Acute diarrhea in adults consulting a general practitioner in France during winter: incidence, clinical characteristics, management and risk factors

International audienceBackgroundData describing the epidemiology and management of viral acute diarrhea (AD) in adults are scant. The objective of this study was to identify the incidence, clinical characteristics, management and risk factors of winter viral AD in adults.MethodsThe incidence of AD in adults during two consecutive winters (from December 2010 to April 2011 and from December 2011 to April 2012) was estimated from the French Sentinelles network. During these two winters, a subset of Sentinelles general practitioners (GPs) identified and included adult patients who presented with AD and who filled out a questionnaire and returned a stool specimen for virological examination. All stool specimens were tested for astrovirus, group A rotavirus, human enteric adenovirus, and norovirus of genogroup I and genogroup II. Age- and sex-matched controls were included to permit a case¿control analysis with the aim of identifying risk factors for viral AD.ResultsDuring the studied winters, the average incidence of AD in adults was estimated to be 3,158 per 100,000 French adults (95% CI [2,321 ¿ 3,997]). The most reported clinical signs were abdominal pain (91.1%), watery diarrhea (88.5%), and nausea (83.3%). GPs prescribed a treatment in 95% of the patients with AD, and 80% of the working patients with AD could not go to work. Stool examinations were positive for at least one enteric virus in 65% (95% CI [57 ¿ 73]) of patients with AD with a predominance of noroviruses (49%). Having been in contact with a person who has suffered from AD in the last 7 days, whether within or outside the household, and having a job (or being a student) were risk factors significantly associated with acquiring viral AD.ConclusionsDuring the winter, AD of viral origin is a frequent disease in adults, and noroviruses are most often the cause. No preventable risk factor was identified other than contact with a person with AD. Thus, at the present time, reinforcement of education related to hand hygiene remains the only way to reduce the burden of disease

Improving incidence estimation in practice-based sentinel surveillance networks using spatial variation in general practitioner density

Abstract Background In surveillance networks based on voluntary participation of health-care professionals, there is little choice regarding the selection of participants’ characteristics. External information about participants, for example local physician density, can help reduce bias in incidence estimates reported by the surveillance network. Methods There is an inverse association between the number of reported influenza-like illness (ILI) cases and local general practitioners (GP) density. We formulated and compared estimates of ILI incidence using this relationship. To compare estimates, we simulated epidemics using a spatially explicit disease model and their observation by surveillance networks with different characteristics: random, maximum coverage, largest cities, etc. Results In the French practice-based surveillance network – the “Sentinelles” network – GPs reported 3.6% (95% CI [3;4]) less ILI cases as local GP density increased by 1 GP per 10,000 inhabitants. Incidence estimates varied markedly depending on scenarios for participant selection in surveillance. Yet accounting for change in GP density for participants allowed reducing bias. Applied on data from the Sentinelles network, changes in overall incidence ranged between 1.6 and 9.9%. Conclusions Local GP density is a simple measure that provides a way to reduce bias in estimating disease incidence in general practice. It can contribute to improving disease monitoring when it is not possible to choose the characteristics of participants

Classification of Spatiotemporal Data for Epidemic Alert Systems: Monitoring Influenza-Like Illness in France

Voir aussi dépôt du preprint : https://hal.archives-ouvertes.fr/hal-02562668v2International audienceSurveillance data used by epidemic alert systems are typically fully aggregated in space at the national level. However, epidemics may be spatially heterogeneous, undergoing distinct dynamics in distinct regions of the surveillance area. We unveiled this in retrospective analyses by classifying incidence time series. We used Pearson correlation to quantify the similarity between local time series and then classified them using modularity maximization. The surveillance area was thus divided into regions with different incidence patterns. We analyzed 31 years (1985-2016) of data on influenza-like illness from the French Sentinelles system and found spatial heterogeneity in 19 of 31 influenza seasons. However, distinct epidemic regions could be identified only 4-5 weeks after a nationwide alert. The impact of spatial heterogeneity on influenza epidemiology was complex. First, when a nationwide alert was triggered, 32%-41% of the administrative regions of France were experiencing an epidemic, while the others were not. Second, the nationwide alert was timely for the whole surveillance area, but subsequently regions experienced distinct epidemic dynamics. Third, the epidemic dynamics were homogeneous in space. Spatial heterogeneity analyses can provide information on the timing of the peak and end of the epidemic, in various regions, for use in tailoring disease monitoring and control

Etude biotique et abiotique de l'habitat préférentiel de l'écrevisse à pattes blanches (Austropotamobius pallipes) dans l'ouest de la France (implications pour sa gestion et sa conservation)

De novembre 2002 à décembre 2005, l'habitat préférentiel de l'écrevisse indigène à pattes blanches (Austropotamobius pallipes) a été défini dans le " pays de Gâtine " (Deux-Sèvres, France). Pour cette étude, huit cours d'eau, répartis dans quatre bassins hydrographiques différents, ont été sélectionnés. Sur chaque ruisseau, deux points de prélèvement ont été choisis : le premier, le plus en amont, était situé au niveau de la population d'A. pallipes et le second, 2 à 3 km en aval, était dépourvu d'écrevisse à pattes blanches. Vingt-trois paramètres physico-chimiques, concernant les composantes minérale et organique de l'eau, ont été très régulièrement mesurés et quatre prélèvements de la faune de macroinvertébrés benthiques ont été réalisés. Ce suivi a permis d'acquérir une importante base de données pour caractériser les tolérances d'A. pallipes vis-à-vis de certains paramètres ce qui nous a conduit à discuter son statut de bioindicateur de la qualité des eaux. L'utilisation d'analyses multivariées (Analyse en Composantes Principales majoritairement) a montré (i) que la matière organique serait un des facteurs discriminants dans la présence/absence d'A. pallipes et (ii) que, précisément, la présence d'A. pallipes est associée à celle de familles de macroinvertébrés les plus sensibles aux pollutions organiques. L'ACP a aussi permis de réduire considérablement le nombre de paramètres abiotiques et biotiques informatifs. De plus, l'utilisation de ces paramètres sélectionnés pour modéliser par Réseaux de Neurones Artificiels (RNA) la présence/absence d'A. pallipes a fourni des résultats satisfaisants et prometteurs en terme de gestion et de conservation de cette espèce menacée.From November 2002 to December 2005, the preferential habitat of the indigenous white-clawed crayfish (Austropotamobius pallipes) was determined in the Pays de Gâtine (Deux-Sèvres, France). For this study, eight brooks, from four different catchments, were selected. Two sampling sites were monitored per brook; the first being where the population was present and the second 2 to 3 km downstream of the population. Twenty-three physico-chemical parameters, concerning both mineral and organic water components, were regularly measured as well as four samplings of benthic macroinvertebrate fauna. This study made it possible to build up a large data base characterizing the tolerance levels of A. pallipes with respect to certain parameters, which led us to discuss its status as a bioindicator of water quality. The use of multivariate analysis (mainly Principal Component Analysis) showed (i) that organic matter seems to discriminate A. pallipes presence/absence and (ii) that A. pallipes presence is closely associated with the occurrence of some families of macroinvertebrates which are very sensitive to organic pollution. PCA also permitted us to considerably reduce the number of abiotic and biotic parameters considered. In addition, the use of these selected parameters to model A. pallipes presence/absence with Artificial Neural Networks (ANN) showed interesting and promising results for the management and the conservation of this threatened species.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Vaccination against varicella as post-exposure prophylaxis in adults: A quantitative assessment

International audienceBACKGROUND: Varicella can be severe in adults. When universal vaccination is not adopted, post-exposure prophylaxis has been recommended in adults with uncertain history of varicella to reduce the burden of the disease in adults, however its impact is not quantified.METHODS:We developed a Bayesian probabilistic framework to estimate the impact of post-exposure prophylaxis in adults. We hypothesized that post-exposure vaccination would be proposed only after varicella exposure in close relatives. Information regarding the nature of the culprit exposure was obtained from a sample of 221 adult varicella cases. The lifelong probability that adults aged 18 would be infected with varicella was determined using data from the French Sentinelles surveillance network. Estimates of post-exposure vaccination efficacy were then used to compute the number of cases and hospitalizations prevented in adults.RESULTS:Familial exposure to varicella was reported by 81 adult cases out of 221. The probability of infection after exposure was 32%, so that six exposures on average were necessary to explain the observed cumulated lifetime incidence of varicella in non-immune 18 years old and over adults. Among the 35% of the 18 years old population with uncertain history of varicella, 11% would truly be non-immune. Post-exposure vaccination would prevent 26% of the cases (13 cases prevented per 100,000 adults per year) and 31% of the hospitalizations (0.2 hospitalizations prevented per 100,000 adults per year) if vaccination acceptance was 70%. An average of 16 adults would be vaccinated to avert one varicella case.CONCLUSIONS:Post-exposure vaccination is associated with a substantial decrease in the burden of the disease in adults in a country where universal vaccination is not recommended. This quantitative information may help inform professionals to uphold the recommendation

Infection par le virus Bluetongue sérotype 8 et performances dans les troupeaux bovins laitiers

National audienceL’émergence de la fièvre catarrhale ovine, due au virus Bluetongue sérotype 8 (BTV-8) en Europe du Nord en 2006 a causé des pertes économiques en élevage bovin. Une vaccination a été mise en place en France sans évaluation ex ante du ratio bénéfice/risque. Les pertes causées par la maladie et les potentiels effets secondaires de la vaccination n’ont pas été précisément estimés. Les objectifs de cet article sont de quantifier les effets moyens de l’exposition au BTV-8 en conditions naturelles sur les performances de production et de reproduction des vaches laitières (1) dans les troupeaux déclarés foyers, (2) dans les troupeaux non déclarés foyers situés dans la zone d’épizootie et (3) de quantifier un potentiel effet secondaire de la vaccination contre le BTV-8 sur la fertilité. Les effets de l’exposition et de la vaccination sur les performances ont été quantifiés à l’aide de modèles statistiques multivariés permettant de prendre en compte les facteurs connus influençant les performances. L’exposition des troupeaux au BTV-8 est associée à une diminution de la fertilité (entre 5 et 16 points de pour cent de retours 90 jours) et de la production de lait (3 % de la production annuelle). Une baisse de fertilité dans les troupeaux non foyers situés en zone exposée suggère qu’une partie de ces troupeaux pourrait avoir été infectée durant l’épizootie. La vaccination contre le BTV-8 avec un vaccin inactivé est associée à une légère diminution de la fertilité (4 points de pour cent de retours 3 semaines) dont l’impact est très limité par rapport à celui de l’exposition. Ces résultats peuvent contribuer à l’évaluation de stratégies de maîtrise et de surveillance du BT

Improving disease incidence estimates in primary care surveillance systems

International audienceBackground:In primary care surveillance systems based on voluntary participation, biased results may arise fromthe lack of representativeness of the monitored population and uncertainty regarding the population denominator,especially in health systems where patient registration is not required.Methods:Based on the observation of a positive association between number of cases reported and number ofconsultations by the participating general practitioners (GPs), we define several weighted incidence estimatorsusing external information on consultation volume in GPs. These estimators are applied to data reported in aFrench primary care surveillance system based on voluntary GPs (theSentinellesnetwork) for comparison.Results:Depending on hypotheses for weight computations, relative changes in weekly national-level incidenceestimates up to 3% for influenza, 6% for diarrhea, and 11% for varicella were observed. The use of consultation-weightedestimates led to bias reduction in the estimates. At the regional level (NUTS2 level -Nomenclature of Statistical TerritorialUnits Level 2), relative changes were even larger betweenincidence estimates, with changes between -40% and +55%.Using bias-reduced weights decreased variation in incidence between regions and increased spatial autocorrelation.Conclusions:Post-stratification using external administrative data may improve incidence estimates in surveillancesystems based on voluntary participatio

Cross-validation of an algorithm detecting acute gastroenteritis episodes from prescribed drug dispensing data in France: comparison with clinical data reported in a primary care surveillance system, winter seasons 2014/15 to 2016/17

International audienceBackground: This study compares an algorithm to detect acute gastroenteritis (AG) episodes from drug dispensing data to the validated data reported in a primary care surveillance system in France.Methods: We used drug dispensing data collected in a drugstore database and data collected by primary care physicians involved in a French surveillance network, from season 2014/15 to 2016/17. We used an adapted version of an AG discrimination algorithm to identify AG episodes from the drugstore database. We used Pearson’s correlation coefficient to evaluate the agreement between weekly AG signals obtained from the two data sources during winter months, in the overall population, by specific age-groups and by regions.Results: Correlations between AG signals for all ages were 0.84 [95%CI 0.69; 0.92] for season 2014/15, 0.87 [95%CI 0.75; 0.93] for season 2015/16 and 0.94 [95%CI 0.88; 0.97] for season 2016/17. The association between AG signals estimated from two data sources varied significantly across age groups in season 2016/17 (p-value < 0.01), and across regions in all three seasons studied (p-value < 0.01).Conclusions: There is a strong agreement between the dynamic of AG activity estimated from drug dispensing data and from validated primary care surveillance data collected during winter months in the overall population but the agreement is poorer in several age groups and in several regions. Once automated, the reuse of drug dispensing data, already collected for reimbursement purposes, could be a cost-efficient method to monitor AG activity at the national level