Risque professionnel d'hépatite virale A au contact des eaux usées

La disponibilité depuis 1992 d'un premier vaccin contre l'hépatite virale A a soulevé la question de son indication chez le personnel exposé aux eaux usées. Nous avons évalué ce risque professionnel grâce à une étude transversale comparant les taux de prévalence des anticorps totaux (ou des IgG) anti-VHA chez 110 sujets exposés aux eaux usées appariés sur l'âge et le niveau de diplôme à 110 sujets non-exposés de la même entreprise. Chaque personne était interrogée sur ses antécédents d'ictère, la notion de voyages en zone d'endémie et la durée de l'exposition professionnelle. La prévalence des anticorps anti-VHA était globalement de 52,7 %, significativement plus élevée chez les exposés (60,9 %) que chez les non-exposés (44,S %) (p < 0,02). Cette séroprévalence augmentait avec l'âge, et apparaissait liée au niveau de diplôme dans les deux groupes. Ces résultats suggèrent fortement l'existence d'un risque professionnel d'infection par le VHA chez les travailleurs exposés aux eaux usées (risque relatif: 2,4; IC 95 % [1,6 - 3,1]). La vaccination du personnel exposé semble justifiée. La stratégie vaccinale à adopter est liée au coût élevé du vaccin et à la situation épidémiologique du VHA dans le pays.The availability of a first hepatitis A vaccine in 1992 raised the possibility of its use for workers exposed to sewage or sludge. This occupational risk was suspected because of the excretion of hepatitis A virus (HAV) in stools and its resulting presence in sewage, because of the resistance of HAV to environmental stresses, and because of the documented wastewater-mediated transmission of HAV in the general population. On the other hand, the decreased diffusion of HAV in industrialized countries probably results in less contamination of sewage. The aim of this study was to evaluate the possible risk of HAV infection from sewage exposure, which could lead to recommendations of vaccination for exposed workers. MethodsIn a large private company involved in water supply, anti HAV IgG were sought in sera from workers in contact with sewage and from workers not exposed to sewage. Subjects were individually matched for age and education level. Cases included workers involved with the wastewater collection network, workers who monitor drinking water distribution networks in Paris (located in sewer mains in Paris), personnel of a large research laboratory involved with wastewater and sludge, as well as a few workers involved with drinking water production who may be frequently exposed to raw Seine river, Marne river or Oise river water (that could be contaminated with sewage). Histories of jaundice, travels to areas of endemic incidence of hepatitis A, and the duration of occupational exposure were noted. Anti-HAV IgG was measured in serum by an enzyme-linked immunosorbent assay (ELISA) method.ResultsAt this time, 110 exposed workers and 110 non-exposed workers have been studied. Ages ranged from 20 to 58 years, with a mean value of 36.5 year. Cases and controls did not differ with respect to social class or travels in areas of endemic exposure. Duration of exposure ranged from 1 year to 36 years, with a mean value of 10.3, and was correlated to age in this company where workers are usually hired when young. The seroprevalence of anti HAV was globally 52.7 %, significantly higher in exposed workers ( 60.9 %) than in controls ( 44.5 % , p < 0.02 ). This seroprevalence varied widely according to age: for workers in their twenties it was 30.0 % vs. 27.5 %, in their thirties 68.0 % vs. 33.3%, in their forties 80.0 % vs. 54.8% and in their fifties 93.3 % vs. 86.7 %, respectively in exposed and non-exposed workers. The seroprevalence was related to education level in each group, but not to social class. History of jaundice was not correlated with anti HAV status, nor with sewage exposure. The relative risk of HAV infection in this matched range was 2.4, CI 95 % (1.6 - 3.1).These results emphasize the role of occupational exposure to sewage in HAV infection. Exposed workers should be vaccinated because of the frequency of the symptomatic form of hepatitis A in adults with severe and relapsing cases. The strategy of vaccination should take into account the high cost of the vaccine and the epidemiological situation of HAV in the country

Modeling Climate Feedbacks to Energy Demand: The Case of China

Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).This paper is an empirical investigation of the effects of climate on the use of electricity by consumers and producers in urban and rural areas within China. It takes advantage of an unusual combination of temporal and regional data sets in order to estimate temperature, as well as price and income elasticities of electricity demand. The estimated positive temperature/electric power feedback implies a continually increasing use of energy to produce electric power which, in China, is primarily based on coal. In the absence of countervailing measures, this will contribute to increased emissions, increased atmospheric concentrations of greenhouse gases, and increases in greenhouse warming.This study received funding from the MIT Joint Program on the Science and Policy of Global Change, which is supported by a consortium of government, industry and foundation sponsors

Relationship Between Body Satisfaction and Exercise Behavior: A Cross Cultural Comparison

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Performance and emission of pollutants of an agricultural engine with two-power take-off settings

Farming operations are usually performed implements driven by a power take-off (PTO) from tractors. Some manufacturers offer PTO settings named as economic (540E). Such configuration drives implements at lower tractor’s engine rotation, thus providing lower fuel consumption. An engine performance using standard (540) or 540E settings are different and poorly studied. The amounts of pollutants emitted by engines vary mainly with the applied load and rotation. The aim of this study was to compare the performance and exhaust emissions of a farming tractor engine under different PTO loads, using both standard (540) and 540E settings. Specific fuel consumption using 540E was an average 14.7% less than the standard setting. However, 540E promoted increasing levels of gas opacity, CO, CO2, NOx, and HC for the highest PTO power demands.Postprint (published version

Permafrost degradation and methane: low risk of biogeochemical climate-warming feedback

Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, we examine the degradation of near-surface permafrost, temporal dynamics of inundation (lakes and wetlands) induced by hydro-climatic change, subsequent methane emission, and potential climate feedback. We find that increases in atmospheric CH[subscript 4] and its radiative forcing, which result from the thawed, inundated emission sources, are small, particularly when weighed against human emissions. The additional warming, across the range of climate policy and uncertainties in the climate-system response, would be no greater than 0.1 ° C by 2100. Further, for this temperature feedback to be doubled (to approximately 0.2 ° C) by 2100, at least a 25-fold increase in the methane emission that results from the estimated permafrost degradation would be required. Overall, this biogeochemical global climate-warming feedback is relatively small whether or not humans choose to constrain global emissions.United States. Dept. of Energy (Climate Change Prediction Program Grant DE-PS02-08ER08-05)United States. Dept. of Energy. Office of Science (Biological and Environmental Research

The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation

Ascariasis is a widespread soil-transmitted helminth infection caused by the intestinal roundworm Ascaris lumbricoides in humans, and the closely related Ascaris suum in pigs. Progress has been made in understanding interactions between helminths and host immune cells, but less is known concerning the interactions of parasitic nematodes and the host microbiota. As the host microbiota represents the direct environment for intestinal helminths and thus a considerable challenge, we studied nematode products, including excretory-secretory products (ESP) and body fluid (BF), of A. suum to determine their antimicrobial activities. Antimicrobial activities against gram-positive and gram-negative bacterial strains were assessed by the radial diffusion assay, while effects on biofilm formation were assessed using the crystal violet static biofilm and macrocolony assays. In addition, bacterial neutralizing activity was studied by an agglutination assay. ESP from different A. suum life stages (in vitro-hatched L3, lung-stage L3, L4, and adult) as well as BF from adult males were analyzed by mass spectrometry. Several proteins and peptides with known and predicted roles in nematode immune defense were detected in ESP and BF samples, including members of A. suum antibacterial factors (ASABF) and cecropin antimicrobial peptide families, glycosyl hydrolase enzymes such as lysozyme, as well as c-type lectin domain-containing proteins. Native, unconcentrated nematode products from intestine-dwelling L4-stage larvae and adults displayed broad-spectrum antibacterial activity. Additionally, adult A. suum ESP interfered with biofilm formation by Escherichia coli, and caused bacterial agglutination. These results indicate that A. suum uses a variety of factors with broad-spectrum antibacterial activity to affirm itself within its microbe-rich environment in the gut

Single Atom Cooling by Superfluid Immersion: A Non-Destructive Method for Qubits

We present a scheme to cool the motional state of neutral atoms confined in sites of an optical lattice by immersing the system in a superfluid. The motion of the atoms is damped by the generation of excitations in the superfluid, and under appropriate conditions the internal state of the atom remains unchanged. This scheme can thus be used to cool atoms used to encode a series of entangled qubits non-destructively. Within realisable parameter ranges, the rate of cooling to the ground state is found to be sufficiently large to be useful in experiments.Comment: 14 pages, 9 figures, RevTeX

Summation and transformation formulas for elliptic hypergeometric series

Using matrix inversion and determinant evaluation techniques we prove several summation and transformation formulas for terminating, balanced, very-well-poised, elliptic hypergeometric series.Comment: 21 pages, AMS-LaTe

Isoforms of Retinol binding protein 4 (RBP4) are increased in chronic diseases of the kidney but not of the liver

<p>Abstract</p> <p>Background</p> <p>The levels of retinol-binding protein 4 (RBP4) – the carrier protein for Vitamin A in plasma – are tightly regulated under healthy circumstances. The kidney, the main site of RBP4 catabolism, contributes to an elevation of RBP4 levels during chronic kidney disease (CKD) whereas during chronic liver disease (CLD) RBP4 levels decrease. Little is known about RBP4 isoforms including apo-RBP4, holo-RBP4 as well as RBP4 truncated at the C-terminus (RBP4-L and RBP4-LL) except that RBP4 isoforms have been reported to be increased in hemodialysis patients. Since it is not known whether CLD influence RBP4 isoforms, we investigated RBP4 levels, apo- and holo-RBP4 as well as RBP4-L and RBP4-LL in plasma of 36 patients suffering from CKD, in 55 CLD patients and in 50 control subjects. RBP4 was determined by ELISA and apo- and holo-RBP4 by native polyacrylamide gel electrophoresis (PAGE). RBP4-L and RBP4-LL were analyzed after immunoprecipitation by mass spectrometry (MALDI-TOF-MS).</p> <p>Results</p> <p>RBP4 isoforms and levels were highly increased in CKD patients compared to controls (P < 0.05) whereas in CLD patients RBP4 isoforms were not different from controls. In addition, in hepatic dysfunction RBP4 levels were decreased whereas the amount of isoforms was not affected.</p> <p>Conclusion</p> <p>The occurrence of RBP4 isoforms is not influenced by liver function but seems to be strongly related to kidney function and may therefore be important in investigating kidney function and related disorders.</p

Species Review of Amphibian Extinction Risks in Madagascar: Conclusions from the Global Amphibian Assessment

We assessed the extinction risks of Malagasy amphibians by evaluating their distribution, occurrence in protected areas, population trends, habitat quality, and prevalence in commercial trade. We estimated and mapped the distribution of each of the 220 described Malagasy species and applied, for the first time, the IUCN Red List categories and criteria to all species described at the time of the assessment. Nine species were categorized as critically endangered, 21 as endangered, and 25 as vulnerable. The most threatened species occur on the High Plateau and/or have been subjected to overcollection for the pet trade, but restricted extent of occurrence and ongoing habitat destruction were identified as the most important factors influencing extinction threats. The two areas with the majority of threatened species were the northern Tsaratanana-Marojejy-Masoala highlands and the southeastern Anosy Mountains. The current system of protected areas includes 82% of the threatened amphibian species. Of the critically endangered species, 6 did not occur in any protected area. For conservation of these species we recommend the creation of a reserve for the species of the Mantella aurantiaca group, the inclusion of two Scaphiophryne species in the Convention on the International Trade in Endangered Species Appendix II, and the suspension of commercial collecting for Mantella cowani . Field surveys during the last 15 years reveal no pervasive extinction of Malagasy amphibians resulting from disease or other agents, as has been reported in some other areas of the world.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75394/1/j.1523-1739.2005.00249.x.pd