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Background Lyme borreliosis (LB) is the most widespread hard tick-borne zoonosis in the northern hemisphere. Existing studies in Europe have focused mainly on acarological risk assessment, with few investigations exploring human LB occurrence. Aim We explored the determinants of spatial and seasonal LB variations in France from 2016 to 2021 by integrating environmental, animal, meteorological and anthropogenic factors, and then mapped seasonal LB risk predictions. Methods We fitted 2016–19 LB national surveillance data to a two-part spatio-temporal statistical model. Spatial and temporal random effects were specified using a Besag-York-Mollie model and a seasonal model, respectively. Coefficients were estimated in a Bayesian framework using integrated nested Laplace approximation. Data from 2020–21 were used for model validation. Results A high vegetation index (≥ 0.6) was positively associated with seasonal LB presence, while the index of deer presence (> 60%), mild soil temperature (15–22 °C), moderate air saturation deficit (1.5–5 mmHg) and higher tick bite frequency were associated with increased incidence. Prediction maps show a higher risk of LB in spring and summer (April–September), with higher incidence in parts of eastern, midwestern and south-western France. Conclusion We present a national level spatial assessment of seasonal LB occurrence in Europe, disentangling factors associated with the presence and increased incidence of LB. Our findings yield quantitative evidence for national public health agencies to plan targeted prevention campaigns to reduce LB burden, enhance surveillance and identify further data needs. This approach can be tested in other LB endemic areas.

SummaryBackgroundLyme Borreliosis (LB) is the most widespread hard tick-borne zoonosis in the Northern Hemisphere and shows a seasonal pattern. Existing studies in Europe mainly focused on acarological risk assessment, with very limited investigations exploring human LB occurrence. We aimed to highlight areas and seasons of higher risk for LB occurrence in mainland France, integrating information on meteorological, environmental, animal hosts and human exposure to quantify the associated spatial and temporal risk factors.MethodsWe fitted 2016–19 French LB surveillance data to a two-part spatiotemporal statistical model, defined with binomial and gamma distributions, to explore the factors associated with the presence and increased LB incidence. Shared spatial and temporal random effects were specified using a Besag-York-Mollie model and a seasonal model, respectively. Coefficients were estimated in a Bayesian framework using integrated nested Laplace approximation. Projections and data for 2020 were used for model validation.FindingsLB presence was associated with a high vegetation index (≥0·6). LB incidence increased in areas highly suitable for deer (≥80% cover per area), with mild soil temperatures (10–15°C) in the season preceding the onset, moderate air saturation deficits (3–5 mmHg), and higher proportion of tick bite reports. Prediction maps showed a higher risk of LB in spring and summer (April-September). Substantial geographical variation in LB incidence was found. Higher incidence was reported in parts of eastern, midwestern, and southwestern France.InterpretationThis is the first national-level assessment of seasonal human LB occurrence in Europe allowing to disentangle factors associated with LB presence and increased incidence. This model illustrates a spatial integrated analysis of meteorological, hosts, and anthropogenic factors for a zoonotic and vector-borne infection of major public health concern, and can be used as a reference model to be calibrated in other LB-affected areas.FundingWF is funded by a Sorbonne University PhD fellowship, JD is supported by a grant overseen by the French National Research Agency (ANR) as part of the «Investissements d’Avenir» program (ANR-11-LABX-0002-01, Lab of Excellence ARBRE).

Background: We aimed to assess the effectiveness of two doses of mRNA COVID-19 vaccines against COVID-19 with the original virus and other lineages circulating in France. Methods: In this nationwide case-control study, cases were SARS-CoV-2 infected adults with onset of symptoms between 14 February and 3 May 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire on recent activity-related exposures and vaccination history. Information about the infecting virus was based on a screening RT-PCR for either B.1.1.7 or B.1.351/P.1 variants. Findings: Included in our analysis were 7 288 adults infected with the original SARS-CoV-2 virus, 31 313 with the B.1.1.7 lineage, 2 550 with B.1.351/P1 lineages, and 3 644 controls. In multivariable analysis, the vaccine effectiveness (95% confidence interval) seven days after the second dose of mRNA vaccine was estimated at 88% (81-92), 86% (81-90) and 77% (63-86) against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively. Recent (2 to 6 months) history of virologically confirmed SARS-CoV-2 infection was found to be 83% (76-88), 88% (85-91) and 83% (71-90) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively; and more distant (> 6 months) infections were 76% (54-87), 84% (75-90), and 74% (41-89) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively. Interpretation: In real-life settings, two doses of mRNA vaccines proved to be effective against COVID-19 with the original virus, B.1.1.7 lineage and B.1.351/P.1 lineages. Funding: Institut Pasteur, Research & Action Emerging Infectious Diseases (REACTing), Fondation de France (Alliance “Tous unis contre le virus”).

Summary: Background: We aimed to assess the role of different setting and activities in acquiring SARS-CoV-2 infection. Methods: In this nationwide case-control study, cases were SARS-CoV-2 infected adults recruited between 27 October and 30 November 2020. Controls were individuals from the Ipsos market research database matched to cases by age, sex, region, population density and time period. Participants completed an online questionnaire on recent activity-related exposures. Findings: Among 3426 cases and 1713 controls, in multivariable analysis, we found an increased risk of infection associated with any additional person living in the household (adjusted-OR: 1•16; 95%CI: 1•11-1•21); having children attending day-care (aOR: 1•31; 95%CI: 1•02-1•62), kindergarten (aOR: 1•27; 95%CI: 1•09-1•45), middle school (aOR: 1•30; 95%CI: 1•15-1•47), or high school (aOR: 1•18; 95%CI: 1•05-1•34); with attending professional (aOR: 1•15; 95%CI: 1•04-1•26) or private gatherings (aOR: 1•57; 95%CI: 1•45-1•71); and with having frequented bars and restaurants (aOR: 1•95; 95%CI: 1•76-2•15), or having practiced indoor sports activities (aOR: 1•36; 95%CI: 1•15-1•62). We found no increase in risk associated with frequenting shops, cultural or religious gatherings, or with transportation, except for carpooling (aOR: 1•47; 95%CI: 1•28-1•69). Teleworking was associated with decreased risk of infection (aOR: 0•65; 95%CI: 0•56-0•75). Interpretation: Places and activities during which infection prevention and control measures may be difficult to fully enforce were those with increased risk of infection. Children attending day-care, kindergarten, middle and high schools, but not primary schools, were potential sources of infection for the household. Funding: Institut Pasteur, Research & Action Emerging Infectious Diseases (REACTing), Fondation de France (Alliance” Tous unis contre le virus”).

Chikungunya virus (CHIKV) emerged in the Caribbean island of Saint-Martin in December 2013. We implemented a hospital-based surveillance system to detect and describe CHIKV cases including severe forms of the infection and deaths in the islands of Martinique and Guadeloupe. A case was defined as a patient with a CHIKV laboratory confirmation cared for in a public hospital for chikungunya for at least 24 hours, and a severe CHIKV case was defined as a CHIKV case presenting one or more organ failures. Sociodemographic, clinical, and laboratory data were collected and cases classified into severe or nonsevere based on medical records. From December 2013 to January 2015, a total of 1,836 hospitalized cases were identified. Rate of hospital admissions for CHIKV infection was 60 per 10,000 suspected clinical CHIKV cases and severity accounted for 12 per 10,000. A total of 74 deaths related to CHIKV infection occurred. Infants and elderly people were more frequently hospitalized compared with others and severity was more frequently reported in elderly subjects and subjects with underlying health condition. Fifteen neonatal infections consecutive to mother-to-child transmission were diagnosed, seven of which were severe. The most vulnerable groups of the population, such as the elderly, infants, individuals with comorbidities, and pregnant women, should remain the main targets of public health priorities.

Introduction La borreliose de Lyme (BL) est la maladie vectorielle transmise par les tiques la plus frequente en France. En l’absence de vaccin, la prevention individuelle contre les piqures de tiques est le seul moyen pour en reduire la transmission. En 2016, un plan national de lutte contre les maladies transmises par les tiques a ete lance par le Ministere de la Sante, incluant l’amelioration de la prevention contre les piqures de tiques. Materiels et methodes Pour evaluer l’impact des campagnes de prevention, nous avons analyse la connaissance de la population francaise sur la BL et la prevention contre les piqures de tiques a partir des Barometre de Sante publique France 2016 et 2019. Ces deux enquetes realisees par telephone ont respectivement interrogees 14 875 et 9 611 personnes âgees de 18 a 75 ans vivant en France metropolitaine sur leurs expositions aux piqures de tiques, leurs comportements et pratiques de prevention vis-a-vis des piqures de tiques et leurs connaissances sur la BL. Pour les analyses, nous avons defini des regions de haute, moyenne et basse incidence a partir du niveau d’incidence estime par un reseau sentinelle de medecins generalistes (> 100 cas pour 100 000 habitants, entre 50 et 100 et inferieur a 50). Resultats En 2019, 30 % de la population a ete piquee par une tique au cours de la vie et 6 % au cours des 12 derniers mois. Ces proportions etaient respectivement de 25 % et 4 % en 2016 (p Conclusion Une proportion importante de la population se sent exposee aux piqures de tiques et applique les mesures de prevention. Une augmentation des connaissances et de l’application des mesures de prevention a ete observee entre 2016 et 2019. Ces resultats permettront de cibler les futures campagnes de prevention aupres de certaines tranches d’âge ou regions plus a risque. Les barrieres a l’utilisation des moyens de prevention necessiteraient neanmoins d’etre etudiees pour adapter au mieux les messages de prevention.

In September 2016, a cluster of seven kayakers with clinical symptoms of leptospirosis with onset since July 2016 was reported to French health authorities. Human and animal investigations were undertaken to describe the outbreak, identify the likely place and source of infection and implement necessary control measures. We identified 103 patients with clinical symptoms of leptospirosis between 1 June and 31 October 2016 who lived in the Ille-et-Vilaine district in Brittany. Of these, 14 (including the original seven) reported contacts with the river Vilaine during the incubation period and were defined as outbreak cases: eight were confirmed by serology tests or PCR and six were probable without a laboratory confirmation for leptospirosis. All 14 cases were kayakers. Three distinct contamination sites were identified on a 30 km stretch of the river Vilaine. Nine cases reported having skin wounds while kayaking. None were vaccinated against leptospirosis. The outbreak was attributed to Leptospira kirschneri serogroup Grippotyphosa. Animal investigations did not allow identifying the possible reservoir. Leptospirosis outbreaks associated with freshwater sports are rare in temperate climates. The prevention of such outbreaks requires control of potential animal reservoirs in zones such as the Vilaine valley and that kayakers adopt the recommended individual prevention measures.

International audience; no abstract

On 1 December 2017, an outbreak of Salmonella Agona infections among infants was identified in France. To date, 37 cases (median age: 4 months) and two further international cases have been confirmed. Five different infant milk products manufactured at one facility were implicated. On 2 and 10 December, the company recalled the implicated products; on 22 December, all products processed at the facility since February 2017. Trace-forward investigations indicated product distribution to 66 countries.

On 1 December 2017, an outbreak of Salmonella Agona infections among infants was identified in France. To date, 37 cases (median age: 4 months) and two further international cases have been confirmed. Five different infant milk products manufactured at one facility were implicated. On 2 and 10 December, the company recalled the implicated products; on 22 December, all products processed at the facility since February 2017. Trace-forward investigations indicated product distribution to 66 countries.

Leptospirosis is an under-reported and emerging zoonotic disease which is potentially fatal in humans. Rodents are the main reservoirs for pathogenic Leptospira spp., but diagnosis in these animals is difficult, and their infection, which does not induce symptoms, usually goes unoticed. Although the exposures of most human cases of leptospirosis are poorly documented, we were able to identify six human cases of leptospirosis which were associated with direct contact with pet rodents (mice or rats) in Belgium and France between 2009 and 2016. All cases had severe disease and for all, the presence of Leptospira spp. DNA in the kidneys of their pet animals was confirmed, strongly suggesting that excretion of leptospires in urine was the way of transmission. Half of the cases shared the serogroup Icterohaemorrhagiae, which is usually associated with severe disease, with the pet rats which they were in contact with. With the popularity of rats and mice as pets, this study should contribute to raising awareness on asymptomatic pet rodents as a source of Leptospira infections.

International audience; Following of the emergence of Zika virus in Brazil in 2015, an epidemiological surveillance system was quickly implemented in the French overseas Territories of America (FTA) according to previous experience with dengue and chikungunya and has detected first cases of Zika. General practitioners and medical microbiologists were invited to report all clinically suspectedcases of Zika, laboratory investigations were systematically conducted (RT-PCR). On 18 December, the first autochthonous case of Zika virus infection was confirmed by RT-PCR on French Guiana and Martinique, indicating introduction of Zika virus inFTA. The viral circulation of Zika virus was then also confirmed on Guadeloupe and Saint-Martin. We report here early findings on 203 confirmed cases of Zika virus infection identified by RT-PCR or seroneutralisation on Martinique Island between 24 November 2015 and 20 January 2016. All cases were investigated. Common clinical signs were observed (maculopapularrash, arthralgia, fever, myalgia and conjunctival hyperaemia) among these patients, but the rash, the foundation of our case definition, may be absent in a significant proportion of patients (16%). These results are important for the implementation of a suspected case definition, the main tool for epidemiological surveillance, in territories that may be affected by ZIKV emergence, including Europe.

International audience; We aimed to identify the optimal strategy that should be used by public health authorities against transmission of chikungunya virus in mainland France. The theoretical model we developed, which mimics the current surveillance system, predicted that without vector control (VC), the probability of local transmission after introduction of viraemic patients was around 2%, and the number of autochthonous cases between five and 15 persons per hectare, depending on the number of imported cases. Compared with this baseline, we considered different strategies (VC after clinical suspicion of a case or after laboratory confirmation, for imported or autochthonous cases): Awaiting laboratory confirmation for suspected imported cases to implement VC had no significant impact on the epidemiological outcomes analysed, mainly because of the delay before entering into the surveillance system. However, waiting for laboratory confirmation of autochthonous cases before implementing VC resulted in more frequent outbreaks. After analysing the economic cost of such strategies, our study suggested implementing VC immediately after the notification of a suspected autochthonous case as the most efficient strategy in settings where local transmission has been proven. Nevertheless, we identified that decreasing reporting time for imported cases should remain a priority.

International audience; In October 2014, an outbreak of 12 autochthonous chikungunya cases, 11 confirmed and 1 probable, was detected in a district of Montpellier, a town in the south of France colonised by the vector Aedes albopictus since 2010. A case returning from Cameroon living in the affected district was identified as the primary case. The epidemiological investigations and the repeated vector control treatments performed in the area and around places frequented by cases helped to contain the outbreak. In 2014, the chikungunya and dengue surveillance system in mainland France was challenged by numerous imported cases due to the chikungunya epidemic ongoing in the Caribbean Islands. This first significant outbreak of chikungunya in Europe since the 2007 Italian epidemic, however, was due to an East Central South African (ECSA) strain, imported by a traveller returning from West Africa. Important lessons were learned from this episode, which reminds us that the threat of a chikungunya epidemic in southern Europe is real.

Introduction La leptospirose est la maladie bacterienne zoonotique la plus repandue a travers le monde en raison du grand nombre de mammiferes reservoirs, qu’ils soient sauvages ou domestiques. Cette pathologie serait responsable de plus de 1 million de cas severes avec environ 60 000 deces par an. Elle reste une maladie largement sous-estimee du fait de l’absence de symptomes specifiques dans la phase primaire de la maladie et d’un manque de sensibilisation au sein de la communaute medicale, en particulier dans les regions non endemiques. L’incidence moyenne sur une periode de plus de vingt ans est de 0,5 cas pour 100 000 habitants en France Metropolitaine. En revanche, elle est endemique dans les departements d’outre-mer avec une incidence pouvant etre 50 fois plus elevee. Materiels et methodes La leptospirose n’etant pas une maladie a declaration obligatoire, sa surveillance au niveau national est une surveillance passive basee sur : – l’activite diagnostic du centre national de reference avec le recueil, si possible, des donnees cliniques, biologiques et epidemiologiques ; – l’analyse des donnees des laboratoires prives Biomnis et Cerba (effectuant les deux tiers des analyses), sans recueil de donnees autres que la demande de diagnostic biologique de leptospirose ; – des collaborations entre differents partenaires (laboratoires hospitaliers, Sante publique France, Agences regionales de sante, Ecoles nationales veterinaires). Le diagnostic biologique s’effectue par la detection de l’ADN bacterien par PCR et par serologie (Elisa IgM, test de micro-agglutination). Resultats Au cours de ces deux dernieres annees (2014–2015), un doublement du nombre de cas en France metropolitaine a ete constate, avec plus de 600 cas par an soit une incidence de 1 cas pour 100 000 habitants. Malgre le manque de donnees disponibles, l’exposition et les facteurs de risques sont principalement associes a des activites recreatives en espace naturel. Cependant, de nouvelles sources de contamination directe semblent apparaitre comme le contact avec des nouveaux animaux de compagnie s . Conclusion Cette augmentation importante de cas humains a egalement ete constatee dans d’autres pays europeens. Actuellement, les raisons de cette emergence ne sont pas clairement identifiees et sont probablement multiples (meilleure performance des tests de diagnostic, changement climatique, surpopulation de rongeurs, augmentation de l’activite de loisirs en espace naturel). La surveillance de la leptospirose en France est basee sur une surveillance passive et, de ce fait, non exhaustive. La sensibilisation des professionnels de sante reste donc essentielle. Il est egalement important de renforcer les etudes sur la leptospirose afin de mieux decrire l’epidemiologie de cette maladie dite negligee, et de minimiser l’impact que cela pourrait avoir dans le futur.

Introduction Les laboratoires de biologie medicale disposent de donnees specifiques sur les maladies infectieuses, d’ou un interet majeur pour la surveillance et l’alerte. Le systeme de surveillance, appele 3labos, repose sur la remontee automatisee des donnees individuelles de 3 laboratoires centralisateurs de prelevements (France metropolitaine et DOM) : Eurofins Biomnis et Cerba. Les objectifs de ce systeme sont le suivi des tendances temporo-spatiales de maladies infectieuses ciblees, la contribution a l’investigation d’epidemies et l’apport de donnees complementaires aux systemes de surveillance existants. Materiels et methodes Les donnees demographiques et biologiques sont anonymisees et envoyees automatiquement depuis 2012 de maniere securisee vers Sante publique France selon un rythme defini (quotidien a mensuel). Les maladies infectieuses suivies sont : arboviroses (chikingunya, dengue, zika), IST (chlamydia, gonocoque, syphilis), maladies respiratoires ou a prevention vaccinale (rougeole, rubeole, tuberculose), parasitoses (bilharziose), zoonoses (borreliose de Lyme, fievre Q, leptospirose). Resultats Utilisees dans le contexte de la surveillance des arboviroses, ces donnees representent un complement notable aux autres systemes de surveillance tels que la declaration obligatoire ou les surveillances specifiques dans les departements ou les moustiques Aedes sont implantes. En metropole, en 2014, 45 % des cas confirmes de chikungunya et de dengue ont ete identifies suite a l’analyse des resultats recus via le reseau 3labos. Ce rattrapage de cas non signales par ailleurs ameliore directement l’exhaustivite de la surveillance des arboviroses. Dans les DFA, la mise a disposition de donnees d’analyses biologiques Zika des le debut de l’epidemie, a permis de recenser les cas confirmes, contribuant au suivi temporo-spatiale de la circulation virale. En 2016, le systeme 3labos a contribue a l’investigation d’un signalement de cas groupes de leptospirose en Ille et Vilaine. L’analyse de ces resultats a permis de mettre en evidence une augmentation du nombre de cas dans le departement, dont plusieurs cas en lien avec les cas groupes signales, non identifies par ailleurs. Conclusion Le systeme 3labos est un outil qui contribue efficacement a la remontee de donnees specifiques dans le cadre d’epidemies ou lors de l’emergence de nouvelles pathologies, en particulier lorsque aucun autre systeme n’est encore en place. Pour les pathologies beneficiant deja d’une surveillance, les donnees 3labos apportent un complement d’information ameliorant leur surveillance epidemiologique.

Introduction Le 9 septembre 2016, un club de kayak de la Vilaine a signale a l’ARS Bretagne sept adherents ayant presente des symptomes compatibles avec une leptospirose depuis juillet 2016. Des investigations humaines et animales ont ete entreprises pour evaluer l’origine et l’ampleur de l’epidemie, et guider les mesures de gestion. Materiels et methodes Une recherche active des personnes ayant presente des signes compatibles avec la leptospirose entre juin et octobre 2016 a ete initiee aupres des clubs de kayak de la Vilaine, des laboratoires avoisinants, des hopitaux et des medecins generalistes. Les cas ont ete interroges a l’aide d’un questionnaire standardise. L’analyse a ete limitee aux patients rapportant une exposition a la Vilaine. Le CNR a realise des analyses PCR, Elisa et MAT pour confirmer les diagnostics de leptospirose. Des animaux sauvages presents dans la zone concernee ont ete pieges avec recherche de leptospire via PCR et MAT. Resultats Quatorze cas de leptospirose ont ete identifies : 7 cas confirmes biologiquement par le CNR, 1 cas probable avec un prelevement initial positif sans confirmation du CNR, et 6 cas possibles avec des signes cliniques evocateurs sans confirmation biologique. Les symptomes les plus frequents etaient de la fievre, des frissons, des maux de tete, des signes digestifs et des douleurs musculaires ou articulaires. Tous les cas etaient kayakistes et avaient eu des contacts etroits avec les eaux de la Vilaine. Les analyses microbiologiques chez les cas ont mis en evidence une seule espece L. kirschneri de serogroupe grippotyphosa. Parmi les 38 animaux sauvages captures, l’ADN de leptospires a ete detecte chez 9 d’entre eux. Trois especes de leptospires (L. interrogans, L. wolffii et L. borgpetersenii), differentes de celle incriminee chez les cas humains, ont ete detectees. Des mesures de gestion ont ete mises en place immediatement (fermeture de la zone, sensibilisation des professionnels de sante, information des mairies et clubs de kayaks, captures de ragondins). Conclusion L’investigation a mis en evidence la survenue d’au moins 14 cas groupes de leptospirose parmi des kayakistes entre juin et septembre 2016. Des regroupements comparables ont ete rapportes dans des departements d’outre-mer mais les cas groupes de leptospirose sont rares en metropole. Cette epidemie est survenue dans un contexte environnementale defavorable (proliferation de rongeurs aquatiques, ete 2016 chaud et sec). Des mesures de gestion permettant de prevenir un nouvel episode seront a mettre en œuvre sur la Vilaine.