Cannabinoid influences on palatability: microstructural analysis of sucrose drinking after Delta(9)-tetrahydrocannabinol, anandamide, 2-arachidonoyl glycerol and SR141716

Rationale: Central cannabinoid systems have been implicated in appetite control through the respective hyperphagic and anorectic actions of CB1 agonists and antagonists. The motivational changes underlying these actions remain to be determined, but may involve alterations to food palatability. Objectives: The mode of action of cannabinoids on ingestion was investigated by examining the effects of exogenous and endogenous agonists, and a selective CB1 receptor antagonist, on licking microstructure in rats ingesting a palatable sucrose solution. Methods: Microstructural analyses of licking for a 10% sucrose solution was performed over a range of agonist and antagonist doses administered to non-deprived, male Lister hooded rats. Results: Delta(9)-tetrahydrocannabinol (0.5, 1 and 3 mg/kg) and anandamide (1 mg/kg and 3 mg/kg) significantly increased total number of licks. This was primarily due to an increase in bout duration rather than bout number. There was a nonsignificant increase in total licks following administration of 2-arachidonoyl glycerol (0.2, 1.0 and 2.0 mg/kg), whereas administration of the CB1 antagonist SR141716 (1 mg/kg and 3 mg/kg) significantly decreased total licks. All drugs, with the exception of anandamide, significantly decreased the intra-bout lick rate. An exponential function fitted to the cumulative lick rate curves for each drug revealed that all compounds altered the asymptote of this function without having any marked effects on the exponent. Conclusions: These data are consistent with endocannabinoid involvement in the mediation of food palatability.

Effects of beverage alcohol taxes and prices on drinking: a meta-analysis of 1003 estimates from 112 studies

Aims: We conducted a systematic review of studies examining relationships between measures of beverage alcohol tax or price levels and alcohol sales or self-reported drinking. A total of 112 studies of alcohol tax or price effects were found, containing 1003 estimates of the tax/price–consumption relationship. Design: Studies included analyses of alternative outcome measures, varying subgroups of the population, several statistical models, and using different units of analysis. Multiple estimates were coded from each study, along with numerous study characteristics. Using reported estimates, standard errors, t-ratios, sample sizes and other statistics, we calculated the partial correlation for the relationship between alcohol price or tax and sales or drinking measures for each major model or subgroup reported within each study. Random-effects models were used to combine studies for inverse variance weighted overall estimates of the magnitude and significance of the relationship between alcohol tax/price and drinking. Findings: Simple means of reported elasticities are -0.46 for beer, -0.69 for wine and -0.80 for spirits. Meta-analytical results document the highly significant relationships (P < 0.001) between alcohol tax or price measures and indices of sales or consumption of alcohol (aggregate-level r = -0.17 for beer, -0.30 for wine, -0.29 for spirits and -0.44 for total alcohol). Price/tax also affects heavy drinking significantly (mean reported elasticity = -0.28, individual-level r = -0.01, P < 0.01), but the magnitude of effect is smaller than effects on overall drinking. Conclusions: A large literature establishes that beverage alcohol prices and taxes are related inversely to drinking. Effects are large compared to other prevention policies and programs. Public policies that raise prices of alcohol are an effective means to reduce drinking.

Poisoning the mind: Arsenic contamination of drinking water wells and children's educational achievement in rural Bangladesh

Bangladesh has experienced the largest mass poisoning of a population in history owing to contamination of groundwater with naturally occurring inorganic arsenic. Prolonged drinking of such water risks development of diseases and therefore has implications for children's cognitive and psychological development. This study examines the effect of arsenic contamination of tubewells, the primary source of drinking water at home, on the learning outcome of school-going children in rural Bangladesh using recent nationally representative data on secondary school children. We unambiguously find a negative and statistically significant correlation between mathematics scores and arsenic-contaminated drinking tubewells at home, net of the child's socio-economic status, parental background and school specific unobserved correlates of learning. Similar correlations are found for an alternative measure of student achievement and subjective well-being (i.e. self-reported measure of life satisfaction), of the student. We conclude by discussing the policy implication of our findings in the context of the current debate over the adverse effect of arsenic poisoning on children.

Assessment of potential climate change impacts on peatland dissolved organic carbon release and drinking water treatment from laboratory experiments

Catchments draining peat soils provide the majority of drinking water in the UK. Over the past decades, concentrations of dissolved organic carbon (DOC) have increased in surface waters. Residual DOC can cause harmful carcinogenic disinfection by-products to form during water treatment processes. Increased frequency and severity of droughts combined with and increased temperatures expected as the climate changes, have potentials to change water quality. We used a novel approach to investigate links between climate change, DOC release and subsequent effects on drinking water treatment. We designed a climate manipulation experiment to simulate projected climate changes and monitored releases from peat soil and litter, then simulated coagulation used in water treatment. We showed that the ‘drought’ simulation was the dominant factor altering DOC release and affected the ability to remove DOC. Our results imply that future short-term drought events could have a greater impact than increased temperature on DOC treatability.

Simulated climate change impact on summer dissolved organic carbon release from peat and surface vegetation: implications for drinking water treatment

Uncertainty regarding changes in dissolved organic carbon (DOC) quantity and quality has created interest in managing peatlands for their ecosystem services such as drinking water provision. The evidence base for such interventions is, however, sometimes contradictory. We performed a laboratory climate manipulation using a factorial design on two dominant peatland vegetation types (Calluna vulgaris and Sphagnum Spp.) and a peat soil collected from a drinking water catchment in Exmoor National Park, UK. Temperature and rainfall were set to represent baseline and future conditions under the UKCP09 2080s high emissions scenario for July and August. DOC leachate then underwent standard water treatment of coagulation/flocculation before chlorination. C. vulgaris leached more DOC than Sphagnum Spp. (7.17 versus 3.00 mg g−1) with higher specific ultraviolet (SUVA) values and a greater sensitivity to climate, leaching more DOC under simulated future conditions. The peat soil leached less DOC (0.37 mg g−1) than the vegetation and was less sensitive to climate. Differences in coagulation removal efficiency between the DOC sources appears to be driven by relative solubilisation of protein-like DOC, observed through the fluorescence peak C/T. Post-coagulation only differences between vegetation types were detected for the regulated disinfection by-products (DBPs), suggesting climate change influence at this scale can be removed via coagulation. Our results suggest current biodiversity restoration programmes to encourage Sphagnum Spp. will result in lower DOC concentrations and SUVA values, particularly with warmer and drier summers.

Drinking water application of Denargard Tiamulin for control of Brachyspira pilosicoli infection of laying poultry

Avian intestinal spirochaetosis (AIS) caused by Brachyspira spp., and notably Brachyspira pilosicoli, is common in layer flocks and reportedly of increasing incidence in broilers and broiler breeders. Disease manifests as diar- rhoea, increased feed consumption, reduced growth rates and occasional mortality in broilers and these signs are shown in layers also associated with a delayed onset of lay, reduced egg weights, faecal staining of eggshells and non-productive ovaries. Treatment with Denagard® Tiamulin has been used to protect against B. pilosicoli colonisation, persistence and clinical presentation of AIS in commercial layers, but to date there has been no de- finitive study validating efficacy. Here, we used a poultry model of B. pilosicoli infection of layers to compare the impact of three doses of Denagard® Tiamulin. Four groups of thirty 17 week old commercial pre-lay birds were all challenged with B. pilosicoli strain B2904 with three oral doses two days apart. All birds were colonised within 2 days after the final oral challenge and mild onset of clinical signs were observed thereafter. A fifth group that was unchallenged and untreated was also included for comparison as healthy birds. Five days after the final oral Brachypira challenge three groups were given Denagard® Tiamulin in drinking water made up following the manufacturer's recommendations with doses verified as 58.7 ppm, 113 ppm and 225 ppm. Weight gain body condition and the level of diarrhoea of birds infected with B. pilosicoli were improved and shedding of the organism reduced significantly (p = 0.001) following treatment with Denagard® Tiamulin irrespective of dose given. The level and duration of colonisation of organs of birds infected with B. pilosicoli was also reduced. Confirming previous findings we showed that the ileum, caeca, colon, and both liver and spleen were colonised and here we demonstrated that treatment with Denagard® Tiamulin resulted in significant reduction in the numbers of Brachyspira found in each of these sites and dramatic reduction in faecal shedding (p b 0.001) to ap- proaching zero as assessed by culture of cloacal swabs. Although the number of eggs produced per bird and the level of eggshell staining appeared unaffected, egg weights of treated birds were greater than those of untreated birds for a period of approximately two weeks following treatment. These data conclusively demonstrate the ef- fectiveness of Denagard® Tiamulin in reducing B. pilosicoli infection in laying hens.

Drinking water application of Denagard® Tiamulin for control of Brachyspira pilosicoli infection of laying poultry

Avian intestinal spirochaetosis (AIS) caused by Brachyspira spp., and notably Brachyspira pilosicoli, is common in layer flocks and reportedly of increasing incidence in broilers and broiler breeders. Disease manifests as diarrhoea,increased feed consumption, reduced growth rates and occasional mortality in broilers and these signs are shown in layers also associated with a delayed onset of lay, reduced egg weights, faecal staining of eggshells and non-productive ovaries. Treatment with Denagard® Tiamulin has been used to protect against B. pilosicoli colonisation, persistence and clinical presentation of AIS in commercial layers, but to date there has been no definitive study validating efficacy. Here, we used a poultry model of B. pilosicoli infection of layers to compare the impact of three doses of Denagard® Tiamulin. Four groups of thirty 17 week old commercial pre-lay birds were all challengedwith B. pilosicoli strain B2904with three oral doses two days apart. All birdswere colonised within 2 days after the final oral challenge and mild onset of clinical signs were observed thereafter. A fifth group that was unchallenged and untreated was also included for comparison as healthy birds. Five days after the final oral Brachypira challenge three groups were given Denagard® Tiamulin in drinking water made up following the manufacturer's recommendations with doses verified as 58.7 ppm, 113 ppm and 225 ppm. Weight gain body condition and the level of diarrhoea of birds infected with B. pilosicoli were improved and shedding of the organism reduced significantly (p = 0.001) following treatment with Denagard® Tiamulin irrespective of dose given. The level and duration of colonisation of organs of birds infected with B. pilosicoli was also reduced. Confirming previous findings we showed that the ileum, caeca, colon, and both liver and spleen were colonised and here we demonstrated that treatment with Denagard® Tiamulin resulted in significant reduction in the numbers of Brachyspira found in each of these sites and dramatic reduction in faecal shedding (p b 0.001) to approaching zero as assessed by culture of cloacal swabs. Although the number of eggs produced per bird and the level of eggshell staining appeared unaffected, egg weights of treated birds were greater than those of untreated birds for a period of approximately two weeks following treatment. These data conclusively demonstrate the effectiveness of Denagard® Tiamulin in reducing B. pilosicoli infection in laying hens.

Aeromonas detection and their toxins from drinking water from reservoirs and drinking fountains

Aeromonads are inhabitants of aquatic ecosystems and are described as being involved in intestinal disturbances and other infections. A total of 200 drinking water samples from domestic and public reservoirs and drinking fountains located in Sao Paulo (Brazil), were analyzed for the presence of Aeromonas. Samples were concentrated by membrane filtration and enriched in APW. ADA medium was used for Aeromonas isolation and colonies were confirmed by biochemical characterization. Strains isolated were tested for hemolysin and toxin production. Aeromonas was detected in 12 samples (6.0%). Aeromonas strains (96) were isolated and identified as: A. caviae (41.7%), A. hydrophila (15.7%), A. allosacharophila (10.4%), A. schubertii (1.0%) and Aeromonas spp. (31.2%). The results revealed that 70% of A. caviare, 66.7% of A. hydrophila, 80% of A. allosacharophila and 46.6% of Aeromonas spp. were hemolytic. The assay for checking production of toxins showed that 17.5% of A. caviae, 73.3% of A. hydrophila, 60% of A. allosacharophila, 100% of A. schubertii, and 33.3% of Aeromonas spp. were able to produce toxins. The results demonstrated the pathogenic potential of Aeromonas, indicating that the presence of this emerging pathogen in water systems is a public health concern.

Risk of Giardia infection for drinking water and bathing in a peri-urban area in Sao Paulo, Brazil

A high incidence of waterborne diseases is observed worldwide and in order to address contamination problems prior to an outbreak, quantitative microbial risk assessment is a useful tool for estimating the risk of infection. The objective of this paper was to assess the probability of Giardia infection from consuming water from shallow wells in a peri-urban area. Giardia has been described as an important waterborne pathogen and reported in several water sources, including ground waters. Sixteen water samples were collected and examined according to the US EPA (1623, 2005). A Monte Carlo method was used to address the potential risk as described by the exponential dose response model. Giardia cysts occurred in 62.5% of the samples (0.1-36.1 cysts/l). A median risk of 10-1 for the population was estimated and the adult ingestion was the highest risk driver. This study illustrates the vulnerability of shallow well water supply systems in peri-urban areas.