Murine typhus is a flea-borne zoonotic disease that has been recently reported on Reunion Island, an oceanic volcanic island located in the Indian Ocean. Five years of survey implemented by the regional public health services have... more
Murine typhus is a flea-borne zoonotic disease that has been recently reported on Reunion Island, an oceanic volcanic island located in the Indian Ocean. Five years of survey implemented by the regional public health services have highlighted a strong temporal and spatial structure of the disease in humans, with cases mainly reported during the humid season and restricted to the dry southern and western portions of the island. We explored the environmental component of this zoonosis in an attempt to decipher the drivers of disease transmission. To do so, we used data from a previously published study (599 small mammals and 175Xenopsyllafleas from 29 sampling sites) in order to model the spatial distribution of rat fleas throughout the island. In addition, we carried out a longitudinal sampling of rats and their ectoparasites over a 12 months period in six study sites (564 rats and 496Xenopsyllafleas) in order to model the temporal dynamics of flea infestation of rats. Generalized Li...
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Modelling spatial dynamics may be used to gather understanding on how insect populations develop in a given environment. Hypotheses and independent knowledge inferred from ground observations can be confronted for consistency, and the... more
Modelling spatial dynamics may be used to gather understanding on how insect populations develop in a given environment. Hypotheses and independent knowledge inferred from ground observations can be confronted for consistency, and the mechanisms requiring finer descriptions can also be identified. Different scenarios of pest management can then be simulated and the possible consequences of the measures taken assessed. However, spatial dynamics are expressions of multiple and complex ongoing processes, and their modelling at different temporal and spatial scales remains a challenging task. Various approaches have been proposed to address this, including cellular automata, agent-based systems, discrete event systems, system dynamics and geographic information systems, each displaying specific benefits in some domains of application, and weaknesses in others. In this area of research, we are exploring an approach based on the manipulation of graphs (mathematical object expressing a set...
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The expansion of mosquito species worldwide is creating a powerful network for the spread of arboviruses. In addition to the destruction of breeding sites (prevention) and mass trapping, methods based on the sterile insect technique... more
The expansion of mosquito species worldwide is creating a powerful network for the spread of arboviruses. In addition to the destruction of breeding sites (prevention) and mass trapping, methods based on the sterile insect technique (SIT), the autodissemination of pyriproxyfen (ADT), and a fusion of elements from both of these known as boosted SIT (BSIT), are being developed to meet the urgent need for effective vector control. However, the comparative potential of these methods has yet to be explored in different environments. This is needed to propose and integrate informed guidelines into sustainable mosquito management plans. We extended a weather-dependent model of Aedes albopictus population dynamics to assess the effectiveness of these different vector control methods, alone or in combination, in a tropical (Reunion island, southwest Indian Ocean) and a temperate (Montpellier area, southern France) climate. Our results confirm the potential efficiency of SIT in temperate clim...
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Purpose: Rift Valley fever virus (RVFV) is a mosquito-borne zoonosis endemic in Africa. Since 1930, outbreaks have occurred in tropical, hot-irrigated or arid ecosystems. In 2008-2009, an outbreak occurred in a temperate and mountainous... more
Purpose: Rift Valley fever virus (RVFV) is a mosquito-borne zoonosis endemic in Africa. Since 1930, outbreaks have occurred in tropical, hot-irrigated or arid ecosystems. In 2008-2009, an outbreak occurred in a temperate and mountainous area of Madagascar highlands. We conducted a 3-year serological follow-up in cattle in a pilot area of these highlands (894 bovine in 2009, 516 in 2010 and 210 in 2011). Cattle exchange and vector population dynamics were investigated. Despite unfavourable climatic conditions and absence of Aedes mosquitoes (main vectors in Africa), results showed that the virus kept circulating till 2011 in absence of clinical cases. The objective of this study was to understand the mechanisms allowing the virus to circulate in this unfavourable ecosystem. We propose a model coupling cattle exchange practices and vector-borne transmission to explain the RVFV spread and persistence in this area. Methods: The model is parameterized to reproduce the local conditions of...
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Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae). To date, only 5 species of... more
Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae). To date, only 5 species of Culicoides are recorded in Reunion Island: Culicoides imicola, C. bolitinos, C. enderleini, C. grahamii, and C. kibatiensis. Among these, at least the first three have been implicated in the transmission of BT and EHD viruses to ruminants. Since January 2016, biweekly monitoring using OVI traps have been set up in 10 sites to study the temporal dynamics of each species. A hurdle model (i.e. a logistic regression presence/ absence model combined with a zero-truncated negative binomial mixed effect abundance model) was developed for each species in order to obtain first insights regarding the climatic and environmental determinants driving presence/absence and abundance of Culicoides. Our first results show that temperature, wind speed, vegetation inde...
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Context. Mosquitoes are vectors of major pathogens worldwide, such as the pathogens of Malaria, Chikungunya, dengue, Rift Valley or Wes t Nile fevers. Accurate understanding and prediction of mosquito population dynamics are needed to... more
Context. Mosquitoes are vectors of major pathogens worldwide, such as the pathogens of Malaria, Chikungunya, dengue, Rift Valley or Wes t Nile fevers. Accurate understanding and prediction of mosquito population dynamics are needed to optimize surveillance and control of mosquito-borne diseases. Objectives. This study had two main objectives i) understanding the relationships between env ironmental conditions and mosquito population dynamics to predict mosquito densities and ii) developing operational tools for surveillance and control of vector-borne diseases, taking the example of Aedes albopictus in Reunion Island. Methods. We developed different models using respectively process-based and data-based approaches to study the relationships between meteorological variables (daily temperature and rainfall), land cover classification derived from SPOT-6 imagery, and entomological collections of Aedes albopictus larvae from 9 sites located around the Island. The best models were implem...
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We have developed an explicit spatial and temporal model to predict the population dynamics and dispersal of the two main mosquito vector species (Aedes vexans and Culex poicilipes) involved in Rift Valley fever virus (RVFV) transmission... more
We have developed an explicit spatial and temporal model to predict the population dynamics and dispersal of the two main mosquito vector species (Aedes vexans and Culex poicilipes) involved in Rift Valley fever virus (RVFV) transmission in Senegal (western Africa). Covering an area of 11x10 km around the village of Barkedji, and located in the Ferlo valley (Northern Senegal), the study area is characterized by a complex and dense network of water bodies and ponds that are filled by rainfall during the rainy season (from July to mid- October). These water bodies are known to be the principal mosquito breeding sites in the area. A spatial diffusion model (Raffy and Tran, 2005) is applied in combination with a vector population dynamic model (Soti et al., 2009), and which takes into account the hydrological conditions of the system (Soti et al., submitted). The vector population dynamic model has been more specifically derived from Porphyre et al. (2005). Daily mosquito abundance for ...
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The unexpected Ebola virus outbreak in West Africa in 2014 involving the Zaire ebolavirus made clear that other regions outside Central Africa, its previously documented niche, were at risk of future epidemics. The complex transmission... more
The unexpected Ebola virus outbreak in West Africa in 2014 involving the Zaire ebolavirus made clear that other regions outside Central Africa, its previously documented niche, were at risk of future epidemics. The complex transmission cycle and a lack of epidemiological data make mapping areas at risk of the disease challenging. We used a Geographic Information System-based multicriteria evaluation (GIS-MCE), a knowledge-based approach, to identify areas suitable for Ebola virus spillover to humans in regions of Guinea, Congo and Gabon where Ebola viruses already emerged. We identified environmental, climatic and anthropogenic risk factors and potential hosts from a literature review. Geographical data layers, representing risk factors, were combined to produce suitability maps of Ebola virus spillover at the landscape scale. Our maps show high spatial and temporal variability in the suitability for Ebola virus spillover at a fine regional scale. Reported spillover events fell in a...
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Background: Reunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect-borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) are the... more
Background: Reunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect-borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) are the vectors of bluetongue (BTV) and epizootic hemorrhagic diseases of deer (EHDV) viruses. In a previous study, statistical models based on environmental and meteorological data were developed for the five Culicoides species present in the island to provide a better understanding of their ecology and predict their presence and abundance. The purpose of this study was to couple these statistical models with a Geographic Information System (GIS) in order to produce dynamic maps of the distribution of Culicoides throughout the island. Methods: Based on meteorological data from ground weather stations and satellite-derived environmental data, the abundance of each Culicoides species was estimated for the 2,214 husbandry locations on the island for the period ran...
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Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF... more
Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF recurrent circulation, we modelled a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics, and nomadic herd movements recorded in Younoufere area [1]. To calibrate the model, serological surveys were performed in 2015-2016 on both resident and nomadic herds in the same area. Mosquito population dynamics were obtained from a published model trained in the same region [2]. Model comparison techniques were used to compare five different scenarios of virus introduction by nomadic herds associated or not with vertical transmission in Aedes vexans. Our serological results confirmed a long lasting RVF endemicity in resident herds (IgG seroprevalence rate of 15.3%, ...
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Research Interests: Ecohealth, Biology, Ecology, Animal Ecology, Medicine, and 14 moreCulex, West nile virus, Cheval, Public health systems and services research, Culicidae, Gestion du risque, Flavivirus, Veterinary Sciences, Epidémiologie, éCologie Animale, Outbreak, hôte, Modèle mathématique, and Distribution spatiale
The Highly Pathogenic Avian Influenza H5N1 (HPAI) virus is now considered endemic in several Asian countries. In Cambodia, the virus has been circulating in the poultry population since 2004, with a dramatic effect on farmers'... more
The Highly Pathogenic Avian Influenza H5N1 (HPAI) virus is now considered endemic in several Asian countries. In Cambodia, the virus has been circulating in the poultry population since 2004, with a dramatic effect on farmers' livelihoods and public health. In Thailand, surveillance and control are still important to prevent any new H5N1 incursion. Risk mapping can contribute effectively to disease surveillance and control systems, but is a very challenging task in the absence of reliable disease data. In this work, we used spatial multicriteria decision analysis (MCDA) to produce risk maps for HPAI H5N1 in poultry. We aimed to i) evaluate the performance of the MCDA approach to predict areas suitable for H5N1 based on a dataset from Thailand, comparing the predictive capacities of two sources of a priori knowledge (literature and experts), and ii) apply the best method to produce a risk map for H5N1 in poultry in Cambodia. Our results showed that the expert-based model had a ve...
Research Interests: Geography, Cambodia, Thailand, Medicine, Vietnamese, and 15 moreDisease Outbreaks, Humans, Animals, CARTOGRAPHIE, Risk factors, Poultry, Aviculture, Gestion du risque, Risk Factors, Multiple Criteria Decision Analysis, Modèle mathématique, Decision Support Techniques, Analyse du risque, grippe aviaire, and Epidemiological monitoring
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Landscape ecology is seldom used in epidemiology. The aim of this study is to assess the possible improvements that can be derived from the use of landscape approaches on several scales when exploring local differences in disease... more
Landscape ecology is seldom used in epidemiology. The aim of this study is to assess the possible improvements that can be derived from the use of landscape approaches on several scales when exploring local differences in disease distribution, using bluetongue (BT) in Corsica as an example. The environment of BT-free and BT-infected sheep farms is described on a fine scale, using high resolution satellite images and a digital elevation model. Land-coverage is characterised by classifying the satellite image. Landscape metrics are calculated to quantify the number, diversity, length of edge and connectance of vegetation patches. The environment is described for three sizes of buffers around the farms. The models are tested with and without landscape metrics to see if such metrics improve the models. Internal and external validation of the models is performed and the relative impact of scale versus variables on the discriminatory ability of the models is explored. Results show that fo...
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Malaria resurgence risk in Morocco depends, among other factors, on environmental changes as well as the introduction of parasite carriers. The aim of this paper is to analyze the receptivity of the Loukkos area, large wetlands in... more
Malaria resurgence risk in Morocco depends, among other factors, on environmental changes as well as the introduction of parasite carriers. The aim of this paper is to analyze the receptivity of the Loukkos area, large wetlands in Northern Morocco, to quantify and to map malaria transmission risk in this region using biological and environmental data. This risk was assessed on entomological risk basis and was mapped using environmental markers derived from satellite imagery. Maps showing spatial and temporal variations of entomological risk forPlasmodium vivaxandP. falciparumwere produced. Results showed this risk to be highly seasonal and much higher in rice fields than in swamps. This risk is lower for AfrotropicalP. falciparumstrains because of the low infectivity ofAnopheles labranchiae, principal malaria vector in Morocco. However, it is very high forP. vivaxmainly during summer corresponding to the rice cultivation period. Although the entomological risk is high in Loukkos reg...
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Research Interests: Geography, Human Geography, Forecasting, Medicine, Humans, and 15 moreEurope, Birds, Animals, CARTOGRAPHIE, Paysage, Risk factors, Flavivirus, Risk Factors, Télédétection, éCologie Animale, Environmental Exposure, Confidence Interval, Normalized Difference Vegetation Index, Modèle mathématique, and Analyse du risque
An accurate understanding and prediction of mosquito population dynamics are needed to identify areas where there is a high risk of mosquito-borne disease spread and persistence. Simulation tools are relevant for supporting... more
An accurate understanding and prediction of mosquito population dynamics are needed to identify areas where there is a high risk of mosquito-borne disease spread and persistence. Simulation tools are relevant for supporting decision-makers in the surveillance of vector populations, as models of vector population dynamics provide predictions of the greatest risk periods for vector abundance, which can be particularly helpful in areas with a highly variable environment. We present a generic weather-driven model of mosquito population dynamics, which was applied to one species of each of the genera Anopheles, Culex, and Aedes, located in the same area and thus affected by similar weather conditions. The predicted population dynamics of Anopheles hyrcanus, Culex pipiens, and Aedes caspius were not similar. An. hyrcanus was abundant in late summer. Cx. pipiens was less abundant but throughout the summer. The abundance of both species showed a single large peak with few variations between...
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Research Interests: Landscape Ecology, Geography, Biology, Medicine, France, and 15 moreDisease Outbreaks, Female, Animals, Male, Environmental Variables, Bluetongue, écologie, Geographic Information, Culicoides, CERATOPOGONIDAE, Logistic Regression Model, High Spatial Resolution, Geographic Information Systems, Logistic Models, and Insect Vectors
Research Interests: Genetics, Geography, Computer Science, Ecology, Medicine, and 15 moreDisease Outbreaks, Humans, Computer Simulation, Dengue fever, Animals, Dengue, Culicidae, Large Scale, Differential equation, Ecological Applications, Diffusion Model, Environmental Parameter, Insect Vectors, Compartmental Model, and diffusion equation
Background The Camargue region is a former malaria endemic area, where potential Anopheles vectors are still abundant. Considering the importation of Plasmodium due to the high number of imported malaria cases in France, the aim of this... more
Background The Camargue region is a former malaria endemic area, where potential Anopheles vectors are still abundant. Considering the importation of Plasmodium due to the high number of imported malaria cases in France, the aim of this article was to make some predictions regarding the risk of malaria re-emergence in the Camargue. Methods Receptivity (vectorial capacity) and infectivity (vector susceptibility) were inferred using an innovative probabilistic approach and considering both Plasmodium falciparum and Plasmodium vivax. Each parameter of receptivity (human biting rate, anthropophily, length of trophogonic cycle, survival rate, length of sporogonic cycle) and infectivity were estimated based on field survey, bibliographic data and expert knowledge and fitted with probability distributions taking into account the variability and the uncertainty of the estimation. Spatial and temporal variations of the parameters were determined using environmental factors derived from satel...
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Research Interests: Forecasting, Medicine, Multidisciplinary, Humans, Early Warning System, and 15 moreEnvironmental public health, Birds, Animals, CARTOGRAPHIE, Paysage, Santé publique, Cheval, Culicidae, Flavivirus, Mediterranean region, Mediterranean Climate, Mediterranean Basin, Santé Animale, Modèle mathématique, and Analyse du risque
Research Interests: Geography, Remote Sensing, Incidence Geometry, Medicine, Disease Outbreaks, and 15 morePopulation, Humans, Q Fever, Land Cover, Mathematical Sciences, French Guiana, Census, American, Population Density, Incidence, Disease Outbreak, Indexation, Medical and Health Sciences, remote sensing data, and Satellite Image
Research Interests: Geography, Medical Microbiology, Research, Medicine, Emerging Infectious Diseases, and 15 moreAedes aegypti, Disease Outbreaks, Humans, Dengue fever, French Guiana, Cluster Analysis, Dengue, Clinical Sciences, Outbreak, Geographic Information System, Geographic Information Systems, Moustique, Relative Risk, fièvre, and Distribution spatiale
Interfaces between protected areas and their peripheries in southern Africa are subject to interactions between wildlife and livestock that vary in frequency and intensity. In these areas, the juxtaposition between production and... more
Interfaces between protected areas and their peripheries in southern Africa are subject to interactions between wildlife and livestock that vary in frequency and intensity. In these areas, the juxtaposition between production and conservation land uses in a context of increasing anthropisation can create issues associated with human-wildlife coexistence and raises concerns for biodiversity conservation, local development and livelihoods. This literature review aimed at addressing the need to consolidate and gather in one article current knowledge on potential uses of satellite remote sensing (SRS) products by movement ecologists to investigate the sympatry of wildlife/domestic ungulates in savanna interface environments. A keyword querying process of peer reviewed scientific paper, thesis and books has been implemented to identify references that (1) characterize the main environmental drivers impacting buffalo (Syncerus caffer caffer) and cattle (Bos taurus & Bos indicus) movements...
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Rift Valley Fever (RVF) is a vector-borne viral zoonosis, transmitted either through exposure to infected animals or through bites from infected mosquitoes, mainly from the Aedes or Culex genera. In semi-arid areas, water bodies, which... more
Rift Valley Fever (RVF) is a vector-borne viral zoonosis, transmitted either through exposure to infected animals or through bites from infected mosquitoes, mainly from the Aedes or Culex genera. In semi-arid areas, water bodies, which are full during the rainy season, allow the development of Aedes and Culex mosquito species. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, which lead to an above normal abundance of the vectorial populations. In Senegal, there is strong evidence that the disease is endemic. Yet, the correlation found in East Africa between extreme rainfall events and RVF outbreaks occurrence is not valid. We propose here a modelling approach which makes use of remote sensing data to investigate i) the role of rainfall temporal distribution in RVF outbreaks and ii) the possibility to develop an early-warning system for RVF in Senegal. The study area is an agropastoral zone located in Northern Senegal, a region characterize...
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Risk factors of Rift Valley fever (RVF) emergence remain partially unknown [1]. RVF is endemic in the Ferlo area (northern Senegal).A serological study performed in this region in small ruminants associated with an entomological study... more
Risk factors of Rift Valley fever (RVF) emergence remain partially unknown [1]. RVF is endemic in the Ferlo area (northern Senegal).A serological study performed in this region in small ruminants associated with an entomological study showed that the risk of RVF transmission, was spatially heterogeneous [2, 3] and linked to the pond structure. In the same area, we identified from satellite images three main landscape indexes potentially linked with the vector dynamic. These indexes were included as explanatory variables in a logistic regression mixed model. The 500-m landscape closure index was significantly correlated with higher serologic incidence. These results highlight the potential of high resolution remote sensing to characterize the landscape structure at a relevant scale to describe RVF risk areas [4]. The re-emergence of the virus during rainy season in this very dry area may be explained by two processes: transovarial transmission within the vector, or introduction of th...
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La superficie de la foret malgache a considerablement diminue sous l'effet de la culture sur brulis, pratique encore utilisee dans le nord-ouest du bassin de la Sofia. Dans cette zone, des pullulations recentes et sans precedent du... more
La superficie de la foret malgache a considerablement diminue sous l'effet de la culture sur brulis, pratique encore utilisee dans le nord-ouest du bassin de la Sofia. Dans cette zone, des pullulations recentes et sans precedent du criquet nomade Nomadacris septemfasciata (Serville, 1838) causant des ravages sur l'agriculture ont ete observees de 2000 a 2003. Le criquet nomade a atteint la phase gregaire en formant des bandes larvaires et des essaims pour la premiere fois dans cette zone en 2002. La disparition de la foret, entrave naturelle aux migrations du criquet, pourrait favoriser les migrations et permettrait le regroupement des populations acridiennes. Pour repondre a cette question, nous avons realise une etude diachronique par teledetection a partir de 2 images SPOT de 1986 et 2004 sur la region nord du bassin de la Sofia. L'evolution du couvert vegetal met en evidence la deforestation et une fragmentation des forets originelles. Comme l'attestent les donne...
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To date, there is no effective treatment to cure dengue fever, a mosquito-borne disease which has a major impact on human populations in tropical and sub-tropical regions. Although the characteristics of dengue infection are well known,... more
To date, there is no effective treatment to cure dengue fever, a mosquito-borne disease which has a major impact on human populations in tropical and sub-tropical regions. Although the characteristics of dengue infection are well known, factors associated with landscape are highly scale dependent in time and space, and therefore difficult to monitor. We propose here a mapping review based on 78 articles that study the relationships between landscape factors and urban dengue cases considering household, neighborhood and administrative levels. Landscape factors were retrieved from survey questionnaires, Geographic Information Systems (GIS), and remote sensing (RS) techniques. We structured these into groups composed of land cover, land use, and housing type and characteristics, as well as subgroups referring to construction material, urban typology, and infrastructure level. We mapped the co-occurrence networks associated with these factors, and analyzed their relevance according to a...
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Mosquitoes are vectors of major pathogen agents worldwide. Population dynamics models are useful tools to understand and predict mosquito abundances in space and time. To be used as forecasting tools over large areas, such models could... more
Mosquitoes are vectors of major pathogen agents worldwide. Population dynamics models are useful tools to understand and predict mosquito abundances in space and time. To be used as forecasting tools over large areas, such models could benefit from integrating remote sensing data that describe the meteorological and environmental conditions driving mosquito population dynamics. The main objective of this study is to assess a process-based modeling framework for mosquito population dynamics using satellite-derived meteorological estimates as input variables. A generic weather-driven model of mosquito population dynamics was applied to Rift Valley fever vector species in northern Senegal, with rainfall, temperature, and humidity as inputs. The model outputs using meteorological data from ground weather station vs satellite-based estimates are compared, using longitudinal mosquito trapping data for validation at local scale in three different ecosystems. Model predictions were consiste...
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Many zoonotic infectious diseases have emerged and re-emerged over the last two decades. There has been a significant increase in vector-borne diseases due to climate variations that lead to environmental changes favoring the development... more
Many zoonotic infectious diseases have emerged and re-emerged over the last two decades. There has been a significant increase in vector-borne diseases due to climate variations that lead to environmental changes favoring the development and adaptation of vectors. This study was carried out to improve knowledge of the ecology of mosquito vectors involved in the transmission of Rift Valley fever virus (RVFV) in Senegal. An entomological survey was conducted in three Senegalese agro-systems, Senegal River Delta (SRD), Senegal River Valley (SRV) and Ferlo, during the rainy season (July to November) of 2014 and 2015. Mosquitoes were trapped using CDC light traps set at ten sites for two consecutive nights during each month of the rainy season, for a total of 200 night-traps. Ecological indices were calculated to characterize the different populations of RVFV mosquito vectors. Generalized linear models with mixed effects were used to assess the influence of climatic conditions on the abu...
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Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk... more
Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts. First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and hum...
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Research Interests: Geography, Medicine, Biological Sciences, Disease Outbreaks, Humans, and 15 moreLivestock, Animals, CARTOGRAPHIE, Risk factors, ROC Curve, Culicidae, Risk Factors, Rift Valley Fever, Rift Valley fever virus, Outbreak, Geographic Information Systems, Modèle mathématique, Data Accuracy, Analyse du risque, and Medical and Health Sciences
In recent years, several vector-borne, parasitic or zoonotic diseases have emerged or re-emerged in different parts of the world, with major public health, socio-economic and political consequences. Emergence of these diseases is linked... more
In recent years, several vector-borne, parasitic or zoonotic diseases have emerged or re-emerged in different parts of the world, with major public health, socio-economic and political consequences. Emergence of these diseases is linked to climatic change, human-induced landscape changes and human activities that have affected disease ecology. The authors illustrate geographic information system-based approaches to understand epidemiological processes and predict disease patterns. Continent-wide approaches are used to explore vector and host distributions and identify areas where substantial changes in vector and vector-borne disease distributions have occurred. Time series of high-resolution satellite data and locally collected data reveal the spatial relationships between factors impacting disease dynamics. Using Rift Valley fever as a case study, a conceptual approach is proposed to integrate all of these data and to identify key parameters for disease modelling. Some of the chal...
Research Interests: Geography, Climate Change, Disease ecology, Ecology, Public Health, and 15 moreRisk assessment, Medicine, Environmental Change, Early Warning, Case Study, Disease, Landscape change, Satellite Data, Emerging disease, Biological Process, Human Activity, Risk Assessment, Rift Valley Fever, Spatial Relationships, and Geographic Information System
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A large number of diseases that affect humans and animals are influenced by environmental factors. For multi-host infectious diseases, various species might be involved in the transmission process and the circulation of the pathogenic... more
A large number of diseases that affect humans and animals are influenced by environmental factors. For multi-host infectious diseases, various species might be involved in the transmission process and the circulation of the pathogenic agent might result from the occurrence of certain specific association(s) between host and vector species. The need to characterise multi-species assemblage requires the development of new methods to derive integrated environmental risk factors. We have given remote sensing an ecological application to study the potential distribution of West Nile virus (WNV) in the Rhone River delta in southern France. West Nile fever is a vector-borne disease transmitted in natural cycles between birds and mosquitoes. Satellite images were used to create an ecological map on land cover. Appropriate typology was employed for the description of both hosts and vectors distributions. A database including the probability of occurrence of bird and mosquito species in each ...