Pierre-André Cabanes

Assessing the Risk of Primary Amoebic Meningoencephalitis from Swimming in the Presence of Environmental Naegleria fowleri

ABSTRACT Free-living Naegleria fowleri amoebae cause primary amoebic meningoencephalitis (PAM). Because of the apparent conflict between their ubiquity and the rarity of cases observed, we sought to develop a model characterizing the risk of PAM after swimming as a function of the concentration of N. fowleri. The probability of death from PAM as a function of the number of amoebae inhaled is modeled according to results obtained from animals infected with amoeba strains. The calculation of the probability of inhaling one or more amoebae while swimming is based on a double hypothesis: that the distribution of amoebae in the water follows a Poisson distribution and that the mean quantity of water inhaled while swimming is 10 ml. The risk of PAM for a given concentration of amoebae is then obtained by summing the following products: the probability of inhaling n amoebae × the probability of PAM associated with inhaling these n amoebae. We chose the lognormal model to assess the risk of PAM because it yielded the best analysis of the studentized residuals. Nonetheless, the levels of risk thereby obtained cannot be applied to humans without correction, because they are substantially greater than those indicated by available epidemiologic data. The curve was thus adjusted by a factor calculated with the least-squares method. This provides the PAM risk in humans as a function of the N. fowleri concentration in the river. For example, the risk is 8.5 × 10−8 at a concentration of 10 N. fowleri amoebae per liter.

Repeated Nitrogen Dioxide Exposures and Eosinophilic Airway Inflammation in Asthmatics: A Randomized Crossover Study

Background: Nitrogen dioxide (NO2), a ubiquitous atmospheric pollutant, may enhance the asthmatic response to allergens through eosinophilic activation in the airways. However, the effect of NO2 on inflammation without allergen exposure is poorly studied. Objectives: We investigated whether repeated peaks of NO2, at various realistic concentrations, induce changes in airway inflammation in asthmatics. Methods: Nineteen nonsmokers with asthma were exposed at rest in a double-blind, crossover study, in randomized order, to 200 ppb NO2, 600 ppb NO2, or clean air once for 30 min on day 1 and twice for 30 min on day 2. The three series of exposures were separated by 2 weeks. The inflammatory response in sputum was measured 6 hr (day 1), 32 hr (day 2), and 48 hr (day 3) after the first exposure, and compared with baseline values measured twice 10–30 days before the first exposure. Results: Compared with baseline measurements, the percentage of eosinophils in sputum increased by 57% after exposure to 600 ppb NO2 (p = 0.003) but did not change significantly after exposure to 200 ppb. The slope of the association between the percentage of eosinophils and NO2 exposure level was significant (p = 0.04). Eosinophil cationic protein in sputum was highly correlated with eosinophil count and increased significantly after exposure to 600 ppb NO2 (p = 0.001). Lung function, which was assessed daily, was not affected by NO2 exposure. Conclusions: We observed that repeated peak exposures of NO2 performed without allergen exposure were associated with airway eosinophilic inflammation in asthmatics in a dose-related manner. Citation: Ezratty V, Guillossou G, Neukirch C, Dehoux M, Koscielny S, Bonay M, Cabanes PA, Samet JM, Mure P, Ropert L, Tokarek S, Lambrozo J, Aubier M. 2014. Repeated nitrogen dioxide exposures and eosinophilic airway inflammation in asthmatics: a randomized crossover study. Environ Health Perspect 122:850–855; http://dx.doi.org/10.1289/ehp.1307240

An Enzyme‐Linked ImmunoSorbent Assay (ELISA) for the Identification of Naegleria fowleri in Environmental Water Samples

Abstract Naegleria fowleri, a free-living amoeba, is the causative agent of primary amoebic meningoencephalitis, a fatal human disease of the central nervous system often contracted after swimming in fresh water. Identifying sites contaminated by N. fowleri is important in order to prevent the disease. An Enzyme-Linked ImmunoSorbent Assay (ELISA) has been developed for the specific identification of N. fowleri in primary cultures of environmental water samples. Of 939 samples isolated from artificially heated river water and screened by ELISA, 283 were positive. These results were subsequently confirmed by isoelectric focusing, the established reference method. A sensitivity of 97.4% and a specificity of 97% were obtained. These results indicate that this ELISA method is reliable and can be considered as a powerful tool for the detection of N. fowleri in environmental water samples.

Isolation of a unique membrane protein from Naegleria fowleri

Abstract Naegleria fowleri, an amoeboflagellate, is the causative agent of Primary Amoebic Meningoencephalitis, a fulminating disease of the central nervous system. In order to elucidate the mechanisms of pathogenicity of this amoeba, a cDNA expression library was prepared from N. fowleri RNA. A specific protein was found to be expressed from a cDNA clone designated Mp2CL5. Northern blot analysis showed that the Mp2CL5 mRNA was expressed in pathogenic N. fowleri but was not expressed in non-pathogenic Naegleria species nor in Acanthamoeba. Western blot analysis using anti-N. fowleri antiserum demonstrated that IPTG-induced Escherichia coli Mp2CL5 expressed a 23-kDa recombinant protein. The Mp2CL5 recombinant protein was histidine-tagged and purified to homogeneity from E. coli. A polyclonal rabbit antiserum was prepared against the purified Mp2CL5 recombinant protein. This antibody was used to further characterize the Mp2CL5 native protein expressed by N. fowleri. Western blot analysis in conjunction with immunofluorescence microscopy demonstrated the presence of a native protein of 17 kDa on the plasma membrane of N. fowleri trophozoites. The native N. fowleri protein was expressed in the logarithmic phase of trophozoite growth and the production of this protein increased through the stationary phase of growth. Studies are in progress to examine further its role as a virulence factor.

Species specificity of a monoclonal antibody produced to Naegleria fowleri and partial characterization of its antigenic determinant.

Abstract Monoclonal antibody (Mab) 5D12 against Naegleria fowleri was analyzed for species specificity. Mab 5D12 reacted with a ubiquitous epitope present on the membrane of N. fowleri but not with soluble antigens. The Mab did not react with N. lovaniensis, N. gruberi, N. australiensis, or Acanthamoeba castellanii. The decreased reactivity of Mab 5D12 with N. fowleri observed after periodate oxidation, after digestion of carbohydrate moieties by three glycosidases, or after treatment of amebas with tunicamycin strongly suggests that the antigenic determinant has a polysaccharide component. Inhibition of the reactivity of Mab 5D12 by soluble saccharides supports the idea that N-acetyl or amino groups may play an important role in the recognition of the carbohydrate component of the epitope by the Mab. The specificity of Mab 5D12 makes this an ideal reagent for the identification of N. fowleri in environmental samples or in clinical specimens.

Outcome of occupational electrical injuries among French electric company workers: A retrospective report of 311 cases, 1996–2005 ☆

This study reviewed records of all electrical incidents involving work-related injury to employees Electricité de France (EDF) from 1996 through 2005 and analysed data for 311 incidents. The results are compared with 1231 electrical incidents that occurred during 1970-1979 and 996 incidents during 1980-1989. A total of 311 electrical incidents were observed. The medical consequences of electrical incident remain severe and particularly, the current fatality rate (3.2%) is similar to that recorded in the 1980s (2.7%) and 1970s (3.3%). Among individuals with non-fatal incidents, any change has occurred in the prevalence of permanent functional sequelae (23.6% in the 1970s vs. 27.6% in the 1980s and 32.5% currently). An increase in the incidence of neuropsychiatric sequelae (5.4% in the 1980s vs. 13% currently) has been observed and they are now the second most common type of sequelae after those directly related to burns. Among the neurological sequelae, peripheral nervous system disorders are the most common, as observed in the 1980s. Since the definition of post-traumatic stress disorder (PTSD) has changed between the two periods, we can only report that the current prevalence of PTSD is 7.6%. This study emphasises the need for specific management of neurological and psychological impairments after electrical injuries, including especially early recognition and initiation of effective treatment.

Fuel poverty in France: Adapting an English methodology to assess the health cost implications

Over five million households in France are estimated to be in fuel poverty and so possibly exposed to low indoor temperatures. Such exposure is a threat to health. Besides the individual’s suffering, negative health outcomes, ranging from mild respiratory conditions to death, create demands on the health sector and costs to society. The health costs associated with energy inefficient dwellings have been calculated in England using a method based on the Housing Health & Safety Rating System (HHSRS); a health-based risk assessment system, adopted in 2006 as the prescribed statutory method for appraising housing conditions in England and Wales. The aim of this study was to use the English approach to estimate the health costs attributable to energy inefficient dwellings and energy vulnerability in France, and to analyse the cost benefits of thermal upgrades. This article details the methodology used to match the English and French housing energy efficiency assessment to provide the foundation necessary for the estimation of costs. This work has demonstrated that it is practicable to adapt the English HHSRS based approach, so that it can be used in another country such as France.

Point de vue sur l’article « Anthropogenic Carbon Nanotubes Found in the Airways of Parisian Children »

Le journal EbioMedicine a publie le 7 octobre 2015 l’article « Anthropogenic Carbon Nanotubes Found in the Airways of Parisian Children », et dont les principaux resultats revelaient la presence de nanotubes de carbone (NTCs) dans le liquide de lavage broncho-alveolaire de 69 enfants asthmatiques vivant en region parisienne. Ces nanotubes, qui se presentaient sous forme d’agregats de nanotubes de carbone multiparois (NTCM) et de faisceaux de nanotubes de carbone monoparois, etaient comparables : (i) a ceux retrouves dans la pollution de l’air interieur et de l’air ambiant dans la meme etude et dans des etudes anterieures ; (ii) a des NTCs manufactures (intentionnellement fabriques a visee industrielle) decrits dans une etude anterieure. A travers cette note, nous proposons un point de vue sur des aspects insuffisamment traites dans l’article du fait de son principal objectif initial qui etait de determiner la methode la plus appropriee pour caracteriser les particules atmospheriques retrouvees dans les poumons des enfants, en recherchant leur fraction carbonee. Nous avons pu montrer a travers notre analyse que des NTCs dont certains ont des caracteristiques proches de NTCs manufactures decrits dans la litteraturepouvaient se retrouver dans les macrophages alveolaires de personnes exposees a la pollution de l’air. Le role direct des NTCs dans la survenue de l’asthme n’est pas demontre chez l’homme a ce jour, mais les NTCs pourraient etre des « transporteurs » a l’interieur de l’organisme humain de molecules allergisantes respiratoires ; ou contribuer a l’aggravation de l’asthme. Leur presence, temoin de leur persistance dans les poumons, doit constituer une alerte pour la mise en place de mesures de reduction de l’exposition des personnes. Des etudes de relargage dans l’environnement de NTCs manufactures a partir de produits en contenant doivent etre encouragees pour reperer les etapes du cycle de vie, de ces produits, a l’origine de la contamination de l’environnement.

Création de la Société française de santé et environnement

Auteur(s) : Denis Bard, Pierre-Andre Cabanes, Alain Grimfeld, Francelyne Marano, Severine Kirchner Institutionnalisee par la creation d’une agence nationale (l’Afsse, devenue l’Afsset1) en 2001, la sante environnementale est aujourd’hui un champ d’expertise reconnu pour lequel des formations universitaires initiales existent. De nombreuses autres agences ou institutions (Afssa, InVS, Ineris, CSTB, INRS, IRSN2 et d’autres encore) contribuent a des degres divers a ce champ d’expertise, [...]