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The need for multisectoral approaches (MSAs) in prevention and control of vector-borne diseases (VBDs) has been identified. VBD programs often involve collaborations between health and nonhealth sectors; however, a systematic framework describing the process, requirements, challenges, and benefits of MSAs has been missing. A recent guidance document from UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases provides a framework to implement MSAs for prevention and control of VBDs. This article gives an introduction to the guidance document and describes the conceptual framework and coordination process. The next steps will be to test the framework through implementation research in specific VBD cases studies. The guidance document will thus be refined based on iterative and comprehensive monitoring and evaluation systems to assess the performance and impact of MSAs. The advocacy for MSA and necessary capacity building will be integrated into the testing of the framework.

Background The role of human mobility in the epidemiology of emerging Aedes-transmitted viral diseases is recognized but not fully understood. The objective of this systematic review and meta-analysis was to examine how human mobility patterns are driving chikungunya outbreaks. Methods Literature was systematically reviewed for studies on chikungunya prevalence in countries/territories with high-level evidence of human mobility-driven outbreaks, based on: (1) emergence of chikungunya outbreaks with epidemic chikungunya virus genotypes among displaced/migrant populations and their hosting communities; and (2) identification of imported index case(s) with epidemic genotypes phylogenetically related to the genotypes circulating during emerging or subsequent outbreaks. Results The meta-analysis of extracted prevalence data revealed that a large proportion of the population in countries/territories afflicted by outbreaks is still at risk of infection during future outbreaks. On the other hand, approximately one-half of suspected chikungunya cases could be infected with other co-circulating acute febrile illnesses. Conclusions We discussed in this paper how human mobility-driven chikungunya outbreaks can be addressed, and how the involvement of several sectors in addition to the health sector in multisectoral approaches (MSAs) is important for prevention and control of chikungunya and other Aedes-transmitted arboviral outbreaks.

Vector-borne diseases are responsible for more than 17% of human cases of infectious diseases. In most situations, effective control of debilitating and deadly vector-bone diseases (VBDs), such as malaria, dengue, chikungunya, yellow fever, Zika and Chagas requires up-to-date, robust and comprehensive information on the presence, diversity, ecology, bionomics and geographic spread of the organisms that carry and transmit the infectious agents. Huge gaps exist in the information related to these vectors, creating an essential need for campaigns to mobilise and share data. The publication of data papers is an effective tool for overcoming this challenge. These peer-reviewed articles provide scholarly credit for researchers whose vital work of assembling and publishing well-described, properly-formatted datasets often fails to receive appropriate recognition. To address this, GigaScience 's sister journal GigaByte partnered with the Global Biodiversity Information Facility (GBIF) to publish a series of data papers, with support from the Special Programme for Research and Training in Tropical Diseases (TDR), hosted by the World Health Organisation (WHO). Here we outline the initial results of this targeted approach to sharing data and describe its importance for controlling VBDs and improving public health.

The burden and causes of residual malaria were investigated between 2015 and 2019 through 5 research projects coordinated by the Special Program for Research and Training in Tropical Diseases (TDR), cosponsored by the United Nations Development Programme, UNICEF, the World Bank, the World Health Organization (WHO) and the WHO Global Malaria Programme. The 5 projects included 10 countries in 4 WHO regions: Africa, the Americas, South-East Asia, and the Western Pacific. The countries represented a range of malaria endemicities, from low to high levels of transmission. The main findings of the projects indicate that overall the core malaria vector control tools (long-lasting insecticidal nets [LLIN] and indoor residual spraying) were not deployed in the optimal way and/or not efficient in many settings of the supported projects. Furthermore, vector biting behavior and human activity–associated factors strongly contributed to malaria persistence. Changes in vector species composition and abundance, with an increase in outdoor biting, were also reported. Some of these factors may be an adaptation of the vectors to the deployment of the tools and/or can be linked to other sectors, such as agricultural practices, environmental changes, social factors, and water management. Human behaviors and sleeping habits that included activities and sleeping outside villages in unprotected dwellings were another part of the problem. The evidence collated demonstrates the need for new approaches, such as the multisectoral one and new vector control tools, all adapted to the local contexts and integrated into current malaria programs.

The Swiss Development Cooperation, Canada’s International Development Research Centre, the Swiss Tropical Public Health Institute, and the UNICEF/United Nations Development Programme (UNDP)/World Bank/World Health Organization (WHO) Special Programme for Research and Training in Tropical Diseases (TDR) collaborated on a project to review, understand and promote the use of multisectoral approaches (MSAs) in the prevention and control of vector-borne diseases (VBDs). The objectives of the project were to support a landscape analysis of how MSAs have been used in the prevention and control of VBDs; to develop a theoretical framework for guiding the implementation of interventions; and to test the recommendations in real-life conditions. To realize these objectives, the project supported several activities, including commissioning a series of scientific reviews on MSAs in 5 thematic areas, sharing the key findings of these reviews in workshops and events, and developing a guidance framework for the implementation of MSAs. These activities have produced the theoretical framework that will be tested in real-life conditions through the support of case studies. The collaboration on implementing multisectoral activities against VBDs will continue among TDR, the Swiss Tropical Public Health Institute, and new partners such as the WHO Water Sanitation and Hygiene Group, UNDP, and UN-Habitat, in order to face the challenges identified and propose solutions tailored to specific contexts. The prevention and control of VBDs require strong and adapted MSAs with the full participation of all relevant sectors.

Background The Preparedness Plan for Surveillance and Interventions on Emerging Vector-Borne Diseases (VBDs) in Southern Switzerland outlines the strategy for preventing and managing potential outbreaks, as well as the surveillance and control activities with a specific focus on Aedes-borne diseases transmitted by Aedes albopictus mosquitoes. The objective of the plan is to provide Public Health Authorities with a framework of preventive and control measures according to the situation and level of epidemic risks. Material and methods The plan is divided into various phases representing the different steps for all potential situations, ranging from no vectors and no transmission risk to epidemic levels with multiple autochthonous/local cases of hospitalization (and deaths) until the end of the epidemic. An algorithm presents how decisions are taken to move from one phase of the plan to another, with detailed activities for different partners and strategies for each specific phase. Results The different phases of the plan include activities on disease surveillance and clinical case management, on vector surveillance and control, communication and coordination of activities. The plan is divided into five phases of activities and decision levels. From phase 0 (no cases) to phase 1 (low number of local cases, less than 5), phase 2 (small outbreak with more than 5 local cases), phase 3 (epidemic) and phase 4 (return to no more cases). Conclusion The plan has been approved by the cantonal authorities and will be submitted to federal authorities. The required implementation tests will begin shortly.

International audience; Human-driven global environmental changes have considerably increased the risk of biological invasions, especially the spread of human parasites and their vectors. Among exotic species that have major impacts on public health, the dengue fever mosquito Aedes aegypti originating from Africa has spread worldwide during the last three centuries. Although considerable progress has been recently made in understanding the history of this invasion, the respective roles of human and abiotic factors in shaping patterns of genetic diversity remain largely unexplored. Using a genome-wide sample of genetic variants (3,530 ddRAD SNPs), we analyzed the genetic structure of Ae. aegypti populations in the Caribbean, the first introduced territories in the Americas. Fourteen populations were sampled in Guyane and in four islands of the Antilles that differ in climatic conditions, intensity of urbanization, and vector control history. The genetic diversity in the Caribbean was low (He = 0.14-0.17), as compared with a single African collection from Benin (He = 0.26) and site-frequency spectrum analysis detected an ancient bottleneck dating back ∼300 years ago, supporting a founder event during the introduction of Ae. aegypti. Evidence for a more recent bottleneck may be related to the eradication program undertaken on the American continent in the 1950s. Among 12 loci detected as FST-outliers, two were located in candidate genes for insecticide resistance (cytochrome P450 and voltage-gated sodium channel). Genome-environment association tests identified additional loci associated with human density and/or deltamethrin resistance. Our results highlight the high impact of human pressures on the demographic history and genetic variation of Ae. aegypti Caribbean populations.

Training and innovation in the field of medical entomology are essential to mitigate the burden of vector-borne diseases globally. However, there is a shortage of medical entomologists worldwide, and there are large discrepancies in capacity building in this field. In this article, we discuss the current situation, what is needed from the medical entomologist of today, and how we can bridge this gap.

Background. Malaria-endemic countries are encouraged to increase, expedite, and standardize care based on parasite diagnosis and treat confirmed malaria using oral artemisinin-based combination therapy (ACT) or rectal artesunate plus referral when patients are unable to take oral medication. Methods. In 172 villages in 3 African countries, trained community health workers (CHWs) assessed and diagnosed children aged between 6 months and 6 years using rapid histidine-rich protein 2 (HRP2)–based diagnostic tests (RDTs). Patients coming for care who could take oral medication were treated with ACTs, and those who could not were treated with rectal artesunate and referred to hospital. The full combined intervention package lasted 12 months. Changes in access and speed of care and clinical course were determined through 1746 random household interviews before and 3199 during the intervention. Results. A total of 15 932 children were assessed: 6394 in Burkina Faso, 2148 in Nigeria, and 7390 in Uganda. Most children assessed (97.3% [15 495/15 932]) were febrile and most febrile cases (82.1% [12 725/15 495]) tested were RDT positive. Almost half of afebrile episodes (47.6% [204/429]) were RDT positive. Children eligible for rectal artesunate contributed 1.1% of episodes. The odds of using CHWs as the first point of care doubled (odds ratio [OR], 2.15; 95% confidence interval [CI], 1.9–2.4; P < .0001). RDT use changed from 3.2% to 72.9% (OR, 80.8; 95% CI, 51.2–127.3; P < .0001). The mean duration of uncomplicated episodes reduced from 3.69 ± 2.06 days to 3.47 ± 1.61 days, Degrees of freedom (df) = 2960, Student's t (t) = 3.2 (P = .0014), and mean duration of severe episodes reduced from 4.24 ± 2.26 days to 3.7 ± 1.57 days, df = 749, t = 3.8, P = .0001. There was a reduction in children with danger signs from 24.7% before to 18.1% during the intervention (OR, 0.68; 95% CI, .59–.78; P < .0001). Conclusions. Provision of diagnosis and treatment via trained CHWs increases access to diagnosis and treatment, shortens clinical episode duration, and reduces the number of severe cases. This approach, recommended by the World Health Organization, improves malaria case management. Clinical Trials Registration. ISRCTN13858170.

Background The climate variables that directly influence vector-borne diseases’ ecosystems are mainly temperature and rainfall. This is not only because the vectors bionomics are strongly dependent upon these variables, but also because most of the elements of the systems are impacted, such as the host behavior and development and the pathogen amplification. The impact of the climate changes on the transmission patterns of these diseases is not easily understood, since many confounding factors are acting together. Consequently, knowledge of these impacts is often based on hypothesis derived from mathematical models. Nevertheless, some direct evidences can be found for several vector-borne diseases. Main body Evidences of the impact of climate change are available for malaria, arbovirus diseases such as dengue, and many other parasitic and viral diseases such as Rift Valley Fever, Japanese encephalitis, human African trypanosomiasis and leishmaniasis. The effect of temperature and rainfall change as well as extreme events, were found to be the main cause for outbreaks and are alarming the global community. Among the main driving factors, climate strongly influences the geographical distribution of insect vectors, which is rapidly changing due to climate change. Further, in both models and direct evidences, climate change is seen to be affecting vector-borne diseases more strikingly in fringe of different climatic areas often in the border of transmission zones, which were once free of these diseases with human populations less immune and more receptive. The impact of climate change is also more devastating because of the unpreparedness of Public Health systems to provide adequate response to the events, even when climatic warning is available. Although evidences are strong at the regional and local levels, the studies on impact of climate change on vector-borne diseases and health are producing contradictory results at the global level. Conclusions In this paper we discuss the current state of the results and draw on evidences from malaria, dengue and other vector-borne diseases to illustrate the state of current thinking and outline the need for further research to inform our predictions and response. Electronic supplementary material The online version of this article (10.1186/s40249-019-0565-1) contains supplementary material, which is available to authorized users.

This study was aimed to identify the chemical compounds of Aedes aegypti that can be potentially used to develop pheromone-based vector control methods. In this study, we compared the chemical compounds collected from the organs of mosquitoes at different developmental stages in the life cycle. We also compared the composition and amount of extracts from the different tissues of male and female adult mosquito. Interestingly, we found large amount of C17-C20 ethyl and methyl esters in the wings of female and antennae of male mosquito. We also found that isopropyl esters, dodelactone, octadecenoic acid and medium-chain fatty acid increase drastically during the late larval stage (L4). Old adult mosquitoes showed remarkable increase in production of C16:1 and C18:1 methyl esters, as a first example of chemical signatures specifically associated with aging in the animals. This knowledge may open the ground to find new behaviorally-important molecules with the ability to control Aedes specifically.

Background \ud Research has been conducted on interventions to control dengue transmission and respond to outbreaks. A summary of the available evidence will help inform disease control policy decisions and research directions, both for dengue and, more broadly, for all Aedes-borne arboviral diseases. \ud \ud Method \ud A research-to-policy forum was convened by TDR, the Special Programme for Research and Training in Tropical Diseases, with researchers and representatives from ministries of health, in order to review research findings and discuss their implications for policy and research. \ud \ud Results \ud The participants reviewed findings of research supported by TDR and others. Surveillance and early outbreak warning. Systematic reviews and country studies identify the critical characteristics that an alert system should have to document trends reliably and trigger timely responses (i.e., early enough to prevent the epidemic spread of the virus) to dengue outbreaks. A range of variables that, according to the literature, either indicate risk of forthcoming dengue transmission or predict dengue outbreaks were tested and some of them could be successfully applied in an Early Warning and Response System (EWARS). Entomological surveillance and vector management. A summary of the published literature shows that controlling Aedes vectors requires complex interventions and points to the need for more rigorous, standardised study designs, with disease reduction as the primary outcome to be measured. House screening and targeted vector interventions are promising vector management approaches. Sampling vector populations, both for surveillance purposes and evaluation of control activities, is usually conducted in an unsystematic way, limiting the potentials of entomological surveillance for outbreak prediction. Combining outbreak alert and improved approaches of vector management will help to overcome the present uncertainties about major risk groups or areas where outbreak response should be initiated and where resources for vector management should be allocated during the interepidemic period. \ud \ud Conclusions \ud The Forum concluded that the evidence collected can inform policy decisions, but also that important research gaps have yet to be filled.

Background In the Guadeloupe and Saint Martin islands, Aedes aegypti mosquitoes are the only recognized vectors of dengue, chikungunya, and Zika viruses. For around 40 years, malathion was used as a mosquito adulticide and temephos as a larvicide. Since the European Union banned the use of these two insecticide molecules in the first decade of the 21st century, deltamethrin and Bacillus thuringiensis var. israelensis are the remaining adulticide and larvicide, respectively, used in Guadeloupe. In order to improve the management of vector control activities in Guadeloupe and Saint Martin, we investigated Ae. aegypti resistance to and mechanisms associated with deltamethrin, malathion, and temephos. Methods Ae. aegypti mosquitoes were collected from six different localities of Guadeloupe and Saint Martin. Larvae were used for malathion and temephos bioassays, and adult mosquitoes for deltamethrin bioassays, following World Health Organization recommendations. Knockdown resistance (Kdr) genotyping for V1016I and F1534C mutations, and expression levels of eight enzymes involved in detoxification mechanisms were examined in comparison with the susceptible reference Bora Bora strain. Results Resistance ratios (RR50) calculated for Ae. aegypti larvae showed high resistance levels to temephos (from 8.9 to 33.1-fold) and low resistance levels to malathion (from 1.7 to 4.4-fold). Adult females displayed moderate resistance levels to deltamethrin regarding the time necessary to affect 50% of individuals, varying from 8.0 to 28.1-fold. Molecular investigations on adult mosquitoes showed high resistant allele frequencies for V1016I and F1534C (from 85 to 96% and from 90 to 98%, respectively), as well as an overexpression of the glutathione S-transferase gene, GSTe2, the carboxylesterase CCEae3a, and the cytochrome genes 014614, CYP6BB2, CYP6M11, and CYP9J23. Conclusions Ae. aegypti populations from Guadeloupe and Saint Martin exhibit multiple resistance to organophosphates (temephos and malathion), and pyrethroids (deltamethrin). The mechanisms associated with these resistance patterns show strong frequencies of F1534C and V1016I Kdr mutations, and an over-expression of CCEae3a, GSTe2, and four cytochrome P450 genes (014614, CYP9J23, CYP6M11, CYP6BB2). These results will form the baseline for a deeper understanding of the insecticide resistance levels and associated mechanisms of Ae. aegypti populations and will be used to improve vector control strategies in Guadeloupe and Saint Martin. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0254-x) contains supplementary material, which is available to authorized users.

Population displacement and other forced movement patterns following natural disasters, armed conflicts or due to socioeconomic reasons contribute to the global emergence of Aedes-borne viral disease epidemics. In particular, dengue epidemiology is critically affected by situations of displacement and forced movement patterns, particularly within and across borders. In this respect, waves of human movements have been a major driver for the changing epidemiology and outbreaks of the disease on local, regional and global scales. Both emerging dengue autochthonous transmission and outbreaks in countries known to be non-endemic and co-circulation and hyperendemicity with multiple dengue virus serotypes have led to the emergence of severe disease forms such as dengue hemorrhagic fever and dengue shock syndrome. This paper reviews the emergence of dengue outbreaks driven by population displacement and forced movements following natural disasters and conflicts within the context of regional and sub-regional groupings.

The transmission of the arboviral agents of dengue, yellow fever, Chikungunya, and Zika by Aedes mosquitoes represents expanding threats to global health. At the 69th World Health Assembly [1], the WHO Director-General Margaret Chan declared that the spread of the Zika virus was "the result of the abandon of mosquito control" by governments since the 1970s and urged Member States to mobilize more efforts and resources to prevent further spread of the diseases. The recent rise of microcephaly cases and other neurological disorders reported in Brazil prompted WHO to declare Zika as a Public Health Emergency of International Concern [2]. After limited early outbreaks in the Pacific in 2007 and 2013, the Zika virus has spread to more than 30 countries in the Americas and the Caribbean, affecting over 1.5 million people [3]. With growing evidence supporting the link between microcephaly and Zika [4, 5] and preliminary evidence confirming Aedes aegypti as the primary vector in the Brazilian outbreak [6], the mandate for control is clear and urgent.

International audience; Major emergency efforts are being mounted for each vector-borne disease epidemiological crisis anew, while knowledge about the biology of arthropods vectors is dwindling slowly but continuously, as is the number of field entomologists. The discrepancy between the rates of production of knowledge and its use and need for solving crises is widening, in particular due to the highly differing time spans of the two concurrent processes. A worldwide web based search using multiple key words and search engines of onsite and online courses in English, Spanish, Portuguese, French, Italian and German concerned with the biology of vectors identified over 140 courses. They are geographically and thematically scattered, the vast majority of them are on-site, with very few courses using the latest massive open online course (MOOC) powerfulness. Over two third of them is given in English and Western Africa is particularity poorly represented. The taxonomic groups covered are highly unbalanced towards mosquitoes. A worldwide unique portal to guide students of all grades and levels of expertise, in particular those in remote locations, is badly needed. This is the objective a new activity supported by the Special Programme for Research and Training in Tropical Diseases (TDR).

International audience; The females of the moths Hylesia metabus have their abdomens covered by urticating hairs looking like micro-arrows and causing a puriginous dermatitis to humans known as "papillonite" in French Guiana and also called yellowtail moth dermatitis or Caripito itch. The densities of the moths show great seasonal and annual variations depending on mechanisms mostly unknown. When H. metabus infestations occur, numerous cases of dermatologic manifestations are reported from people living near the mangrove swamps where the moths are developing. One hundred years after the first "papillonite" epidemic reported from French Guiana in 1912, the data presented herein summarize the actual state of knowledge on H. metabus biology and ecology and on the lepidopterism. Some recommendations are proposed for the surveillance and warning systems of H. metabus infestations and to avoid contact with the moths. Research priorities are suggested to improve the control against this problem emerging between nuisance and public health.

Population genetics of peri-domestic Aedes aegypti (Diptera: Culicidae), vector of dengue and yellow fever, were investigated by gel electrophoresis of 10 enzyme loci in 14 samples of mosquito larvae collected in 1997-1998 from localities separated by distances of 3-275 km in French Guiana. Genetic differentiation between geographical populations was generally high (mean FST = +0.111, p < 10(-5)) even among seven sites < 30 km apart (FST = + 0.137, P < 0.05), but not positively correlated with distance. Thus, Ae. aegypti comprises a mosaic of genetically differentiated populations in French Guiana. This may be attributed to reinvasion from diverse origins through repeated founder events after this vector species was eliminated during the 1940s to 1960s.

Phlebotomine sand flies are known to transmit Leishmania, bacteria, and viruses that affect humans and animals in many countries worldwide. Sand fly-borne viruses belong mainly to the Phlebovirus, Vesiculovirus, and Orbivirus genera, and some of them are associated with outbreaks or sporadic human cases in the Mediterranean Europe. Up to now, Toscana virus is the only phlebovirus of medical importance identified in France. To study the diversity of the sand fly population living in the southeastern France, an entomological study was conducted from May to October, 2007. Most of the trapped sand flies belonged to Phlebotomus perniciosus (82.0%) and Sergentomyia minuta (17.3%) species; only three specimens were Phlebotomus ariasi. Molecular characterization of the P. perniciosus specimen based on the mitochondrial cytochrome b gene demonstrated different subpopulations living in the same areas. Most of the specimens belonged to the haplotypes pern01 and pern09, already described in France, but some belonged to original new haplotypes. The detection of one viral sequence clustering with Massilia/Granada virus, and of four sequences corresponding to two potential new phleboviruses (proposed names Olbia and Provencia viruses, respectively), revealed an unexpected diversity of phlebovirus species in France.

During the past ten years, the islands of Guadeloupe (French West Indies) are facing dengue epidemics with increasing numbers of cases and fatal occurrences. The vectorAedes aegyptiis submitted to intensive control, with little effect on mosquito populations. The hypothesis that importantAe. aegyptibreeding sites are not controlled is investigated herein. For that purpose, the roof gutters of 123 houses were systematically investigated, and the percentage of gutters positive forAe. aegyptivaried from 17.2% to 37.5%, from humid to dry locations. In the dryer location, most of houses had no other breeding sites. The results show that roof gutters are becoming the most importantAe. aegyptibreeding sites in some locations in Guadeloupe, with consequences on dengue transmission and vector control.

Host-feeding patterns play a key role in the transmission of vector-borne diseases such as West Nile fever, which involves two kinds of vertebrates, birds and mammals. In this study, we propose a theoretical formulation for mosquito host-feeding patterns using three quantities, as follows: the apparent attractiveness/contact probabilities, the conditional host(-feeding) preferences, and the enzootic versus bridge probabilities. Using results from host-baited trap collections, the quantities defined above were assessed for the most abundant mosquito species in the main West Nile virus focus of southern France. We found that host availability is important in determining the efficiency of bridge vectors, and that even ornithophilic mosquitoes like Culex species, classically classified as enzootic vectors, may turn out to be efficient bridge vectors in certain contexts of host abundance. Our developed theoretical framework can easily be adapted and applied to other experimental data and other vector-borne diseases.

Phlebotomine sandflies are known to transmit leishmaniases, bacteria and viruses that affect humans and animals in many countries worldwide. These sandfly-borne viruses are mainly the Phlebovirus, the Vesiculovirus and the Orbivirus. Some of these viruses are associated with outbreaks or human cases in the Mediterranean Europe. In this paper, the viruses transmitted by Phlebotomine sandflies in Europe (Toscana virus, Sicilian virus, sandfly fever Naples virus) are reviewed and their medical importance, geographical distribution, epidemiology and potential spreading discussed. Data on vertebrate reservoirs is sparse for sandfly fever viruses. The factor currently known to limit the spread of diseases is mainly the distribution areas of potential vectors. The distribution areas of the disease may not be restricted to the areas where they have been recorded but could be as wide as those of their vectors, that is to say Larroussius and P. papatasi mainly but not exclusively. Consequently, field work in form of viral isolation from sandflies and possible reservoirs as well as laboratory work to establish vectorial competence of colonised sandflies need to be encouraged in a near future, and epidemiological surveillance should be undertaken throughout the European Union.

Background With an Annual Parasite Incidence (API) of 132.1, in the high and moderate risks zones, the Maroni area of French Guiana has the second highest malaria incidence of South-America after Guyana (API = 183.54) and far above Brazil (API = 28.25). Malaria transmission is occurring despite strong medical assistance and active vector control, based on general WHO recommendations. This situation is generated by two main factors that are the social and cultural characteristics of this border area, where several ethnic groups are living, and the lack of understanding of transmission dynamics of the main mosquito vector, Anopheles darlingi. In this context, entomological data collected in two villages belonging to two different ethnic groups of the French border of the Maroni River, were retrospectively analysed to find out how the mosquito bionomics are related to the malaria transmission patterns. Methods Data were provided by human landing catches of mosquitoes carried out each month for two years in two villages belonging to two ethnic groups, the Amerindians Wayanas and the Aloukous of African origin. The mosquitoes were sorted by species, sex, date, hour and place of collection and processed for Plasmodium sp. parasite detection. The data were compiled to provide the following variables: human biting rates (HBR), parity rates (PR), numbers of infective bites (IB), entomological inoculation rates (EIR) and numbers of infected mosquitoes surviving enough to transmit (IMT). Spatial and temporal differences of variables between locations and during the night were tested by the Kruskall-Wallis analysis of variance to find out significant variations. Results The populations of the main mosquito vector An. darlingi showed significant variations in the spatial and temporal HBR/person/night and HBR/person/hour, IB/person/month and IB/person/hour, and IMT/village/night and IMT/village/hour. In the village of Loca (Aloukous), the IMT peaked from June to August with a very low transmission during the other months. The risks were higher during the first part of the night and an EIR of 10 infective bites per person and per year was estimated. In the village of Twenke (Wayanas), high level of transmission was reported all year with small peaks in March and October. The risk was higher during the second part of the night and an EIR of 5 infective bites per person and per year was estimated. Conclusion For the first time in the past 40 years, the mosquito bionomics was related to the malaria transmission patterns in French Guiana. The peak of malaria cases reported from August to October in the Maroni region is concomitant with the significant peak of An. darlingi IMT, reported from the village of Loca where transmission is higher. However, the persistent number of cases reported all year long may also be related to the transmission in the Amerindian villages. The An. darlingi bionomics for these two close populations were found significantly different and may explain why a uniform vector control method is inadequate. Following these findings, malaria prevention measures adapted to the local conditions are needed. Finally, the question of the presence of An. darlingi sub-species is raised.

International audience; French Guiana is one of the areas in South America most affected by malaria and where the disease has become a serious public health problem. In spite of this situation, little recent entomological data are available from the main localities where the disease occurs, even though they are crucial for development of an effective vector control strategy. A longitudinal entomological survey was carried out from March 2000-February 2002 in three Amerindian villages, namely Twenké, Taluène and Cayodé, located in the Amazonian forest of the Upper-Maroni area, to assess anopheline mosquitoes and malaria transmission dynamics. Anopheles darlingi (Diptera: Culicidae) was the most abundant mosquito species caught during the study. This efficient American malaria vector was active the entire year, but showed an evident peak of abundance during the main rainfall season, from April-June, with an average human biting rate of 255.5 bites per person per night. Parity rates were homogeneous all year, indicating no significant seasonal variability in female survival rates. Estimated vectorial capacity indices were higher during the rainy season, even though the risk of transmission was present throughout the year (VCI > 1). A total of 14 An. darlingi were found infected with Plasmodium falciparum, Plasmodium vivax or Plasmodium malariae. The annual circumsporozoite indices were 0.15, 0.14 and 0.05, and the entomological inoculation rates were 22.8, 27.4 and 14.4 infected bites per person per year in Twenké, Taluène and Cayodé, respectively. An. darlingiwas endo-exophagic and rather exophilic in these localities. The species was collected throughout the night but was more aggressive between 21:30-03:30 h and after 05:30 h. Parity rates were homogeneous during the entire night. Impregnated hammock and/or bed nets, coupled with the use of mosquito repellents, as well as the early treatment of malarial cases, appear to be the most suitable tools for fighting malaria in these Amerindian villages since the spraying of residual insecticides is inefficient because of vector biology and the housing structure.

To identify the mosquito species able to sustain the transmission of West Nile Virus (WNV) in the Camargue region (the main WNV focus of southern France), we assessed the vector competence of Culex modestus and Culex pipiens, the most abundant bird-feeders, and Aedes caspius, the most abundant mammophilic species occasionally found engorged with avian blood. Female mosquitoes were exposed to the infectious meal (10(10.3) plaque forming units (PFU)/mL) by membrane feeding, and hold at 26 degrees C. After the incubation period, disseminated infection was assessed by WNV detection using an indirect fluorescent antibody assay (IFA) on head squashes, and the transmission rate was assessed by the presence of WNV RNA in salivary secretions with a real-time reverse transcriptase-polymerase chain reaction (RT-PCR). After 14 incubation days, the disseminated infection and the transmission rates were 89.2% and 54.5% for Cx. modestus, 38.5% and 15.8% for Cx. pipiens, and 0.8% and 0 for Ae. caspius. Culex modestus was found to be an extremely efficient laboratory WNV vector and could thus be considered the main WNV vector in wetlands of the Camargue. Culex pipiens was a moderately efficient laboratory WNV vector, but in dry areas of the region it could play the main role in WNV transmission between birds and from birds to mammals. Aedes caspius was an inefficient vector of WNV in the laboratory, and despite its high densities, its role in WNV transmission may be minor in southern France.

The spreading dynamic of the 2004 dengue fever outbreak that occurred in Tartagal, Northwestern Argentina, was investigated. A total of 487 suspected dengue cases were recorded and geo-referenced. Maps of daily cases were generated for the 109 days of the outbreak. The epidemic affected the majority of the city within 11 days. The age-distribution of the cases was different from the population age-distribution. The spatio–temporal clustering of the cases was analyzed using Knox test concept. Results of the space and time geo-referencing of the cases showed outbreak spotlights and spreading patterns that could be related to entomologic and epidemiologic factors. An environmental risk prediction model was developed based on a synthetic multi-band image created from LandSat 5 TM satellite image. The potential and limitations of remote sensing data and spatial statistics as landscape epidemiology tools for a dengue surveillance strategy and prevention are discussed. © 2007 Elsevier B.V. All rights reserved.

International audience; Field survival of Aedes aegypti females is a key parameter for estimating the dengue transmission potential of a mosquito population. The objectives of this study were to explore the dynamics of these survival rates at different times of the year in French Guiana and to analyze the results from the perspective of dengue patterns. The mosquitoes were captured, marked, released, and recaptured during four consecutive days in six houses every month, for three to 24 months, from January 1997 to December 1998. Laboratory experiments showed no effects on female survival but some effect on the survival of males. Females' daily survival in the field varied from 0.525 to 1 but was mostly between 0.8 and 0.95 during the entire year, with a mean value of 0.913. The field survival of Ae. aegypti females in French Guiana was thus in agreement with the likely transmission of dengue and the dengue endemic patterns throughout the year. On the other hand, heavy rainfalls during this time were less favorable to Ae. aegypti survival, which may explain part of the El Ni?ffect on dengue epidemics in French Guiana. The methods and results on Ae. aegypti survival will be implemented in a global dengue surveillance network in French Guiana.

In French Guiana, at least five Leishmania species are known to be sympatically transmitted in sylvatic ecotopes. However, the previous surveys on the phlebotomine sand fly fauna were published 20 years ago. During that period, many ecological changes have occurred. Sand fly collections were conducted with CDC light traps in five stations representing the main ecotopes of French Guiana. A total of 817 sand flies belonging to 2 genera, 18 sub-genera, and 46 different species were identified. The species Lutzomyia umbratilis (16.6% of the collected specimens), Lu. infraspinosa (12.7%), Lu. ininii (8.0%), and Lu. flaviscutellata (6.1%) were the most common species. The stratification by height, activity period, and resting site preferences of the most abundant sand flies were analyzed. Population abundance and diversity were compared for each ecotope. The potential of certain sand fly species in leishmaniasis transmission is discussed.

We surveyed the disease epidemiology of dengue in French Guiana after the first dengue haemorrhagic fever epidemic from 1991 to 1993 and during an endemic period from 1993 to 1995. DEN-1, DEN-2 and DEN-4 viruses were isolated from patients and DEN-4 was also isolated from Aedes aegypti mosquitoes. Cases of dengue were reported from all over the country, not only from urban areas, but also from rural areas and isolated human settlements, indicating widespread circulation of the viruses. The mosquito vector A. aegypti was found in all inhabited areas of French Guiana and small outdoor containers were the most common breeding grounds. Some ecological features of A. aegypti, such as larvae breeding in Bromeliad plants in the rainforest, a non-exclusive anthropophily and a high vertical transmission rate for dengue viruses, indicate that A. aegypti can behave as a reservoir for dengue viruses in silent areas. Dengue viruses may survive at an endemic level and cause outbreaks when unknown conditions become more favourable. This finding adds to our knowledge of the natural history of dengue viruses in the Americas.

The objectives of the present study were to broaden the survey of simuliid species in French Guiana and to cytologically analyze the species in the Simulium perflavum species group. Twelve species of Simulium were collected from which S. goeldii, S. quadrifidum, S. trombetense, S. near incrustatum, S. metallicum (s.l.) sp1, S. metallicum (s.l.) sp2 and S. ochraceum (s.l.) are reported for the first time for this region. The only species collected in the S. perflavum group was S. rorotaense; 34 larvae of this species were cytologically analyzed, all of which had the standard sequence. S. metallicum (s.l.), S. ochraceum (s.l.), S. guianense (s.l.) and S. oyapockense (s.l.) are involved with transmission of onchocerciasis in Central and South America, however, in French Guiana these species were not found biting humans during the sampling period. With the few collections made during this study, we increase the number of simulid species known in French Guiana from 6 to 13. It is clear that more simuliid species can be expected to be found when more sampling is done, including collections in other ecoregions in French Guiana.

International audience; Twenty-seven samples of Aedes aegypti (F1 generation) from French Guiana were tested for their susceptibility to dengue serotype 2 virus. Very high infection rates were observed by indirect fluorescent antibody (IFA) test. Ae. aegypti samples were pooled according to two groups: the first group (N=10) represented mosquitoes from the urbanized area of Cayenne and surroundings, and the second group (N=17) corresponded to mosquitoes collected in the countryside. Infection rates were found to be similar in these two cases. These findings are discussed in relation with the history of Ae. aegypti in this part of the world.