'Forest malaria' in Myanmar? Tracking transmission landscapes in a diversity of environments

BACKGROUND

In the Greater Mekong Subregion, case-control studies and national-level analyses have shown an association between malaria transmission and forest activities. The term 'forest malaria' hides the diversity of ecosystems in the GMS, which likely do not share a uniform malaria risk. To reach malaria elimination goals, it is crucial to document accurately (both spatially and temporally) the influence of environmental factors on malaria to improve resource allocation and policy planning within given areas. The aim of this ecological study is to characterize the association between malaria dynamics and detailed ecological environments determined at village level over a period of several years in Kayin State, Myanmar.

METHODS

We characterized malaria incidence profiles at village scale based on intra- and inter-annual variations in amplitude, seasonality, and trend over 4 years (2016-2020). Environment was described independently of village localization by overlaying a 2-km hexagonal grid over the region. Specifically, hierarchical classification on principal components, using remote sensing data of high spatial resolution, was used to assign a landscape and a climate type to each grid cell. We used conditional inference trees and random forests to study the association between the malaria incidence profile of each village, climate and landscape. Finally, we constructed eco-epidemiological zones to stratify and map malaria risk in the region by summarizing incidence and environment association information.

RESULTS

We identified a high diversity of landscapes (n = 19) corresponding to a gradient from pristine to highly anthropogenically modified landscapes. Within this diversity of landscapes, only three were associated with malaria-affected profiles. These landscapes were composed of a mosaic of dense and sparse forest fragmented by small agricultural patches. A single climate with moderate rainfall and a temperature range suitable for mosquito presence was also associated with malaria-affected profiles. Based on these environmental associations, we identified three eco-epidemiological zones marked by later persistence of Plasmodium falciparum, high Plasmodium vivax incidence after 2018, or a seasonality pattern in the rainy season.

CONCLUSIONS

The term forest malaria covers a multitude of contexts of malaria persistence, dynamics and populations at risk. Intervention planning and surveillance could benefit from consideration of the diversity of landscapes to focus on those specifically associated with malaria transmission.

Motivational interview-based health mediator interventions increase intent to vaccinate among disadvantaged individuals

Coverage for recommended COVID-19 and diphtheria-tetanus-poliomyelitis (DTP) booster shots is often inadequate, especially among disadvantaged populations. To help health mediators (HMs) involved in outreach programs deal with the problems of vaccine hesitancy (VH) in these groups, we trained them in motivational interviewing (MI). We evaluated the effectiveness of this training among HMs on their MI knowledge and skills (objective 1) and among the interviewees on their vaccination readiness (VR) and intention to get vaccinated or accept a booster against COVID-19 and/or DTP (objective 2). Two MI specialists trained 16 HMs in a two-day workshop in May 2022. The validated MISI questionnaire evaluated HMs' acquisition of MI knowledge and skills (objective 1). Trained HMs offered an MI-based intervention on vaccination to people in disadvantaged neighborhoods of Marseille (France). Those who consented completed a questionnaire before and after the interview to measure VR with the 7C scale and intentions regarding vaccination/booster against COVID-19 and DTP (objective 2). The training resulted in HMs acquiring good MI skills (knowledge, application, self-confidence in using it). HMs enrolled 324 interviewees, 96% of whom completed both questionnaires. VR increased by 6%, and intentions to get vaccinated or update COVID-19 and DTP vaccination increased by 74% and 52% respectively. Nearly all interviewees were very satisfied with the interview, although 21% still had questions about vaccination. HMs assimilated MI principles well. MI use in outreach programs appears to show promise in improving vaccine confidence and intentions among disadvantaged people.

Hypoparathyroidism-related health care utilization and expenditure during the first postoperative year after total thyroidectomy for cancer: a comprehensive national cohort study

Objectives

Hypoparathyroidism is the most common complication of total thyroidectomy for cancer, and requires calcium and/or vitamin D supplementation for an unpredictable period of time. The additional cost associated with this complication has not hitherto been assessed. The aim of this study was to assess the economic burden of postoperative hypoparathyroidism after total thyroidectomy for cancer in France.

Methods

Based on the French national cancer cohort, which extracts data from the French National Health Data System (SNDS), all adult patients who underwent a total thyroidectomy for cancer in France between 2011 and 2015 were identified, and their healthcare resource use during the first postoperative year was compared according to whether they were treated postoperatively with calcium and/or vitamin D or not. Univariate and multivariate cost analyses were performed with the non-parametric Wilcoxon test and generalized linear model (gamma distribution and log link), respectively.

Results

Among the 31,175 patients analyzed (75% female, median age: 52y), 13,247 (42%) started calcium and/or vitamin D supplementation within the first postoperative month, and 2,855 patients (9.1%) were still treated at 1 year. Over the first postoperative year, mean overall and specific health expenditures were significantly higher for treated patients than for untreated patients: €7,233 vs €6,934 per patient (p<0.0001) and €478.6 vs €332.7 per patient (p<0.0001), respectively. After adjusting for age, gender, Charlson Comorbidity index, ecological deprivation index, types of thyroid resection, lymph node dissection and complications, year and region, the incremental cost of overall health care utilization was €142 (p<0.004).

Conclusion

Our study found a significant additional cost in respect of health expenditures for patients who had hypoparathyroidism after thyroidectomy for cancer, over the first postoperative year. Five-year follow-up is planned to assess the impact of more severe long-term complications on costs.

Social deprivation and SARS-CoV-2 testing: a population-based analysis in a highly contrasted southern France region

Background

Testing was the cornerstone of the COVID-19 epidemic response in most countries until vaccination became available for the general population. Social inequalities generally affect access to healthcare and health behaviors, and COVID-19 was rapidly shown to impact deprived population more drastically. In support of the regional health agency in Provence-Alpes-Côte d'Azur (PACA) in South-Eastern France, we analyzed the relationship between testing rate and socio-demographic characteristics of the population, to identify gaps in testing coverage and improve targeting of response strategies.

Methods

We conducted an ecological analysis of SARS-CoV-2/COVID-19 testing rate in the PACA region, based on data aggregated at the finest spatial resolution available in France (IRIS) and by periods defined by public health implemented measures and major epidemiological changes. Using general census data, population density, and specific deprivation indices, we used principal component analysis followed by hierarchical clustering to define profiles describing local socio-demographic characteristics. We analyzed the association between these profiles and testing rates in a generalized additive multilevel model, adjusting for access to healthcare, presence of a retirement home, and the age profile of the population.

Results

We identified 6 socio-demographic profiles across the 2,306 analyzed IRIS spatial units: privileged, remote, intermediate, downtown, deprived, and very deprived (ordered by increasing social deprivation index). Profiles also ranged from rural (remote) to high density urban areas (downtown, very deprived). From July 2020 to December 2021, we analyzed SARS-CoV-2/COVID-19 testing rate over 10 periods. Testing rates fluctuated strongly but were highest in privileged and downtown areas, and lowest in very deprived ones. The lowest adjusted testing rate ratios (aTRR) between privileged (reference) and other profiles occurred after implementation of a mandatory healthpass for many leisure activities in July 2021. Periods of contextual testing near Christmas displayed the largest aTRR, especially during the last periods of 2021 after the end of free convenience testing for unvaccinated individuals.

Conclusion

We characterized in-depth local heterogeneity and temporal trends in testing rates and identified areas and circumstances associated with low testing rates, which the regional health agency targeted specifically for the deployment of health mediation activities.

Malaria Temporal Dynamic Clustering for Surveillance and Intervention Planning

BACKGROUND

Targeting interventions where most needed and effective is crucial for public health. Malaria control and elimination strategies increasingly rely on stratification to guide surveillance, to allocate vector control campaigns, and to prioritize access to community-based early diagnosis and treatment (EDT). We developed an original approach of dynamic clustering to improve local discrimination between heterogeneous malaria transmission settings.

METHODS

We analysed weekly malaria incidence records obtained from community-based EDT (malaria posts) in Karen/Kayin state, Myanmar. We smoothed longitudinal incidence series over multiple seasons using functional transformation. We regrouped village incidence series into clusters using a dynamic time warping clustering and compared them to the standard, 5-category annual incidence standard stratification.

RESULTS

We included 1115 villages from 2016 to 2020. We identified eleven P. falciparum and P. vivax incidence clusters which differed by amplitude, trends and seasonality. Specifically the 124 villages classified as "high transmission area" in the standard P. falciparum stratification belonged to the 11 distinct groups when accounting to inter-annual trends and intra-annual variations. Likewise for P. vivax, 399 "high transmission" villages actually corresponded to the 11 distinct dynamics.

CONCLUSION

Our temporal dynamic clustering methodology is easy to implement and extracts more information than standard malaria stratification. Our method exploits longitudinal surveillance data to distinguish local dynamics, such as increasing inter-annual trends or seasonal differences, providing key information for decision-making. It is relevant to malaria strategies in other settings and to other diseases, especially when many countries deploy health information systems and collect increasing amounts of health outcome data.

FUNDING

The Bill & Melinda Gates Foundation, The Global Fund against AIDS, Tuberculosis and Malaria (the Regional Artemisinin Initiative) and the Wellcome Trust funded the METF program.

Concerted and multidisciplinary management of COVID-19 drug therapies during the first two epidemic waves in a tertiary hospital in Marseille, France: Results of the PHARMA-COVID study

OBJECTIVES

To evaluate the impact of local therapeutic recommendation updates made by the COVID multidisciplinary consultation meeting (RCP) at the Hôpital Européen Marseille (HEM) through the description of the drug prescriptions for COVID-19 during the first two waves of the epidemic.

METHODS

This retrospective observational study analysed data from the hospital's pharmaceutical file. We included all patients hospitalized for COVID-19 between February 1, 2020 and January 21, 2021 and extracted specific anti-COVID-19 therapies (ST) from computerized patient record, as well as patients' demographic characteristics, comorbidities and outcome. The evolution of ST prescriptions during the study period was described and put into perspective with the updates of local recommendations made during the first (V1, from 2/24/2020 to 7/27/2020), and second (V2, from 7/28/2020 to 1/21/2021) epidemic waves.

RESULTS

A total of 607 COVID-19 hospitalized patients, 197 during V1 and 410 during V2. Their mean age was 65 years-old, and they presented frequent comorbidities. In total, 93% of hospitalized patients received ST: anticoagulants (90%), glucocorticoids (39%) mainly during V2 (49% vs 17%, P<0.001), and azithromycin (30%) mainly during V1 (71% vs 10%, P<0.001). Lopinavir/ritonavir and hydroxychloroquine were prescribed to 17 and 7 inpatients, respectively, and only during V1. Remdesivir was never administered. A total of 22 inpatients were enrolled into clinical trials.

CONCLUSIONS

The effective dissemination of evidence-based and concerted recommendations seems to have allowed an optimized management of COVID-19 drug therapies in the context of this emerging infection with rapidly evolving therapeutic questions.

Anti-spike protein to determine SARS-CoV-2 antibody levels: Is there a specific threshold conferring protection in immunocompromised patients?

BACKGROUND

Identifying a specific threshold level of SARS-CoV-2 antibodies that confers protection in immunocompromised patients has been very challenging. The aim was to assess the threshold of 264 binding antibody units (BAU)/ml using four different SARS-CoV-2 antibody assays (Abbott, Beckman, Roche, and Siemens) and to establish a new optimal threshold of protection for each of the four antibody assays.

METHODS

This study was performed on data retrieved from 69 individuals, who received at least one dose of the Pfizer/BioNTech BNT162b2 or Moderna COVID-19 vaccine (Spikevax) at the Alphabio Laboratory in Marseille, France (European Hospital, Alphabio-Biogroup). The results were compared to the percent inhibition calculated using a functional surrogate of a standardized virus neutralization test (Genscript).

RESULTS

Samples from 69 patients were analyzed. For a reference cutoff of 264 BAU/ml, assays showed moderate to good overall concordance with Genscript: 87% concordance for Abbott, 78% for Beckman, 75% for Roche, and 88% for Siemens. Overall concordance increased consistently after applying new thresholds, i.e., 148 BAU/ml (Abbott), 48 (Beckman), 559 (Roche), and 270 (Siemens).

CONCLUSION

We suggest specific adjusted thresholds (BAU/ml) for the four commercial antibody assays that are used to assess pre-exposure prophylaxis in immunocompromised patients.

Long-term neuromuscular consequences of SARS-Cov-2 and their similarities with myalgic encephalomyelitis/chronic fatigue syndrome: results of the retrospective CoLGEM study

Background

Patients with long-COVID often complain of continuous fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise. No data are available on EMG recording of evoked myopotentials (M-waves) or exercise-induced alterations in long-COVID patients, providing evidence of muscle membrane fatigue. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develops in more than half of patients after an infectious disease, particularly viral diseases. A large proportion (around 70%) of these patients have neuromuscular disorders with M-wave alterations during and after exercise. Our hypothesis was that M-wave alterations would be also found in long-COVID patients, in association with neuromuscular symptoms, similar to ME/CFS.

Methods

This retrospective observational ColGEM (Covid LonG Encéphalomyelite Myalgique) study compared 59 patients with long-COVID and 55 ME/CFS patients with a history of severe infection who presented before the COVID pandemic. All of these patients underwent the same protocol consisting of a questionnaire focusing on neural and neuromuscular disorders and M-wave recording in the rectus femoris muscle before, during, and 10 min after a progressive cycling exercise. Maximal handgrip strength (MHGS) and maximal exercise power were also measured. The frequency of symptoms and magnitude of M-wave changes in the two groups were compared using non-parametric and parametric tests.

Results

The frequency of fatigue, myalgia, sleep problems, cognitive dysfunction, and post-exertional malaise as well as the magnitude of exercise-induced M-wave alterations were the same in the two groups. By contrast, digestive problems were less present in long-COVID. M-wave alterations were greater in ME/CFS patients as in those with long-COVID when the highest muscle strength and highest exercise performance were measured.

Conclusions

These high clinical and biological similarities between long-COVID and ME/CFS support the hypothesis that SARS-Cov-2 infection can cause ME/CFS symptoms.

Trial registration Registered retrospectively.

Cholera in Haiti

The cholera epidemic that hit Haiti from October 2010 to February 2019 was the world's deadliest of the last 25 years. Officially, the successive waves caused 9789 deaths, although numerous additional casualties could not be recorded. The origin of this epidemic has been the subject of a controversy involving two opposing theories. The first hypothesis, put forward by renowned American academics, was that the cholera epidemic originated from the environment, due to the proliferation and transmission of aquatic Vibrio cholerae bacteria driven by a confluence of circumstances, i.e., the earthquake followed by a hot summer and, ultimately, heavy rainfall and flooding. The alternative hypothesis, which was subsequently confirmed by epidemiological and genomic studies, attributed the epidemic to the recent importation of cholera by UN peacekeepers having recently arriving from Nepal, and to a river polluted with sewage. In late 2016, the Secretary General of the United Nations finally begged the Haitian people for forgiveness. This implicit recognition of the role of the UN in the cholera epidemic helped to fund the ongoing fight against it. Case-area targeted interventions aimed at interrupting cholera transmission were reinforced, which resulted in the extinction of the epidemic within two years. In the meantime, several phylogenetic studies on Vibrio cholerae during the seventh cholera pandemic demonstrated that local environmental and global epidemic Vibrio populations were distinct. These studies also showed that epidemics arose when the bacterium had diversified and that it had spread during transmission events associated with human travel.

Défavorisation sociale et facteurs associés au dépistage du SARS-CoV-2 à l'échelle locale dans une région du Sud de la France entre Juillet 2020 et Janvier 2022

Introduction

Les inégalités sociales sont fortement associées aux inégalités de santé, que ce soit pour les maladies chroniques ou infectieuses. Le SARS-CoV-2 ne fait pas exception, l'étude nationale EpiCov ayant montré dès juin 2020 un risque de COVID-19 croissant avec la défavorisation sociale.

Le dépistage demeure un des piliers du contrôle de cette pandémie, tant à l'échelle individuelle pour l'isolement des cas et de leurs contacts à risque, que populationnelle pour identifier et cibler certaines mesures d'accompagnement. L'accès au dépistage ne saurait être considéré comme uniforme, tant l'accès au soin apparaît déficitaire dans certains territoires (zones urbaines défavorisées, rurales). Par ailleurs, le manque de prise en compte des inégalités sociales dans les mesures de suivi des cas a été souligné.

Notre objectif était de prendre en compte le sous-diagnostic du SARS-CoV-2 lié à la défavorisation sociale afin d'améliorer le ciblage des actions de santé publique à l'échelle régionale.

Matériels et méthodes

Le nombre de tests (RT-PCR et antigéniques) et de cas de COVID-19 positifs enregistrés dans la base SI-DEP ont été agrégées à l'échelle spatiale des IRIS (subdivision géographique d'environ 2000 habitants) et temporelle selon des périodes correspondant aux grandes mesures de contrôle de l'épidémie (pré-, pendant, post-confinement, passe sanitaire…). Les taux de dépistage, d'incidence de COVID-19 et de positivité des tests ont été définis par IRIS et par période.

Nous avons caractérisé le profil socio-démographique de chaque IRIS à partir de données de population et d'accès au soin (source INSEE et DREES), et de l'European Deprivation Index (EDI), indicateur spécifique de défavorisation sociale.

Enfin, nous avons analysé le ratio de taux de dépistage (RTD) selon le profil socio-démographique après ajustement sur l'accès au soin, au moyen d'un modèle additif généralisé hiérarchique prenant en compte l'autocorrélation spatiale entre les IRIS voisins.

Résultats

Nous avons distingué 10 périodes entre Juillet 2020 et Janvier 2022, et identifié six profils d'IRIS : un profil rural, un rural/péri-urbain, et quatre profils urbains correspondant respectivement à des IRIS aisés, denses de centre-ville, défavorisées, et denses très défavorisées.

Le taux de dépistage des IRIS urbains très défavorisés était systématiquement inférieur au taux de dépistage des IRIS urbains/péri-urbains aisés (RTD entre 0.85 (IC95 %=0.80-0.91) et 0.64 (0.59-0.69)). Les pics d'incidence de COVID-19 ont été atteints plus tardivement dans les IRIS très défavorisées que dans les IRIS aisés lors de périodes de confinement (novembre 2020) ou de périodes de vaccination massive (juillet 2021).

Conclusion

Cette étude a permis d'identifier une liste limitée d'IRIS caractérisés par un sous-dépistage et un retard d'efficacité des mesures sanitaires de freinage de la COVID-19. Ils ont ainsi pu être priorisés dans les interventions mises en place par les acteurs régionaux et locaux de la réponse à la pandémie.

Aucun lien d'intérêt

Conséquences neuromusculaires à long terme de la COVID-19 : analogies avec l’encéphalomyélite myalgique/syndrome de fatigue chronique

Introduction

De nombreux patients infectés par SARS-CoV-2 présentent dans les mois qui suivent l’infection des symptômes non spécifiques de type fatigue non résolutive, myalgies, céphalées, troubles cognitifs, faiblesse musculaire…[1]. On appelle la persistance de ces symptômes « syndrome post-COVID » ou « COVID long ». Une métanalyse de Wong et Weitzer [2] portant sur des patients souffrant de syndrome post-COVID suggère des analogies cliniques avec l’encéphalomyélite myalgique/syndrome de fatigue chronique (EM/SFC), qui fait suite dans plus de 50 % des cas à une infection bactérienne ou virale. Une majorité de patients souffrant de EM/SFC présentent des désordres neuromusculaires caractérisés par une altération des myopotentiels (onde M) déclenchée par l’exercice et persistant en récupération.

L’objectif de ce travail était de comparer l’existence d’altérations des ondes M chez des patients souffrants de syndrome post-COVID et d’EM/SFC post infectieuse datant de moins de 2 ans.

Patients et méthodes

Cette étude rétrospective a inclu 55 patients souffrant de syndrome post-COVID ainsi que 62 patients souffrant de EM/SFC (explorés sur la même période et relatant un ou plusieurs épisodes d’infection sévère ayant précédé dans les 2 ans la survenue de la fatigue chronique). Le protocole d’exploration de la fatigue chronique consistait en un interrogatoire sur la symptomatologie neuromusculaire associée et un test d’effort sur ergocycle atteignant au moins 80 % de la puissance maximale théorique. Avant, pendant et après l’exercice un électromyogramme de surface du muscle Rectus femoris avec mesure de l’onde M déclenchée par neurostimulation directe de ce muscle (mesure d’amplitude et de durée) a été réalisé.

Résultats

La moyenne d’âge était respectivement de 46 ans (±2) pour le groupe post-COVID et 44 ans (± 3) pour le groupe EM/SFC, avec une nette prédominance féminine (71 % pour le groupe EM/SFC et 74 % pour le groupe post-COVID). La fréquence des symptômes neuromusculaires (myalgies, dégradation du sommeil, troubles cognitifs, et malaise post-exercice) était identique dans les deux groupes post-COVID et EM/SFC (respectivement : 78 % versus 84 %, 82 % versus 76 %, 82 % versus 86 %, 73 % versus 73 %). La fréquence des altérations des ondes M était similaire dans les groupes post-covid et EM/SFC (respectivement 48 % et 41 %). Le pourcentage de réduction d’amplitude et d’allongement de durée étaient identiques dans les 2 groupes (respectivement −43 ± 4 % et + 16 ±4 %).

Conclusion

Cette étude suggère que certains patients souffrant de syndrome post-COVID présentent de façon précoce des anomalies neuromusculaires fréquemment retrouvées dans l’EM/SFC. Des études longitudinales pourront permettre de déterminer si ces troubles persistent et s’autonomisent dans le temps.

[COVID-19 innovative mobile strategy of test and care among homeless people in Marseille]

INTRODUCTION

Homeless people are particularly at risk of becoming infected with COVID-19 because their precarious living conditions make prevention measure difficult.

OBJECTIVE

We describe an innovative approach with the aim of implementing testing and monitoring adapted to the needs of the homeless people of Marseille (inhabitants of slums, squats or those living on the street).

RESULTS

The intervention included 1) the coordination of 18 support organizations for homeless people, 2) the training and the provision of rapid serological and antigenic tests, 3) a mobile outreach team with community mediators in order to provide tests, including COVID-19 PCR on point of care, prevention and monitoring of positive cases. Acceptability of the intervention by participants, field organization was good. The lack of adapted places of accommodation was an important restricting factor for optimal care and support.

CONCLUSION

The emergence of COVID-19 has highlighted discontinuities in health care among homeless people. Specific mobile outreach teams could limit the impact on this high-risk population.

Séquelles physiques et psychiques 3–6 mois après la COVID-19 : premiers résultats de la cohorte prospective ALCOVID

Introduction

Patients et méthodes

Résultats

Conclusion

Intraoperative Mapping Angiograms of the Parathyroid Glands Using Indocyanine Green During Thyroid Surgery: Results of the Fluogreen Study

BACKGROUND

During thyroid surgery, preservation of parathyroid gland (PG) feeding vessels is often impossible. The aim of the Fluogreen study was to determine the feasibility of using indocyanine green (ICG)-based intraoperative mapping angiograms of the PG (iMAP) to improve vascular preservation.

STUDY DESIGN

This prospective study enrolled all patients undergoing thyroid lobectomy or total thyroidectomy at the Hôpital Européen Marseille between September and December 2018. After exploring the thyroid lobe by autofluorescence to locate the PGs, ICG solution was injected intravenously to locate the PG feeding vessels and guide dissection. A second ICG injection was administered at the end of the lobectomy to assess perfusion of the PGs. The primary outcome was the quality of the angiogram, scaled as iMAP 0 (not informative), iMAP 1 (general vascular pattern visible but no clear vascular pedicle flowing into the PG), or iMAP 2 (clear vascular pedicle flowing into the PG). The secondary outcome was the PG perfusion score at the end of surgery, scaled from ICG 0 (no perfusion) to ICG 2 (intense uptake).

RESULTS

A total of 47 adult patients were analyzed, including 34 total thyroidectomies and 13 lobectomies. ICG angiography assessed 76 PGs, which were scored as iMAP 2 in 24 cases (31.6%), iMAP 1 in 46 (60.5%) and iMAP 0 in six (7.9%). At the end of dissection, the ICG perfusion score was significantly better for the PGs with informative angiography (iMAP 1 or 2), than for the PGs with uninformative angiography (iMAP 0), or the PGs not evaluated by vascular angiography (p < 0.05).

CONCLUSION

iMAP is feasible and provides direct vascular information in one-third of the cases. Further improvements to this technology are necessary, and the influence of this technique on patient outcomes during thyroidectomy will need to be further evaluated.

Toward Cholera Elimination, Haiti

This study describes the apparent discontinuation of cholera transmission in Haiti since February 2019. Because vulnerabilities persist and vaccination remains limited, our findings suggest that case-area targeted interventions conducted by rapid response teams played a key role. We question the presence of environmental reservoirs in Haiti and discuss progress toward elimination.

Delineating and Analyzing Locality-Level Determinants of Cholera, Haiti

Centre Department, Haiti, was the origin of a major cholera epidemic during 2010–2019. Although no fine-scale spatial delineation is officially available, we aimed to analyze determinants of cholera at the local level and identify priority localities in need of interventions. After estimating the likely boundaries of 1,730 localities by using Voronoi polygons, we mapped 5,322 suspected cholera cases reported during January 2015–September 2016 by locality alongside environmental and socioeconomic variables. A hierarchical clustering on principal components highlighted 2 classes with high cholera risk: localities close to rivers and unimproved water sources (standardized incidence ratio 1.71, 95% CI 1.02–2.87; p = 0.04) and urban localities with markets (standardized incidence ratio 1.69, 95% CI 1.25–2.29; p = 0.0006). Our analyses helped identify and characterize areas where efforts should be focused to reduce vulnerability to cholera and other waterborne diseases; these methods could be used in other contexts.

Cold and dry winter conditions are associated with greater SARS-CoV-2 transmission at regional level in western countries during the first epidemic wave

Higher transmissibility of SARS-CoV-2 in cold and dry weather conditions has been hypothesized since the onset of the COVID-19 pandemic but the level of epidemiological evidence remains low. During the first wave of the pandemic, Spain, Italy, France, Portugal, Canada and USA presented an early spread, a heavy COVID-19 burden, and low initial public health response until lockdowns. In a context when testing was limited, we calculated the basic reproduction number (R₀) in 63 regions from the growth in regional death counts. After adjusting for population density, early spread of the epidemic, and age structure, temperature and humidity were negatively associated with SARS-CoV-2 transmissibility. A reduction of mean absolute humidity by 1 g/m³ was associated with a 0.15-unit increase of R₀. Below 10 °C, a temperature reduction of 1 °C was associated with a 0.16-unit increase of R₀. Our results confirm a dependency of SARS-CoV-2 transmissibility to weather conditions in the absence of control measures during the first wave. The transition from summer to winter, corresponding to drop in temperature associated with an overall decrease in absolute humidity, likely contributed to the intensification of the second wave in north-west hemisphere countries. Non-pharmaceutical interventions must be adjusted to account for increased transmissibility in winter conditions.

Factors associated with the spatial heterogeneity of the first wave of COVID-19 in France: a nationwide geo-epidemiological study

BACKGROUND

The objective of this study was to better understand the factors associated with the heterogeneity of in-hospital COVID-19 morbidity and mortality across France, one of the countries most affected by COVID-19 in the early months of the pandemic.

METHODS

This geo-epidemiological analysis was based on data publicly available on government and administration websites for the 96 administrative departments of metropolitan France between March 19 and May 11, 2020, including Public Health France, the Regional Health Agencies, the French national statistics institute, and the Ministry of Health. Using hierarchical ascendant classification on principal component analysis of multidimensional variables, and multivariate analyses with generalised additive models, we assessed the associations between several factors (spatiotemporal spread of the epidemic between Feb 7 and March 17, 2020, the national lockdown, demographic population structure, baseline intensive care capacities, baseline population health and health-care services, new chloroquine and hydroxychloroquine dispensations, economic indicators, degree of urbanisation, and climate profile) and in-hospital COVID-19 incidence, mortality, and case fatality rates. Incidence rate was defined as the cumulative number of in-hospital COVID-19 cases per 100 000 inhabitants, mortality rate as the cumulative number of in-hospital COVID-19 deaths per 100 000, and case fatality rate as the cumulative number of in-hospital COVID-19 deaths per cumulative number of in-hospital COVID-19 cases.

FINDINGS

From March 19 to May 11, 2020, hospitals in metropolitan France notified a total of 100 988 COVID-19 cases, including 16 597 people who were admitted to intensive care and 17 062 deaths. There was an overall cumulative in-hospital incidence rate of 155·6 cases per 100 000 inhabitants (range 19·4-489·5), in-hospital mortality rate of 26·3 deaths per 100 000 (1·1-119·2), and in-hospital case fatality rate of 16·9% (4·8-26·2). We found clear spatial heterogeneity of in-hospital COVID-19 incidence and mortality rates, following the spread of the epidemic. After multivariate adjustment, the delay between the first COVID-19-associated death and the onset of the national lockdown was positively associated with in-hospital incidence (adjusted standardised incidence ratio 1·02, 95% CI 1·01-1·04), mortality (adjusted standardised mortality ratio 1·04, 1·02-1·06), and case fatality rates (adjusted standardised fatality ratio 1·01, 1·01-1·02). Mortality and case fatality rates were higher in departments with older populations (adjusted standardised ratio for populations with a high proportion older than aged >85 years 2·17 [95% CI 1·20-3·90] for mortality and 1·43 [1·08-1·88] for case fatality rate). Mortality rate was also associated with incidence rate (1·0004, 1·0002-1·001), but mortality and case fatality rates did not appear to be associated with baseline intensive care capacities. We found no association between climate and in-hospital COVID-19 incidence, or between economic indicators and in-hospital COVID-19 incidence or mortality rates.

INTERPRETATION

This ecological study highlights the impact of the epidemic spread, national lockdown, and reactive adaptation of intensive care capacities on the spatial distribution of COVID-19 morbidity and mortality. It provides information for future geo-epidemiological analyses and has implications for preparedness and response policies to current and future epidemic waves in France and elsewhere.

FUNDING

None.

Outbreak of pneumococcal pneumonia among shipyard workers in Marseille, France, January to February 2020

We report the third outbreak of pneumococcal pneumonia within one year among workers in European shipyards. During January and February 2020, 37 cases of pneumonia were identified in a shipyard in Marseille, south-eastern France. Outbreak control measures were implemented, including a mass vaccination campaign with 23-valent pneumococcal polysaccharide vaccine targeting all shipyard workers. Given the high mobility of shipyard workers, coordinated responses between European public health institutes are necessary to avoid further outbreaks.

Les indicateurs d’alerte et de surveillance de la Covid-19

Face à la crise sanitaire provoquée par la pandémie de Covid-19 en France, Santé publique France a mis en place un système de surveillance évolutif fondé sur des définitions de cas possible, probable et confirmé. Le décompte quotidien se limite cependant aux cas confirmés par reverse transcriptase polymerase chain reaction ou sérologie SARS-CoV-2 (actuellement via la plateforme SI-DEP), aux cas hospitalisés (via le Système d’information pour le suivi des victimes d’attentats) et aux décès hospitaliers par Covid-19. Ce suivi de la circulation virale est forcément non exhaustif, et l’estimation de l’incidence est complétée par d’autres indicateurs comme les appels au 15, les recours à SOS Médecins, les passages dans les services d’accueil des urgences, les consultations de médecine de ville via le réseau Sentinelle. Le suivi de la mortalité non hospitalière s’est heurté aux délais de transmission des certificats de décès et au manque de diagnostic fiable. Seule la létalité hospitalière a pu être mesurée de manière fiable. Moyennant un certain nombre de précautions statistiques et d’hypothèses de travail, les modèles ont permis d’anticiper l’évolution de l’épidémie à partir de deux indicateurs essentiels : le ratio de reproduction R et le temps de doublement épidémique. En Île-de-France, l’Assistance publique– Hôpitaux de Paris a complété ce tableau de bord grâce à son entrepôt de données de santé et a ainsi pu modéliser de manière fine le parcours de soins des patients. L’ensemble de ces indicateurs a été essentiel pour assurer une planification de la réponse à la crise.

Impact of patron saint festivities on cholera in three communes in Haiti

BACKGROUND

Religious pilgrimages are among the anthropogenic factors known to be associated with the transmission of diarrheal diseases, such as cholera. This ecological study aimed to describe the evolution of cholera and assess the relationship between the implementation of the 'coup de poing' strategy during the patron saint festivities and the incidence of cholera in the three communes of Cabaret, Carrefour, and Croix-des-Bouquets in Haiti in 2017.

METHODS

An epidemiological curve was produced to illustrate the evolution of cholera at the communal level. Generalized linear models assuming a Poisson distribution were used to weight the annual cholera incidence of communal sections against variables such as the number of patronal festivities, population density and annual precipitation rates. The number of cases in the week of the festivity as well as one and 2 weeks later was weighted against patronal festivities and weekly precipitation rates.

RESULTS

In total, 3633 suspected cholera cases were continuously reported in three communes in Haiti (Cabaret, Carrefour, Croix-des-bouquets) during the 52-epidemiological week period in 2017. After controlling for rainfall and population density, the implementation of the 'coup de poing' strategy during the patron saint festivities was associated with a significant reduction in cholera incidence of 57.23% [PR = 0.4277 (97.5% CI: 0.2798-0.6193), p = 0.0000244]. The implementation of the strategy was associated with a reduction in cholera incidence of 25.41% 1 week following patronal festivities.

CONCLUSION

This study showed a continuous presence of cholera in three communes in Haiti in 2017 and an association between the implementation of the 'coup de poing' strategy during patronal festivities and a reduction in cholera incidence. The findings imply that the multi-partner 'coup de poing' strategy may have contributed to the reduced cholera incidence following patron saint festivities and in Ouest department in Haiti in 2017.

Association of Autofluorescence-Based Detection of the Parathyroid Glands During Total Thyroidectomy With Postoperative Hypocalcemia Risk: Results of the PARAFLUO Multicenter Randomized Clinical Trial

Importance

Because inadvertent damage of parathyroid glands can lead to postoperative hypocalcemia, their identification and preservation, which can be challenging, are pivotal during total thyroidectomy.

Objective

To determine if intraoperative imaging systems using near-infrared autofluorescence (NIRAF) light to identify parathyroid glands could improve parathyroid preservation and reduce postoperative hypocalcemia.

Design, Setting, and Participants

This randomized clinical trial was conducted from September 2016 to October 2018, with a 6-month follow-up at 3 referral hospitals in France. Adult patients who met eligibility criteria and underwent total thyroidectomy were randomized. The exclusion criteria were preexisting parathyroid diseases.

Interventions

Use of intraoperative NIRAF imaging system during total thyroidectomy.

Main Outcomes and Measures

The primary outcome was the rate of postoperative hypocalcemia (a corrected calcium <8.0 mg/dL [to convert to mmol/L, multiply by 0.25] at postoperative day 1 or 2). The main secondary outcomes were the rates of parathyroid gland autotransplantation and inadvertent parathyroid gland resection.

Results

A total of 245 of 529 eligible patients underwent randomization. Overall, 241 patients were analyzed for the primary outcome (mean [SD] age, 53.6 [13.6] years; 191 women [79.3%]): 121 who underwent NIRAF-assisted thyroidectomy and 120 who underwent conventional thyroidectomy (control group). The temporary postoperative hypocalcemia rate was 9.1% (11 of 121 patients) in the NIRAF group and 21.7% (26 of 120 patients) in the control group (between-group difference, 12.6% [95% CI, 5.0%-20.1%]; P = .007). There was no significant difference in permanent hypocalcemia rates (0% in the NIRAF group and 1.6% [2 of 120 patients] in the control group). Multivariate analyses accounting for center and surgeon heterogeneity and adjusting for confounders, found that use of NIRAF reduced the risk of hypocalcemia with an odds ratio of 0.35 (95% CI, 0.15-0.83; P = .02). Analysis of secondary outcomes showed that fewer patients experienced parathyroid autotransplantation in the NIRAF group than in the control group: respectively, 4 patients (3.3% [95% CI, 0.1%-6.6%) vs 16 patients (13.3% [95% CI, 7.3%-19.4%]; P = .009). The number of inadvertently resected parathyroid glands was significantly lower in the NIRAF group than in the control group: 3 patients (2.5% [95% CI, 0.0%-5.2%]) vs 14 patients (11.7% [95% CI, 5.9%-17.4%], respectively; P = .006).

Conclusions and Relevance

The use of NIRAF for the identification of the parathyroid glands may help improve the early postoperative hypocalcemia rate significantly and increase parathyroid preservation after total thyroidectomy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02892253.

Spatio-temporal variation of malaria hotspots in Central Senegal, 2008-2012

Background

In malaria endemic areas, identifying spatio-temporal hotspots is becoming an important element of innovative control strategies targeting transmission bottlenecks. The aim of this work was to describe the spatio-temporal variation of malaria hotspots in central Senegal and to identify the meteorological, environmental, and preventive factors that influence this variation.

Methods

This study analysed the weekly incidence of malaria cases recorded from 2008 to 2012 in 575 villages of central Senegal (total population approximately 500,000) as part of a trial of seasonal malaria chemoprevention (SMC). Data on weekly rainfall and annual vegetation types were obtained for each village through remote sensing. The time series of weekly malaria incidence for the entire study area was divided into periods of high and low transmission using change-point analysis. Malaria hotspots were detected during each transmission period with the SaTScan method. The effects of rainfall, vegetation type, and SMC intervention on the spatio-temporal variation of malaria hotspots were assessed using a General Additive Mixed Model.

Results

The malaria incidence for the entire area varied between 0 and 115.34 cases/100,000 person weeks during the study period. During high transmission periods, the cumulative malaria incidence rate varied between 7.53 and 38.1 cases/100,000 person-weeks, and the number of hotspot villages varied between 62 and 147. During low transmission periods, the cumulative malaria incidence rate varied between 0.83 and 2.73 cases/100,000 person-weeks, and the number of hotspot villages varied between 10 and 43. Villages with SMC were less likely to be hotspots (OR = 0.48, IC95%: 0.33–0.68). The association between rainfall and hotspot status was non-linear and depended on both vegetation type and amount of rainfall. The association between village location in the study area and hotspot status was also shown.

Conclusion

In our study, malaria hotspots varied over space and time according to a combination of meteorological, environmental, and preventive factors. By taking into consideration the environmental and meteorological characteristics common to all hotspots, monitoring of these factors could lead targeted public health interventions at the local level. Moreover, spatial hotspots and foci of malaria persisting during LTPs need to be further addressed.

Trial registration

The data used in this work were obtained from a clinical trial registered on July 10, 2008 at www.clinicaltrials.gov under NCT00712374.

Altered muscle membrane potential and redox status differentiates two subgroups of patients with chronic fatigue syndrome

Background

In myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), altered membrane excitability often occurs in exercising muscles demonstrating muscle dysfunction regardless of any psychiatric disorder. Increased oxidative stress is also present in many ME/CFS patients and could affect the membrane excitability of resting muscles.

Methods

Seventy-two patients were examined at rest, during an incremental cycling exercise and during a 10-min post-exercise recovery period. All patients had at least four criteria leading to a diagnosis of ME/CFS. To explore muscle membrane excitability, M-waves were recorded during exercise (rectus femoris (RF) muscle) and at rest (flexor digitorum longus (FDL) muscle). Two plasma markers of oxidative stress (thiobarbituric acid reactive substance (TBARS) and oxidation–reduction potential (ORP)) were measured. Plasma potassium (K⁺) concentration was also measured at rest and at the end of exercise to explore K⁺ outflow.

Results

Thirty-nine patients had marked M-wave alterations in both the RF and FDL muscles during and after exercise while the resting values of plasma TBARS and ORP were increased and exercise-induced K⁺ outflow was decreased. In contrast, 33 other patients with a diagnosis of ME/CFS had no M-wave alterations and had lower baseline levels of TBARS and ORP. M-wave changes were inversely proportional to TBARS and ORP levels.

Conclusions

Resting muscles of ME/CFS patients have altered muscle membrane excitability. However, our data reveal heterogeneity in some major biomarkers in ME/CFS patients. Measurement of ORP may help to improve the diagnosis of ME/CFS.

Trial registration Ethics Committee “Ouest II” of Angers (May 17, 2019) RCB ID: number 2019-A00611-56

Estimating effectiveness of case-area targeted response interventions against cholera in Haiti

Case-area targeted interventions (CATIs) against cholera are conducted by rapid response teams, and may include various activities like water, sanitation, hygiene measures. However, their real-world effectiveness has never been established. We conducted a retrospective observational study in 2015-2017 in the Centre department of Haiti. Using cholera cases, stool cultures and CATI records, we identified 238 outbreaks that were responded to. After adjusting for potential confounders, we found that a prompt response could reduce the number of accumulated cases by 76% (95% confidence interval, 59 to 86) and the outbreak duration by 61% (41 to 75) when compared to a delayed response. An intense response could reduce the number of accumulated cases by 59% (11 to 81) and the outbreak duration by 73% (49 to 86) when compared to a weaker response. These results suggest that prompt and repeated CATIs were significantly effective at mitigating and shortening cholera outbreaks in Haiti.

Whole genome sequence of Vibrio cholerae directly from dried spotted filter paper

Background

Global estimates for cholera annually approximate 4 million cases worldwide with 95,000 deaths. Recent outbreaks, including Haiti and Yemen, are reminders that cholera is still a global health concern. Cholera outbreaks can rapidly induce high death tolls by overwhelming the capacity of health facilities, especially in remote areas or areas of civil unrest. Recent studies demonstrated that stool specimens preserved on filter paper facilitate molecular analysis of Vibrio cholerae in resource limited settings. Specimens preserved in a rapid, low-cost, safe and sustainable manner for sequencing provides previously unavailable data about circulating cholera strains. This may ultimately contribute new information to shape public policy response on cholera control and elimination.

Methodology/Principal findings

Whole genome sequencing (WGS) recovered close to a complete sequence of the V. cholerae O1 genome with satisfactory genome coverage from stool specimens enriched in alkaline peptone water (APW) and V. cholerae culture isolates, both spotted on filter paper. The minimum concentration of V. cholerae DNA sufficient to produce quality genomic information was 0.02 ng/μL. The genomic data confirmed the presence or absence of genes of epidemiological interest, including cholera toxin and pilus loci. WGS identified a variety of diarrheal pathogens from APW-enriched specimen spotted filter paper, highlighting the potential for this technique to explore the gut microbiome, potentially identifying co-infections, which may impact the severity of disease. WGS demonstrated that these specimens fit within the current global cholera phylogenetic tree, identifying the strains as the 7^th pandemic El Tor.

Conclusions

WGS results allowed for mapping of short reads from APW-enriched specimen and culture isolate spotted filter papers. This provided valuable molecular epidemiological sequence information on V. cholerae strains from remote, low-resource settings. These results identified the presence of co-infecting pathogens while providing rare insight into the specific V. cholerae strains causing outbreaks in cholera-endemic areas.

Cholera affects more than 4 million people globally every year; people predominantly living in poverty or in resource-constrained conditions including political crises or natural disasters. Cholera’s typical presentation is characterized by rapid onset of acute watery diarrhea and vomiting which can progress from watery stool to shock in as little as four hours. Laboratory conditions needed for culture confirmation and strain preservation are rarely to never present in these affected areas. In fact, many cholera endemic areas in Sub-Saharan African are so remote that even treatment response alone is often challenging. Here we present the genomic analysis of DNA extracted from dried filter paper, which is a low-cost, low-tech and sustainable method. Previously this method has facilitated cholera confirmation by PCR, but we demonstrate that this method is also suitable for whole genome sequencing and subsequent strain characterization by presenting the analysis of samples from an outbreak in a remote area of Cameroon. This method will facilitate the understanding of the molecular epidemiology in cholera-prone areas, which were previously too challenging to attempt. It also introduces a method that can be used on a broader scale for diarrheal disease surveillance, including providing a window into co-infection and microbiome analyses.

The case-area targeted rapid response strategy to control cholera in Haiti: a four-year implementation study

BACKGROUND

In October 2010, Haiti was struck by a large-scale cholera epidemic. The Haitian government, UNICEF and other international partners launched an unprecedented nationwide alert-response strategy in July 2013. Coordinated NGOs recruited local rapid response mobile teams to conduct case-area targeted interventions (CATIs), including education sessions, household decontamination by chlorine spraying, and distribution of chlorine tablets. An innovative red-orange-green alert system was also established to monitor the epidemic at the communal scale on a weekly basis. Our study aimed to describe and evaluate the exhaustiveness, intensity and quality of the CATIs in response to cholera alerts in Haiti between July 2013 and June 2017.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed the response to 7,856 weekly cholera alerts using routine surveillance data and severity criteria, which was based on the details of 31,306 notified CATIs. The odds of CATI response during the same week (exhaustiveness) and the number of complete CATIs in responded alerts (intensity and quality) were estimated using multivariate generalized linear mixed models and several covariates. CATIs were carried out significantly more often in response to red alerts (adjusted odds ratio (aOR) [95%-confidence interval, 95%-CI], 2.52 [2.22-2.87]) compared with orange alerts. Significantly more complete CATIs were carried out in response to red alerts compared with orange alerts (adjusted incidence ratio (aIR), 1.85 [1.73-1.99]). Over the course of the eight-semester study, we observed a significant improvement in the exhaustiveness (aOR, 1.43 [1.38-1.48] per semester) as well as the intensity and quality (aIR, 1.23 [1.2-1.25] per semester) of CATI responses, independently of funds available for the strategy. The odds of launching a CATI response significantly decreased with increased rainfall (aOR, 0.99 [0.97-1] per each accumulated cm). Response interventions were significantly heterogeneous between NGOs, communes and departments.

CONCLUSIONS/SIGNIFICANCE

The implementation of a nationwide case-area targeted rapid response strategy to control cholera in Haiti was feasible albeit with certain obstacles. Such feedback from the field and ongoing impact studies will be very informative for actors and international donors involved in cholera control and elimination in Haiti and in other affected countries.

Epidemiological and molecular forensics of cholera recurrence in Haiti

Cholera has affected Haiti with damping waves of outbreaks since October 2010. However, mechanisms behind disease persistence during lull periods remain poorly understood. By mid 2014, cholera transmission seemed to only persist in the northern part of Haiti. Meanwhile, cholera appeared nearly extinct in the capital, Port-au-Prince, where it eventually exploded in September 2014. This study aimed to determine whether this outbreak was caused by local undetected cases or by re-importation of the disease from the north. Applying an integrated approach between November 2013 and November 2014, we assessed the temporal and spatial dynamics of cholera using routine surveillance data and performed population genetics analyses of 178 Vibrio cholerae O1 clinical isolates. The results suggest that the northern part of the country exhibited a persisting metapopulation pattern with roaming oligoclonal outbreaks that could not be effectively controlled. Conversely, undetected and unaddressed autochthonous low-grade transmission persisted in the Port-au-Prince area, which may have been the source of the acute outbreak in late-2014. Cholera genotyping is a simple but powerful tool to adapt control strategies based on epidemic specificities. In Haiti, these data have already yielded significant progress in cholera surveillance, which is a key component of the strategy to eventually eliminate cholera.

Spatiotemporal analysis of malaria for new sustainable control strategies

Malaria transmission is highly heterogeneous through time and space, and mapping of this heterogeneity is necessary to better understand local dynamics. New targeted policies are needed as numerous countries have placed malaria elimination on their public health agenda for 2030. In this context, developing national health information systems and collecting information at sufficiently precise scales (at least at the 'week' and 'village' scales), is of strategic importance. In a recent study, Macharia et al. relied on extensive prevalence survey data to develop malaria risk maps for Kenya, including uncertainty assessments specifically designed to support decision-making by the National Malaria Control Program. Targeting local persistent transmission or epidemiologic changes is necessary to maintain efficient control, but also to deploy sustainable elimination strategies against identified transmission bottlenecks such as the reservoir of subpatent infections. Such decision-making tools are paramount to allocate resources based on sound scientific evidence and public health priorities.Please see related article: https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2489-9 .

[Simplified Protocols for Cholera Diagnosis in the National Public Health Laboratory, Port-au-Prince, Haiti]

While the incidence of cholera is decreasing in Haiti, the time required to render stool culture results with antibiogram using the standard method practiced at the National Public Health Laboratory (LNSP) remains at an average of 80 hours. This delay can be further lengthened by the process of rendering the analysis reports to the sites of care which significantly delays the community responses to cholera. Through this study, we have aimed to assess the reliability of partial results. We have studied 250 stool samples that were analyzed between January and September 2017 at the LNSP by determining the specificity, positive predictive value and positive likelihood ratio of i) the identification of yellowish colonies and ii) the identification of yellowish colonies with a positive oxidase assay in comparison to the stool culture. Compared to the entire process, the identification of yellowish colonies showed a specificity of 56%, a positive predictive value of 69% and a positive likelihood ratio of 2.27. The identification of yellowish colonies with a positive oxidase assay showed a specificity of 77%, a positive predictive value of 81% and a positive likelihood ratio of 4.31. The communication of partial results at these steps would likely guide community interventions despite a relative decrease in reliability of the results.

[Cholera]

Cholera. Cholera is caused by Vibrio cholerae, a Gram-negative bacteria. Some strains can synthesize an enterotoxin - the cholera toxin - which is responsible for the disease. Cholera has already caused seven pandemics since the beginning of the 19th century; the seventh started from Indonesia in 1961 and was provoked by the emergence of an epidemic clone, V. cholerae O1 El Tor. Most cases occure in South Asia, Africa, Haiti and most recently Yemen. Contamination is by ingestion, due to close contact with a patient, or by contaminated water and food. Patients present with acute watery diarrhea and vomiting as a result of the toxin-induced fluid intestinal leakage. The severity of dehydration determines the prognosis, which can be fatal in a few hours if intense rehydration is not started immediately. Prevention is based on universal access to water, sanitation and hand hygiene. An oral vaccine can help prevent or control epidemics.

Mathematical models for predicting human mobility in the context of infectious disease spread: introducing the impedance model

Background

Mathematical models of human mobility have demonstrated a great potential for infectious disease epidemiology in contexts of data scarcity. While the commonly used gravity model involves parameter tuning and is thus difficult to implement without reference data, the more recent radiation model based on population densities is parameter-free, but biased. In this study we introduce the new impedance model, by analogy with electricity. Previous research has compared models on the basis of a few specific available spatial patterns. In this study, we use a systematic simulation-based approach to assess the performances.

Methods

Five hundred spatial patterns were generated using various area sizes and location coordinates. Model performances were evaluated based on these patterns. For simulated data, comparison measures were average root mean square error (aRMSE) and bias criteria. Modeling of the 2010 Haiti cholera epidemic with a basic susceptible–infected–recovered (SIR) framework allowed an empirical evaluation through assessing the goodness-of-fit of the observed epidemic curve.

Results

The new, parameter-free impedance model outperformed previous models on simulated data according to average aRMSE and bias criteria. The impedance model achieved better performances with heterogeneous population densities and small destination populations. As a proof of concept, the basic compartmental SIR framework was used to confirm the results obtained with the impedance model in predicting the spread of cholera in Haiti in 2010.

Conclusions

The proposed new impedance model provides accurate estimations of human mobility, especially when the population distribution is highly heterogeneous. This model can therefore help to achieve more accurate predictions of disease spread in the context of an epidemic.

Electronic supplementary material

The online version of this article (10.1186/s12942-017-0115-7) contains supplementary material, which is available to authorized users.

Impact of autofluorescence-based identification of parathyroids during total thyroidectomy on postoperative hypocalcemia: a before and after controlled study

BACKGROUND

The clinical impact of intraoperative autofluorescence-based identification of parathyroids using a near-infrared camera remains unknown.

METHODS

In a before and after controlled study, we compared all patients who underwent total thyroidectomy by the same surgeon during Period 1 (January 2015 to January 2016) without near-infrared (near-infrared- group) and those operated on during Period 2 (February 2016 to September 2016) using a near-infrared camera (near-infrared+ group). In parallel, we also compared all patients who underwent surgery without near-infrared during those same periods by another surgeon in the same unit (control groups). Main outcomes included postoperative hypocalcemia, parathyroid identification, autotransplantation, and inadvertent resection.

RESULTS

The near-infrared+ group displayed significantly lower postoperative hypocalcemia rates (5.2%) than the near-infrared- group (20.9%; P < .001). Compared with the near-infrared- patients, the near-infrared+ group exhibited an increased mean number of identified parathyroids and reduced parathyroid autotransplantation rates, although no difference was observed in inadvertent resection rates. Parathyroids were identified via near-infrared before they were visualized by the surgeon in 68% patients. In the control groups, parathyroid identification improved significantly from Period 1 to Period 2, although autotransplantation, inadvertent resection and postoperative hypocalcemia rates did not differ.

CONCLUSION

Near-infrared use during total thyroidectomy significantly reduced postoperative hypocalcemia, improved parathyroid identification and reduced their autotransplantation rate.

Spatio-Temporal Dynamics of Asymptomatic Malaria: Bridging the Gap Between Annual Malaria Resurgences in a Sahelian Environment

In areas of seasonal malaria transmission, the incidence rate of malaria infection is presumed to be near zero at the end of the dry season. Asymptomatic individuals may constitute a major parasite reservoir during this time. We conducted a longitudinal analysis of the spatio-temporal distribution of clinical malaria and asymptomatic parasitemia over time in a Malian town to highlight these malaria transmission dynamics. For a cohort of 300 rural children followed over 2009–2014, periodicity and phase shift between malaria and rainfall were determined by spectral analysis. Spatial risk clusters of clinical episodes or carriage were identified. A nested-case-control study was conducted to assess the parasite carriage factors. Malaria infection persisted over the entire year with seasonal peaks. High transmission periods began 2–3 months after the rains began. A cluster with a low risk of clinical malaria in the town center persisted in high and low transmission periods. Throughout 2009–2014, cluster locations did not vary from year to year. Asymptomatic and gametocyte carriage were persistent, even during low transmission periods. For high transmission periods, the ratio of asymptomatic to clinical cases was approximately 0.5, but was five times higher during low transmission periods. Clinical episodes at previous high transmission periods were a protective factor for asymptomatic carriage, but carrying parasites without symptoms at a previous high transmission period was a risk factor for asymptomatic carriage. Stable malaria transmission was associated with sustained asymptomatic carriage during dry seasons. Control strategies should target persistent low-level parasitemia clusters to interrupt transmission.