Modeling the Worldwide Spread of Pandemic Influenza: Baseline Case and Containment Interventions

We present a study of the worldwide spread of a pandemic influenza and its possible containment at a global level taking into account all available information on air travel. We studied a metapopulation stochastic epidemic model on a global scale that considers airline travel flow data among urban areas. We provided a temporal and spatial evolution of the pandemic with a sensitivity analysis of different levels of infectiousness of the virus and initial outbreak conditions (both geographical and seasonal). For each spreading scenario we provided the timeline and the geographical impact of the pandemic in 3,100 urban areas, located in 220 different countries. We compared the baseline cases with different containment strategies, including travel restrictions and the therapeutic use of antiviral (AV) drugs. We show that the inclusion of air transportation is crucial in the assessment of the occurrence probability of global outbreaks. The large-scale therapeutic usage of AV drugs in all hit countries would be able to mitigate a pandemic effect with a reproductive rate as high as 1.9 during the first year; with AV supply use sufficient to treat approximately 2% to 6% of the population, in conjunction with efficient case detection and timely drug distribution. For highly contagious viruses (i.e., a reproductive rate as high as 2.3), even the unrealistic use of supplies corresponding to the treatment of approximately 20% of the population leaves 30%-50% of the population infected. In the case of limited AV supplies and pandemics with a reproductive rate as high as 1.9, we demonstrate that the more cooperative the strategy, the more effective are the containment results in all regions of the world, including those countries that made part of their resources available for global use.Comment: 16 page

Association of environmental markers with childhood type 1 diabetes mellitus revealed by a long questionnaire on early life exposures and lifestyle in a case–control study

First available in BioRxiv doi: http://dx.doi.org/10.1101/063438International audienceBackground. The incidence of childhood type 1 diabetes (T1D) incidence is rising in many countries, supposedly because of changing environmental factors, which are yet largely unknown. The purpose of the study was to unravel environmental markers associated with T1D.Methods. Cases were children with T1D from the French Isis-Diab cohort. Controls were schoolmates or friends of the patients. Parents were asked to fill a 845-item questionnaire investigating the child’s environment before diagnosis. The analysis took into account the matching between cases and controls. A second analysis used propensity score methods.Results. We found a negative association of several lifestyle variables, gastroenteritis episodes, dental hygiene, hazelnut cocoa spread consumption, wasp and bee stings with T1D, consumption of vegetables from a farm and death of a pet by old age.Conclusions. The found statistical association of new environmental markers with T1D calls for replication in other cohorts and investigation of new environmental areas.Trial registration. Clinical-Trial.gov NCT02212522. Registered August 6, 2014.

Biosécurité et surveillance épidémiologique

Biosecurity is a word including, in French, two concepts which are differently expressed in the English literature: the biosafety (to prevent accidental releases of infectious agents, for example, in research laboratories) and the biosecurity (to prevent the voluntary dispersion of infectious agents by bioterrorists, for example). Up to now, bioterrorism using a biological weapon has been very rare. Epidemiological surveillance is frequently seen as an efficient tool to achieve a better biosafety, and increase biosecurity. However, biosecurity requires an alert system. Traditional surveillance, which was developed to help to design the health policies, lacks the sensitivity and rapid response delay necessary for alert. Biology brings new opportunities for alert and surveillance. Examples are the monitoring of sewer systems and the development of CRISPR tools for detection of biological agents. A new problem is that these tools can be used out of the research laboratories, because they are relatively cheap and easy to develop. Finally, whatever the method used to identify quickly a new hazard, the key problem is the “preparedness” to identify and connect quickly the biomedical experts able to provide the best response to this hazard

Causes of early-onset type 1 diabetes: toward data-driven environmental approaches

A new study reveals distinctive metabolic changes that precede the development of type 1 diabetes (T1D), tossing a stone into the quiet waters of T1D immunology and genetics. The causes of these metabolic changes and their relationship to autoimmunity and β cell destruction are not yet known, but the identification of a metabolic phenotype linked to susceptibility to type I diabetes may help pave the way to a new era of investigation of T1D causality

Risk Assessment of Transmission of Sporadic Creutzfeldt-Jakob Disease in Endodontic Practice in Absence of Adequate Prion Inactivation

BACKGROUND: Experimental results evidenced the infectious potential of the dental pulp of animals infected with transmissible spongiform encephalopathies (TSE). This route of iatrogenic transmission of sporadic Creutzfeldt-Jakob disease (sCJD) may exist in humans via reused endodontic instruments if inadequate prion decontamination procedures are used. METHODOLOGY/PRINCIPAL FINDINGS: To assess this risk, 10 critical parameters in the transmission process were identified, starting with contamination of an endodontic file during treatment of an infectious sCJD patient and ending with possible infection of a subsequent susceptible patient. It was assumed that a dose-risk response existed, with no-risk below threshold values. Plausible ranges of those parameters were obtained through literature search and expert opinions, and a sensitivity analysis was conducted. Without effective prion-deactivation procedures, the risk of being infected during endodontic treatment ranged between 3.4 and 13 per million procedures. The probability that more than one case was infected secondary to endodontic treatment of an infected sCJD patient ranged from 47% to 77% depending on the assumed quantity of infective material necessary for disease transmission. If current official recommendations on endodontic instrument decontamination were strictly followed, the risk of secondary infection would become quasi-null. CONCLUSION: The risk of sCJD transmission through endodontic procedure compares with other health care risks of current concern such as death after liver biopsy or during general anaesthesia. These results show that single instrument use or adequate prion-decontamination procedures like those recently implemented in dental practice must be rigorously enforced