Hepatitis E Virus Seroprevalence and Associated Risk Factors in Pregnant Women Attending Antenatal Consultations in Senegal.

In West Africa, research on the hepatitis E virus (HEV) is barely covered, despite the recorded outbreaks. The low level of access to safe water and adequate sanitation is still one of the main factors of HEV spread in developing countries. HEV infection induces acute or sub-clinical liver diseases with a mortality rate ranging from 0.5 to 4%. The mortality rate is more alarming (15 to 25%) among pregnant women, especially in the last trimester of pregnancy. Herein, we conducted a multicentric socio-demographic and seroepidemiological survey of HEV in Senegal among pregnant women. A consecutive and non-redundant recruitment of participants was carried out over the period of 5 months, from March to July 2021. A total of 1227 consenting participants attending antenatal clinics responded to a standard questionnaire. Plasma samples were collected and tested for anti-HEV IgM and IgG by using the WANTAI HEV-IgM and IgG ELISA assay. The overall HEV seroprevalence was 7.8% (n = 96), with 0.5% (n = 6) and 7.4% (n = 91) for HEV IgM and HEV IgG, respectively. One of the participant samples was IgM/IgG-positive, while four were declared indeterminate to anti-HEV IgM as per the manufacturer's instructions. From one locality to another, the seroprevalence of HEV antibodies varied from 0 to 1% for HEV IgM and from 1.5 to 10.5% for HEV IgG. The data also showed that seroprevalence varied significantly by marital status (p < 0.0001), by the regularity of income (p = 0.0043), and by access to sanitation services (p = 0.0006). These data could serve as a basis to setup national prevention strategies focused on socio-cultural, environmental, and behavioral aspects for a better management of HEV infection in Senegal.

Remediation of a marine shore tailings deposit and the importance of water-rock interaction on element cycling in the coastal aquifer.

We present the study of the geochemical processes associated with the first successful remediation of a marine shore tailings deposit in a coastal desert environment (Bahía de Ite, in the Atacama Desert of Peru). The remediation approach implemented a wetland on top of the oxidized tailings. The site is characterized by a high hydraulic gradient produced by agricultural irrigation on upstream gravel terraces that pushed river water (∼500 mg/L SO(4)) toward the sea and through the tailings deposit. The geochemical and isotopic (δ(2)H(water) and δ(18)O(water), δ(34)S(sulfate), δ(18)O(sulfate)) approach applied here revealed that evaporite horizons (anhydrite and halite) in the gravel terraces are the source of increased concentrations of SO(4), Cl, and Na up to ∼1500 mg/L in the springs at the base of the gravel terraces. Deeper groundwater interacting with underlying marine sequences increased the concentrations of SO(4), Cl, and Na up to 6000 mg/L and increased the alkalinity up to 923 mg/L CaCO(3) eq. in the coastal aquifer. These waters infiltrated into the tailings deposit at the shelf-tailings interface. Nonremediated tailings had a low-pH oxidation zone (pH 1-4) with significant accumulations of efflorescent salts (10-20 cm thick) at the surface because of upward capillary transport of metal cations in the arid climate. Remediated tailings were characterized by neutral pH and reducing conditions (pH ∼7, Eh ∼100 mV). As a result, most bivalent metals such as Cu, Zn, and Ni had very low concentrations (around 0.01 mg/L or below detection limit) because of reduction and sorption processes. In contrast, these reducing conditions increased the mobility of iron from two sources in this system: (1) The originally Fe(III)-rich oxidation zone, where Fe(III) was reduced during the remediation process and formed an Fe(II) plume, and (2) reductive dissolution of Fe(III) oxides present in the original shelf lithology formed an Fe-Mn plume at 10-m depth. These two Fe-rich plumes were pushed toward the shoreline where more oxidizing and higher pH conditions triggered the precipitation of Fe(III)hydroxide coatings on silicates. These coatings acted as a filter for the arsenic, which naturally infiltrated with the river water (∼500 µg/L As natural background) into the tailings deposit.

Statistical assessment of variability of terminal restriction fragment length polymorphism analysis applied to complex microbial communities.

The variability of terminal restriction fragment polymorphism analysis applied to complex microbial communities was assessed statistically. Recent technological improvements were implemented in the successive steps of the procedure, resulting in a standardized procedure which provided a high level of reproducibility.

Microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine waste.

The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) 'oxidation zone' characterized by low-pH (2.5-4), a 'neutralization zone' (70-80 to 300-400 cm) and an unaltered 'primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (10(9) g(-1) dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium-like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment.