Relationship between ozone and temperature during the 2003 heat wave in France: consequences for health data analysis

BACKGROUND: PAPRICA is a research program designed to estimate the impact on the health of patients with chronic respiratory insufficiency of a prevention strategy based on notification of ozone pollution. The first year of this study was conducted during the 2003 heat wave, and high temperatures were therefore considered as a confounding factor in the data analysis. The aim of the present study was to assess the relationship between ozone and temperature in order to propose a methodology to distinguish between the effects of ozone and temperature on the impact of a prevention strategy with regard to ozone pollution. METHODS: Multivariate analyses were used to identify associated climate and ozone pollution profiles. This descriptive method is of great value to highlight the complexity of interactions between these parameters. RESULTS: Ozone concentration and temperature were strongly correlated, but the health impact of ozone pollution alone will be evaluated by focusing on situations characterized by ozone concentrations above 110 μg/m(3)/8h (air quality guidelines to protect human health defined by the French legislation) and temperatures lower than 26°C, below the discomfort threshold. CONCLUSION: The precise relationship between ambient ozone concentration and temperature identified during the PAPRICA 2003 study period will be used in analysing the PAPRICA health data

Post-Epidemic Chikungunya Disease on Reunion Island: Course of Rheumatic Manifestations and Associated Factors over a 15-Month Period

Although the acute manifestations of Chikungunya virus (CHIKV) illness are well-documented, few data exist about the long-term rheumatic outcomes of CHIKV-infected patients. We undertook between June and September 2006 a retrospective cohort study aimed at assessing the course of late rheumatic manifestations and investigating potential risk factors associated with the persistence of these rheumatic manifestations over 15 months. 147 participants (>16 yrs) with laboratory-confirmed CHIKV disease diagnosed between March 1 and June 30, 2005, were identified through a surveillance database and interviewed by telephone. At the 15-month-period evaluation after diagnosis, 84 of 147 participants (57%) self-reported rheumatic symptoms. Of these 84 patients, 53 (63%) reported permanent trouble while 31 (37%) had recurrent symptoms. Age ≥45 years (OR = 3.9, 95% CI 1.7–9.7), severe initial joint pain (OR = 4.8, 95% CI 1.9–12.1), and presence of underlying osteoarthritis comorbidity (OR = 2.9, 95% CI 1.1–7.4) were predictors of nonrecovery. Our findings suggest that long-term CHIKV rheumatic manifestations seem to be a frequent underlying post-epidemic condition. Three independent risk factors that may aid in early recognition of patients with the highest risk of presenting prolonged CHIKV illness were identified. Such findings may be particularly useful in the development of future prevention and care strategies for this emerging virus infection

An alternative pathway for alphavirus entry

The study of alphavirus entry has been complicated by an inability to clearly identify a receptor and by experiments which only tangentially and indirectly examine the process, producing results that are difficult to interpret. The mechanism of entry has been widely accepted to be by endocytosis followed by acidification of the endosome resulting in virus membrane-endosome membrane fusion. This mechanism has come under scrutiny as better purification protocols and improved methods of analysis have been brought to the study. Results have been obtained that suggest alphaviruses infect cells directly at the plasma membrane without the involvement of endocytosis, exposure to acid pH, or membrane fusion. In this review we compare the data which support the two models and make the case for an alternative pathway of entry by alphaviruses

[Decision tools for selecting industrial sites where a systematic blood lead screening should be implemented].

International audienceBACKGROUND: Children exposure to lead, even at low doses, can induce neurobehavioral and cognitive effects. In France, a consensus conference about lead poisoning in children has recently stated that exposure near an industrial site was a priority for blood lead screening. Selection criteria for industrial sites have therefore to be defined, especially because screening for lead poisoning requires a blood lead sample, that is an invasive procedure. METHODS: We propose here an operational procedure to select sites where systematic blood lead screenings have to be implemented. It is based on modeling blood lead levels of children aged 1-6 years. This is made by indirect dose estimation from environmental measurements, human exposure parameters and a dose/blood lead level relationship. Decision criteria are based on mean and extreme predicted blood lead level. The procedure is illustrated with a real life smelter case study. RESULTS: For the studied smelter, estimated blood lead levels are less than 100 microg(Pb)/l(blood) and therefore do not lead to recommend a systematic blood lead screening. CONCLUSIONS: Indirect dose estimation associated with blood lead level modeling is a useful tool for selecting where blood lead screenings have to be implemented around industrial sites. Possible improvements of the method are listed

[Decision tools for selecting industrial sites where a systematic blood lead screening should be implemented].

International audienceBACKGROUND: Children exposure to lead, even at low doses, can induce neurobehavioral and cognitive effects. In France, a consensus conference about lead poisoning in children has recently stated that exposure near an industrial site was a priority for blood lead screening. Selection criteria for industrial sites have therefore to be defined, especially because screening for lead poisoning requires a blood lead sample, that is an invasive procedure. METHODS: We propose here an operational procedure to select sites where systematic blood lead screenings have to be implemented. It is based on modeling blood lead levels of children aged 1-6 years. This is made by indirect dose estimation from environmental measurements, human exposure parameters and a dose/blood lead level relationship. Decision criteria are based on mean and extreme predicted blood lead level. The procedure is illustrated with a real life smelter case study. RESULTS: For the studied smelter, estimated blood lead levels are less than 100 microg(Pb)/l(blood) and therefore do not lead to recommend a systematic blood lead screening. CONCLUSIONS: Indirect dose estimation associated with blood lead level modeling is a useful tool for selecting where blood lead screenings have to be implemented around industrial sites. Possible improvements of the method are listed

Lessons raised by the major 2010 dengue epidemics in the French West Indies

International audienceDengue fever has been endemo-epidemic in the whole Region of America. In 2010, Guadeloupe and Martinique experienced historical epidemics, with an estimated attack rate of 10% in two islands. When considering the temporal evolution of epidemiological indicators, an unusual increase in the number of dengue cases could be detected very early. Two main factors might have facilitated the settlement of a viral transmission despite the dry season: a low immunity of the population against the circulating serotype and particular climatic conditions, notably very high temperatures which could have improved both virus and vector efficiency. This unusual situation was considered as a warning sign, and indeed led to major outbreaks in both islands a few weeks later. This event underlines that follow-up of epidemiological indicators is necessary to detect the unusual situations as soon as possible. Furthermore, development of biological and modelling tools should be promoted, as well as integrated management strategies for dengue prevention and control

Local and regional spread of chikungunya fever in the Americas

Chikungunya fever (CHIKV), a viral disease transmitted by mosquitoes, is currently affecting several areas in the Caribbean. The vector is found in the Americas from southern Florida to Brazil, and the Caribbean is a highly connected region in terms of population movements. There is therefore a significant risk for the epidemic to quickly expand to a wide area in the Americas. Here, we describe the spread of CHIKV in the first three areas to report cases and between areas in the region. Local transmission of CHIKV in the Caribbean is very effective, the mean number of cases generated by a human case ranging from two to four. There is a strong spatial signature in the regional epidemic, with the risk of transmission between areas estimated to be inversely proportional to the distance rather than driven by air transportation. So far, this simple distance-based model has successfully predicted observed patterns of spread. The spatial structure allows ranking areas according to their risk of invasion. This characterisation may help national and international agencies to optimise resource allocation for monitoring and control and encourage areas with elevated risks to act

Local and regional spread of chikungunya fever in the Americas

International audienceChikungunya fever (CHIKV), a viral disease transmitted by mosquitoes, is currently affecting several areas in the Caribbean. The vector is found in the Americas from southern Florida to Brazil, and the Caribbean is a highly connected region in terms of population movements. There is therefore a significant risk for the epidemic to quickly expand to a wide area in the Americas. Here, we describe the spread of CHIKV in the first three areas to report cases and between areas in the region. Local transmission of CHIKV in the Caribbean is very effective, the mean number of cases generated by a human case ranging from two to four. There is a strong spatial signature in the regional epidemic, with the risk of transmission between areas estimated to be inversely proportional to the distance rather than driven by air transportation. So far, this simple distance-based model has successfully predicted observed patterns of spread. The spatial structure allows ranking areas according to their risk of invasion. This characterisation may help national and international agencies to optimise resource allocation for monitoring and control and encourage areas with elevated risks to act