Attributable risk and potential impact of interventions to reduce household air pollution associated with under-five mortality in South Asia

Abstract Background Solid fuel use is the major source of household air pollution (HAP) and accounts for a substantial burden of morbidity and mortality in low and middle income countries. To evaluate and compare childhood mortality attributable to HAP in four South Asian countries. Methods A series of Demographic and Health Survey (DHS) datasets for Bangladesh, India, Nepal and Pakistan were used for analysis. Estimates of relative risk and exposure prevalence relating to use of cooking fuel and under-five mortality were used to calculate population attributable fractions (PAFs) for each country. Potential impact fractions (PIFs) were also calculated assessing theoretical scenarios based on published interventions aiming to reduce exposure prevalence. Results There are an increased risk of under-five mortality in those exposed to cooking fuel compared to those not exposed in the four South Asian countries (OR = 1.30, 95% CI = 1.07–1.57, P = 0.007). Combined PAF estimates for South Asia found that 66% (95% CI: 43.1–81.5%) of the 13,290 estimated cases of under-five mortality was attributable to HAP. Joint PIF estimates (assuming achievable reductions in HAP reported in intervention studies conducted in South Asia) indicates 47% of neonatal and 43% of under-five mortality cases associated with HAP could be avoidable in the four South Asian countries studied. Conclusions Elimination of exposure to use of cooking fuel in the household targeting valuable intervention strategies (such as cooking in separate kitchen, improved cook stoves) could reduce substantially under-five mortality in South Asian countries

Mixed culture fermentation using Torulaspora delbrueckii and Saccharomyces cerevisiae with direct and indirect contact: impact of anaerobic growth factors

The role of the initial concentration of anaerobic growth factors (AGF) on interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae was investigated in strict anaerobiosis. Experiments were performed in a synthetic grape must medium in a membrane bioreactor, a special tool designed for studying direct and indirect interactions between microorganisms. In pure culture fermentations, increased AGF concentration had no impact on S. cerevisiae behaviour, whereas it induced an extension of T. delbrueckii latency. Surprisingly, T. delbrueckii used only 75 to 80% of the consumed sugar to produce biomass, glycerol and ethanol. Physical separation influenced the population dynamics of co-fermentations. S.cerevisiae dominated the co-cultures having a single dose of AGF as its presence indirectly induced a decrease in numbers of living T. delbrueckii cells and physical contact with T. delbrueckii stimulated S.cerevisiae growth. Increasing the AGF initial concentration completely upset this domination: S. cerevisiae growth was not stimulated and T. delbrueckii living cells did not decrease. Yeasts incorporate exogenous AGFs, which probably impact their response to competing yeasts. The increase in AGF might have induced changes in the lipid composition of the T. delbrueckii membrane, which would hinder its interaction with S. cerevisiae antimicrobial peptides. The initial concentration of anaerobic growth factors influenced co-culture fermentation population dynamics tremendously, thus highlighting a new way to monitor population evolution and eventually wine organoleptic properties

Histo-blood group antigen-binding specificities of human rotaviruses are associated with gastroenteritis but not with in vitro infection

Human strains of rotavirus A (RVAs) recognize fucosylated glycans belonging to histo-blood group antigens (HBGAs) through their spike protein VP8*. Lack of these ligands due to genetic polymorphisms is associated with resistance to gastroenteritis caused by P[8] genotype RVAs. With the aim to delineate the contribution of HBGAs in the process, we analyzed the glycan specificity of VP8* proteins from various P genotypes. Binding to saliva of VP8* from P[8] and P[4] genotypes required expression of both FUT2 and FUT3 enzymes, whilst binding of VP8* from the P[14] genotype required FUT2 and A enzymes. We further defined a glycan motif, GlcNAc beta 3Gal beta 4GlcNAc, recognized by P[6] clinical strains. Conversion into Lewis antigens by the FUT3 enzyme impaired recognition, explaining their lower binding to saliva of Lewis positive phenotype. In addition, the presence of neutralizing antibodies was associated with the presence of the FUT2 wild type allele in sera from young healthy adults. Nonetheless, in vitro infection of transformed cell lines was independent of HBGAs expression, indicating that HBGAs are not human RV receptors. The match between results from saliva-based binding assays and the epidemiological data indicates that the polymorphism of human HBGAs controls susceptibility to RVAs, although the exact mechanism remains unclear.Funding Agencies|Agence Nationale de la Recherche (France): GASTROVIM; Region des Pays de la Loire (France): ARMINA; Merieux Research Grant GOMMs; Russian Science Foundation [14-5-00131]; Swedish Research Council [320301]</p