Can economic indicators predict infectious disease spread? A cross-country panel analysis of 13 European countries.

Aims: It is unclear how economic factors impact on the epidemiology of infectious disease. We evaluated the relationship between incidence of selected infectious diseases and economic factors, including economic downturn, in 13 European countries between 1970 and 2010. Methods: Data were obtained from national communicable disease surveillance centres. Negative binomial forms of the generalised additive model (GAM) and the generalised linear model were tested to see which best reflected transmission dynamics of: diphtheria, pertussis, measles, meningococcal disease, hepatitis B, gonorrhoea, syphilis, hepatitis A and salmonella. Economic indicators were gross domestic product per capita (GDPpc), unemployment rates and (economic) downturn. Results: GAM models produced the best goodness-of-fit results. The relationship between GDPpc and disease incidence was often non-linear. Strength and directions of association between population age, tertiary education levels, GDPpc and unemployment were disease dependent. Overdispersion for almost all diseases validated the assumption of a negative binomial relationship. Downturns were not independently linked to disease incidence. Conclusions: Social and economic factors can be correlated with many infections. However, the trend is not always in the same direction, and these associations are often non-linear. Economic downturn or recessions as indicators of increased disease risk may be better replaced by GDPpc or unemployment measures.

Selecting Household Water Treatment Options on the Basis of World Health Organization Performance Testing Protocols.

The World Health Organization's International Scheme to Evaluate Household Water Treatment Technologies serves to benchmark microbiological performance of existing and novel technologies and processes for small-scale drinking water treatment according to a tiered system. There is widespread uncertainty around which tiers of performance are most appropriate for technology selection and recommendation in humanitarian response or for routine safe water programming. We used quantitative microbial risk assessment (QMRA) to evaluate attributable reductions in diarrheal disease burden associated with water treatment technologies meeting the three tiers of performance under this Scheme, across a range of conditions. According to mean estimates and under most modeling conditions, potential health gains attributable to microbiologically improved drinking water are realized at the middle tier of performance: "comprehensive protection: high pathogen removal (★★)" for each reference pathogen. The highest tier of performance may yield additional marginal health gains where untreated water is especially contaminated and where adherence is 100%. Our results highlight that health gains from improved efficacy of household water treatment technology remain marginal when adherence is less than 90%. While selection of water treatment technologies that meet minimum WHO efficacy recommendations for comprehensive protection against waterborne pathogens is critical, additional criteria for technology choice and recommendation should focus on potential for correct, consistent, and sustained use.

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.

Carrying water may be a major contributor to disability from musculoskeletal disorders in low income countries: a cross-sectional survey in South Africa, Ghana and Vietnam.

BACKGROUND: The Sustainable Development Goals include commitments to end poverty, and promote education for all, gender equality, the availability of water and decent work for all. An important constraint is the fact that each day, many millions of women and children, and much less frequently men, carry their household's water home from off-plot sources. The burden of fetching water exacerbates gender inequality by keeping women out of education and paid employment. Despite speculation about the potential health impacts of fetching water, there is very little empirical evidence. We report the first large study of the health impacts of carrying water on women and children. METHODS: A cross-sectional survey was conducted in South Africa, Ghana and Vietnam during 2012. It investigated water carrying methods and health status. Because areas of self-reported pain were correlated we undertook factor analysis of sites of reported pain, to interpret patterns of pain reporting. Regression analysis using Generalised Estimating Equations (GEE) investigated water carrying as a risk factor for general health and self-reported pain. RESULTS: People who previously carried water had increased relative risk of reporting pain in the hands (risk ratio RR 3.62, 95% confidence interval CI 1.34 to 9.75) and upper back (RR 2.27, 95% CI 1.17 to 4.40), as did people who currently carry water (RR hand pain 3.11, 95% CI 1.34 to 7.23; RR upper back pain 2.16, 95% CI 1.25 to 3.73). The factor analysis results indicate that factor 1, 'axial compression', which is correlated with pain in the head and upper back, chest/ribs, hands, feet and abdomen/stomach, is associated with currently (0.30, 95% CI 0.17 to 0.43) or previously (0.21, 95% CI 0.01 to 0.42) carrying water. Factor 2, 'soft tissue strain', which is correlated with pain in the neck, shoulders/arms, lower back and hips/pelvis or legs, is marginally negatively associated with currently (-0.18, 95% CI -0.32 to -0.04) carrying water. The factor 'axial compression' was more strongly associated with carrying water containers on the head. CONCLUSIONS: Participants who reported a history of current or past water carrying more frequently reported pain in locations most likely to be associated with sustained spinal axial compression in the cervical region. Given the fact that cervical spinal conditions are globally one of the more common causes of disability, our findings suggest that water carrying, especially by head loading is a major contributing factor in musculoskeletal disease burden in low income countries. Our findings support the proposed indicator for monitoring SDG6.1: "Percentage of population using safely managed drinking water services at home."

How Do Households Respond to Unreliable Water Supplies? A Systematic Review.

Although the Millennium Development Goal (MDG) target for drinking water was met, in many developing countries water supplies are unreliable. This paper reviews how households in developing countries cope with unreliable water supplies, including coping costs, the distribution of coping costs across socio-economic groups, and effectiveness of coping strategies in meeting household water needs. Structured searches were conducted in peer-reviewed and grey literature in electronic databases and search engines, and 28 studies were selected for review, out of 1643 potentially relevant references. Studies were included if they reported on strategies to cope with unreliable household water supplies and were based on empirical research in developing countries. Common coping strategies include drilling wells, storing water, and collecting water from alternative sources. The choice of coping strategies is influenced by income, level of education, land tenure and extent of unreliability. The findings of this review highlight that low-income households bear a disproportionate coping burden, as they often engage in coping strategies such as collecting water from alternative sources, which is labour and time-intensive, and yields smaller quantities of water. Such alternative sources may be of lower water quality, and pose health risks. In the absence of dramatic improvements in the reliability of water supplies, a point of critical avenue of enquiry should be what coping strategies are effective and can be readily adopted by low income households.

Assessing rural small community water supply in Limpopo, South Africa: water service benchmarks and reliability.

Although a number of studies have reported on water supply improvements, few have simultaneously taken into account the reliability of the water services. The study aimed to assess whether upgrading water supply systems in small rural communities improved access, availability and potability of water by assessing the water services against selected benchmarks from the World Health Organisation and South African Department of Water Affairs, and to determine the impact of unreliability on the services. These benchmarks were applied in three rural communities in Limpopo, South Africa where rudimentary water supply services were being upgraded to basic services. Data were collected through structured interviews, observations and measurement, and multi-level linear regression models were used to assess the impact of water service upgrades on key outcome measures of distance to source, daily per capita water quantity and Escherichia coli count. When the basic system was operational, 72% of households met the minimum benchmarks for distance and water quantity, but only 8% met both enhanced benchmarks. During non-operational periods of the basic service, daily per capita water consumption decreased by 5.19l (p<0.001, 95% CI 4.06-6.31) and distances to water sources were 639 m further (p ≤ 0.001, 95% CI 560-718). Although both rudimentary and basic systems delivered water that met potability criteria at the sources, the quality of stored water sampled in the home was still unacceptable throughout the various service levels. These results show that basic water services can make substantial improvements to water access, availability, potability, but only if such services are reliable.

Health impact of small-community water supply reliability.

There is still debate and uncertainty in the literature about the health benefits of community water supply interventions. This paper reports on a changing incidence of self-reported diarrhoea associated with the implementation of two community water supplies. We conducted prospective weekly recording of diarrhoeal disease in three communities. Two of the communities were scheduled to receive an improved water supply and one was expected to continue to rely on an unimproved source during the study period. Data of self-reported diarrhoea was collected from each participating household on a weekly basis for up to 56 weeks, of which some 17 weeks were prior to implementation of the new water supply systems. Data was modelled using Generalized Estimating Equations (GEE) to account for possible clustering within households and within villages. For the two intervention communities in the study, the incidence rate ratio (IRR) for all ages after the intervention was 0.43 (95% CI 0.24-0.79) when compared to the control community (who did not receive an intervention), implying a 57% reduction of diarrhoea. Both of the new water systems were unreliable, one not operating on 4 weeks and the other on 16 weeks. The more reliable of the two intervention systems was also associated with less illness than in the least reliable system (IRR=0.41, 95% CI 0.21-0.80). We also noted anecdotal reports that during supply failures in the new systems some people were starting to use household water treatment. The implementation of improved water systems does appear to have been associated with a reduction of diarrhoeal disease in the communities. However the health impact was most obvious in the community with the more reliable system. Further research needs to be done to determine whether public health gains from community water supply interventions can be leveraged by occasional use of household water treatment (HWT) during supply failures.