for effective and reliable measurement of HEV infectivity over a wide range of virus concentrations. The assay should then be harnessed to a procedure which can extract HEV from pork products, to produce a method suitable for further use. The method can then be used to determine the effect of heat or other elimination processes on HEV in pork meat and products, or to assess whether HEV detected in any surveyed foodstuffs is infectious and therefore poses a risk to public health.     

Prenatal evaluation of fetal neck masses in preparation for the EXIT procedure: the value of pulmonary Doppler ultrasonography (PDU)

Sonographic demonstration of normal tracheal diameter and breathing-related lung fluid flow at 30 weeks' gestation in a fetus with a giant neck mass confirmed patent airways, thus avoiding an EXIT procedure. Copyright © 2001 John Wiley & Sons, Ltd.     

Sewing climate-resilient seeds: implementing climate change adaptation best practices in rural Cambodia

Multilateral support through programs like the Least Developed Countries Fund (LDCF) targets countries widely considered to be the most vulnerable to climate change. Cambodia is one of the six Asian LDCF recipients and with UNDP support is implementing the first adaptation project to arise from its National Adaptation Program of Action. Drawing on primary research conducted in August 2010 through interviews with key stakeholders, this article investigates the project for the likely benefits and challenges it will face in promoting institutional, infrastructural, and community resilience to climate change impacts. We find that the country??s ongoing decentralization reforms offer an effective opportunity to mainstream climate change planning into sub-national government operations, but that competing priorities for immediate investment in education, roads, and healthcare may prevent government officers from sustaining a focus on preventative adaptation measures. We conclude that through careful planning, water resources infrastructure and agricultural practices can be designed to withstand climate variability and avoid the need to replace or rehabilitate systems whose specifications were prematurely determined by international donors.     

Influence of hydrodynamic conditions on the production and fate of Posidonia oceanica in a semi-enclosed shallow basin (Stagnone di Marsala, Western Sicily)

An integrated approach using hydrodynamic and transport numerical models, lepidochronology and stable isotope analysis was used to investigate how local hydrodynamic conditions influence the primary production and fate of the seagrass Posidonia oceanica in a Mediterranean semi-enclosed marine system (Stagnone di Marsala). The water mass exchange aptitude of different sectors of the basin was analysed, and data collected were used to select two sectors (colonized by Posidonia oceanica showing the lowest and highest water exchange values) for biological analyses. According to the mean dispersal coefficient differences simulated by the hydrodynamic model, growth rate and primary production of P. oceanica differed between sectors, with average values lower in the central sector where water exchange is lower than in the southern sector. Although P. oceanica coverage and primary production were higher in the southern sector, carbon and nitrogen stable isotope analysis suggests that the transfer of seagrass organic matter to higher trophic levels of the food web was higher in the central sector. The possibility of a link between hydrodynamism, production and fate of organic matter is proposed to explain the observed patterns.     

Cadmium adsorption on vermiculite, zeolite and pumice: batch experimental studies

Batch experiments were performed to evaluate the combined effects of ionic activity, pH, and contact time on the cadmium sorption in three different minerals, vermiculite, zeolite, and pumice, commonly employed as substrata in nurseries and recently considered for their potential use in remediation methods. The extent of cadmium sorption was vermiculite>zeolite>pumice, as shown by the Langmuir and Freundlich parameters, and it was highly dependent on mineral characteristics. The percentage of cadmium sorption in zeolite and vermiculite did not depend on cadmium concentration, while in pumice this percentage was positively correlated to the initial cadmium concentration. At low cadmium concentrations (30-120 microM), the metal sorbed on zeolite was mainly present in the nonexchangeable form (70%) at levels much higher than those found for vermiculite and pumice. The primary variable responsible for determination of cadmium mobility in these minerals was confirmed to be pH. The ionic concentrations of Hoagland nutrient solution were significantly modified by both pH and mineral composition, while the presence of cadmium caused no changes. With vermiculite and zeolite, the time-course of cadmium sorption was related to mineral composition to a greater extent than to cadmium concentration. While with pumice, the percentage of cadmium sorbed after 6 weeks was lower than with the other two minerals, and it was inversely correlated to the initial cadmium concentration.     

Detection of Hepatitis A Virus in Strawberries Implicated in an Outbreak in the USA in 1997

Food and Environmental Virology - Hepatitis A virus (HAV) was detected in frozen strawberries which had been implicated in a large outbreak of hepatitis A in 1997. The sample was analysed after...     

Simultaneous personnel and vehicle shift scheduling in the waste management sector

Urban waste management is becoming an increasingly complex task, absorbing a huge amount of resources, and having a major environmental impact. The design of a waste management system consists in various activities, and one of these is related to the definition of shift schedules for both personnel and vehicles. This activity has a great incidence on the tactical and operational cost for companies. In this paper, we propose an integer programming model to find an optimal solution to the integrated problem. The aim is to determine optimal schedules at minimum cost. Moreover, we design a fast and effective heuristic to face large-size problems. Both approaches are tested on data from a real-world case in Southern Italy and compared to the current practice utilized by the company managing the service, showing that simultaneously solving these problems can lead to significant monetary savings.     

Nucleic Acid Amplification-Based Methods for Detection of Enteric Viruses: Definition of Controls and Interpretation of Results

The most effective methods for virus detection in food and environmental samples are those based on nucleic acid amplification. Complex methods must be applied by the analyst in order to control for false negative results of virus detection assays in those samples that may be contaminated by virus concentrations above the detection level. The verification of analytical results is a necessity and this depends on using an appropriate suite of controls to monitor the efficacy of the critical steps in the method and allow correct result interpretations to be made. We describe the suite of controls necessary for analysing food and environmental samples for the presence of enteric viruses by nucleic acid amplification-based methods. To exclude false negative and positive interpretations of results, the inclusion of this suite of controls will be essential when considering incorporating monitoring of viruses in food or environmental safety management plans.     

Landscape changes and environmental quality: the evolution of land vulnerability and potential resilience to degradation in Italy

Resilience, considered as the ability of a system to absorb and compensate pressures derived from human and natural systems, is a topic of interest in the Mediterranean region whose landscape is the joint result of social, economic and environmental factors. The present study analyses the changes in the Italian landscape over two periods (1960–1990 and 1990–2010) of the last 50 years through a composite index of environmental resilience and vulnerability to land degradation. Results indicate that the spatial distribution of this index has been considerably changed from a relatively simple geography (mainly reflecting a latitude gradient) to a more complex pattern. The level of vulnerability of southern Italian land maintained quite stable while increasing significantly in Northern and Central Italy. The (potential) resilience level decreased over time in Central and Northern Italy while growing moderately in Southern Italy. This means that important processes of environmental changes impacting landscape resilience occurred with a different spatial trend in Italy. The composite index derived from vulnerability and potential resilience estimates at the regional scale revealed crucial to map over time the increase of surface land exposed to desertification risk. Results support the adoption of measures promoting a sustainable land management in environmentally vulnerable land with low potential to resilience.     

HYDRODYNAMIC SIMULATIONS OF A CONSTRUCTED WETLAND IN SOUTH FLORIDA1

ABSTRACT: This paper describes the application of the SHEET2D model to the Florida's Everglades Nutrient Removal (ENR) Project. The ENR Project is a 3815 acre (1545 ha) pilot project, located in Palm Beach County. The operation of the treatment system will be used to demonstrate the performance of larger scale constructed wetland systems for removal of phosphorus from Everglades Agricultural Area (EAA) stormwater runoff. It is currently the largest stormwater wetland treatment system in the world. The SHEET2D model was used to analyze the performance of the ENR Project. SHEET2D is a two-dimensional, depth-averaged hydrodynamic model that is applicable to shallow water flow conditions. Subsequently, results from SHEET2D simulations were used to develop the ENEMOD model. ENRMOD is a lumped parameter box water quality model that can be used to analyze the long term performance of the ENR project with respect to hydrology and phosphorus uptake. Localized short-circuiting in the agricultural ditches within the project area was analyzed by using the RBFVM-2D model, which is a finite volume hydrodynamic model that is also applicable to shallow water flow conditions. The SHEET2D model was employed to simulate the hydraulics of the structures between cells and the hydrodynamics of the sheet-flow moving across the buffer cell and treatment cells. Collection, distribution, and larger discharge canals within the project were simulated by means of the MultiBasin Routing (MBR) model features that are built into the SHEET2D model. Constant inflows (75 to 600 cfs [2.1 to 17 m³/s]) were used in all runs to simulate the discharge of the ENR Project based on the proposed operating schedule for the outflow pump station. The model simulated 30 days to reach steady state conditions. Under steady state conditions, the hydraulic retention times were computed for the project and the split of flow between the two treatment trains of the entire project from the common buffer cell. Additionally, design components such as height of the levees, capacity of the structures, and hydrographs at specified grids were obtained.