Reducing occurrence of Giardia duodenalis in children living in semiarid regions: impact of a large scale rainwater harvesting initiative.

BACKGROUND: In Brazil, about two million people living in rural semiarid regions were benefited with the construction of rainwater cement cisterns, as an initiative from the program "One Million Cisterns" (P1MC). Nevertheless, few epidemiological studies have been conducted to assess health risks or protection effects associated with consumption of this water source. The aim of this study was to evaluate whether access to rainwater harvesting cisterns is associated with the decrease in the occurrence of Giardia duodenalis infections in children, compared to other children living in households supplied by other water sources. METHODOLOGY/PRINCIPAL FINDINGS: A quasi-experimental study with two concurrent cohorts was developed in two rural municipalities of the semiarid region of Brazil. A sample of 664 children, aged between 4 months and 5 years old, was followed up, of which 332 had access to rainwater cisterns (cistern group) and 332 did not, having water supplied from alternative sources (comparison group). In a period of approximately one year (2010) intestinal parasites were investigated in feces three times. The prevalence of G. duodenalis in children from the cistern group ranged from 4.8 to 10.5%, while the prevalence in the comparison group ranged from 7.6 to 16.7%. Multivariate analysis (GEE) showed a higher risk of G. duodenalis infection in children who did not have access to rainwater cisterns, when compared to children who did (OR 1.72; 95% CI 1.14-2.59). The other variables associated with G. duodenalis infection were: number of rooms per house (OR 0.89; 95% CI 0.80-0.99); family income (OR0.48; 95% CI 0.26-0.88); birth order (OR 1.72; 95% CI 1.17-2.51); preterm children (OR 1.70; 95% CI 1.19-2.43); and improper hand hygiene prior to food preparation (OR 4.78; 95% CI 1.95-11.76). CONCLUSIONS/SIGNIFICANCE: Ownership of a rainwater cistern is associated with a lower prevalence of G. duodenalis infection in children after adjustment for environmental and family-related factors. Nevertheless, the study suggests the necessity to complement physical interventions with actions related to personal and domestic hygiene to enable further reductions in parasite infections affecting mainly the underprivileged populations

A comparative study of the TF-Test®, Kato-Katz, Hoffman-Pons-Janer, Willis and Baermann-Moraes coprologic methods for the detection of human parasitosis.

This study compares the diagnostic accuracy of the TF-Test® (TFT) for human parasitosis with results obtained us¬ing the traditional Kato-Katz (KK), Hoffman-Pons-Janer (HPJ), Willis and Baermann-Moraes (BM) techniques. Over¬all, four stool samples were taken from each individual; three alternate-day TFT stool samples and another sample that was collected in a universal container. Stool samples were taken from 331 inhabitants of the community of Quilombola Santa Cruz. The gold standard (GS) for protozoa detection was defined as the combined results for TFT, HPJ and Willis coproscopic techniques; for helminth detection, GS was defined as the combined results for all five coproscopic tech¬niques (TFT, KK, HPJ, Willis and BM). The positivity rate of each method was compared using the McNemar test. While the TFT exhibited similar positivity rates to the GS for Entamoeba histolytica/dispar (82.4%) and Giardia duodenalis (90%), HPJ and Willis techniques exhibited significantly lower positivity rates for these protozoa. All tests exhibited significantly lower positivity rates compared with GS for the diagnosis of helminths. The KK technique had the highest positivity rate for diagnosing Schistosoma mansoni (74.6%), while the TFT had the highest positivity rates for Ascaris lumbricoides (58.1%) and hookworm (75%); HPJ technique had the highest positivity rate for Strongyloides stercoralis (50%). Although a combination of tests is the most accurate method for the diagnosis of enteral parasites, the TFT reliably estimates the prevalence of protozoa and selected helminths, such as A. lumbricoides and hookworm. Further studies are needed to evaluate the detection accuracy of the TFT in samples with varying numbers of parasites

Prevalência de parasitos intestinais na comunidade indígena Maxakali, Minas Gerais, Brasil, 2009 Prevalencia de parásitos intestinales en la comunidad indígena Maxakali, Minas Gerais, Brasil, 2009 Prevalence of intestinal parasites in the Maxakali indigenous community in Minas Gerais, Brazil, 2009

O objetivo deste estudo foi determinar a prevalência de parasitos intestinais na etnia Maxakali em Minas Gerais, Brasil. Os exames parasitológico das fezes foram realizados através da técnica TF-Test, sendo as amostras fecais coletadas em três dias alternados, em tubos independentes, contendo formol a 10%, unificados para dupla filtragem por centrifugação. Triplicatas de uma alíquota do sedimento foram examinadas em microscópio (10x e 40x) para identificação de ovos, cistos e larvas. A prevalência de parasitos (89,5%) e do poliparasitismo (46%) foi semelhante quanto ao sexo e idade, e variou entre as aldeias. As espécies prevalentes foram: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) e Trichuris trichiura (0,5%). Os Maxakali vivem em condições de vulnerabilidade social, e medidas de infraestrutura e de educação em saúde necessitam ser implementadas pelas instituições governamentais.El objetivo de este estudio fue determinar la prevalencia de parásitos intestinales en la etnia Maxakali. Los exámenes parasitológicos de las heces se realizaron a través de la técnica TF-Test, las muestras fecales se recogieron en tres días alternados, en tubos independientes, conteniendo formol a un 10%, unificados para un doble filtrado por centrifugación. Triplicados de una alícuota del sedimento se examinaron en microscopio (10x y 40x) para la identificación de huevos, quistes y larvas. La prevalencia de parásitos (89,5%) y del poliparasitismo (46%) fue semejante en cuanto al sexo y edad, y varió entre las aldeas. Las especies prevalentes fueron: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) y Trichuris trichiura (0,5%). Los Maxakali viven en condiciones de vulnerabilidad social, y medidas de infraestructura y de educación en salud necesitan ser implementadas por instituciones gubernamentales.A prevalence survey using the TF-Test technique to identify intestinal parasites was conducted in the Maxakali indigenous villages in Minas Gerais State, Brazil. Stool samples were collected on three alternating days, in separate tubes, containing 10% formalin, and unified in a laboratory by double filtering centrifugation. Samples of sediment aliquot were prepared in triplicate and examined by microscope (10x and 40x) for eggs, cysts, and larvae. Prevalence of parasites (89.5%) and polyparasitism (46%) were similar by sex and age, but varied by village. Prevalent species were: Entamoeba histolytica/Entamoeba dispar (48.9%), Giardia duodenalis (32%), Entamoeba coli (40.8%), Endolimax nana (10.3%), hookworms (37.9%), Schistosoma mansoni (23.7%), Hymenolepis nana (18.6%), Strongyloides stercoralis (5.4%), Ascaris lumbricoides (4.9%), and Trichuris trichiura (0.5%). The Maxakali population lives in socially vulnerable conditions, and government agencies need to introduce measures to improve sanitation infrastructure and health education

Prevalência de parasitos intestinais na comunidade indígena Maxakali, Minas Gerais, Brasil, 2009

O objetivo deste estudo foi determinar a prevalência de parasitos intestinais na etnia Maxakali em Minas Gerais, Brasil. Os exames parasitológico das fezes foram realizados através da técnica TF-Test, sendo as amostras fecais coletadas em três dias alternados, em tubos independentes, contendo formol a 10%, unificados para dupla filtragem por centrifugação. Triplicatas de uma alíquota do sedimento foram examinadas em microscópio (10x e 40x) para identificação de ovos, cistos e larvas. A prevalência de parasitos (89,5%) e do poliparasitismo (46%) foi semelhante quanto ao sexo e idade, e variou entre as aldeias. As espécies prevalentes foram: Entamoeba histolytica/Entamoeba dispar (48,9%), Giardia duodenalis (32%), Entamoeba coli (40,8%), Endolimax nana (10,3%), ancilostomídeos (37,9%), Schistosoma mansoni (23,7%), Hymenolepis nana (18,6%), Strongyloides stercoralis (5,4%), Ascaris lumbricoides (4,9%) e Trichuris trichiura (0,5%). Os Maxakali vivem em condições de vulnerabilidade social, e medidas de infraestrutura e de educação em saúde necessitam ser implementadas pelas instituições governamentais

Characterization of the crystallographic preferred orientation relationships of the magnetite-hematite-goethite phase transformation during martitization

The most frequent crystallographic preferred orientations developed during the progressive phase transformation of magnetite-hematite-goethite are described and analyzed in two natural samples of banded iron formations from Carajás Mineral Province. Microtextures of martitized grains containing the three phases and the microplaty matrix were analyzed in a scanning electron microscope equipped with a detector for electron backscatter diffraction. For identifying the correlation between magnetite, hematite and goethite lattice and topotaxity during transformation, multiple orientation relationships between the three phases were tested and verified using three-dimensional misorientation analysis. The results show that basal planes of goethite coincide with basal planes of hematite, which coincide with octahedral planes of magnetite. This indicates that transformation between the three minerals happens topotactically, and the oxygen lattice framework is preserved in all members of the reaction as a form of crystallographic memory. As a result of progressive and cyclical changes in oxidation/reduction conditions, an assemblage of high-order orientation relationships is observed and assigned to a complex process of transformation twinning in-between phase transformation of magnetite, hematite and goethite. In the N4WS iron ore deposit, iron oxides/hydroxides from martitized grains work as susceptible markers of environmental changes still in solid state during the diagenetic process.Instituto de Geociências (IG

Characterization of the Crystallographic Preferred Orientation Relationships of the Magnetite-Hematite-Goethite Phase Transformation during Martitization

The most frequent crystallographic preferred orientations developed during the progressive phase transformation of magnetite-hematite-goethite are described and analyzed in two natural samples of banded iron formations from Carajás Mineral Province. Microtextures of martitized grains containing the three phases and the microplaty matrix were analyzed in a scanning electron microscope equipped with a detector for electron backscatter diffraction. For identifying the correlation between magnetite, hematite and goethite lattice and topotaxity during transformation, multiple orientation relationships between the three phases were tested and verified using three-dimensional misorientation analysis. The results show that basal planes of goethite coincide with basal planes of hematite, which coincide with octahedral planes of magnetite. This indicates that transformation between the three minerals happens topotactically, and the oxygen lattice framework is preserved in all members of the reaction as a form of crystallographic memory. As a result of progressive and cyclical changes in oxidation/reduction conditions, an assemblage of high-order orientation relationships is observed and assigned to a complex process of transformation twinning in-between phase transformation of magnetite, hematite and goethite. In the N4WS iron ore deposit, iron oxides/hydroxides from martitized grains work as susceptible markers of environmental changes still in solid state during the diagenetic process

Characterization of the Crystallographic Preferred Orientation Relationships of the Magnetite-Hematite-Goethite Phase Transformation during Martitization

The most frequent crystallographic preferred orientations developed during the progressive phase transformation of magnetite-hematite-goethite are described and analyzed in two natural samples of banded iron formations from Carajás Mineral Province. Microtextures of martitized grains containing the three phases and the microplaty matrix were analyzed in a scanning electron microscope equipped with a detector for electron backscatter diffraction. For identifying the correlation between magnetite, hematite and goethite lattice and topotaxity during transformation, multiple orientation relationships between the three phases were tested and verified using three-dimensional misorientation analysis. The results show that basal planes of goethite coincide with basal planes of hematite, which coincide with octahedral planes of magnetite. This indicates that transformation between the three minerals happens topotactically, and the oxygen lattice framework is preserved in all members of the reaction as a form of crystallographic memory. As a result of progressive and cyclical changes in oxidation/reduction conditions, an assemblage of high-order orientation relationships is observed and assigned to a complex process of transformation twinning in-between phase transformation of magnetite, hematite and goethite. In the N4WS iron ore deposit, iron oxides/hydroxides from martitized grains work as susceptible markers of environmental changes still in solid state during the diagenetic process

Losses regarding the return of stool samples for parasitological examination.

<p>Losses regarding the return of stool samples for parasitological examination.</p

Characteristics of children from cistern group compared with children from comparison group.

a<p>The children's classification was considered in the first stage (332 children in cistern group and 332 children in comparison group).</p