Anthropic impacts on Sub-Saharan urban water resources through their pharmaceutical contamination (Yaoundé, Center Region, Cameroon).

Sub-Saharan urban centers have to tackle high population growth, lack of sanitation infrastructures and the need for good quality water resources. To characterize the impacts of anthropization on the water resources of the capital of Cameroon (Yaoundé), a multi-disciplinary approach was used in ten sub-watersheds (peri-urban and urban) of the Méfou watershed. Pharmaceutical residues were used as tracers of surface and groundwater contamination caused by the release of domestic wastewater from pit latrines and landfills. A water use survey was conducted in the vicinity of the sampling sites to better assess water use, treatment and management. Available land use and hydro-geomorphological data completed characterization of the sub-watersheds. The combined data showed that natural features (elevation, slope, and hydrography) and human activities (land use) favor rainfall-runoff events and hence surface water contamination. Pharmaceutical monitoring revealed contamination of both surface and groundwater especially in the urban sub-watersheds. Analgesics/anti-inflammatory drugs and anti-epileptic carbamazepine were the most frequently found compounds (in up to 91% of water samples) with concentrations of acetaminophen reaching 5660 ng/L. In urban sub-watersheds, 50% of the groundwater sites used for drinking water were contaminated by diclofenac (476-518 ng/L), carbamazepine (263-335 ng/L), ibuprofen (141-276 ng/L), sulfamethoxazole (<2-1285 ng/L) and acetaminophen (110-111 ng/L), emphasizing the need for a deeper understanding of the interactions between surface and groundwater. The use of groundwater as drinking water by 68% of the total population surveyed raises concerns about population exposure and potential health risks. This case study highlights the need for strategies to limit contamination of the water resource given the predicted future expansion of Sub-Saharan urban centers.

Grafting {Cp*Rh}(2+) on the surface of Nb and Ta Lindqvist-type POM.

New hybrid POM based on Lindqvist-type polyoxometalates [M6O19](8-) (M = Nb, Ta) and organometallic fragment {Cp*Rh}(2+) have been isolated and characterized. X-ray quality crystals of K4[(Cp*Rh)2Nb6O19]·20H2O () and Cs4[(Cp*Rh)2Ta6O19]·18H2O () were obtained from solutions with {Cp*Rh} : [M6O19](8-) stoichiometry 2 : 1. The solution behavior of the hybrid polyoxoanions was studied with ESI-MS and (1)H DOSY NMR. Amongst the poorly investigated chemistry of polyoxotantalates, complex is the first complex bearing a grafted organometallic fragment. The formation of 1 : 1 complexes was detected by ESI-MS techniques.

Coordination-induced condensation of [Ta6O19](8-): synthesis and structure of [{(C6H6)Ru}2Ta6O19](4-) and [{(C6H6)RuTa6O18}2(µ-O)](10-).

Reaction of [(C6H6)RuCl2]2 and Na8[Ta6O19] gives two new hybrid organometallic POM complexes, Na10[{(C6H6)RuTa6O18}2(µ-O)]·39.4H2O (Na10-1) and Na4(trans-[{(C6H6)Ru}2Ta6O19]·20H2O (Na4-2). In both cases the half-sandwich fragments {(C6H6)Ru}(2+) are coordinated as additional vertices to the {Ta3(µ2-O)3} triangles of the hexatantalate. According to NMR and ESI-MS data, the dimeric complex [{(C6H6)RuTa6O18}2(µ-O)](10-) dissociates in water with the formation of monomeric [(C6H6)RuTa6O19](6-) species (1a). X-ray structural characterization and aqueous speciation of the complexes by (13)C, (1)H, and DOSY NMR; ESI-MS; and capillary electrophoresis (CE) have been carried out.

Trapping {BW12}2 tungstoborate: synthesis and crystal structure of hybrid [{(H2BW12O42)2O}{Mo6O6S6(OH)4(H2O)2}]14- anion.

Reaction between monolacunary {BW(11)} tungstoborate and oxothiocationic building block, {Mo(2)O(2)S(2)}, results in the formation of a new polyoxothiometalate with a unique architecture in which two [H(2)BW(12)O(43)](9-) tungstoborate subunits are linked together with a hexamolybdate [Mo(V)(6)O(6)S(6)(OH)(4)(H(2)O)(2)](2+) bridge.

[Family environment and dental health disparities among urban children in Burkina Faso]. / Environnement familial et disparités de santé dentaire des enfants en milieu urbain au Burkina Faso.

BACKGROUND: Dental caries is the most common multifactorial disease in children and has substantial negative impact on daily life. In sub-Saharan Africa, few data are available on the relationship between dental caries and the social and family environment of children. The objectives of the present study were firstly to assess the level of prevalence and severity of dental caries of children in Ouagadougou, the capital city of Burkina Faso and secondly to determine whether or not individual factors, family and living conditions are linked with dental health disparities within the population. METHODS: Interview and clinical data were obtained from a household-based cross-sectional survey. A two-stage stratified sampling technique was applied in four areas of Ouagadougou representing different stages of urbanization. RESULTS: The final study population included 1606 children aged 6-12 years. For the overall group the total caries prevalence rate was 48.2%. Results showed that the dental health status of the mother, social integration of the householder and socioeconomic level of the household were associated with the dental health of children. Disparities in dental health were prominent; poor dental health was relatively frequent in children from households poorly integrated into social networks with rather acceptable standard in terms of material wealth. CONCLUSION: Our study showed that individual factors as well as family-related and environmental factors had an influence on their caries experience. The rapidly changing lifestyle affects oral health and the burden of oral diseases is expected to increase initially in people of upper classes and later in disadvantaged people. Disease prevention focussing on common risk factors of chronic diseases should be enhanced. In addition, the accessibility of quality fluoride products (e.g. toothpaste, salt, water) should be facilitated as soon as possible.

Excess deaths during the August 2003 heat wave in Paris, France.

BACKGROUND: During the August 2003 heat wave in France, almost 15,000 excess deaths were recorded. Paris was severely affected, with an excess death rate of 141%. This study had two aims: to identify individual factors associated with excess deaths during a heat wave in an urban environment and to describe the spatial distribution of deaths within the French capital. METHODS: The study population included all people who died at home between August 1st and 20th, 2003 (N=961). We identified factors associated with excess deaths by comparing the sociodemographic characteristics of the study population with those of people who died at home during the same period in reference years (2000, 2001, 2002) (N=530). Spatial differences were analysed by calculating comparative mortality rates within Paris during August 2003. Mortality ratio was determined to demonstrate temporal variations in mortality between the heat wave period and reference years. RESULTS: The major factors associated with excess death were: age over 75 years (adjusted OR=1.44 (1.10-1.90), being female (adjusted OR=1.43 (1.11-1.83)), not being married (adjusted OR=1.63 (1.23-2.15)), particularly for men. Being a foreigner appeared to be a protective factor for women. Comparative mortality rates by neighbourhood showed a gradient in excess deaths from North-West to South-East. The mortality ratio was 5.44 (5.10-5.79), with very high rates of excess death in the South (12th, 13th, 14th and 15th "arrondissement"). CONCLUSION: The August 2003 heat wave in Paris was associated with both an exceptional increase in mortality rates and changes in the characteristics of those dying and spatial distribution of mortality. Understanding the effects of a heat wave on mortality can probably be improved by an analysis of risk at two levels: individual and contextual.

[Land-use and urinary schistosomiasis in Daloa (Côte d'Ivoire)]. / Gestion de l'espace et schistosomose urinaire a Daloa (Côte d'Ivoire).

The relation between agricultural land development of inland-valleys and health population has been studied in a town of the Ivorian forest area using urinary schistosomiasis as an indicator. Snails were collected during 4 months in rice fields and water holes used for market gardening of two urban inland-valleys (Batagnihi and Gakognihi). Prevalence of schistosomiasis was evaluated in two districts, Kennedy II and Fadiga, located close to the investigated inland-valleys. Schistosomiasis risk was higher in the Batagnihi where rice cultivation was more developed and prevalence of urinary schistosomiasis was higher in the Kennedy II district which is close to this inland-valley particularly among the Northern migrant people. The Kennedy II population has much more contacts with the inland-valley because of rice cultivation and social status. The higher socio-economic level of the Fadiga population limiting its contacts with the inland-valley can explain this result.

About the Keggin isomers: crystal structure of [N(C4H9)4]-gamma-[SiMo2W10O40]n- (n= 4 or 6).

The tetrabutylammonium gamma-dodecatungstosilicate has been crystallized in a 6/1 acetonitrile/water solvent. An X-ray single-crystal analysis was carried out on [N(C4H9)4]4-gamma-[SiW12O40] which crystallizes in the orthorhombic system, space group P2(1)2(1)2(1), with a = 19.0881(3) A, b = 21.4435(3) A, c = 26.0799(1) A, V = 10674.9(2) A3, Z = 4, and rho(calcd) = 2.392 g/cm3. The idealized C2v arrangement of the anion results from the rotation of 60 degrees of two trigonal [W3O13] groups in the Keggin anion. Taking as reference the geometrical characteristics of the Keggin anion, it appears that the bond lengths and bonds angles within the four [W3O13] groups are not significantly modified while the mu-oxo junctions between the two rotated groups and those between the two unrotated groups involve more acute and opened W-O-W angles, respectively. The syntheses and 183W NMR characterizations of the mixed gamma-[SiW10Mo2O40]n- compounds corresponding to the oxidized (Mo(VI); n = 4) and to the two electron-reduced (Mo(V); n = 6) anions are reported. Structural analysis by 183W NMR has proved unambiguously that the C2v structure of the gamma-[SiW10O36]8- subunit is retained in both the compounds. The electronic behavior of the series gamma-[SiW10M2E2O36]6- (M = Mo or W; E = O or S) is examined, compared and related to 183W NMR data.

Impact of the development of agricultural land on the transmission of sleeping sickness in Daloa, Côte d'Ivoire.

Although tools to control sleeping sickness do exist, their use is difficult; areas where intervention is most required often cannot be targeted for lack of appropriate risk indicators. The importance of human behaviour and habits in the manifestation of the disease is clear. In the development of effective new approaches to the control of the disease, information must be gathered about human populations, and their interaction with the environment, in rural as well as in urban and peri-urban areas. The results of a study carried out in Daloa show that use of some methods for the development of agricultural land leads to increased human-vector contact and, as a result, increased risk of sleeping sickness. Such land-management methods may therefore be useful as risk indicators for transmission. Transmission does not occur in the town of Daloa itself but in surrounding areas under cultivation. The use of the epidemiological risk index seems to be inappropriate in urban (and perhaps peri-urban) areas. The results emphasise not only the importance of environmental and demographic data in elucidating the epidemiology of human trypanosomiasis but also the need for further investigations in peri-urban areas.

[Geographic determinants of onchocerciasis transmission in a forest-savannah transition zone: an example of 2 villages of the Mbam focus (central region, Cameroon)]. / Les déterminants géographiques de la transmission de l'onchocercose en zone de transition forêt-savane: l'exemple de deux villages du foyer du Mbam (région du Centre, Cameroun).

Mbam, a focus of onchocerciasis outbreaks, is located in the forest/savannah transition zone of Cameroon. Transmission of the disease in this area is similar to that sometimes observed in West Africa. Geographical factors affecting transmission must be identified to determine the areas for priority action. The locations of breeding sites for black flies (the vector of the disease) and factors favorable to their dispersion, the social behavior of these population and the way that she occupy space, must be investigated to identify areas in which the flies and man are in close contact. This geographical study shows that the closest contact between men and black flies occurs in cocoa plantations, due to the proximity of the breeding sites. The areas of closet contact for women and children are unknown, but their identification is important because women and children may be bitten by the flies during their daily activities.

[Geographic approach to urinary schistosomiasis in an average African town, Daloa (Ivory Coast)]. / Approche géographique de la schistosomiase urinaire dans une ville moyenne africaine, Daloa (Côte d'Ivoire).

Agricultural activity occurs within many medium size towns in developing countries. Rural influences and urbanization, which may be well or poorly managed, combine to create new health problems. A geographical approach is useful for evaluating the ability of the health care system to deal efficiently with these problems. Such an approach should take into account the urban environment and human population, health care and spatial differentiation factors. Relevant health indicators were selected to analyze the geographical patterns of health risk and of the health care system. These factors were analyzed according to area, at various levels. Field studies were carried out and aerial photographs and the various available maps were also studied. Results were compared to determine whether the health care system was appropriate for the health needs of the town. Urinary schistosomiasis is a useful example for assessing the value of the suggested methodology. The risk of transmission of this disease is high so its early detection is vital. The ability of the health care system to detect infection was assessed.

Geographical determinants of onchocerciasis transmission in a forest/savannah transition zone : two villages of the mbam focus

Mbam, a focus of onchocerciasis outbreaks, is located in the forest/savannah transition zone of Cameroon. Transmission of the disease in this area is similar to that sometimes observed in West Africa. Geographical factors affecting transmission must be identified to determine the areas for priority action. The locations of breeding sites for black flies (the vector of the disease) and factors favorable to their dispersion, the social behavior of these population and the way that she occupy space, must be investigated to identify areas in which the flies and man are in close contact. This geographical study shows that the closest contact between men and black flies occurs in cocoa plantations, due to the proximity of the breeding sites. The areas of closest contact for women and children are unknown, but their identification is important because women and children may be bitten by the flies during their daily activities.

Geographic approach to urinary schistosomiasis in an average african town, daloa

Agricultural activity occurs within many medium size towns in developing countries. Rural influences and urbanization, which may be well or poorly managed, combine to create new health problems. A geographical approach is useful for evaluating the ability of the health care system to deal efficiently with these problems. Such an approach should take into account the urban environment and human population, health care and spatial differentiation factors. Relevant health indicators were selected to analyze the geographical patterns of health risk and of the health care system. These factors were analyzed according to area, at various levels. Field studies were carried out and aerial photographs and the various available maps were also studied. Results were compared to determine whether the health care system was appropriate for the health needs of the town. Urinary schistosomiasis is a useful example for assessing the value of the suggested methodology. The risk of transmission of this disease is high so its early detection is vital. The ability of the health care system to detect infection was assessed.

Syntheses and Characterization of gamma-[SiW(10)M(2)S(2)O(38)](6)(-) (M = Mo(V), W(V)). Two Keggin Oxothio Heteropolyanions with a Metal-Metal Bond.

The oxothio polyanions gamma-[SiW(10)M(2)S(2)O(38)](6)(-) (M = Mo(V), W(V)) were obtained through stereospecific addition of the dication [M(2)S(2)O(2)](2+) (M = Mo, W) to the divacant gamma-[SiW(10)O(36)](8)(-) anion in dimethylformamide. These compounds were isolated as crystals and are stable in usual organic solvents and in aqueous medium from pH = 1 to pH = 7. NEt(4)Cs(3)H(2)[SiW(10)Mo(2)S(2)O(38)].6H(2)O (a gamma-isomer derived from the alpha Keggin structure capped by the [Mo(2)S(2)O(2)](2+) fragment containing a metal-metal bond) crystallizes in the triclinic space group P&onemacr; with a = 12.050(3) Å, b = 12.695(2) Å, c = 20.111(4) Å, alpha = 74.35(2) degrees, beta = 86.83(2) degrees, gamma = 63.50(2) degrees, Z = 2. NEt(4)Cs(5)[SiW(12)S(2)O(38)].7H(2)O is isostructural and crystallizes in the triclinic space group P&onemacr; with a = 12.197(4) Å, b = 12.714(3) Å, c = 20.298(3) Å, alpha = 74.75(1) Å, beta = 86.48(2) degrees, gamma = 61.80(2) degrees, Z = 2. (183)W NMR spectra of Li(+) salts in aqueous solution agree with the solid state structures and reveal 100% purity for both anions. Polarographic, infrared and UV-vis data are also given.

Ivermectin-based control of onchocerciasis in northern Cameroon: individual factors influencing participation in community treatment.

A study aimed at determining individual factors associated with participation in community treatment with ivermectin was conducted in a village hyperendemic for onchocerciasis in northern Cameroon. The respective influences of sex, age, place of residence, distance between the compound and the dosing point, compound size, and participation in treatment by authoritative individuals in the compound was evaluated using univariate and multivariate analysis. Participation in treatment was closely associated with the attitude of the compound heads. Participation of compound heads in treatment increased as the household size increased, and as the distance to the distribution point diminished. This may be explained by the fact that getting information on health programmes is easier in large households whose members are involved in various social activities, and in compounds located near the village centre. Staff involved in health education should take this issue into account, and try to ensure circulation of information particularly to those living in small or remote compounds.