Childhood lead exposure in France: benefit estimation and partial cost-benefit analysis of lead hazard control

BACKGROUND

Lead exposure remains a public health concern due to its serious adverse effects, such as cognitive and behavioral impairment: children younger than six years of age being the most vulnerable population. In Europe, the lead-related economic impacts have not been examined in detail. We estimate the annual costs in France due to childhood exposure and, through a cost benefit analysis (CBA), aim to assess the expected social and economic benefits of exposure abatement.

METHODS

Monetary benefits were assessed in terms of avoided national costs. We used results from a 2008 survey on blood-lead (B-Pb) concentrations in French children aged one to six years old. Given the absence of a threshold concentration being established, we performed a sensitivity analysis assuming different hypothetical threshold values for toxicity above 15 μg/L, 24 μg/L and 100 μg/L. Adverse health outcomes of lead exposure were translated into social burden and economic costs based on literature data from literature. Direct health benefits, social benefits and intangible avoided costs were included. Costs of pollutant exposure control were partially estimated in regard to homes lead-based paint decontamination, investments aiming at reducing industrial lead emissions and removal of all lead drinking water pipes.

RESULTS

The following overall annual benefits for the three hypothetical thresholds values in 2008 are: €22.72 billion, €10.72 billion and €0.44 billion, respectively. Costs from abatement ranged from €0.9 billion to 2.95 billion/year. Finally, from a partial CBA of lead control in soils and dust the estimates of total net benefits were € 3.78 billion, € 1.88 billion and €0.25 billion respectively for the three hypothesized B-Pb effect values.

CONCLUSIONS

Prevention of childhood lead exposure has a high social benefit, due to reduction of B-Pb concentrations to levels below 15 μg/L or 24 μg/L, respectively. Reducing only exposures above 100 μg/L B-Pb has little economic impact due to the small number of children who now exhibit such high exposure levels. Prudent public policies would help avoiding future medical interventions, limit the need for special education and increase future productivity, and hence lifetime income for children exposed to lead.

An international trial of quantitative PCR for monitoring Legionella in artificial water systems

AIMS

  To perform an international trial to derive alert and action levels for the use of quantitative PCR (qPCR) in the monitoring of Legionella to determine the effectiveness of control measures against legionellae.

METHODS AND RESULTS

  Laboratories (7) participated from six countries. Legionellae were determined by culture and qPCR methods with comparable detection limits. Systems were monitored over ≥10 weeks. For cooling towers (232 samples), there was a significant difference between the log mean difference between qPCR (GU l(-1) ) and culture (CFU l(-1) ) for Legionella pneumophila (0·71) and for Legionella spp. (2·03). In hot and cold water (506 samples), the differences were less, 0·62 for Leg. pneumophila and 1·05 for Legionella spp. Results for individual systems depended on the nature of the system and its treatment. In cooling towers, Legionella spp. GU l(-1) always exceeded CFU l(-1) , and usually Legionella spp. were detected by qPCR when absent by culture. The pattern of results by qPCR for Leg. pneumophila followed the culture trend. In hot and cold water, culture and qPCR gave similar results, particularly for Leg. pneumophila. There were some marked exceptions with temperatures ≥50°C, or in the presence of supplementary biocides. Action and alert levels for qPCR were derived that gave results comparable to the application of the European Guidelines based on culture. Algorithms are proposed for the use of qPCR for routine monitoring.

CONCLUSIONS

  Action and alert levels for qPCR can be adjusted to ensure public health is protected with the benefit that remedial actions can be validated earlier with only a small increase in the frequency of action being required.

SIGNIFICANCE AND IMPACT OF THE STUDY

  This study confirms it is possible to derive guidelines on the use of qPCR for monitoring the control of legionellae with consequent improvement to response and public health protection.

Quantitative microbial risk assessment of cryptosporidiosis and giardiasis from very small private water supplies

This article reports a quantitative microbial risk assessment of the risk of Giardia and Cryptosporidium in very small private water supplies. Both pathogens have been implicated in causing outbreaks of waterborne disease associated with such supplies, though the risk of endemic disease is not known. For exposure assessments, we used existing data to derive regression equations describing the relationships between the concentration of these pathogens and Escherichia coli in private water supplies. Pathogen concentrations were then estimated using national surveillance data of E. coli in private water supplies in England and France. The estimated risk of infection was very high with the median annual risk being of the order of 25-28% for Cryptosporidium and 0.4% to 0.7% for Giardia, though, in the poorer quality supplies the risk could be much higher. These risks are substantially greater than for public water supplies and well above the risk considered tolerable. The observation that observed infection rates are generally much lower may indicate increased immunity in people regularly consuming water from private supplies. However, this increased immunity is presumed to derive from increased disease risk in young children, the group most at risk from severe disease.

Epidemiology of MRSA and current strategies in Europe and Japan

The prevalence of health-care associated infections caused by multi-drug resistant organisms has significantly increased over the past decade. Among these organisms, Methicillin-resistant Staphylococcus aureus (MRSA) plays a prominent and increasing role. Because of consequences for patients and the economic burden in course of prolonged treatment following MRSA infections and additional indirect costs for e.g. isolation or antiseptic treatment, this trend will further damage European health-care systems.

In 2006, a workshop was initiated at the 8^th International Congress of the German Society of Hospital Hygiene held in Berlin. The aim of this workshop was to give an overview of the current situation of MRSA in selected European countries and to elaborate on potential strategies to prevent MRSA-infections and dissemination. A questionnaire encompassing 20 questions addressed topics such as epidemiology, current measures and future prospects was distributed to representatives from various European countries and Japan. A variety of widely different answers was obtained. It was shown that in all countries prevalence of MRSA is on a rising tide. This trend is observable in all European countries, albeit less strong in The Netherlands, Slovenia, France, Austria and Scandinavian countries. It was conclude that prevention strategies in a united and expanding European Community will become of utmost importance and that rapid screening strategies, e.g. PCR, might be of assistance in such an approach. A potential strategy to improve infection control measures could be the requirement of health-insurance providers to sign contracts only with hospitals able to proof having an infection control management in place.

The case for re-evaluating the upper limit value for selenium in drinking water in Europe

Selenium is an essential trace element for life, which can be toxic for humans when intakes reach a certain amount. Therefore, since the margin between healthy intake and toxic intake is narrow, the selenium concentration of tap water is a parameter that must be monitored because of its potential for increased intake. The present work gives an overview of the different approaches used to calculate safe limits for selenium. As recommended by WHO, the guidelines for drinking water form the basis of national legislated standards for drinking water. Before setting a maximum acceptable level in drinking water, it is necessary to take into account the total intake of selenium in both food and beverage. The limit value of 10 microg l(-1) for drinking water laid down in the European regulations for all countries should be adapted depending on geographic area, as previously recommended by WHO.

A prospective study of the impact of colonization following hospital admission by glycopeptide-resistant Enterococci on mortality during a hospital outbreak

BACKGROUND

This study was designed to investigate the impact on mortality of colonization by glycopeptide-resistant Enterococci (GRE) during hospitalization.

METHODS

Between 2004 and 2006, a hospital in Nancy, France, was subject to a GRE van A outbreak. Some 113 patients who had acquired GRE after hospital admission were matched with 113 controls. Basic demographic data, such as sex, age, principal pathology, history of surgery, and presence of associated pathology, were obtained for each case and control. Information on whether or not the case subject was still alive was obtained by searching the hospital mortality database and the civil death register and by phoning the patient's home. Statistical analysis used the Cox proportional hazards model for calculating survival function with SPSS software version 9.1 (SPSS Inc., Chicago, IL).

RESULTS

The mean age was 71.2 in the GRE+ group and 70.8 in the control group (P = .80). There was a significant difference between the groups for severity status health (P = .035). The mortality rate was 30.1% in the case group and 19.5% in the control group. Single predictor variable analysis showed a hazard ratio of death in the case group of 4.61 (95% confidence interval [CI]: 2.58-8.28], P = 2 x 10(-7)). The final Cox regression model with multiple predictor variables showed that only GRE presence (OR, 1.63 [95% CI: 1.04-2.57], P = .035) and severity of comorbidity (P = .013) were independently significant predictors of mortality.

CONCLUSION

This study shows that the GRE acquisition has a poor prognosis and that this is independent of the other prognostic factors such as age and severity of underlying disease. Survival in GRE+ patients was significantly shorter.

[Quantifying errors in the identification of patients' medical records in an active filing]

The aim of this study was to quantify and qualify mistaken identities in a current medical records archive. The medical records are classified by identification indexes (day and month of birth, the first letter of their surname) by category where their placement is a function of the record's status defined as "current", "semi-current" or "dead". All of the medical records marked as "current" (n=43,592), dating between 12 February 2004 to 11 March 2004, were analysed. 1397 (3.2%) contained at least one error, totalling 1456 errors, or an average of 1.04 errors per record. The errors were classified into two types: misidentification (1254 or 86.1%) and logistical errors (202 or 13.9%). 256 serious mistakes were identified as representing 17.6% of the cases. The staff costs associated with managing these errors totalled 12,408 Euro, corresponding to a cost of 8.88 Euro per error. The immediate impact is a reduction in the workload of staff directly due to the absence of the missing file. The depth of this problem was more significant than had been suggested by the indicators, both qualitatively and quantitatively. These results should be used to advocate for the implementation of a policy on continuous quality assessment (scoring the quality of the creation of the record, and scoring the intervention).

Short-term assessment of training of medical students in the use of alcohol-based hand rub using fluorescent-labeled hand rub and skin hydration measurements

This study evaluated 2 measurements of the effectiveness of alcohol-based hand rub application: skin hydration and percentage of skin area covered by fluorescent-labeled hand rub. The use of fluorescent-labeled hand rub is an effective and rapid way to assess the effectiveness of hand rub application and correlates well with the effectiveness of hand hygiene technique, as evaluated by microbial counts on the hands. Measurement of skin hydration also is correlated with effectiveness of coverage and is useful in demonstrating that alcohol-based hand rub does not dehydrate the skin.

Estimating the impact on health of poor reliability of drinking water interventions in developing countries

Recent evidence suggests that many improved drinking water supplies suffer from poor reliability. This study investigates what impact poor reliability may have on achieving health improvement targets. A Quantitative Microbiological Risk Assessment was conducted of the impact of interruptions in water supplies that forced people to revert to drinking raw water. Data from the literature were used to construct models on three waterborne pathogens common in Africa: Rotavirus, Cryptosporidium and Enterotoxigenic E. coli. Risk of infection by the target pathogens is substantially greater on days that people revert to raw water consumption. Over the course of a few days raw water consumption, the annual health benefits attributed to consumption of water from an improved supply will be almost all lost. Furthermore, risk of illness on days drinking raw water will fall substantially on very young children who have the highest risk of death following infection. Agencies responsible for implementing improved drinking water provision will not make meaningful contributions to public health targets if those systems are subject to poor reliability. Funders of water quality interventions in developing countries should put more effort into auditing whether interventions are sustainable and whether the health benefits are being achieved.

Estimating the impact on health of poor reliability of drinking water interventions in developing countries

Recent evidence suggests that many improved drinking water supplies suffer from poor reliability. This study investigates what impact poor reliability may have on achieving health improvement targets. A Quantitative Microbiological Risk Assessment was conducted of the impact of interruptions in water supplies that forced people to revert to drinking raw water. Data from the literature were used to construct models on three waterborne pathogens common in Africa: Rotavirus, Cryptosporidium and Enterotoxigenic E. coli. Risk of infection by the target pathogens is substantially greater on days that people revert to raw water consumption. Over the course of a few days raw water consumption, the annual health benefits attributed to consumption of water from an improved supply will be almost all lost. Furthermore, risk of illness on days drinking raw water will fall substantially on very young children who have the highest risk of death following infection. Agencies responsible for implementing improved drinking water provision will not make meaningful contributions to public health targets if those systems are subject to poor reliability. Funders of water quality interventions in developing countries should put more effort into auditing whether interventions are sustainable and whether the health benefits are being achieved.

Legionella bacteria in shower aerosols increase the risk of Pontiac fever among older people in retirement homes

BACKGROUND

828 elderly subjects residing in nursing homes were followed up during 4 months to ascertain incidence of symptoms associated with Pontiac fever (PF) in a non-epidemic setting.

METHODS

The exposure situation was inhalation of Legionella bacteria while showering. An audit of the hot water system in all institutions allowed ascribing each subject to a water quality area wherefrom one shower was sampled for Legionella assays at the end of the follow-up period. Legionella were detected in water and aerosols using the culture (CFU, colony forming units) and in situ hybridization (FISH) techniques.

RESULTS

Among 32 Pontiac-like episodes, 29 cases complied with the operational definition of PF elaborated for this study. Incidence density was 0.11 case/person-year (95% CI 0.07 to 0.15). Water concentrations greater than 105 Legionella FISH/l and 104 Legionella CFU/l were associated with an increased risk of PF (respectively RR 2.23, p = 0.05 and RR 2.39, p = 0.11, with significant dose-response patterns: p for trend <0.04). The condition also seems associated with aerosol concentrations above 103 Legionella FISH/l of air. A significantly higher risk of Pontiac-like episodes (RR 6.24, 95% CI 2.12 to 18.38) was seen for elderly subjects receiving corticosteroid therapy.

CONCLUSION

The water and threshold values identified in this research could be used to inform guidance measures aimed at protecting institutionalised older people from Legionnaires' disease. Immunosuppressive therapy in the same population group can significantly enhance susceptibility to Legionella bacteria.

Overview of diagnostic and detection methods for legionellosis and Legionella spp

Since 1977, the diagnostic tools for Legionnaires' disease have been based on culture and serological investigations. Both methods require considerable time to produce results and have 'low' to 'reasonable' sensitivity. Since the introduction of urinary antigen tests in the mid 1990s, underdiagnosis has diminished and mortality has declined, thanks to early diagnosis. To obtain the most accurate diagnosis, culture, serological investigation, and urinary antigen testing should all be performed. In the last decade, advances in polymerase chain reaction technology allowed the development of assays detecting Legionella nucleic acids in clinical and environmental samples. Thus far, only widely varying results with relatively small series have been reported. Furthermore, these assays which are still labour intensive and complicated are not yet practicable for the average medical and/or environmental microbiological laboratory.