A New High-Throughput Tool to Screen Mosquito-Borne Viruses in Zika Virus Endemic/Epidemic Areas

International audienceMosquitoes are vectors of arboviruses affecting animal and human health. Arboviruses circulate primarily within an enzootic cycle and recurrent spillovers contribute to the emergence of human-adapted viruses able to initiate an urban cycle involving anthropophilic mosquitoes. The increasing volume of travel and trade offers multiple opportunities for arbovirus introduction in new regions. This scenario has been exemplified recently with the Zika pandemic. To incriminate a mosquito as vector of a pathogen, several criteria are required such as the detection of natural infections in mosquitoes. In this study, we used a high-throughput chip based on the BioMark™ Dynamic arrays system capable of detecting 64 arboviruses in a single experiment. A total of 17,958 mosquitoes collected in Zika-endemic/epidemic countries (Brazil, French Guiana, Guadeloupe, Suriname, Senegal, and Cambodia) were analyzed. Here we show that this new tool can detect endemic and epidemic viruses in different mosquito species in an epidemic context. Thus, this fast and low-cost method can be suggested as a novel epidemiological surveillance tool to identify circulating arboviruses

A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites

Bloodsucking insects : work fields, colonies, infections : studies on Cimex lectularius and Phlebotomus perniciosus

Les insectes hématophages impactent sur la santé humaine et animale par la nuisance et l’allergie induite par la piqûre ou par leur risque de transmission d’agents pathogènes. Les étudier permet de mieux prévenir, gérer ou traiter l’ensemble des pathologies induites. Au cours de cette thèse, nous avons étudié deux insectes que sont la punaise de lit et le phlébotome.- Pour les punaises de lit une revue de la littérature sur les méthodes d'élevage a été rédigée. Nous avons déterminé deux aspects que sont les facteurs physiques (température, humidité relative, photopériode) et physiologiques (type, fréquence des repas) à prendre en considération. Un travail de terrain de recueil de spécimens a permis d’étudier la génétique des spécimens par localités et d’évaluer le portage de pathogènes notamment la bactérie Wolbachia sp.- Pour le phlébotome, un élevage de l’espèce Phlebotomus perniciosus a été mis en place permettant d'évaluer deux modèles infectieux expérimentaux à Leishmania infantum sur souris BALB/c et sur gorgeur artificiel. Des captures de terrain ont été réalisées et une étude de la génétique de population de Phlebotomus ariasi a été publiée. Une revue de la littérature sur les principaux événements historiques et évolutifs des Leishmanies, des phlébotomes et des réservoirs animaux associés a été publiée.- Dans le cadre de cette thèse nous avons collaboré à un nouveau mode d’identification des diptères hématophages (dépôt d’un brevet).- Au cours de ces 3 années de thèse, nos activités entomologiques hospitalières ont permis la description de cas entomologiques originaux.Cette thèse a fait l'objet d'une bourse CIFRE financée par les Laboratoires VIRBAC.Bloodsucking insects have an impact on the human and animal health particularly for the risk of pathogens transmission and the nuisance caused by their bite. To have knowledge on these insects can help and apply to prevent, manage or treat the diseases. In this thesis, we mainly focused on two insects: bedbugs and sandflies.- For bedbug, a literature review was carried out to classify the published data demonstrating preferred bedbug colony conditions. We showed that physical factors (temperature, relative humidity, photoperiod), and physiological factors (type, frequency of blood meals) play important roles in the laboratory colonies. A huge number of Cimex lectularius species was sampled from infested regions to study the spatial genetic structure and restricted gene flow in bed bugs in France and to evaluate the symbiotic flora including Wolbachia bacteria.- For sandfly, Phlebotomus perniciosus species was colonized for experimental infections by Leishmania infantum using murine model and artificial feeder. A local sandfly sampling was carried out in the rural regions of Nice city and were served in a study targeting the genetic population structure of Phlebotomus ariasi. Moreover, a historical study was conducted on the classification, evolution and dispersion of Leishmania parasites, sandflies and animals reservoirs.- A new identification method of bloodsucking Diptera was invented (submitted patent).- Thanks to the hospital-entomological activities, an original case report of phthiriasis on an old person was reported.- During this thesis with a scholarship CIFRE funded by Virbac Laboratories, I succeeded tosubmit and publish 7 articles and 1 patent

A review of data on laboratory colonies of bed bugs (Cimicidae), an insect of emerging medical relevance

Cimicidae are hematophagous Heteroptera, feeding on human blood, that have been the subject of significant medical investigation. In particular, they have been colonized under laboratory conditions to study their medical relevance. Laboratory colonization of these bugs is a multifactorial phenomenon. Our goal was to conduct a comparative literature review to classify the published data, demonstrating preferred bed bug colony conditions. We show that physical factors including temperature, relative humidity and photoperiod, and physiological factors such as type and frequency of blood meals play important roles in laboratory colonies. Any change in these factors produces changes in life-cycle duration. Temperature and blood meal are the most important factors, with a marked impact on the life-cycle of laboratory populations, depending on the species. A wide range of temperatures (15–34 °C) and relative humidity (46–75%) with an average of 25 °C and 59% were found for these colonies. Two widely used blood sources for the colonies were rabbits and humans

Impact on Aedes aegypti Mosquitoes Exposed to Honey-Impregnated Flinders Technology Associates (FTA®) Cards

International audiencePrograms to control viruses transmitted by mosquitoes requires the implementation of surveillance tools. Over the past decade, Flinders Technology Associates (FTA®) cards, which preserve nucleic acids, have emerged as an innovating surveillance system for collecting arboviruses expectorated during mosquito sugar feeding. In this study, we evaluate the survival rates of two strain of Aedes aegypti (New Orleans (NO) and Cayenne (CAY)) in the laboratory after exposing to either honey-impregnated FTA® cards or untreated filter paper (UFP) card. Experimental exposure of mosquitoes to FTA® cards during sugar feeding significantly negatively impacted their survival, as compared to untreated filter paper. The median survival time was 2 days (95% confidence interval [CI] 1 day, 3 days) for mosquitoes exposed to FTA cards from strain NO and 3 days (95% CI 2 days, 3 days) for mosquitoes exposed to FTA cards from strain CAY. Mosquitoes exposed to UFP did not survive until the end of the experiment (4 days for strain NO and 7 days for strain CAY). Although this finding does not preclude the use of FTA® cards in surveillance, it is crucial to consider and incorporate this factor into study designs

A review of data on laboratory colonies of bed bugs (Cimicidae), an insect of emerging medical relevance

Cimicidae are hematophagous Heteroptera, feeding on human blood, that have been the subject of significant medical investigation. In particular, they have been colonized under laboratory conditions to study their medical relevance. Laboratory colonization of these bugs is a multifactorial phenomenon. Our goal was to conduct a comparative literature review to classify the published data, demonstrating preferred bed bug colony conditions. We show that physical factors including temperature, relative humidity and photoperiod, and physiological factors such as type and frequency of blood meals play important roles in laboratory colonies. Any change in these factors produces changes in life-cycle duration. Temperature and blood meal are the most important factors, with a marked impact on the life-cycle of laboratory populations, depending on the species. A wide range of temperatures (15–34 °C) and relative humidity (46–75%) with an average of 25 °C and 59% were found for these colonies. Two widely used blood sources for the colonies were rabbits and humans

Screening of natural Wolbachia infection in Aedes aegypti, Aedes taeniorhynchus and Culex quinquefasciatus from Guadeloupe (French West Indies)

International audienceGuadeloupe islands are threatened by several mosquito-borne viruses such as Dengue, Chikungunya, Zika and West Nile virus. It appears essential to look for alternative mosquito control methods such as the incompatible insect technique (ITT) aiming at sterilizing wild females by inundative releases of incompatible males. Before considering the implementation of such a strategy, the characterization of genetic diversity of the endocellular bacterium Wolbachia regarding the local mosquito populations is a critical issue. Here, for the first time, we describe the prevalence and diversity of Wolbachia in natural populations of three mosquito species from Guadeloupe: Aedes aegypti, Aedes taeniorhynchus and Culex quinquefasciatus. The detection of Wolbachia in natural Ae. aegypti, Ae. taeniorhynchus and Cx. quinquefasciatus populations was conducted by studying Wolbachia 16S ribosomal RNA gene using a TaqMan quantitative real-time PCR and results were confirmed by conventional PCR and sequencing. In addition, molecular typing of wPip strains in Cx. quinquefasciatus was done by PCR-RFLP. We did not find Wolbachia infection in any of Ae. aegypti and Ae. taeniorhynchus studied populations. Natural Wolbachia infection was detected in Cx. quinquefasciatus with prevalence varying from 79.2% to 95.8%. In addition, no polymorphism was found between the Wolbachia strains infecting Cx. quinquefasciatus specimens, all carrying an infection from the same Wolbachia genetic wPip-I group. These results pave the way for the evaluation of the feasibility of IIT programs to fight against these medically-important mosquito species in Guadeloupe