Dataset Information

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation.

ABSTRACT:

Background

The involvement of particulate matter (PM) in cardiorespiratory diseases is now established in developed countries whereas in developing areas such as Africa with a high level of specific pollution, PM pollution and its effects are poorly studied. Our objective was to characterize the biological reactivity of urban African aerosols on human bronchial epithelial cells in relation to PM physico-chemical properties to identify toxic sources.

Methods

Size-speciated aerosol chemical composition was analyzed in Bamako (BK, Mali, 2 samples with one having desert dust event BK1) and Dakar (DK; Senegal) for Ultrafine UF, Fine F and Coarse C PM. PM reactivity was studied in human bronchial epithelial cells investigating six biomarkers (oxidative stress responsive genes and pro-inflammatory cytokines).

Results

PM mass concentrations were mainly distributed in coarse mode (60%) and were impressive in BK1 due to the desert dust event. BK2 and DK samples showed a high content of total carbon characteristic of urban areas. The DK sample had huge PAH quantities in bulk aerosol compared with BK that had more water soluble organic carbon and metals. Whatever the site, UF and F PM triggered the mRNA expression of the different biomarkers whereas coarse PM had little or no effect. The GM-CSF biomarker was the most discriminating and showed the strongest pro-inflammatory effect of BK2 PM. The analysis of gene expression signature and of their correlation with main PM compounds revealed that PM-induced responses are mainly related to organic compounds. The toxicity of African aerosols is carried by the finest PM as with Parisian aerosols, but when considering PM mass concentrations, the African population is more highly exposed to toxic particulate pollution than French population. Regarding the prevailing sources in each site, aerosol biological impacts are higher for incomplete combustion sources resulting from two-wheel vehicles and domestic fires than from diesel vehicles (Dakar). Desert dust events seem to produce fewer biological impacts than anthropogenic sources.

Discussion

Our study shows that combustion sources contribute to the high toxicity of F and UF PM of African urban aerosols, and underlines the importance of emission mitigation and the imperative need to evaluate and to regulate particulate pollution in Africa.

SUBMITTER: Val S

PROVIDER: S-EPMC3637552 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature

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Publications

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation.

Val Stéphanie S Liousse Cathy C Doumbia El Hadji Thierno el HT Galy-Lacaux Corinne C Cachier Hélène H Marchand Nicolas N Badel Anne A Gardrat Eric E Sylvestre Alexandre A Baeza-Squiban Armelle A

Particle and fibre toxicology 20130402

<h4>Background</h4>The involvement of particulate matter (PM) in cardiorespiratory diseases is now established in developed countries whereas in developing areas such as Africa with a high level of specific pollution, PM pollution and its effects are poorly studied. Our objective was to characterize the biological reactivity of urban African aerosols on human bronchial epithelial cells in relation to PM physico-chemical properties to identify toxic sources.<h4>Methods</h4>Size-speciated aerosol ...[more]

PMID: 23548138

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Project description:BACKGROUND:Maternal undernutrition is a leading cause of maternal mortality. Furthermore, health statuses and habits of mothers influence health statuses of newborns as well as healthy habits and mortality of children. The Senegal government is aware of the severity of these issues and has devised a national policy goal of reducing maternal, infant, and adolescent mortality rates by the end of 2018. This study aimed to identify nutritional knowledge, attitudes, and practices of lactating women in Senegal, and determine factors related to nutritional practices to obtain basic data for developing a maternal and child nutrition project. METHOD:This study used a mixed-method approach, collecting data via structured questionnaires administered to lactating women in Senegal and semistructured interviews with seven stake-holders. Questions for stuctured questionnaires were about nutritional knowledge, attitudes, and practices. For the quantitative analysis of the structured questionnaires, data from 171 participants analyzed using independent t-tests, Pearson's correlation coefficients, and multiple linear regression analysis. Interview data were analyzed using an inductive thematic analysis approach. The questions for the interviews concerned maternal and child nutritional status, causes of undernutrition, and restrictions. RESULTS:Factors significantly related to healthy nutritional practices(explaining 27.1% of variance) included having a household (B = 1.03, p = .015) and a mother (B = 0.96, p = .017) with an above primary school education, and being in the 5th quintile of income level (B = 1.24, p = .014). The interviews with seven stakeholders revealed obstructive factors of nutritional management were insufficient nutritional programs within health centers, incomplete national policy on nutrition, lack of general interest in undernutrition-related topics, inadequate economic environment, and the absence of partnerships to produce sustainable solutions. CONCLUSION:Education and income levels, rather than knowledge and attitudes, had a strong relationship with healthy nutritional practices. Therefore, economic factors and educational background must be considered to succeed in Senegalese nutrition projects.

Project description:BackgroundCurrent tools and strategies are not sufficient to reliably address threats and outbreaks of arboviruses including Zika, dengue, chikungunya, and yellow fever. Hence there is a growing public health challenge to identify the best new control tools to use against the vector Aedes aegypti. In this study, we investigated Ae. aegypti sugar feeding strategies in Bamako, Mali, to determine if this species can be controlled effectively using attractive toxic sugar baits (ATSB).MethodologyWe determined the relative attraction of Ae. aegypti males and females to a variety of sugar sources including flowers, fruits, seedpods, and honeydew in the laboratory and using plant-baited traps in the field. Next, we observed the rhythm of blood feeding versus sugar feeding activity of Ae. aegypti in vegetation and in open areas. Finally, we studied the effectiveness of spraying vegetation with ATSB on Ae. aegypti in sugar rich (lush vegetation) and in sugar poor (sparse vegetation) urban environments.Principal findingsMale and female laboratory sugar feeding rates within 24 h, on 8 of 16 plants offered were over 80%. The survival rates of mosquitoes on several plant sources were nearly as long as that of controls maintained on sucrose solution. In the field, females were highly attracted to 11 of 20 sugar sources, and 8 of these were attractive to males. Peak periods of host attraction for blood-feeding and sugar feeding in open areas were nearly identical and occurred shortly after sunrise and around sunset. In shaded areas, the first sugar-seeking peak occurred between 11:30 and 12:30 while the second was from 16:30 to 17:30. In a 50-day field trial, ATSB significantly reduced mean numbers of landing / biting female Ae. aegypti in the two types of vegetation. At sugar poor sites, the mean pre-treatment catch of 20.51 females on day 14 was reduced 70-fold to 0.29 on day 50. At sugar rich sites, the mean pre-treatment catch of 32.46 females on day 14 was reduced 10-fold to a mean of 3.20 females on day 50.ConclusionsThis is the first study to show how the vector Ae. aegypti depends on environmental resources of sugar for feeding and survival. The demonstration that Ae. aegypti populations rapidly collapsed after ATSB treatment, in both sugar rich and sugar poor environments, is strong evidence that Ae. aegypti is sugar-feeding frequently. Indeed, this study clearly demonstrates that Ae. aegypti mosquitoes depend on natural sugar resources, and a promising new method for vector control, ATSB, can be highly effective in the fight against Aedes-transmitted diseases.

Dataset Information

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation.

Background

Methods

Results

Discussion

Publications

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation.

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