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This study examines the relationships between concentrations of human noroviruses (NoV) genogroups I (GI) and II (GII) and Escherichia coli monitored in oysters from 31 commercial harvesting areas on the coast of England and Wales from May 2009 to April 2011 and demographic, hydrometric, climatic and pollution source characteristics of upstream river catchments using multiple regression techniques. The predictive environmental factors for E. coli contamination in the oysters were rainfall (cumulative 7days before sampling) while the predictive factors for NoV (GI+GII) were water temperature, catchment area and the combined volume of continuous sewage discharges in the catchment. Oysters from cold waters (5°C) had significantly higher NoV content than those from warmer waters (10°C). The association with water temperature may be consequential on the seasonal prevalence of the virus in the community or linked with oyster metabolic function. In a group of 10 study sites, mean concentrations of NoV increased as the number of stormwater spills at those sites also increased. The results of this study could be used to evaluate the likely impact of sewerage infrastructure improvements in catchments at risk of NoV contamination and to help identify sites suitable for shellfish farming.

Fisheries and aquaculture production, imports, exports and equitability of distribution determine the supply of aquatic food to people. Aquatic food security is achieved when a food supply is sufficient, safe, sustainable, shockproof and sound: sufficient, to meet needs and preferences of people; safe, to provide nutritional benefit while posing minimal health risks; sustainable, to provide food now and for future generations; shock-proof, to provide resilience to shocks in production systems and supply chains; and sound, to meet legal and ethical standards for welfare of animals, people and environment. Here, we present an integrated assessment of these elements of the aquatic food system in the United Kingdom, a system linked to dynamic global networks of producers, processors and markets. Our assessment addresses sufficiency of supply from aquaculture, fisheries and trade; safety of supply given biological, chemical and radiation hazards; social, economic and environmental sustainability of production systems and supply chains; system resilience to social, economic and environmental shocks; welfare of fish, people and environment; and the authenticity of food. Conventionally, these aspects of the food system are not assessed collectively, so information supporting our assessment is widely dispersed. Our assessment reveals trade-offs and challenges in the food system that are easily overlooked in sectoral analyses of fisheries, aquaculture, health, medicine, human and fish welfare, safety and environment. We highlight potential benefits of an integrated, systematic and ongoing process to assess security of the aquatic food system and to predict impacts of social, economic and environmental change on food supply and demand.

Temporal trends in Escherichia coli concentrations in bivalve shellfish were examined using data collected from 57 production areas around the coast of England and Wales during 1999–2008. Downward trends were detected in annual geometric means of E. coli in shellfish from 12% of the sampling points. The percentage of class B areas ( E. coli ⩽ 4600/100 g shellfish in 90% of samples) increased from 69% to 86% during the 10-year period. The improvement in the microbial quality of shellfish is associated with sewerage improvement schemes largely implemented during 2000–2005. Upward trends were detected in 9% of the points. The causes of these increases are not known. It is recommended that quantitative sanitary profiling of shellfish waters and cost–benefit appraisal over long-term planning horizons are considered as part of sewerage investment programmes under the Water Framework Directive. This would allow greater scope to secure protection and improvement of shellfish water quality.

Rainfall and river flows are environmental variables influencing the microbial status of bivalve mollusc harvesting areas. This study investigated spatial and temporal relationships between rainfall, river flows and concentrations of Escherichia coli in mussels (Mytilus spp.) and Pacific oysters (C. gigas) from three harvesting areas in the Dart Estuary over the period 1996–2009. Mussels growing on the riverbed were found to be more contaminated than oysters growing in the water column. A step change in the levels of the microbial indicator was identified in both species from all harvesting areas. The highest levels of E. coli were detected when total rainfall exceeded 2 mm and water levels in the main tributaries exceeded the mean flow. The magnitude of response in levels of E. coli to these hydrological events varied between species and monitoring points, but was consistently higher between the 3rd and 4th days after the rainfall event. This lag time is assumed to result from catchment topography and geology determining peak levels of runoff at the headwaters 12–24 h after rainfall events. It is considered that future risk management measures may include sampling targeting hydrograph events.

Background:Tropical Spastic Paraparesis/HTLV-I Associated Myelopathy (HAM/TSP) is a chronic, progressive myelopathy endemic to the Caribbean. In HAM/TSP, peripheral motor pathways have been assessed using electromyography and nerve conduction studies; central motor pathways have been assessed to a limited extent using electrocortical stimulation. We used magnetic cortical stimulation (a painless alternative to electrocortical stimulation) and F-wave analysis to study conduction in the central and peripheral motor pathways in 18 HTLV-I seropositive, Jamaican TSP patients (ages 29- 70 years; duration of symptoms 3-20 years) and 22 normal controls.Methods:Magnetic cortical stimulation was effected using a 9 cm diameter undamped MES10 coil. F-waves and M-responses were elicited by electrical stimulation of the ulnar nerve at the wrist, and deep peroneal stimulation at the knee. Stimulation and recording of response latencies in abductor digitii minimi (ADM) and tibialis anterior (TA) were carried out using a Cadwell Excel system.Results:With cortical stimulation, response latencies (TMCTs) to ADM and TA were prolonged in the patients relative to controls. F-wave and M-response latencies were unaffected, suggesting no peripheral pathology. Latency (CMCT) between cortex and lumbar cord was significantly prolonged; that between cortex and C7/T1, also, but less markedly (P < 0.0005). Amplitudes of cortically evoked responses were significantly reduced only in the lower limbs (TA). CMCT increased as the disease progressed from mild to moderate, thereafter remaining largely unchanged.Conclusions:Meta-analysis of interlaboratory control data revealed no significant differences in TMCTs between our controls and others studied using similar techniques. The observations are consistent with pathology affecting mainly the thoracolumbar cord in HAM/TSP.