114 research outputs found
The effect of irrigated urban agriculture on malaria, schistosomiasis and soil-transmitted helminthiasis in different settings of Côte d'Ivoire
No full textMalaria is responsible for more than one million deaths every year, mainly children under the age of five years living in sub-Saharan Africa. At least one billion people harbor one or several of the three main soil-transmitted helminths, namely Ascaris lumbricoides, hookworms and Trichuris trichiura, and about 207 million people are infected with schistosomes. An estimated 70,000 people die each year from amoebiasis, caused by Entamoeba histolytica. Giardiasis, caused by Giardia duodenalis, is responsible for 2.8 million annual infections. Poor rural and urban communities in developing countries bear the highest burden of the above-mentioned diseases. Their causes are multifactorial including lack of access to clean water, improved sanitation and health services, as well as inadequate treatment, protection and prevention. The highest rates of urbanization currently occur in the less developed regions of Africa and Asia, and it is predicted that the majority of the population will be living in small and medium urban centers in the near future. The maintenance of traditional livelihoods, including agriculture, is a typical feature in urban settings across Africa, especially in small towns where population densities and land pressure are lower than in big cities. Urban agriculture contributes to food security and livelihood opportunities for poor urban dwellers. However, the adaptation of disease vectors and intermediate hosts to urban ecosystems has been observed, which might further enhance the negative effects associated with persistent rural lifestyles. For example, the creation of malaria vector breeding sites and contact with contaminated water and soil in areas of irrigated agriculture may increase the transmission of vector-borne, water-related and soil-transmitted parasitic diseases. This PhD focused on the interface of agriculture and human health in two different urban settings of Côte d’Ivoire. The overarching goal was to contribute to a better understanding of the effects of irrigated urban agriculture on the transmission of malaria, schistosomiasis, soil-transmitted helminthiasis and intestinal protozoan infections. The research entailed a considerable amount of fieldwork, carried out between April 2004 and July 2005. In a first step, six zones of irrigated agricultural land use were identified both in Abidjan, the economic capital of Côte d’Ivoire (3.3 million inhabitants), and in the mediumsized town of Man (115,000 inhabitants) in the western part of the country. Next, two standardized mosquito breeding site assessments were conducted in these agricultural zones in the rainy season (September 2004) and in the dry season (February 2005). In each urban setting, a minimum of 120 farming households and additionally 30 non-farming households were randomly selected. Geographic coordinates of houses and the main agricultural plots were recorded. Name, age and sex of all household members were registered. In October
2004, interviews on agricultural land use, farming practices and water storage were
conducted with the heads of the farming households. In a cross-sectional survey done in
May/June 2005, questionnaires were administered to all households to assess the socioeconomic
status, sanitary facilities and common water contact patterns. From each study
participant, a finger prick blood sample and a stool sample were collected. Thick and thin
blood films were stained with Giemsa and examined for Plasmodium spp. under a light
microscopy. The stool samples were prepared based on the Kato-Katz technique and eggs of
Schistosoma mansoni, A. lumbricoides, hookworm and T. trichiura were recorded separately.
Cysts or trophozoites of intestinal protozoa, including Entamoeba histolytica/E. dispar and G.
duodenalis were identified using an ether-formalin concentration method. Risk factors were
identified by fitting multivariate non-random and random effects Bayesian regression models
integrating spatial correlation of infection.
Agricultural land use in Abidjan was characterized by market gardens on lagoon shores
and high-yield vegetable production. The vegetable production areas in Abidjan developed as
a consequence of land access difficulties in unexploited public and private areas near poor
settlements, mainly at lagoon shores. In Man, farming was family- and subsistence-based.
Predominant agricultural activities were traditional irrigated rice farming and vegetable
production in lowlands and along the Kô River.
The typical demographic and socio-economic profile of a vegetable producer in
Abidjan is that he is an immigrant from Burkina Faso, illiterate and lacking a professional
agricultural training. Malaria and intestinal parasitic infections were most prevalent among
the final study cohort of 370 farmers and family members from 121 farming households. We
found overall prevalences of T. trichiura, P. falciparum and hookworm of 42.6%, 24.3% and
17.3%, respectively. The parasites were heterogeneously distributed between the six market
garden zones. Prior health issues were suppressed by the farmers with the daily livelihood
struggle and reported symptoms due to intestinal parasitic infections were of less importance
when compared to malaria. In-depth focus group discussions revealed that the working
environment was discerned as unhealthy, and waste dumps and human defecation grounds
were perceived as main health risks. Farmer communities and their network are indicative for
the degree of social coherence and stability in a vegetable production area because these
zones are characterized by highly dynamic land use patterns.
In the town of Man, Anopheles larvae were present in 50.7% and 42.4% of 369 and 589
examined potential mosquito breeding sites in the rainy and in the dry season, respectively.
The most productive habitats were man-made, i.e. agricultural trenches, irrigation wells, and
flooded and recently transplanted rice plots. The overall prevalence of P. falciparum
infections in the final study cohort of 574 individuals from 112 farming households was
32.1%. Risk factors for P. falciparum in children <15 years of age included living in specific
agricultural zones (i.e. traditional irrigated rice plots, mixed crops and a large rice perimeter),
proximity to permanent man-made ponds and fish ponds, periodic stays overnight in farm
huts and low socio-economic status.
The final study cohort for S. mansoni and soil-transmitted helminthiasis comprised 586
individuals from 113 farming households. The overall prevalences of S. mansoni, hookworm,
E. histolytica/E. dispar and G. duodenalis were 51.4%, 24.7%, 20.2% and 6.3%, respectively.
Members from farming households harbored significantly more often an infection with
E. histolytica/E. dispar and G. duodenalis when compared to non-farming households.
Predictors for an S. mansoni infection included close proximity to the Kô River, contact with
irrigation wells and ponds on the agricultural plots and low educational attainment. Risk
factors for hookworm infection comprised living in agricultural zones of traditional
smallholder irrigated rice plots and a large rice perimeter, using water from domestic wells
and low socio-economic status. Infection prevalences of P. falciparum, S. mansoni and
hookworm were spatially highly heterogeneous between the agricultural zones and highest
infections occurred in a zone of a large rice perimeter. P. falciparum infection intensity and
hookworm infection prevalence were best explained by spatial random effect models. Spatial
correlation between farmers’ houses was not significant.
The findings of the present work illustrated a clear picture of the interconnections
between specific irrigated agricultural land use and agricultural activities, and malaria and
intestinal parasitic infections in different urban settings of Côte d’Ivoire. The outcomes lead
to an enhanced understanding of their epidemiology in local agro-ecological urban settings
and related contextual determinants (i.e. agricultural, behavioural, demographic, socioeconomic
and environmental factors) and allows the design of readily adapted prevention and
control interventions (e.g. tangible vector control strategies and prevention measures for
helminth infections) which actively involve farming communities in the subsequent
implementation and control management
FLOTAC for the diagnosis of Hymenolepis spp. infection : proof-of-concept and comparing diagnostic accuracy with other methods
No full textHymenolepis nana is the most common cestode parasitizing humans, yet it is under-diagnosed. We determined the optimal flotation solution (FS) for the diagnosis of this intestinal parasite with the FLOTAC method, and compared its diagnostic accuracy with an ether-concentration technique and the Kato-Katz method. Zinc sulphate (specific gravity 1.20) proved to be the best-performing FS. Using this FS, we detected 65 H. nana infections among 234 fixed fecal samples from Tajik and Sahrawi children (prevalence 27.8 %). The ether-concentration technique detected 40 infections (prevalence 17.1 %) in the same samples. Considering the combined results as a reference, the sensitivities of FLOTAC and ether-concentration were 95.6 % and 58.8 %, respectively. The Kato-Katz method resulted in a prevalence of only 8.7 %. In terms of eggs per gram of stool, a significantly (P >0.05) higher value was obtained with the FLOTAC and Kato-Katz techniques compared to ether-concentration. In another study carried out in China, the FLOTAC method detected six Hymenolepis diminuta infections in 302 fecal samples, whereas five samples were found positive with the Kato-Katz technique. We conclude that FLOTAC is an accurate coprodiagnostic technique for H. nana and H. diminuta, two species which join a growing list of intestinal parasites that can be reliably diagnosed by this techniqu
Iodine nutritional status and risk factors for goitre among schoolchildren in south Tajikistan
No full textIodine deficiency affects nearly 1.9 billion people worldwide, but it can be prevented by salt iodization. This cross-sectional survey assessed current iodine status, iodized salt coverage and risk factors for goitre among schoolchildren in South Tajikistan.; Ten primary schools in four districts in South Tajikistan were randomly selected. In schoolchildren aged 7 to 11 years, a spot urine sample was collected for measurement of urinary iodine, dried blood spots were collected for measurement of thyroglobulin, and goitre was assessed by palpation. Iodine content of salt samples and local selling points was determined by coloration using rapid test kits and titration method.; Of 623 schoolchildren enrolled, complete data was obtained from 589. The overall median urinary iodine concentration (UIC) was 51.2 mug/L indicating mild-to-moderate iodine deficiency. Among all children, 46.6% (95% Confidence Interval (CI) = 42.4%-50.6%) of children were found to be goitrous (grade 1 goitre: 30.6%, 95% CI = 26.9%-34.5%; grade 2 goitre: 16.0%, 95% CI = 13.1%-19.2%). The risk factor for goitre remaining significant in the multivariable logistic regression model was 'buying salt once a month' (OR = 2.89, 95% CI = 1.01-8.22) and 'buying salt once every six months' (OR = 2.26, 95% CI = 1.01-5.04) compared to 'buying salt every one or two weeks'. The overall median thyroglobulin concentration was elevated at 13.9 mug/L. Of the salt samples from households and selling points, one third were adequately iodised, one third insufficiently and one third were not iodised.; Iodine deficiency remains a serious health issue among children in southern Tajikistan. There is a persisting high prevalence of goitre, elevated thyroglobulin and low UIC despite interventions implemented by Tajikistan and international partners. Quality control of salt iodine content needs to be improved. Continued efforts to raise awareness of the health effects of iodine deficiency are needed to increase consum demand for iodised salt
Influence of curing conditions on alkali-activated mortars intended for concrete repair
No full textRepair mortars are costly materials with high level of Portland cement and various additives which questions their eco-efficiency. In this respect, cement free material solutions such as alkali-activated mortars based on ground granulated blast furnace slag (BFS) are gaining interest for structural repair. The aim of this research is to study blast furnace slag as a precursor for producing ambient cured alkali-activated repair mortars. To achieve this purpose, a total of four mixtures were prepared using four different molar ratios of the silicate solution. The fresh and hardened properties of the produced mortars including flow retention, dry density, compressive and flexural strength are studied comparing ambient-cured and sealedcured specimens. Furthermore, the tensile bond strength between the repair mortars and a grit blasted concrete substrate was verified (after 7 days sealed + 21 days ambient curing). The results demonstrate, for the tested configurations, the feasibility of the alkali-activated repair mortar, including a good adherence. Given the limited scope of the tests, more work is needed to confirm the observations further
Joodse kinderen en hun vrije tijd : een kwalitatieve studie naar het vrijetijdsgedrag van orthodox Joodse kinderen in Antwerpen
No full textAccuracy of the Kato-Katz, adhesive tape and FLOTAC techniques for helminth diagnosis among children in Kyrgyzstan.
No full textThe purpose of this study was to assess the accuracy of three copro-microscopic techniques for helminth diagnosis: Kato-Katz, adhesive tape and FLOTAC. A total of 163 children from a peri-urban municipality near Bishkek, Kyrgyzstan, participated and submitted multiple stool samples and adhesive tapes. Ninety children supplied at least two stool samples and two adhesive tapes. Three stool samples and three adhesive tapes were available from 71 and 64 children, respectively. From each stool sample, a single Kato-Katz thick smear was prepared and examined quantitatively. Additionally, the first stool sample was subjected to the FLOTAC technique and helminth eggs were counted. Adhesive tapes were checked for the presence of Enterobius vermicularis eggs. Using pooled results as a diagnostic 'gold' standard, the prevalence of Ascaris lumbricoides, E. vermicularis, Hymenolepis nana and Dicrocoelium dendriticum were 54.4%, 13.3%, 11.1% and 11.1%, respectively. Infection intensities were low. When compared to triplicate Kato-Katz, a single FLOTAC was more sensitive for the diagnosis of A. lumbricoides (89.5% versus 39.5%) and D. dendriticum (88.9% versus 33.3%), but less sensitive for H. nana (66.7% versus 88.9%). For E. vermicularis, three adhesive tapes showed much higher sensitivity than a single FLOTAC (92.9% versus 14.3%). FLOTAC yielded significantly higher faecal egg counts than Kato-Katz for A. lumbricoides and D. dendriticum. Overall results suggest that, although FLOTAC represents a promising technique for helminth diagnosis in Kyrgyzstan, the repeated adhesive tape test remains so far the method of choice for diagnosing E. vermicularis
Foods contributing to vitamin B-6, folate, and vitamin B-12 intakes and biomarkers status in European adolescents: The HELENA study
No full textPURPOSE: To examine the association between food groups consumption and vitamin B6, folate and B12 intakes and biomarkers in adolescents. METHODS: In total 2189 individuals participating in the cross-sectional Healthy Lifestyle in Europe by Nutrition in Adolescence study met the eligibility criteria for analysis of dietary intakes (46 % males) and 632 for biomarker analysis (47 % males). Food intakes were assessed by two non-consecutive 24-h recalls. Biomarkers were measured by chromatography and immunoassay. Food groups which best discriminated participants in the extreme tertiles of the distribution of vitamins were identified by discriminant analyses. Food groups with standardised canonical coefficients higher or equal to 0.3 were selected as valid discriminators of vitamins intake and biomarkers extreme tertiles. Linear mixed model elucidated the association between food groups and vitamins intakes and biomarkers. RESULTS: Vitamin B6 intakes and biomarkers were best discriminated by meat (males and females), margarine and mixed origin lipids only in males and breakfast cereals (females). Breakfast cereals (males), and fruits, margarine and mixed origin lipids, vegetables excluding potatoes, breakfast cereals, and soups/bouillon (females) determined the most folate intakes and biomarkers. Considering vitamin B12 intakes and biomarkers, meat, and white and butter milk (males and females), snacks (males), and dairy products (females) best discriminated individual in the extremes of the distribution. Fewer associations were obtained with mixed model for biomarkers than for vitamins intakes with food groups. CONCLUSIONS: Whereas B-vitamin intakes were associated with their food sources, biomarkers did with overall food consumption. Low-nutrient-density foods may compromise adolescents' vitamin status.sponsorship: HELENA study received funding from the European Union's Sixth RTD Framework Programme (Contract FOODCT-2005-007034). Additional support from the Spanish Ministry of Education (AGL2007-29784-E/ALI), Axis-Shield Diagnostics Ltd (Oslo, Norway), Abbot Cientifica S.A. (Spain). The first author was financially supported by EURRECA-Network of Excellence-. This analysis was also supported by the Spanish Ministry of Science and Innovation (JCT-2010-07055) with the contribution of the European Regional Development Fund (FEDER). The authors would like to acknowledge all the adolescents who made possible the HELENA study with their participation. Many thanks to Petra Pickert, Rosa Torres and Ulrike Albers for their contribution to laboratory work. (European Union|FOODCT-2005-007034, Spanish Ministry of Education|AGL2007-29784-E/ALI, Axis-Shield Diagnostics Ltd (Oslo, Norway), Abbot Cientifica S.A. (Spain), EURRECA-Network of Excellence-, Spanish Ministry of Science and Innovation|JCT-2010-07055)status: Publishe
The dynamics of theologies: A transdisciplinary description
No full textIn this article, the author asks why the South African public, especially Afrikaans communities, is largely unaware of the knowledge generated in the field of science and religion. The author describes theologies as complex systems that interact with their environment. To illuminate the environment, the author turns to the theatre system and illustrates how the theatre system can illuminate the modelling choices of theologians
Private security companies and private military companies: a comparative and economical analysis
No full textThis book constructs theoretical models of how States can cope with the increased interest in private security, provides a functional breakdown of “police services” as we understand the term now, and examines the entry barriers several Western jurisdictions have imposed on the companies that are willing to provide these different police functions on a private basis. Lastly, a new input is given to a fairly unexplored market segment: a combination of a security contract with an insurance contract. In a separate chapter, the book touches upon the concept of private military companies. One specific subset of these can be closely linked to the private security industry. When contracted by State agencies, challenges are encountered that also exist with other public-private contracts, but in a more exasperated way. The author proposes some methods, using existing instruments, to minimise costs, maximise benefits, and increase accountability to the benefit of both the State and the company
FRP systems for structural rehabilitation: growth or maturity ?
No full textThe use of fibre reinforced polymer (FRP) based advanced composite systems for the repair and strengthening of structures has evolved from an emerging technology to an established engineering technique. Structural rehabilitation with externally bonded FRP reinforcement has a track record of over 15 years of widespread commercial applications world-wide and this has been reflected in growing availability of standards and codes. Moreover, it has been 26 years since the first on-site application of bonded FRP strips. Hence, one could state that the technology life cycle reached maturity and that it is time to rest on our tremendous achievements as a research community? Reflecting on this statement, the author believes and demonstrates the opposite, and proposes some challenges and focal points for academia and industry on the use of FRP systems for the construction sector and more specific looking into FRP systems for structural rehabilitation
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