Hydraulic conductivity in response to exchangeable sodium percentage and solution salt concentration

Hydraulic conductivity is determined in laboratory assays to estimate the flow of water in saturated soils. However, the results of this analysis, when using distilled or deionized water, may not correspond to field conditions in soils with high concentrations of soluble salts. This study therefore set out to determine the hydraulic conductivity in laboratory conditions using solutions of different electrical conductivities in six soils representative of the State of Pernambuco, with the exchangeable sodium percentage adjusted in the range of 5-30%. The results showed an increase in hydraulic conductivity with both decreasing exchangeable sodium percentage and increasing electrical conductivity in the solution. The response to the treatments was more pronounced in soils with higher proportion of more active clays. Determination of hydraulic conductivity in laboratory is routinely performed with deionized or distilled water. However, in salt affected soils, these determinations should be carried out using solutions of electrical conductivity different from 0 dS m-1, with values close to those determined in the saturation extracts.

The impact of improvement of water supply and sanitation facilities on diarrhea and intestinal parasites: a Brazilian experience with children in two low-income urban communities

During the second half of 1986 the impact of the improvement of water supply and excreta disposal facilities on diarrheal diseases and intestinal parasitosis was studied in 254 children up to six years of age from two favelas (shanty towns) of Belo Horizonte, Brazil. The estimated incidence of diarrhea was 6.2 episodes/child year and the estimated period prevalence reached 31.0 episode days/ child/ year. The point prevalence of parasitosis was 70.7% (Ascaris lumbricoides: 55.4%, Trichuris trichiura: 19.6%, Giardia lamblia: 17.9%). The estimated prevalence of diarrhea decreased with improvement of water supply and sanitation facilities to 45% and 44% respectively, but no statistically significant impact was observed in the case of parasitosis. School education and weaning practice were found to be other important determinants of diarrhea.

Analysis of antidiarrhoeic effect of plants used in popular medicine

People customarily use the extracts of plants known to have antidiarrhoeal effects without any scientific base to explain the action of the extract. For this reason, an investigation was undertaken with a view to determining the efficacy of the effects of the brute aqueous extract (BAE) of the leaves of Psidium guajava (guava), Stachytarpheta cayenensis (bastard vervain), Polygonum punctatum (water. smartweed), Eugenia uniflora (Brazil or Surinam cherry) and Aster squamatus (zé-da-silva) on the intestinal transport of water in rats and on the gastrointestinal propulsion in mice. With the exception of the BAE of S. cayenensis, all other BAE's have increased the absorption of water in one or more intestinal portion in relation to the control group. All tested BAE, except that of P. punctatum, reduced the gastrointestinal propulsion in relation to that of the control group. The results indicate that the BAE of the leaves of P. guajava, S. cayenensis, P. punctatum, E. uniflora and A. squamatus have a potential antidiarrhoeic effect to be confirmed by additional investigations in animals infected with enteropathogenic agents.

Environmental impact on the bacteriological quality of domestic water supplies in Lagos, Nigeria

OBJECTIVE: To assess the impact of town planning, infrastructure, sanitation and rainfall on the bacteriological quality of domestic water supplies. METHODS: Water samples obtained from deep and shallow wells, boreholes and public taps were cultured to determine the most probable number of Escherichia coli and total coliform using the multiple tube technique. Presence of enteric pathogens was detected using selective and differential media. Samples were collected during both periods of heavy and low rainfall and from municipalities that are unique with respect to infrastructure planning, town planning and sanitation. RESULTS: Contamination of treated and pipe distributed water was related with distance of the collection point from a utility station. Faults in pipelines increased the rate of contamination (p<0.5) and this occurred mostly in densely populated areas with dilapidated infrastructure. Wastewater from drains was the main source of contamination of pipe-borne water. Shallow wells were more contaminated than deep wells and boreholes and contamination was higher during period of heavy rainfall (p<0.05). E. coli and enteric pathogens were isolated from contaminated supplies. CONCLUSIONS: Poor town planning, dilapidated infrastructure and indiscriminate siting of wells and boreholes contributed to the low bacteriological quality of domestic water supplies. Rainfall accentuated the impact.

Microbiological quality of drinking water of urban and rural communities, Brazil

OBJECTIVE: To evaluate the microbiological quality of treated and untreated water samples came from urban and rural communities and to examine the relationship between coliforms occurrence and average water temperature, and a comparison of the rainfall levels. METHODS: A sample of 3,073 untreated and treated (chlorinated) water from taps (1,594), reservoir used to store treated water (1,033), spring water (96) and private well (350) collected for routine testing between 1996 and 1999 was analyzed by the multiple dilution tube methods used to detect the most probable number of total and fecal coliforms. These samples were obtained in the region of Maringá, state of Paraná, Brazil. RESULTS: The highest numbers water samples contaminated by TC (83%) and FC (48%) were found in the untreated water. TC and FC in samples taken from reservoirs used to store treated water was higher than that from taps midway along distribution lines. Among the treated water samples examined, coliform bacteria were found in 171 of the 1,033 sampling reservoirs. CONCLUSIONS: Insufficient treatment or regrowth is suggested by the observation that more than 17% of these treated potable water contained coliform. TC and FC positive samples appear to be similar and seasonally influenced in treated water. Two different periods must be considered for the occurrence of both TC and FC positive samples: (i) a warm-weather period (September-March) with high percentage of contaminated samples; and (ii) cold-weather period (April-August) were they are lower. Both TC and TF positive samples declined with the decreased of water temperature.

Anaphylaxis with Schistosoma mansoni extracts in normal and infected mice

Methods generally utilized for studies on anaphylaxis to protein antigens such as determination of histamine release to the blood, hemoconcentration, histamine release from peritoneal mast cells and passive cutaneous anaphylaxis (PCA) were used to investigate some aspects of the anaphylaxis to parasite antigens in Schistosoma mansoni infected mice. The release of histamine to the blood and significant rates of hemoconcentration were induced by intravenous injection of schistosomula or cercarial extracts into 10-13 weeks infected mice. Cercarial, schistosomula, worm tegument and soluble egg antigens were able to trigger histamine release from peritoneal mast cells from chronically infected mice. In spite of the PCA reaction beeing detected within 2 hours of sensitization (IgG1antibodies) in 6 of 8 tested sera from chronically infected mice, no detectable reactions were obtained after 48 hours sensitization (IgE antibodies). Although IgE was not detected in the circulation, by the PCA technique, the results indicate that the infected mice contained IgE antibodies bound to their mast cells.

Water-contact patterns and schistosoma mansoni infection in a rural community in northeast Brazil

We evaluated the influence of water-related human activities, contaminative behaviour, house location, education and socio-economic status on endemic Schistosoma mansoni infection. The study was conducted in a hilry non-irrigated area of rural northeast Brazil amongst a defined population of subsistence farmers, of whom 93% were infected by age 20. The area was mapped, water bodies were surveyed, and a detailed questionnaire was performed on each household. Infection was assessed by duplicate stool examinations using the sensitive Bell technique to quantify egg excretion. For each household, and index of intensity of infection was computed by grouping individual log-transformed egg counts as an age-sex adjusted Z score. Few households had a sanitary installation or a domestic water supply. However, neither water-contact nor contaminative behavior were indiscriminate. The people made considerable effort to defaecate far from a water source, to obtain household drinking water from the cleanest source, and to bathe only at certain sites where privacy is assured. Land ownership and literacy correlated poorly with the household index of intensity of infection. The key influence on infection status was the relative location of the house and snail-free or snail colonized water sources. In this area, a safe domestic water supply is the critical input needed to achieve definitive control of endemic Schistosomiasis.

A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil

Associations between socio-demographic factors, water contact patterns and Schistosoma mansoni infection were investigated in 506 individuals (87% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino), aiming at determining priorities for public health measures to prevent the infection. Those who eliminated S. mansoni eggs (n = 198) were compared to those without eggs in the stools (n = 308). The following explanatory variables were considered: age, sex, color, previous treatment with schistosomicide, place of birth, quality of the houses, water supply for the household, distance from houses to stream, and frequency and reasons for water contact. Factors found to be independently associated with the infection were age (10-19 and > 20 yrs old), and water contact for agricultural activities, fishing, and swimming or bathing (Adjusted relative odds = 5.0, 2.4, 3.2, 2.1 and 2.0, respectively). This suggests the need for public health measures to prevent the infection, emphasizing water contact for leisure and agricultural activities in this endemic area.

Malaria serology: performance of six Plasmodium falciparum antigen extracts and of three ways of determining serum titers in IgG and IgM-ELISA

The study evaluated six Plasmodium falciparum antigen extracts to be used in the IgG and IgM enzyme-linked immunosorbent assays (ELISA), for malaria diagnosis and epidemiological studies. Results obtained with eighteen positive and nine negative control sera indicated that there were statistically significant differences among these antigen extracts (Multifactor ANOVA, p< 0.0001). Urea, sodium deoxycholate and Zwittergent antigen extracts performed better than did the three others, their features being very similar for the detection of IgG antibodies. Urea, alkaline and sodium deoxycholate antigen extracts proved to be better than the others for the detection of IgM antibodies. A straight line relationship was found between the optical densities (or their respective log 10) and the log 10 of antibody dilutions, with a very constant slope. Thus serum titers could be determined by direct titration and by two different equations, needing only one serum dilution. For IgM antibody detections, log 10 expression gave results that better correlated with direct titration (95% Bonferroni). For IgG antibody detections, the titer differences were not significant. The reproducibility of antibody titers and antigen batches was also evaluated, giving satisfactory results.

REACTIVITY OF ANTI-GP43 ANTIBODIES FROM PARACOCCIDIOIDES BRASILIENSIS ANTISERUM WITH EXTRACTS FROM CUTANEOUS LESIONS OF LOBO'S DISEASE: PRELIMINARY NOTE

We demonstrated through several immunochemical tests the presence of GP-43 from P. brasiliensis in extracts of cutaneous lesions from Jorge Lobo's disease. This glicoprotein is one of the immunodominant antigens in this species, and is used to identify it. The demonstration of GP-43 tissues infected by the agent of Jorge Lobo's disease is an additional evidence for classifying it in the genera Paracoccidioides, species loboi

Water-contact patterns and risk factors for Schistosoma mansoni infection in a rural village of Northeast Brazil

Schistosomiasis mansoni in the Serrano village, municipality of Cururupu, state of Maranhão, Brazil, is a widely spread disease. The PECE (Program for the Control of Schistosomiasis), undertaken since 1979 has reduced the prevalence of S. mansoni infection and the hepatosplenic form of the disease. Nevertheless piped water is available in 84% of the households, prevalence remains above 20%. In order to identify other risk factors responsible for the persistence of high prevalence levels, a cross-sectional survey was carried out in a systematic sample of 294 people of varying ages. Socioeconomic, environmental and demographic variables, and water contact patterns were investigated. Fecal samples were collected and analyzed by the Kato-Katz technique. Prevalence of S. mansoni infection was 24.1%, higher among males (35.5%) and between 10-19 years of age (36.6%). The risk factors identified in the univariable analysis were water contacts for vegetable extraction (Risk Ratio - RR = 2.92), crossing streams (RR = 2.55), bathing (RR = 2.35), fishing (RR = 2.19), hunting (RR = 2.17), cattle breeding (RR = 2.04), manioc culture (RR = 1.90) and leisure (RR = 1.56). After controlling for confounding variables by proportional hazards model the risks remained higher for males, vegetable extraction, bathing in rivers and water contact in rivers or in periodically inundated parts of riverine woodland (swamplands)

Evaluation of the allergenicity of spore and mycelia extracts of Pisolithus tinctorius

The antigenic and allergenic chemical analysis of spore and mycelia extracts of Pisolithus tinctorius was carried out. The spores were collected from basidiocarps in plantations of Eucalyptus spp and the mycelia from culture in MNM medium. With basis on the fungus growth curve, the mycelia masses were obtained after 10, 20, 30, and 40 days of incubation, which correspond, respectively, to the beginning, middle and end of the log phase, and beginning of the decline phase. The mycelia masses, together with the spores, were submitted to the action of three extractors (Coca, Tris-HCl, and ammonium bicarbonate). The contents of carbohydrates and proteins were determined. The SDS-PAGE electrophoretical analysis revealed separate fractions in these extracts, besides common fractions, in function of cultivation time and extraction methods. The selected extracts for the allergic tests were the ones with the highest number of fractions. The prick-tests were conducted in 374 patients – rural workers, eucalyptus plantation works and college students. The positivity to the "prick test" with the antigenic extract of P. tinctorius was, respectively, 3.78%, 28.20% and 6.40%. Most prick-test positive patients (82.75%) also presented symptoms of respiratory allergy (asthma and rhinitis). There was no reactivity difference when the spore and mycelia extracts were employed. The analysis of the positive patients’ sera revealed the presence of IgE specific to the P. tinctorius antigens. Since Pisolithus tinctorius is found as mycorrhyza of Eucalyptus spp, and this plant is used in reforestation in most countries, the importance of that fungus should be regarded as a possible cause of respiratory allergies, especially in occupationally exposed workers

QUESTIONNAIRES IN THE SCREENING FOR Schistosoma mansoni INFECTION: A STUDY OF SOCIO DEMOGRAPHIC AND WATER CONTACT VARIABLES IN FOUR COMMUNITIES IN BRAZIL

The use of questionnaires has been recommended for identifying, at a lower cost, individuals at risk for schistosomiasis. In this study, validity of information obtained by questionnaire in the screening for Schistosoma mansoni infection was assessed in four communities in the State of Minas Gerais, Brazil. Explanatory variables were water contact activities, sociodemographic characteristics and previous treatment for schistosomiasis. From 677, 1474, 766 and 3290 individuals eligible for stool examination in the communities, 89 to 97% participated in the study. The estimated probability of individuals to be infected, if they have all characteristics identified as independently associated with S.mansoni infection, varied from 15% in Canabrava, to 42% in Belo Horizonte, 48% in Comercinho and 80% in São José do Acácio. Our results do not support the hypothesis that a same questionnaire on risk factors could be used in screening for S.mansoni infection in different communities.

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia river, Campinas, Brazil

Cryptosporidium parvum and Giardia duodenalis are waterborne parasites that have caused several outbreaks of gastrointestinal disease associated with drinking water. Due to the lack of studies about the occurrence of these protozoa in water in the Southeast of Brazil, an investigation was conducted to verify the presence of cysts and oocysts in superficial raw water of the Atibaia River. The water samples were submitted to membrane filtration (3.0 mum) and elution was processed by (1) scraping and rinsing of membrane (RM method) and (2) acetone-dissolution (ADM method). Microbiologic and chemical parameters were analyzed. Aliquots of the pellets were examined by immunofluorescence (Merifluor, Meridian Diagnostics, Cincinnati, Ohio). All water samples were positive for Cryptosporidium and Giardia, in spite of the high turbidity. Higher recovery rates occurred in samples treated by the RM method than by the ADM technique. The goal for future work is the assessment of viability of cysts and oocysts to determine the public health significance of this finding.

Antibacterial activity of GUAVA, Psidium guajava Linnaeus, leaf extracts on diarrhea-causing enteric bacteria isolated from Seabob shrimp, Xiphopenaeus kroyeri (Heller)

Guava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.