Intrinsic Vulnerability of Human-Water Contact Sites to Contamination with Schistosoma mansoni Ova in an Endemic Focus in Western Kenya

Human intestinal schistosomiasis caused by Schistosoma mansoni occurs in localized foci restricted to specific vector sub population areas. The molluscan vectors, Biomphalaria spp, have a widespread distribution within the lake region and elsewhere in Kenya, but the disease is endemic only in areas with certain physical characteristics and risk factors. A comprehensive study was conducted in Budalangi endemic focus of Western Kenya between May 2006 and June 2008 to determine the bionomics of intestinal schistosomiasis transmission with regards to proximity to various contact sites relative to contamination of ova of the worm in the vector breeding habitats with a view of instituting a deworming programme in primary schools. A survey of sanitation relative to presence, distribution and/or absence of latrines was conducted in the whole study area. The main human contact sites were identified and checked for the possibility of contamination with human stool. Distance of the main human water contact site from sampled homesteads without latrines was estimated and recorded within three categories. Vector snails were sampled from four permanent water habitats using standard procedures. Only 30.5% of the homesteads surveyed had pit latrines (c2; p<0.05) and 70.1% of them were situated less than 100m from various water contact sites. The actual density of vector snails and their mean counts per 10 scoops from the different sites in each type of breeding habitat varied widely (One way ANOVA; Lake Victoria: F = 8.11, df (5, 66), p<0.05; Dam: F = 3.65, df(7, 88), p<0.05; River Nzoia: F = 0.54, df (2, 33), p > 0.05; F = 6.76, df (3, 44), p<0.05) showing that their role in harbouring the vector snails and transmission of intestinal schistosomiasis was variable. However the mean vector snail count from all the different habitats showed no significant difference between them being suggestive of the fact that the four habitats were equally important for the purposes of vector breeding in the study area (One way ANOVA; F= 1.32, df(3, 17); p > 0.051). The study showed that there was a continuous low level of contamination of S. mansoni ova in area among the various other habitats in addition to the lake and that they were equally vulnerable. This information has a bearing on planning and implementing combined mass treatment of people who reside in the study area and vector control programmes in an integrated venture. Keywords: Vulnerability, Contact sites, Contamination, Schistosoma mansoni ov

The impact of a school-based hygiene, water quality and sanitation intervention on soil-transmitted helminth reinfection: a cluster-randomized trial.

We conducted a cluster-randomized trial to assess the impact of a school-based water treatment, hygiene, and sanitation program on reducing infection with soil-transmitted helminths (STHs) after school-based deworming. We assessed infection with STHs at baseline and then at two follow-up rounds 8 and 10 months after deworming. Forty government primary schools in Nyanza Province, Kenya were randomly selected and assigned to intervention or control arms. The intervention reduced reinfection prevalence (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.31-1.00) and egg count (rate ratio [RR] 0.34, CI 0.15-0.75) of Ascaris lumbricoides. We found no evidence of significant intervention effects on the overall prevalence and intensity of Trichuris trichiura, hookworm, or Schistosoma mansoni reinfection. Provision of school-based sanitation, water quality, and hygiene improvements may reduce reinfection of STHs after school-based deworming, but the magnitude of the effects may be sex- and helminth species-specific

Consequences of prenatal geophagy for maternal prenatal health, risk of childhood geophagy and child psychomotor development

Objective To investigate the relationship between prenatal geophagy, maternal prenatal haematological indices, malaria, helminth infections and cognitive and motor development among offspring. Methods: At least a year after delivery, 552 of 863 HIV-negative mothers with singleton births who completed a clinical trial comparing the efficacy of sulfadoxine-pyrimethamine and mefloquine during pregnancy in Allada, Benin, responded to a nutrition questionnaire including their geophagous habits during pregnancy. During the clinical trial, helminth infection, malaria, haemoglobin and ferritin 3 concentrations were assessed at 1st and 2nd antenatal care visits (ANV) and at delivery. After the first ANV, women were administered daily iron and folic acid supplements until three months postdelivery. Singleton children were assessed for cognitive function at age 1 year using the Mullen Scales of Early Learning. Results: The prevalence of geophagy during pregnancy was 31.9%. Pregnant women reporting geophagy were more likely to be anaemic (AOR = 1.9, 95% CI [1.1, 3.4]) at their first ANV if they reported geophagy at the first trimester. Overall, prenatal geophagy was not associated with maternal haematological indices, malaria or helminth infections, but geophagy during the third trimester and throughout pregnancy was associated with poor motor function (AOR = -3.8, 95% CI [-6.9, -0.6]) and increased odds of geophagous behaviour in early childhood, respectively. Conclusions: Prenatal geophagy is not associated with haematological indices in the presence of micronutrient supplementation. However, it may be associated with poor child motor function and infant geophagy. Geophagy should be screened early in pregnancy

Toward a Comprehensive Approach to the Collection and Analysis of Pica Substances, with Emphasis on Geophagic Materials

Pica, the craving and subsequent consumption of non-food substances such as earth, charcoal, and raw starch, has been an enigma for more than 2000 years. Currently, there are little available data for testing major hypotheses about pica because of methodological limitations and lack of attention to the problem.In this paper we critically review procedures and guidelines for interviews and sample collection that are appropriate for a wide variety of pica substances. In addition, we outline methodologies for the physical, mineralogical, and chemical characterization of these substances, with particular focus on geophagic soils and clays. Many of these methods are standard procedures in anthropological, soil, or nutritional sciences, but have rarely or never been applied to the study of pica.Physical properties of geophagic materials including color, particle size distribution, consistency and dispersion/flocculation (coagulation) should be assessed by appropriate methods. Quantitative mineralogical analyses by X-ray diffraction should be made on bulk material as well as on separated clay fractions, and the various clay minerals should be characterized by a variety of supplementary tests. Concentrations of minerals should be determined using X-ray fluorescence for non-food substances and inductively coupled plasma-atomic emission spectroscopy for food-like substances. pH, salt content, cation exchange capacity, organic carbon content and labile forms of iron oxide should also be determined. Finally, analyses relating to biological interactions are recommended, including determination of the bioavailability of nutrients and other bioactive components from pica substances, as well as their detoxification capacities and parasitological profiles.This is the first review of appropriate methodologies for the study of human pica. The comprehensive and multi-disciplinary approach to the collection and analysis of pica substances detailed here is a necessary preliminary step to understanding the nutritional enigma of non-food consumption

Study of e+e−→ppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

Using 2917 $\rm{pb}^{-1}$ of data accumulated at 3.773~$\rm{GeV}$, 44.5~$\rm{pb}^{-1}$ of data accumulated at 3.65~$\rm{GeV}$ and data accumulated during a $\psi(3770)$ line-shape scan with the BESIII detector, the reaction $e^+e^-\rightarrow p\bar{p}$ is studied considering a possible interference between resonant and continuum amplitudes. The cross section of $e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}$, $\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p})$, is found to have two solutions, determined to be ($0.059\pm0.032\pm0.012$) pb with the phase angle $\phi = (255.8\pm37.9\pm4.8)^\circ$ ($<$0.11 pb at the 90% confidence level), or $\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12$) pb with $\phi = (266.9\pm6.1\pm0.9)^\circ$ both of which agree with a destructive interference. Using the obtained cross section of $\psi(3770)\rightarrow p\bar{p}$, the cross section of $p\bar{p}\rightarrow \psi(3770)$, which is useful information for the future PANDA experiment, is estimated to be either ($9.8\pm5.7$) nb ($<17.2$ nb at 90% C.L.) or $(425.6\pm42.9)$ nb

The effects of maternal and infant vitamin A supplementation on vitamin A status: a randomised trial in Kenya.

Postpartum vitamin A supplementation of mothers and infants is recommended, but the efficacy has been questioned. In this double-blind, placebo-controlled trial, Kenyan mother-infant pairs were randomised to maternal vitamin A (400,000 IU) or placebo 0.06%) at 26 weeks, vitamin A to infants, but not mothers, resulted in a lower proportion of infants with deficient vitamin A stores (69 v. 78 %). High-dose postpartum vitamin A supplementation failed to increase serum retinol and infant stores, despite modest effects on milk retinol. Infant supplementation, however, increased stores. There is a need for a better understanding of factors affecting absorption and metabolism of vitamin A