Drinking Water Salinity and Maternal Health in Coastal Bangladesh: Implications of Climate Change.

Background: Drinking water from natural sources in coastal Bangladesh has become contaminated by varying degrees of salinity due to saltwater intrusion from rising sea levels, cyclone and storm surges and upstream withdrawal of freshwater. Objective: Our objective was to estimate salt intake from drinking water sources and examine environmental factors that may explain a seasonal excess of hypertension in pregnancy. Methods: Water salinity data (1998-2000) for Dacope, in rural coastal Bangladesh, were obtained from the Centre for Environment and Geographic Information System. Information on drinking water sources, 24-hour urine samples and blood pressure were obtained from 343 pregnant Dacope women during the dry season (October 2009 - March 2010). The hospital-based prevalence of hypertension in pregnancy was determined for 969 pregnant women (July 2008 - March 2010). Results: Average estimated sodium intakes from drinking water ranged from 5 to 16 g/day in the dry season, compared to 0.6 - 1.2 g/day in the rainy season. Average daily sodium excretion in urine was 3.4 g/day (range 0.4 - 7.7 g/d). Women who drank shallow tubewell water were more likely to have urine sodium > 100 mmol/d than women who drank rainwater (OR=2.05, 95% CI: 1.11 - 3.80). The annual hospital prevalence of hypertension in pregnancy was higher in the dry season (12.2%, 95% CI: 9.5 - 14.8) than the rainy season (5.1%, 95% CI: 2.91 - 7.26). Conclusions: The estimated salt intake from drinking water in this population exceeded recommended limits. The problem of saline intrusion into drinking water has multiple causes and is likely to be exacerbated by climate change induced sea-level rise

Role of the cyclic lipopeptide massetolide A in biological control of Phytophthora infestans and in colonization of tomato plants by Pseudomonas fluorescens

Pseudomonas strains have shown promising results in biological control of late blight caused by Phytophthora infestans. However, the mechanism(s) and metabolites involved are in many cases poorly understood. Here, the role of the cyclic lipopeptide massetolide A of Pseudomonas fluorescens SS101 in biocontrol of tomato late blight was examined. Pseudomonas fluorescens SS101 was effective in preventing infection of tomato (Lycopersicon esculentum) leaves by P. infestans and significantly reduced the expansion of existing late blight lesions. Massetolide A was an important component of the activity of P. fluorescens SS101, since the massA-mutant was significantly less effective in biocontrol, and purified massetolide A provided significant control of P. infestans, both locally and systemically via induced resistance. Assays with nahG transgenic plants indicated that the systemic resistance response induced by SS101 or massetolide A was independent of salicylic acid signalling. Strain SS101 colonized the roots of tomato seedlings significantly better than its massA-mutant, indicating that massetolide A was an important trait in plant colonization. This study shows that the cyclic lipopeptide surfactant massetolide A is a metabolite with versatile functions in the ecology of P fluorescens SS101 and in interactions with tomato plants and the late blight pathogen P. infestans

The Immune Response to Herpes Simplex Virus Type 1 Infection in Susceptible Mice is a Major Cause of CNS Pathology Resulting in Fatal Encephalitis

This study was undertaken to investigate possible immune mechanisms in fatal HSV-1 encephalitis (HSE) after HSV-1 corneal inoculation. Susceptible 129S6 (129) but not resistant C57BL/6 (B6) mice developed intense focal inflammatory brainstem lesions of primarily F4/80+ macrophages and Gr-1+ neutrophils detectable by MRI as early as day 6 post infection (PI). Depletion of macrophages and neutrophils significantly enhanced survival of infected 129 mice. Immunodeficient B6 (IL-7R-/-Kitw41/w41) mice lacking adaptive cells (B6-E mice) transplanted with 129 bone marrow showed significantly accelerated fatal HSE compared to B6-E mice transplanted with B6 marrow or control non-transplanted B6-E mice. In contrast, there was no difference in ocular viral shedding in B6-E mice transplanted with 129 bone marrow or B6 bone marrow. Acyclovir treatment of 129 mice beginning day 4 PI (24 h after HSV-1 first reaches the brain stem) reduced nervous system viral titers to undetectable levels but did not alter brainstem inflammation or mortality. We conclude that fatal HSE in 129 mice results from widespread damage in the brainstem caused by destructive inflammatory responses initiated early in infection by massive infiltration of innate cells

The Tychonoff uniqueness theorem for the G-heat equation

In this paper, we obtain the Tychonoff uniqueness theorem for the G-heat equation

A systematic review of hot weather impacts on infant feeding practices in low-and middle-income countries

Background: Increased rates of exclusive breastfeeding could significantly improve infant survival in low- and middle-income countries. There is a concern that increased hot weather due to climate change may increase rates of supplemental feeding due to infants requiring fluids, or the perception that infants are dehydrated. Objective: To understand how hot weather conditions may impact infant feeding practices by identifying and appraising evidence that exclusively breastfed infants can maintain hydration levels under hot weather conditions, and by examining available literature on infant feeding practices in hot weather. Methods: Systematic review of published studies that met inclusion criteria in MEDLINE, EMBASE, Global Health and Web of Science databases. The quality of included studies was appraised against predetermined criteria and relevant data extracted to produce a narrative synthesis of results. Results: Eighteen studies were identified. There is no evidence among studies of infant hydration that infants under the age of 6months require supplementary food or fluids in hot weather conditions. In some settings, healthcare providers and relatives continue to advise water supplementation in hot weather or during the warm seasons. Cultural practices, socio-economic status, and other locally specific factors also affect infant feeding practices and may be affected by weather and seasonal changes themselves. Conclusion: Interventions to discourage water/other fluid supplementation in breastfeeding infants below 6 months are needed, especially in low-middle income countries. Families and healthcare providers should be advised that exclusive breastfeeding (EBF) is recommended even in hot conditions

The effectiveness of public health interventions to reduce the health impact of climate change:a systematic review of systematic reviews

Climate change is likely to be one of the most important threats to public health in the coming years. Yet despite the large number of papers considering the health impact of climate change, few have considered what public health interventions may be of most value in reducing the disease burden. We aimed to evaluate the effectiveness of public health interventions to reduce the disease burden of high priority climate sensitive diseases

The association between overall health, psychological distress, and occupational heat stress among a large national cohort of 40,913 Thai workers

Background: Occupational heat stress is a well-known problem, particularly in tropical countries, affecting workers, health and well-being. There are very few recent studies that have reported on the effect of heat stress on mental health, or overall health in workers, although socioeconomic development and rapid urbanization in tropical developing countries like Thailand create working conditions in which heat stress is likely. Objective: This study is aimed at identifying the relationship between self-reported heat stress and psychological distress, and overall health status in Thai workers. Results: 18% of our large national cohort (>40,000 subjects) often works under heat stress conditions and males are exposed to heat stress more often than females. Furthermore, working under heat stress conditions is associated with both worse overall health and psychological distress (adjusted odds ratios ranging from 1.49 to 1.84). Conclusions: This association between occupational heat stress and worse health needs more public health attention and further development on occupational health interventions as climate change increases Thailand's temperatures

Impacts of Climate Change on indirect human exposure to pathogens and chemicals from agriculture

Objective: Climate change is likely to affect the nature of pathogens and chemicals in the environment and their fate and transport. Future risks of pathogens and chemicals could therefore be very different from those of today. In this review, we assess the implications of climate change for changes in human exposures to pathogens and chemicals in agricultural systems in the United Kingdom and discuss the subsequent effects on health impacts. Data sources: In this review, we used expert input and considered literature on climate change ; health effects resulting from exposure to pathogens and chemicals arising from agriculture ; inputs of chemicals and pathogens to agricultural systems ; and human exposure pathways for pathogens and chemicals in agricultural systems. Data synthesis: We established the current evidence base for health effects of chemicals and pathogens in the agricultural environment ; determined the potential implications of climate change on chemical and pathogen inputs in agricultural systems ; and explored the effects of climate change on environmental transport and fate of different contaminant types. We combined these data to assess the implications of climate change in terms of indirect human exposure to pathogens and chemicals in agricultural systems. We then developed recommendations on future research and policy changes to manage any adverse increases in risks. Conclusions: Overall, climate change is likely to increase human exposures to agricultural contaminants. The magnitude of the increases will be highly dependent on the contaminant type. Risks from many pathogens and particulate and particle-associated contaminants could increase significantly. These increases in exposure can, however, be managed for the most part through targeted research and policy changes

Sialylation of campylobacter jejuni lipo-oligosaccharides: impact on phagocytosis and cytokine production in mice

<p>Background: Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown.</p> <p>Methodology/Principal Findings: In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-β by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC.</p> <p>Conclusions/Significance: These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS</p&gt

A comparison of weather variables linked to infectious disease patterns using laboratory addresses and patient residence addresses

Background: To understand the impact of weather on infectious diseases, information on weather parameters at patient locations is needed, but this is not always accessible due to confidentiality or data availability. Weather parameters at nearby locations are often used as a proxy, but the accuracy of this practice is not known. Methods: Daily Campylobacter and Cryptosporidium cases across England and Wales were linked to local temperature and rainfall at the residence postcodes of the patients and at the corresponding postcodes of the laboratory where the patient’s specimen was tested. The paired values of daily rainfall and temperature for the laboratory versus residence postcodes were interpolated from weather station data, and the results were analysed for agreement using linear regression. We also assessed potential dependency of the findings on the relative geographic distance between the patient’s residence and the laboratory. Results: There was significant and strong agreement between the daily values of rainfall and temperature at diagnostic laboratories with the values at the patient residence postcodes for samples containing the pathogens Campylobacter or Cryptosporidium. For rainfall, the R-squared was 0.96 for the former and 0.97 for the latter, and for maximum daily temperature, the R-squared was 0.99 for both. The overall mean distance between the patient residence and the laboratory was 11.9 km; however, the distribution of these distances exhibited a heavy tail, with some rare situations where the distance between the patient residence and the laboratory was larger than 500 km. These large distances impact the distributions of the weather variable discrepancies (i.e. the differences between weather parameters estimated at patient residence postcodes and those at laboratory postcodes), with discrepancies up to ±10 °C for the minimum and maximum temperature and 20 mm for rainfall. Nevertheless, the distributions of discrepancies (estimated separately for minimum and maximum temperature and rainfall), based on the cases where the distance between the patient residence and the laboratory was within 20 km, still exhibited tails somewhat longer than the corresponding exponential fits suggesting modest small scale variations in temperature and rainfall. Conclusion: The findings confirm that, for the purposes of studying the relationships between meteorological variables and infectious diseases using data based on laboratory postcodes, the weather results are sufficiently similar to justify the use of laboratory postcode as a surrogate for domestic postcode. Exclusion of the small percentage of cases where there is a large distance between the residence and the laboratory could increase the precision of estimates, but there are generally strong associations between daily weather parameters at residence and laboratory