In vivo imaging of the tonoplast intrinsic protein family in Arabidopsis roots

Background: Tonoplast intrinsic proteins (TIPs) are widely used as markers for vacuolar compartments in higher plants. Ten TIP isoforms are encoded by the Arabidopsis genome. For several isoforms, the tissue and cell specific pattern of expression are not known. Results: We generated fluorescent protein fusions to the genomic sequences of all members of the Arabidopsis TIP family whose expression is predicted to occur in root tissues (TIP1;1 and 1;2; TIP2;1, 2;2 and 2;3; TIP4;1) and expressed these fusions, both individually and in selected pairwise combinations, in transgenic Arabidopsis. Analysis by confocal microscopy revealed that TIP distribution varied between different cell layers within the root axis, with extensive co-expression of some TIPs and more restricted expression patterns for other isoforms. TIP isoforms whose expression overlapped appeared to localise to the tonoplast of the central vacuole, vacuolar bulbs and smaller, uncharacterised structures. Conclusion: We have produced a comprehensive atlas of TIP expression in Arabidopsis roots, which reveals novel expression patterns for not previously studied TIPs

Have we substantially underestimated the impact of improved sanitation coverage on child health?:A generalized additive model panel analysis of global data on child mortality and malnutrition

Background: Although widely accepted as being one of the most important public health advances of the past hundred years, the contribution that improving sanitation coverage can make to child health is still unclear, especially since the publication of two large studies of sanitation in India which found no effect on child morbidity. We hypothesis that the value of sanitation does not come directly from use of improved sanitation but from improving community coverage. If this is so we further hypothesise that the relationship between sanitation coverage and child health will be non-linear and that most of any health improvement will accrue as sanitation becomes universal. Methods: We report a fixed effects panel analysis of country level data using Generalized Additive Models in R. Outcome variables were under 5 childhood mortality, neonatal mortality, under 5 childhood mortality from diarrhoea, proportion of children under 5 with stunting and with underweight. Predictor variables were % coverage by improved sanitation, improved water source, Gross Domestic Product per capita and Health Expenditure per capita. We also identified three studies reporting incidence of diarrhoea in children under five alongside gains in community coverage in improved sanitation. Findings: For each of the five outcome variables, sanitation coverage was independently associated with the outcome but this association was highly non-linear. Improving sanitation coverage was very strongly associated with under 5 years diarrhoea mortality, under 5years all-cause mortality, and all-cause neonatal mortality. There was a decline as sanitation coverage increased up to about 20% but then no further decline was seen until about 70% (60% for diarrhoea mortality and 80% for neonatal mortality, respectively). The association was less strong for stunting and underweight but a threshold about 50% coverage was also seen. Three large trials of sanitation on diarrhoea morbidity gave results that were similar to what would have been predicted by our model. Conclusions: Improving sanitation coverage may be one of the more effective means to reduce childhood mortality, but only if high levels of community coverage are achieved. Studies of the impact of sanitation that focus on the individual’s use of improved sanitation as the predictor variable rather than community coverage is likely to severely underestimate the impact of sanitation

Multi-locus analysis of human infective Cryptosporidium species and subtypes using ten novel genetic loci

Background: Cryptosporidium is a protozoan parasite that causes diarrheal illness in a wide range of hosts including humans. Two species, C. parvum and C. hominis are of primary public health relevance. Genome sequences of these two species are available and show only 3-5% sequence divergence. We investigated this sequence variability, which could correspond either to sequence gaps in the published genome sequences or to the presence of species-specific genes. Comparative genomic tools were used to identify putative species-specific genes and a subset of these genes was tested by PCR in a collection of Cryptosporidium clinical isolates and reference strains. Results: The majority of the putative species-specific genes examined were in fact common to C. parvum and C. hominis. PCR product sequence analysis revealed interesting SNPs, the majority of which were species-specific. These genetic loci allowed us to construct a robust and multi-locus analysis. The Neighbour-Joining phylogenetic tree constructed clearly discriminated the previously described lineages of Cryptosporidium species and subtypes. Conclusions: Most of the genes identified as being species specific during bioinformatics in Cryptosporidium sp. are in fact present in multiple species and only appear species specific because of gaps in published genome sequences. Nevertheless SNPs may offer a promising approach to studying the taxonomy of closely related species of Cryptosporidia

What is the impact of water sanitation and hygiene in healthcare facilities on care seeking behaviour and patient satisfaction? A systematic review of the evidence from low-income and middle-income countries

Patient satisfaction with healthcare has clear implications on service use and health outcomes. Barriers to care seeking are complex and multiple and delays in seeking care are associated with significant morbidity and mortality. We sought to assess the relationship between water, sanitation and hygiene (WASH) provision in healthcare facilities (HCF) and patient satisfaction/care seeking behaviour in low-income and middle-income countries. Pubmed and Medline Ovid were searched using a combination of search terms. 984 papers were retrieved and only 21 had a WASH component warranting inclusion. WASH was not identified as a driver of patient satisfaction but poor WASH provision was associated with significant patient dissatisfaction with infrastructure and quality of care. However, this dissatisfaction was not sufficient to stop patients from seeking care in these poorly served facilities. With specific regard to maternal health services, poor WASH provision was the reason for women choosing home delivery, although providers’ attitudes and interpersonal behaviours were the main drivers of patient dissatisfaction with maternal health services. Patient satisfaction was mainly assessed via questionnaires and studies reported a high risk of courtesy bias, potentially leading to an overestimation of patient satisfaction. Patient satisfaction was also found to be significantly affected by expectation, which was strongly influenced by patients’ socioeconomic status and education. This systematic review also highlighted a paucity of research to describe and evaluate interventions to improve WASH conditions in HCF in low-income setting with a high burden of healthcare-associated infections. Our review suggests that improving WASH conditions will decrease patience dissatisfaction, which may increase care seeking behaviour and improve health outcomes but that more rigorous research is needed

Reliability of water supplies in low and middle-income countries: A structured review of definitions and assessment criteria

The unreliability of water supplies in developing countries is a widely recognized concern. However, unreliability means different things in the variety of literature on water supplies, and no unified definition or assessment criteria exist. We review definitions of water supply reliability used in existing literature, as well as the various ways in which it is assessed. Thirty-three papers were selected for review that reported on reliability of domestic water supply and if they were based on empirical research in developing countries. Explicit definitions of reliability are given in four out of the 33 papers reviewed. These definitions vary, but features common in them are the functionality of the water supply system itself, and the extent to which it meets the needs of water users. Assessment criteria also vary greatly, with the most common criterion in urban settings being the duration / continuity of supply in hours per day, while in rural settings, the proportion of functional water systems is commonly used. The heterogeneity in the definitions and assessment criteria found in the review is perhaps indicative of a multi-attribute nature of the concept of reliability and any unifying definition and assessment criteria might do well to take this into account

A re-assessment of the safety of silver in household water treatment: rapid systematic review of mammalian in vivo genotoxicity studies

Background: Despite poor evidence of their effectiveness, colloidal silver and silver nanoparticles are increasingly being promoted for treating potentially contaminated drinking water in low income countries. Recently, however, concerns have been raised about the possible genotoxicity of particulate silver. Objectives: The goal of this paper was to review the published mammalian in vivo genotoxicity studies using silver micro and nanoparticles. Methods: SCOPUS and Medline were searched using the following search string: (“DNA damage” OR genotox* OR Cytotox* OR Embryotox*) AND (silver OR AgNP). Included papers were any mammalian in vivo experimental studies investigating genotoxicity of silver particles. Studies were quality assessed using the ToxRTool. Results: 16 relevant papers were identified. There were substantial variations in study design including the size of silver particles, animal species, target organs, silver dose, route of administration and the method used to detect genotoxicity. Thus, it was not possible to produce a definitive pooled result. Nevertheless, most studies showed evidence of genotoxicity unless using very low doses. We also identified one human study reporting evidence of “severe DNA damage” in silver jewellery workers occupationally exposed to silver particles. Conclusions: With the available evidence it is not possible to be definitive about risks to human health from oral exposure to silver particulates. However, the balance of evidence suggests that there should be concerns especially when considering the evidence from jewellery workers. There is an urgent need to determine whether people exposed to particulate silver as part of drinking water treatment have evidence of DNA damage

An agent-based model about the effects of fake news on a norovirus outbreak

Concern about health misinformation is longstanding, especially on the Internet. Using agent-based models, we considered the effects of such misinformation on a norovirus outbreak, and some methods for countering the possible impacts of ‘good’ and ‘bad’ health advice. The work explicitly models spread of physical disease and information (both online and offline) as two separate but interacting processes. The models have multiple stochastic elements; repeat model runs were made to identify parameter values that most consistently produced the desired target baseline scenario. Next, parameters were found that most consistently led to a scenario when outbreak severity was clearly made worse by circulating poor quality disease prevention advice. Strategies to counter ‘fake’ health news were tested. A 10% reduction in circulating bad advice or making at least 20% of people fully resistant to believing in and sharing bad health advice were effective thresholds to counteract the negative impacts of bad advice during a norovirus outbreak. How feasible it is to achieve these targets within communication networks (online and offline) should be explored

Risk factors for Cryptosporidium infection in low and middle income countries: A systematic review and meta-analysis

Background: Cryptosporidium infection causes gastrointestinal disease and has a worldwide distribution. The highest burden is in developing countries. Objectives: We sought to conduct a systematic review and meta-analysis to identify Cryptosporidium risk factors in Low and Middle Income countries (LMICs). Methods: Medline Ovid and Scopus databases were searched with no restriction on year or language of publication. All references were screened independently in duplicate and were included if they presented data on at least 3 risk factors. Meta-analyses using random effects models were used to calculate overall estimates for each exposure. Results: The most frequently reported risk factors in the 15 included studies were overcrowding, household diarrhoea, poor quality drinking water, animal contact, open defecation/ lack of toilet and breastfeeding. The combined odds ratio for animal contact was 1.98 (95%CI: 1.11–3.54) based on 11 studies and for diarrhoea in the household 1.98 (95%CI: 1.13–3.49) based on 4 studies. Open defecation was associated with a pooled odds ratio of 1.82 (95%CI: 1.19–2.8) based on 5 studies. Poor drinking water quality was not associated with a significant Cryptosporidium risk, odds ratio 1.06 (95%CI: 0.77–1.47). Breastfeeding was protective with pooled odds ratio 0.4 (95%CI: 0.13–1.22), which was not statistically significant. Conclusions: Based on the included studies, crowded living conditions, animal contact and open defecation are responsible for the majority of Cryptosporidium cases in LMICs. Future studies investigating Cryptosporidium risk factors should have a good study design and duration, include appropriate number of cases, select suitable controls, investigate multiple relevant risk factors, fully report data and perform multivariate analysis

Communication, perception and behaviour during a natural disaster involving a 'Do Not Drink' and a subsequent 'Boil Water' notice:a postal questionnaire study

BackgroundDuring times of public health emergencies, effective communication between the emergency response agencies and the affected public is important to ensure that people protect themselves from injury or disease. In order to investigate compliance with public health advice during natural disasters, we examined consumer behaviour during two water notices that were issued as a result of serious flooding. During the summer of 2007, 140,000 homes in Gloucestershire, United Kingdom, that are supplied water from Mythe treatment works, lost their drinking water for up to 17 days. Consumers were issued a 'Do Not Drink' notice when the water was restored, which was subsequently replaced with a 'Boil Water' notice. The rare occurrence of two water notices provided a unique opportunity to compare compliance with public health advice. Information source use and other factors that may affect consumer perception and behaviour were also explored.MethodA postal questionnaire was sent to 1,000 randomly selected households. Chi-square, ANOVA, MANOVA and generalised estimating equation (with and without prior factor analysis) were used for quantitative analysis.ResultsIn terms of information sources, we found high use of and clear preference for the local radio throughout the incident, but family/friends/neighbours also proved crucial at the onset. Local newspapers and the water company were associated with clarity of advice and feeling informed, respectively. Older consumers and those in paid employment were particularly unlikely to read the official information leaflets. We also found a high degree of confusion regarding which notice was in place at which time, with correct recall varying between 23.2%-26.7%, and a great number of consumers believed two notices were in place simultaneously. In terms of behaviour, overall non-compliance levels were significantly higher for the 'Do Not Drink' notice (62.9%) compared to the 'Boil Water' notice (48.3%); consumers in paid employment were not likely to comply with advice. Non-compliance with the general advice to boil bowser water was noticeably lower (27.3%).ConclusionHigher non-compliance during the 'Do Not Drink' notice was traced to the public's limited knowledge of water notices and their folk beliefs about the protection offered from boiling water. We suggest that future information dissemination plans reduce reliance on official leaflets and maximise the potential of local media and personal networks. Current public health education programmes are recommended to attend to insufficient and incorrect public knowledge about precautionary actions