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Germline mutations that activate genes in the canonical RAS/MAPK signaling pathway are responsible for rare human developmental disorders known as RASopathies. Here, we analyzed the molecular determinants of Costello syndrome (CS) using a mouse model expressing HRAS p.G12S, patient skin fibroblasts, hiPSC-derived human cardiomyocytes, a HRAS p.G12V zebrafish model, and human fibroblasts expressing lentiviral constructs carrying HRAS p.G12S or HRAS p.G12A mutations. The findings revealed alteration of mitochondrial proteostasis and defective oxidative phosphorylation in the heart and skeletal muscle of CS mice that were also found in the cell models of the disease. The underpinning mechanisms involved the inhibition of the AMPK signaling pathway by mutant forms of HRAS, leading to alteration of mitochondrial proteostasis and bioenergetics. Pharmacological activation of mitochondrial bioenergetics and quality control restored organelle function in HRAS p.G12A and p.G12S cell models, reduced left ventricle hypertrophy in CS mice, and diminished the occurrence of developmental defects in the CS zebrafish model. Collectively, these findings highlight the importance of mitochondrial proteostasis and bioenergetics in the pathophysiology of RASopathies and suggest that patients with CS may benefit from treatment with mitochondrial modulators.

International audience; Japanese Encephalitis (JE) is the most important cause of human encephalitis in Southeast Asia, and this zoonosis is mainly transmitted from pigs to human by mosquitoes. A better understanding of the host-feeding preference of Japanese encephalitis virus (JEV) major vectors is crucial for identifying risk areas, defining bridge vector species and targeting adapted vector control strategies. To assess host-feeding preference of JE vectors in a rural Cambodian area where JE is known to circulate, in 2017, we implemented four sessions of mosquito trapping (March, June, September, December), during five consecutive nights, collecting four times a night (6 p.m. to 6 a.m.), and using five baited traps simultaneously, i.e., cow, chicken, pig, human, and a blank one for control. In addition, blood meals of 157 engorged females trapped at the same location were opportunistically analyzed with polymerase chain reaction (PCR), using cow, pig, human, and dog blood primers. More than 95% of the 36,709 trapped mosquitoes were potential JE vectors. These vectors were trapped in large numbers throughout the year, including during the dry season, and from 6 p.m. to 6 a.m. Despite the apparent host-feeding preference of Culex vishnui, Cx. gelidus, and Cx. tritaenhyorhincus for cows, statistical analysis suggested that the primary target of these three mosquito species were pigs. Dog blood was detected in eight mosquitoes of the 157 tested, showing that mosquitoes also bite dogs, and suggesting that dogs may be used as proxy of the risk for human to get infected by JE virus.

Between 2016 and 2020, the Medical and Veterinary Entomology unit of the Institut Pasteur du Cambodge collected over 230,000 mosquitoes. Based on this sampling effort, a checklist of 290 mosquito species in Cambodia is presented. This is the first attempt to list the Culicidae fauna of the country. We report 49 species for the first time in Cambodia. The 290 species belong to 20 genera: Aedeomyia (1 sp.), Aedes (55 spp.), Anopheles (53 spp.), Armigeres (26 spp.), Coquillettidia (3 spp.), Culex (57 spp.), Culiseta (1 sp.), Ficalbia (1 sp.), Heizmannia (10 spp.), Hodgesia (3 spp.), Lutzia (3 spp.), Malaya (2 spp.), Mansonia (5 spp.), Mimomyia (7 spp.), Orthopodomyia (3 spp.), Topomyia (4 spp.), Toxorhynchites (4 spp.), Tripteroides (6 spp.), Uranotaenia (27 spp.), and Verrallina (19 spp.). The Cambodian Culicidae fauna is discussed in its Southeast Asian context. Forty-three species are reported to be of medical importance, and are involved in the transmission of pathogens., Entre 2016 et 2020, plus de 230 000 moustiques ont été capturés par l’Unité d’Entomologie Médicale et Vétérinaire de l’Institut Pasteur du Cambodge. Sur la base de ces collectes, une liste des 290 espèces de moustiques présentes au Cambodge est présentée. Il s’agit de la première tentative de répertorier la faune Culicidae du pays. Quarante-neuf espèces sont signalées pour la première fois au Cambodge. Les 290 espèces appartiennent à vingt genres : Aedeomyia (1 sp.), Aedes (55 spp.), Anopheles (53 spp.), Armigeres (26 spp.), Coquillettidia (3 spp.), Culex (57 spp.), Culiseta (1 sp.), Ficalbia (1 sp.), Heizmannia (10 spp.), Hodgesia (3 spp.), Lutzia (3 spp.), Malaya (2 spp.), Mansonia (5 spp.), Mimomyia (7 spp.), Orthopodomyia (3 spp.), Topomyia (4 spp.), Toxorhynchites (4 spp.), Tripteroides (6 spp.), Uranotaenia (27 spp.) et Verrallina (19 spp.). La faune des Culicidés cambodgiens est discutée dans son contexte sud-est asiatique. Quarante-trois espèces sont d’importance médicale et impliquées dans la transmission de pathogènes.

Between 2016 and 2020, the Medical and Veterinary Entomology unit of the Institut Pasteur du Cambodge collected over 230,000 mosquitoes. Based on this sampling effort, a checklist of 290 mosquito species in Cambodia is presented. This is the first attempt to list the Culicidae fauna of the country. We report 49 species for the first time in Cambodia. The 290 species belong to 20 genera: Aedeomyia (1 sp.), Aedes (55 spp.), Anopheles (53 spp.), Armigeres (26 spp.), Coquillettidia (3 spp.), Culex (57 spp.), Culiseta (1 sp.), Ficalbia (1 sp.), Heizmannia (10 spp.), Hodgesia (3 spp.), Lutzia (3 spp.), Malaya (2 spp.), Mansonia (5 spp.), Mimomyia (7 spp.), Orthopodomyia (3 spp.), Topomyia (4 spp.), Toxorhynchites (4 spp.), Tripteroides (6 spp.), Uranotaenia (27 spp.), and Verrallina (19 spp.). The Cambodian Culicidae fauna is discussed in its Southeast Asian context. Forty-three species are reported to be of medical importance, and are involved in the transmission of pathogens.Liste des moustiques (Diptera, Culicidae) du Cambodge.Entre 2016 et 2020, plus de 230 000 moustiques ont été capturés par l’Unité d’Entomologie Médicale et Vétérinaire de l’Institut Pasteur du Cambodge. Sur la base de ces collectes, une liste des 290 espèces de moustiques présentes au Cambodge est présentée. Il s’agit de la première tentative de répertorier la faune Culicidae du pays. Quarante-neuf espèces sont signalées pour la première fois au Cambodge. Les 290 espèces appartiennent à vingt genres : Aedeomyia (1 sp.), Aedes (55 spp.), Anopheles (53 spp.), Armigeres (26 spp.), Coquillettidia (3 spp.), Culex (57 spp.), Culiseta (1 sp.), Ficalbia (1 sp.), Heizmannia (10 spp.), Hodgesia (3 spp.), Lutzia (3 spp.), Malaya (2 spp.), Mansonia (5 spp.), Mimomyia (7 spp.), Orthopodomyia (3 spp.), Topomyia (4 spp.), Toxorhynchites (4 spp.), Tripteroides (6 spp.), Uranotaenia (27 spp.) et Verrallina (19 spp.). La faune des Culicidés cambodgiens est discutée dans son contexte sud-est asiatique. Quarante-trois espèces sont d’importance médicale et impliquées dans la transmission de pathogènes.

Du fait des nuisances et des épidémies qu'ils génèrent (dengue, fièvre à virus Chikungunya...), les moustiques de l'île de La Réunion sont régulièrement à la une de l'actualité, mais paradoxalement aucun ouvrage ne leur a été consacré jusqu'à présent. C'est désormais chose faite avec ce livre, qui rassemble les connaissances actuelles sur la systématique et la biologie des espèces réunionnaises et de l'ouest de l'océan Indien. Responsables d'épidémies touchant la population de l'île depuis plusieurs siècles, les peuplements de moustiques sont étroitement liés aux activités humaines, qui bien souvent ont entraîné leur installation sur ces milieux insulaires. Ce livre retrace à la fois les étapes du peuplement de La Réunion par ces insectes vecteurs et l'histoire des principales maladies transmises sur l'île. Il décrit les principaux moyens de protection mis en oeuvre au niveau institutionnel et personnel. Des éléments de morphologie et de taxonomie permettent d'identifier les genres présents sur les îles du sud-ouest de l'océan Indien et les espèces de La Réunion. L'ouvrage présente également la taxonomie et la biologie de chacune de ces espèces, ainsi que leur importance médicale. Des cartes de répartition et des clés d'identification illustrées complètent l'information.Pédagogique et richement illustré, l'ouvrage s'adresse à un large public : acteurs de la santé publique, personnels de santé, habitants de La Réunion ainsi qu'étudiants, scientifiques et techniciens, qui pourront enrichir leurs connaissances sur l'origine, les modes de transmission et la gestion sanitaire des maladies à vecteurs dans l'ouest de l'océan Indien.

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International audience; Loss-of-function mutations in the SDHB subunit of succinate dehydrogenase predispose patients to aggressive tumors characterized by pseudohypoxic and hypermethylator phenotypes. The mechanisms leading to DNA hypermethylation and its contribution to SDH-deficient cancers remain undemonstrated. We examine the genome-wide distribution of 5-methylcytosine and 5-hydroxymethylcytosine and their correlation with RNA expression in SDHB-deficient tumors and murine Sdhb−/− cells. We report that DNA hypermethylation results from TET inhibition. Although it preferentially affects PRC2 targets and known developmental genes, PRC2 activity does not contribute to the DNA hypermethylator phenotype. We also prove, in vitro and in vivo, that TET silencing, although recapitulating the methylation profile of Sdhb−/− cells, is not sufficient to drive their EMT-like phenotype, which requires additional HIF2α activation. Altogether, our findings reveal synergistic roles of TET repression and pseudohypoxia in the acquisition of metastatic traits, providing a rationale for targeting HIF2α and DNA methylation in SDH-associated malignancies.

International audience; Simple Summary: Aedes albopictus is a well-established competent arbovirus vector in Reunion Island, a French overseas territory in the Indian Ocean, occurring in a range of natural to urban environments where it represents a major threat to public health. Following the 2006 Chikungunya outbreak and periodic occurrence of dengue epidemics, the sterile insect technique (SIT) emerged as the most environment-friendly option for integration with the current vector control strategy that relies mainly on the elimination of breeding sites and insecticide applications. This paper describes the trajectory that has been followed in assessing the feasibility of SIT against Ae. albopictus in Reunion Island, and reviews some of the main achievements since 2009. These include essential scientific information so far obtained on the biology and ecology of Ae. albopictus, and the development of the requisite technological capabilities for the production and release of sexually competitive sterile males. Furthermore, it also draws attention to the strategies established to streamline the decision-making process, including an awareness campaign to enhance public understanding, efforts to secure public acceptance and regulatory validation of SIT pilot testing for small-scale suppression of wild Ae. albopictus in selected urban sites on the island. Abstract: The global expansion of Aedes albopictus, together with the absence of specific treatment and vaccines for most of the arboviruses it transmits, has stimulated the development of more sustainable and ecologically acceptable methods for control of disease transmission through the suppression of natural vector populations. The sterile insect technique (SIT) is rapidly evolving as an additional tool for mosquito control, offering an efficient and more environment-friendly alternative to the use of insecticides. Following the devastating chikungunya outbreak, which affected 38% of the population on Reunion Island (a French overseas territory in the southwest of the Indian Ocean), there has been strong interest and political will to develop effective alternatives to the existing vector control strategies. Over the past 10 years, the French Research and Development Institute (IRD) has established an SIT feasibility program against Ae. albopictus on Reunion Island in collaboration with national and international partners. This program aimed to Insects 2020, 11, 770 2 of 25 determine whether the SIT based on the release of radiation-sterilized males is scientifically and technically feasible, and socially acceptable as part of a control strategy targeting the local Ae. albopictus population. This paper provides a review of a multi-year and a particularly broad scoping process of establishing the scientific and technological feasibility of the SIT against Ae. albopictus on Reunion Island. It also draws attention to some prerequisites of the decision-making process, through awareness campaigns to enhance public understanding and support, social adoption, and regulatory validation of the SIT pilot tests.

International audience; Seabirds are well known to be attracted by fishing boats to forage on offal and baits. Weused recently developed loggers that record accurate GPS position and detect the presenceof boats through their radar emissions to examine how albatrosses use Area RestrictedSearch (ARS) and if so, have specific ARS behaviours, when attending boats. As much as78.5% of locations with a radar detection (contact with boat) during a trip occurred withinARS: 36.8% of all large-scale ARS (n = 212) and 14.7% of all small-scale ARS (n = 1476)were associated with the presence of a boat. During small-scale ARS, birds spent moretime and had greater sinuosity during boat-associated ARS compared with other ARS thatwe considered natural. For, small-scale ARS associated with boats, those performed overshelves were longer in duration, had greater sinuosity, and birds spent more time sitting onwater compared with oceanic ARS associated with boats. We also found that the proportionof small-scale ARS tend to be more frequently nested in larger-scale ARS was higher forbirds associated with boats and that ARS behaviour differed between oceanic (tuna fisheries)and shelf-edge (mainly Patagonian toothfish fisheries) habitats. We suggest that, inseabird species attracted by boats, a significant amount of ARS behaviours are associatedwith boats, and that it is important to be able to separate ARS behaviours associated toboats from natural searching behaviours. Our study suggest that studying ARS characteristicsshould help attribute specific behaviours associated to the presence of boats and understandassociated risks between fisheries.

International audience; Les progrès des connaissances, de la médecine et le développement des insecticides ont durant un temps laissé penser qu'on viendrait à bout des nuisances occasionnées par les moustiques, les tiques et les mouches, ainsi que des maladies comme le paludisme, la dengue, la maladie de Chagas, la fièvre catarrhale ovine et bien d'autres maladies infectieuses transmises par voie vectorielle. Mais en ce début de XXe siècle, la réalité s'avère tout autre. Écrit par un collectif de spécialistes, cet ouvrage présente un état actualisé des connaissances sur tous les groupes d'arthropodes d'intérêt médical et vétérinaire. Il s'appuie sur les recherches les plus récentes en systématique, écologie, génétique, anthropologie, histoire, médecine, santé publique et génie sanitaire. Pragmatique et opérationnel, il décrit les techniques d'identification et de lutte à mettre en place pour limiter les nuisances et les effets pathogènes consécutifs à la transmission vectorielle de virus, bactéries, protozoaires et filaires. Véritable voyage au coeur de l'entomologie médicale et vétérinaire, ce livre permettra aux enseignants, aux étudiants, aux personnels de santé, aux chercheurs et aux décideurs en santé publique d'avoir une vision complète, mise à jour et fonctionnelle du contexte, des enjeux et des solutions à mettre en oeuvre dans un domaine majeur de la santé humaine et animale.

This preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (https://dx.doi.org/10.24072/pci.evolbiol.100057).; International audience; Whether the malaria parasite Plasmodium falciparum can manipulate mosquito host choice in ways that enhance parasite transmission toward humans is unknown. We assessed the influence of P. falciparum on the blood-feeding behaviour of three of its major vectors (Anopheles coluzzii, An. gambiae and An. arabiensis) in Burkina Faso. Host preference assays using odour-baited traps revealed no effect of infection on mosquito long-range anthropophily. However, the identification of the blood meal origin of mosquitoes showed that females carrying sporozoites, the mature transmissible stage of the parasite, displayed a 24% increase in anthropophagy compared to both females harbouring oocysts, the parasite immature stage, and uninfected individuals. Using a mathematical model, we further showed that this increased anthropophagy in infectious females resulted in a > 250% increase in parasite transmission potential, everything else being equal. This important epidemiological consequence highlights the importance of vector control tools targeting infectious females.

Japanese encephalitis is mainly considered a rural disease, but there is growing evidence of a peri-urban and urban transmission in several countries, including Cambodia. We, therefore, compared the epidemiologic dynamic of Japanese encephalitis between a rural and a peri-urban setting in Cambodia. We monitored two cohorts of 15 pigs and determined the force of infection–rate at which seronegative pigs become positive–in two study farms located in a peri-urban and rural area, respectively. We also studied the mosquito abundance and diversity in proximity of the pigs, as well as the host densities in both areas. All the pigs seroconverted before the age of 6 months. The force of infection was 0.061 per day (95% confidence interval = 0.034–0.098) in the peri-urban cohort and 0.069 per day (95% confidence interval = 0.047–0.099) in the rural cohort. Several differences in the epidemiologic dynamic of Japanese encephalitis between both study sites were highlighted. The later virus amplification in the rural cohort may be linked to the later waning of maternal antibodies, but also to the higher pig density in direct proximity of the studied pigs, which could have led to a dilution of mosquito bites at the farm level. The force of infection was almost identical in both the peri-urban and the rural farms studied, which shifts the classic epidemiologic cycle of the virus. This study is a first step in improving our understanding of Japanese encephalitis virus ecology in different environments with distinct landscapes, human and animal densities., Author summary The number of Japanese encephalitis cases has decreased substantially over the past decades with the implementation of childhood vaccination programs. Japanese encephalitis virus, however, remains the most important cause of acute viral encephalitis in Eastern and Southern Asia, with an estimated 68,000 cases reported annually worldwide. Our results demonstrate that Japanese encephalitis virus circulates intensely both in a rural and a peri-urban setting in Cambodia, which raises important public health concerns as peri-urban areas are densely populated. These results support the importance of changing vaccination recommendations for travelers and of not focusing national immunization programs against Japanese encephalitis solely on rural areas.

International audience; Mutations in GFPT1 (glutamine-fructose-6-phosphate transaminase 1), a gene encoding an enzyme involved in glycosylation of ubiquitous proteins, cause a limb-girdle congenital myasthenic syndrome (LG-CMS) with tubular aggregates (TAs) characterized predominantly by affection of the proximal skeletal muscles and presence of highly organized and remodeled sarcoplasmic tubules in patients’ muscle biopsies. GFPT1 is the first and rate-limiting enzyme of the hexosamine biosynthetic pathway (HBP) involved in ubiquitous glycosylation processes (Senderek J. et al., 2011). Since 2011, a total of 52 patients with GFPT1 mutations have been clinically reported (Guergueltcheva V. et al., 2012; Senderek et al., 2011;Selcen D. et al., 2013; Huh S-Y. et al., 2012). In this study, we report the retrospective clinical description and the molecular investigations of 11 individuals from 9 unrelated families with LG-CMS linked to recessively-inherited mutations in GFPT1.Interestingly, GFPT1 is expressed in various tissues, including skeletal muscle and motor nerve, raising the intriguing question of why mutations in such a ubiquitous gene would specifically lead to synaptic and muscular disorganization.In this study, we report here the first long-term clinical follow-up of 11 French individuals suffering from LG-CMS with TAs due to GFPT1 mutations, of which 9 are new. Our retrospective clinical evaluation stresses an evolution toward a myopathic weakness that occurs concomitantly to ineffectiveness of usual CMS treatments. Analysis of neuromuscular biopsies from 3 unrelated individuals demonstrates that the maintenance of neuromuscular junctions (NMJs) is dramatically impaired with loss of post-synaptic junctional folds and evidence of denervation-reinnervation processes affecting the 3 main NMJ components. Moreover, molecular analyses of the human muscle biopsies confirm glycosylation defects of proteins with reduced O-glycosylation and show reduced sialylation of transmembrane proteins in extrajunctional area. Altogether, these results pave the way for understanding the etiology of this rare neuromuscular disorder that may be considered as a “tubular aggregates myopathy with synaptopathy”

Chromosome inversions have fascinated the scientific community, mainly because of their role in the rapid adaption of different taxa to changing environments. However, the ecological traits linked to chromosome inversions have been poorly studied. Here, we investigated the roles played by 23 chromosome inversions in the adaptation of the four major African malaria mosquitoes to local environments in Africa. We studied their distribution patterns by using spatially explicit modeling and characterized the ecogeographical determinants of each inversion range. We then performed hierarchical clustering and constrained ordination analyses to assess the spatial and ecological similarities among inversions. Our results show that most inversions are environmentally structured, suggesting that they are actively involved in processes of local adaptation. Some inversions exhibited similar geographical patterns and ecological requirements among the four mosquito species, providing evidence for parallel evolution. Conversely, common inversion polymorphisms between sibling species displayed divergent ecological patterns, suggesting that they might have a different adaptive role in each species. These results are in agreement with the finding that chromosomal inversions play a role in Anopheles ecotypic adaptation. This study establishes a strong ecological basis for future genome-based analyses to elucidate the genetic mechanisms of local adaptation in these four mosquitoes., Fieldwork was supported by the Institut de Recherche pour le Développement and the National Institutes of Health grant R01-AI063508 awarded to Nora J. Besansky. P. Acevedo is funded by a MINECO and Universidad de Castilla-La Mancha (UCLM) through “Ramon y Cajal” contract (RYC-2012-11970).

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International audience; Recent studies have highlighted the large diversity of malaria parasites infecting African great apes (subgenus Laverania) and their strong host specificity. Although the existence of genetic incompatibilities preventing the cross-species transfer may explain host specificity, the existence of vectors with a high preference for a determined host represents another possibility. To test this hypothesis , we undertook a 15-mo-long longitudinal entomological survey in two forest regions of Gabon, where wild apes live, at different heights under the canopy. More than 2,400 anopheline mosquitoes belonging to 18 species were collected. Among them, only three species of Anopheles were found infected with ape Plasmodium: Anopheles vinckei, Anopheles moucheti, and Anopheles marshallii. Their role in transmission was confirmed by the detection of the parasites in their salivary glands. Among these species, An. vinckei showed significantly the highest prevalence of infection and was shown to be able to transmit parasites of both chimpanzees and gorillas. Transmission was also shown to be conditioned by seasonal factors and by the heights of capture under the canopy. Moreover, human landing catches of sylvan Anopheles demonstrated the propensity of these three vector species to feed on humans when available. Our results suggest therefore that the strong host specificity observed in the Laveranias is not linked to a specific association between the vertebrate host and the vector species and highlight the potential role of these vectors as bridge between apes and humans. Plasmodium | Laverania | Anopheles | ape-to-human infection | African rainforest R ecent studies on great apes in Africa have revealed the existence of a large diversity of Plasmodium parasites infecting chimpanzees and gorillas, some being related to the most deadly human parasite Plasmodium falciparum (subgenus Laverania), others to the human parasites Plasmodium malariae, Plasmodium ovale, or Plasmodium vivax (subgenus Plasmodium) (1-4). Within the subgenus Laverania, eight species are currently recognized. Among them, four species (Plasmodium reichenowi, Plasmodium gaboni, Plasmodium billcollinsi, and Plasmodium billbrayi) were observed only in chimpanzees and three (Plas-modium praefalciparum, Plasmodium adleri, and Plasmodium blacklocki) only in gorillas (2, 3, 5). In this subgenus, only P. falciparum infects humans. In natura, although these different host species cooccur in the same habitat where their ranges overlap, no transfer of Laverania parasites was ever documented between humans and apes or between gorillas and chimpanzees despite large sampling efforts (2, 3, 6). Similarly, ancient reciprocal transplant experiments of Laverania parasites between humans and apes (mostly chimpanzees) failed to produce infections (5). On the contrary , for parasites of the subgenus Plasmodium, like P. vivax or P. malariae, transfers were documented in natural populations (2, 4, 7) or during experimental infections (5). All this suggests therefore a strong host specificity of the Laverania parasites. The origin of this host specificity in the Laverania could result from an incompatibility at the parasite/vertebrate host interface, at the vector/host interface, or at the parasite/vector interface (5). The first hypothesis has already received much attention and some studies have concluded to the potential existence of a genetic barrier precluding the transfer of parasites from one host species to another (especially from great apes to humans) (5, 8). This barrier would be the consequence of specific receptor/ligand interactions at the host red blood cell/parasite interface. However, this hypothesis is at odds with observations made in conditions of artificial confinement such as in ape sanctuaries, where different host species (humans and great apes) live in close proximity and where human-to-ape transfers were documented. For instance, bonobos (Pan paniscus), from a sanctuary in the Democratic Republic of Congo, were found infected with P. falciparum, a parasite supposed to be human-specific (4). A similar phenomenon was observed in chimpanzees in a Cameroonian Significance African great apes were recently found to host a large diversity of parasites (subgenus Laverania) related to the main agent of human malaria (Plasmodium falciparum). Despite their close genetic relationships, these parasites are highly host-specific, infecting either chimpanzees or gorillas. This host specificity could result from incompatibilities between parasites and hosts or from a strong host tropism of the vectors. To test this second hypothesis, we performed a large entomological survey in the heart of the Gabonese rainforest (central Africa) to identify the vector species involved in ape Plasmodium transmission. Our results demonstrated that all ape parasites are transmitted by the same three vector species, thus rejecting the hypothesis that vectors could be responsible for the Laverania host specificity.

International audience; An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species), Aedes (35 species), Anopheles (26 species), Coquillettidia (3 species), Culex (at least 50 species), Eretmapodites (4 species), Ficalbia (2 species), Hodgesia (at least one species), Lutzia (one species), Mansonia (2 species), Mimomyia (22 species), Orthopodomyia (8 species), Toxorhynchites (6 species), and Uranotaenia (73 species). Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%). Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27%) with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar.; Une liste mise à jour des 235 espèces de moustiques de Madagascar est présentée. Le nombre d’espèces a considérablement augmenté par rapport à celui donné dans les listes précédentes, en particulier la dernière, publiée en 2003 (178 espèces). Cette liste fournit des informations concises sur l’endémisme, la position taxonomique, les stades de développement, les gîtes larvaires, la distribution, le comportement des moustiques, et aussi sur les maladies potentiellement transmises par les moustiques vecteurs. Ces 235 espèces sont réparties dans 14 genres : Aedeomyia (3 espèces), Aedes (35 espèces), Anopheles (26 espèces), Coquillettidia (3 espèces), Culex (au moins 50 espèces), Eretmapodites (4 espèces), Ficalbia (2 espèces), Hodgesia (au moins une espèce), Lutzia (une espèce), Mansonia (2 espèces), Mimomyia (22 espèces), Orthopodomyia (8 espèces), Toxorhynchites (6 espèces), Uranotaenia (73 espèces). En raison de complexes d’espèces non résolus, plusieurs espèces sont toujours non décrites. La principale caractéristique remarquable de la faune malgache de moustiques est la grande biodiversité avec 138 espèces endémiques (59 %). La présence et l’abondance des espèces, et leur association dans un endroit donné, pourrait être un bio-indicateur des particularités environnementales telles que les habitats urbains, ruraux, forestiers, déboisés et montagneux. Enfin, compte tenu que la faune malgache de moustiques comprend 64 espèces (27 %) ayant un intérêt médical ou vétérinaire connu dans le monde, la connaissance de leur biologie et de leur préférence d’hôtes résumée dans le présent document permet de comprendre leur implication dans la transmission d’agents pathogènes à Madagascar.

Targeted trapping of mosquito disease vectors plays an important role in the surveillance and control of mosquito-borne diseases. The Asian tiger mosquito, Aedes albopictus (Skuse), is an invasive species, which is spreading throughout the world, and is a potential vector of 24 arboviruses, particularly efficient in the transmission of chikungunya, dengue, and zika viruses. Using a 4 x 4 Latin square design, we assessed the efficacy of the new BG-Sentinel 2 mosquito trap using the attractants BG-lure and (R)-1-octen-3-ol cartridge, alone or in combination, and with and without carbon dioxide, for the field collection of Ae. albopictus mosquitoes. We found a synergistic effect of attractant and carbon dioxide that significantly increased twofold to fivefold the capture rate of Ae. albopictus. In combination with carbon dioxide, BG-lure cartridge is more effective than (R)-1-octen-3-ol in attracting females, while a combination of both attractants and carbon dioxide is the most effective for capturing males. In the absence of carbon dioxide, BG-lure cartridge alone did not increase the capture of males or females when compared with an unbaited trap. However, the synergistic effect of carbon dioxide and BG-lure makes this the most efficient combination in attracting Ae. albopictus.

Background Ultra-low volume (ULV) insecticidal aerosols dispensed from vehicle-mounted cold-foggers are widely considered the method of choice for control of Aedes aegypti and Ae. albopictus during outbreaks of dengue and chikungunya and, more recently, Zika. Nevertheless, their effectiveness has been poorly studied, particularly in Europe. Nearly all published studies of ULV efficacy are bio-assays based on the mortality of caged mosquitoes. In our study we preferred to monitor the direct impact of treatments on the wild mosquito populations. This study was undertaken to evaluate the efficiency of the two widely used space spraying methods to control Ae. albopictus and Ae. aegypti. Methods We determined the susceptibility of local Ae. albopictus to deltamethrin by two methods: topical application and the “WHO Tube Test”. We used ovitraps baited with hay infusion and adult traps (B-G Sentinel) baited with a patented attractant to monitor the mosquitoes in four residential areas in Nice, southern France. The impact of deltamethrin applied from vehicle-mounted ULV fogging-machines was assessed by comparing trap results in treated vs untreated areas for 5 days before and 5 days after treatment. Four trials were conducted at the maximum permitted application rate (1 g.ha-1). We also made two small-scale tests of the impact of the same insecticide dispensed from a hand-held thermal fogger. Results Susceptibility to the insecticide was high but there was no discernable change in the oviposition rate or the catch of adult female mosquitoes, nor was there any change in the parous rate. In contrast, hand-held thermal foggers were highly effective, with more than 90% reduction of both laid eggs and females. Conclusions We believe that direct monitoring of the wild mosquito populations gives a realistic assessment of the impact of treatments and suggest that the lack of efficacy is due to lack of interaction between the target mosquitoes and the ULV aerosol. We discuss the factors that influence the effectiveness of both methods of spraying in the context of epidemic situations. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1881-y) contains supplementary material, which is available to authorized users.

International audience; Des dizaines de maladies touchant l'homme sont dues à un agent pathogène transmis par un vecteur (insecte ou tique). La lutte contre ces maladies, en particulier grâce à la lutte antivectorielle, nécessite de comprendre les mécanismes écologiques, cellulaires et génétiques de la transmission. En cela l'entomologie médicale est une discipline incontournable de l'infectiologie. Ce plaidoyer présente le contexte, les enjeux et les recherches à conduire en entomologie médicale et vétérinaire.

International audience; Invasion of new territories by insect vector species that can transmit pathogens is one of the most important threats for human health. The spread of the mosquito Aedes albopictus in Europe is emblematic, because of its major role in the emergence and transmission of arbo-viruses such as dengue or chikungunya. Here, we modeled the spread of this mosquito species in France through a statistical framework taking advantage of a long-term surveillance dataset going back to the first observation of Ae. albopictus in the Metropolitan area. After validating the model, we show that human activities are especially important for mosquito dispersion while land use is a major factor for mosquito establishment. More importantly, we show that Ae. albopictus invasion is accelerating through time in this area, resulting in a geographic range extending further and further year after year. We also show that sporadic " jump " of Ae. albopictus in a new location far from the colonized area did not succeed in starting a new invasion front so far. Finally, we discuss on a potential adaptation to cooler climate and the risk of invasion into Northern latitudes.

International audience; In Tunisia, malaria transmission has been interrupted since 1980. However, the growing number of imported cases and the persistence of putative vectors stress the need for additional studies to assess the risk of malaria resurgence in the country. In this context, our aim was to update entomological data concerning Anopheles mosquitoes in Tunisia. From May to October of 2012, mosquito larval specimens were captured in 60 breeding sites throughout the country and identified at the species level using morphological keys. Environmental parameters of the larval habitats were recorded. Specimens belonging to the An. maculipennis complex were further identified to sibling species by the ribosomal deoxyribonucleic acid (rDNA)-internal transcribed spacer 2 (ITS2) polymerase chain reaction (PCR) technique. In total, 647 Anopheles larvae were collected from 25 habitats. Four species, including An. labranchiae, An. multicolor, An. sergentii, and An. algeriensis, were morphologically identified. rDNA-ITS2 PCR confirmed that An. labranchiae is the sole member of the An. maculipennis complex in Tunisia. An. labranchiae was collected throughout northern and central Tunisia, and it was highly associated with rural habitat, clear water, and sunlight areas. Larvae of An. multicolor and An. sergentii existed separately or together and were collected in southern Tunisia in similar types of breeding places.

The genus Anopheles includes mosquito vectors of human malaria and arboviruses. In sub-Saharan Africa, the anopheline fauna is rich of nearly 150 species, few of which are anthropophilic and capable of transmitting pathogens to humans. Some of the remaining species are found in forests far from human environments and are vectors of wildlife pathogens. The diversity and the biology of these species have yet to be fully described. As a contribution to furthering knowledge of sylvan Anophelinae, using morphological and molecular tools we describe a new Anopheles species collected in Gabon (Central Africa), which we have named Anopheles gabonensis n. sp. We also molecularly screened this species to detect infections by Plasmodium parasites. The results showed the species to have been infected by Plasmodium vinckei, a rodent parasite. We discuss the role of An. gabonensis n. sp. in the transmission of P. vinckei in the rainforest areas of Central Africa and its potential to transfer pathogens to humans.

International audience

Arbovirus vector dynamics and spread are influenced by climatic, environmental and geographic factors. Major Chikungunya and Dengue fever outbreaks occurring the last 10 years have coincided with the expansion of the mosquito vector Aedes albopictus to nearly all the continents. We characterized the ecological (larval development sites, population dynamics, insemination and daily survival rates) and genetic (diversity, gene flow, population structure) features of two Aedes albopictus populations from distinct environments (rural and urban) on Réunion Island, in the South-West Indian Ocean. Microsatellite analysis suggests population sub-structuring Ae. albopictus populations. Two genetic clusters were identified that were significantly linked to natural versus urban habitats with a mixed population in both areas. Ae. albopictus individuals prefer urban areas for mating and immature development, where hosts and containers that serve as larval development sites are readily available and support high population densities, whereas natural environments appear to serve as reservoirs for the mosquito., Author Summary The objective of our research was to study the movements the mosquito Aedes albopictus. This mosquito transmits more than 20 viruses to humans throughout the world and is the vector of the recent major epidemics of Dengue and Chikungunya on Reunion Island and the Indian Ocean Region and is, therefore, of great interest for human health. We set out to determine whether reservoirs of populations could be found in natural environments and whether or not these populations are capable of re-colonising urban areas. Until now, only limited data has been available on the population dynamics of Aedes albopictus in this part of the world, information critical for guiding vector control strategies and predicting or preventing epidemics. We chose two areas where a serious CHIKV epidemic occurred. We then used genetic markers and ecological data to estimate patterns of gene flow and behaviour. We were able to demonstrate that populations were structured with limited gene flow despite observing migration. We found that Ae. albopictus preferred urban areas for mating and to lay their eggs because of the availability of hosts and permanent containers that favoured higher mosquito densities. We also show, however, that natural environments are reservoirs for re-colonisation of urban areas.

International audience; In Madagascar, Anopheles gambiae has been found below altitudes of 1,000 m. We sampled An. gambiae sensu lato (sl) between 2008 and 2010 in the Central Highlands of Madagascar at altitudes over 1,200 m. The study site consists of rainforest, rainforest edge, and an open savanna biotope. Anopheles gambiae and An. arabiensis, as well as molecular forms of An. gambiae, were identified molecularly. An. gambiae accounted for 26.7% at the edge of the rainforest and 2.3% in the open savanna biotope. One specimen of this species was caught in the forest. An. arabiensis accounted for 66.3% at the edge of the rainforest and 97.7 % in the open savanna biotope. All An. gambiae adults tested belonged to the S molecular form. An. gambiae is present at high altitudes in Madagascar, with a high prevalence at the rainforest edge. Several factors, including the appearance of new favorable biotopes, recolonization after a reduction of indoor vector control, and climate change, may contribute to its distribution. The changing distribution of An. gambiae may have consequences for the distribution and incidence of malaria in the Malagasy Highlands.

Background Anopheles funestus is one of the major malaria vectors in tropical Africa. Because of several cycles of drought events that occurred during the 1970s, this species had disappeared from many parts of sahelian Africa, including the Senegal River basin. However, this zone has been re-colonized during the last decade by An. funestus, following the implementation of two dams on the Senegal River. Previous studies in that area revealed heterogeneity at the biological and chromosomal level among these recent populations. Methods Here, we studied the genetic structure of the newly established mosquito populations using eleven microsatellite markers in four villages of the Senegal River basin and compared it to another An. funestus population located in the sudanian domain. Results Our results presume Hardy Weinberg equilibrium in each An. funestus population, suggesting a situation of panmixia. Moreover, no signal from bottleneck or population expansion was detected across populations. The tests of genetic differentiation between sites revealed a slight but significant division into three distinct genetic entities. Genetic distance between populations from the Senegal River basin and sudanian domain was correlated to geographical distance. In contrast, sub-division into the Senegal River basin was not correlated to geographic distance, rather to local adaptation. Conclusions The high genetic diversity among populations from Senegal River basin coupled with no evidence of bottleneck and with a gene flow with southern population suggests that the re-colonization was likely carried out by a massive and repeated stepping-stone dispersion starting from the neighboring areas where An. funestus endured.

International audience; Background: Anthropogenic habitat disturbance is a prime cause in the current trend of the Earth's reduction in biodiversity. Here we show that the human footprint on the Central African rainforest, which is resulting in deforestation and growth of densely populated urban agglomerates, is associated to ecological divergence and cryptic speciation leading to adaptive radiation within the major malaria mosquito Anopheles gambiae.Methodology/Principal Findings: In southern Cameroon, the frequency of two molecular forms-M and S-among which reproductive isolation is strong but still incomplete, was correlated to an index of urbanisation extracted from remotely sensed data, expressed as the proportion of built-up surface in each sampling unit. The two forms markedly segregated along an urbanisation gradient forming a bimodal cline of ,6-km width: the S form was exclusive to the rural habitat, whereas only the M form was present in the core of densely urbanised settings, co-occurring at times in the same polluted larval habitats of the southern house mosquito Culex quinquefasciatus-a species association that was not historically recorded before.Conclusions/Significance: Our results indicate that when humans create novel habitats and ecological heterogeneities, they can provide evolutionary opportunities for rapid adaptive niche shifts associated with lineage divergence, whose consequences upon malaria transmission might be significant.

The outbreak of chikungunya that occurred on French Island territories in the southwest Indian Ocean in 2005 and 2006 caused severe morbidity and mortality. In the aftermath, French authorities set up a scientific task force including experts in epidemiology, public health, entomology, virology, immunology, sociology, animal health, community and hospital medicine. The mission of the task force was to conceive and propose research programs needed to increase understanding of the disease and epidemic and to help public health officials in improving epidemic response measures. The purpose of this article is to describe the findings of the task force at the end of its two-year existence and initial outcomes in the the areas studied. Discussion emphasizes topics requiring further study.

International audience; Five trapping methods were compared for monitoring potential vectors of the West Nile virus in four areas in the Camargue Plain of France: carbon dioxide traps, bird-baited traps, gravid traps, resting boxes, and human landing catches. A total of 73,721 specimens, representing 14 species, was trapped in 2006. Results showed significant differences in species and abundance between the type of traps. Many more specimens were collected using CO 2 traps than any other method, with an average of 212 specimens per night per trap (p

International audience; Studies on the biology and mating behaviour of male mosquitoes are of major importance in a frame of a Sterile Insect Technique which could be used against mosquito vector species. Most particularly, the assumption of possible multiple inseminations in mosquito species must be investigated in order to optimize alternative mosquito control methods (Sterile Insect Techniques with genetically modified mosquitoes, cytoplasmic incompatibility, radiation…). The occurrence of multiple insemination events was investigated after 2 field samplings of Aedes albopictus (Diptera: Culicidae) in La Reunion Island using microsatellite markers. Respectively, 14 and 13 females after the first and the second sampling laid eggs. Seven wild females out of the 27 laying females were found with a progeny involving more than one father. This result is important for the new alternative mosquito control methods and raises the importance of pre- and post-copulatory competition.

Aedes albopictus and Aedes aegypti are the two main worldwide arbovirus vectors that have experienced invasion phases. Aedes aegypti is a pantropical species that spread centuries ago whereas Ae. albopictus started the main wave of invasion in the 1980s. Both species have been at various times on the different islands in Southwestern Indian Ocean (SWIO). This area provides an opportunity to examine the extent to which mosquitoes colonization patterns are influenced by different introductory events likely linked with human settlement and migration between the islands. To explore this hypothesis, we propose a CO1-based phylogeny using a large sampling of fresh Ae. albopictus, Ae. aegypti, and Ae. mascarensis, and 50-year-old dry specimens originating from different Indian Ocean islands. Our data allow us to hypothesize the existence of at least two waves of invasion for Ae. albopictus in the islands of SWIO. The first one most likely occurred several centuries ago with establishments in Madagascar, Mauritius and Reunion Island. The other one that appears to currently still on-going, reached almost all the islands of SWIO during the 1990s or later. The low genetic diversity found between the ancient invasive strain and the contemporary one, indicates with great certainty that Ae. albopictus is not indigenous to the islands of SWIO. Recently, in Madagascar, an invasive lineage of Ae. albopictus has expanded all over the island while Ae. aegypti populations have declined in urban areas. Three clusters of Aedes aegypti have been observed, two fitting with the wild form Ae. aegypti formosus and the other one fitting with the more domestic form Ae. ae. aegypti. Sequence of Ae. mascarensis, endemic to Mauritius suggest that this species might belong to Ae. aegypti species and on this basis we propose to classify it as a sub species or form of Ae. aegypti species. Given the increase of human population flux on these islands, the occurrence of these vectors and their ability to spread quickly are of high importance of arbovirus transmission and the epidemicity of the associated diseases in these islands.

Background In the malaria vector Anopheles gambiae, understanding diversity in natural populations and genetic components of important phenotypes such as resistance to malaria infection is crucial for developing new malaria transmission blocking strategies. The design and interpretation of many studies here depends critically on Linkage disequilibrium (LD). For example in association studies, LD determines the density of Single Nucleotide Polymorphisms (SNPs) to be genotyped to represent the majority of the genomic information. Here, we aim to determine LD in wild An. gambiae s.l. populations in 4 genes potentially involved in mosquito immune responses against pathogens (Gambicin, NOS, REL2 and FBN9) using previously published and newly generated sequences. Results The level of LD between SNP pairs in cloned sequences of each gene was determined for 7 species (or incipient species) of the An. gambiae complex. In all tested genes and species, LD between SNPs was low: even at short distances (< 200 bp), most SNP pairs gave an r2 < 0.3. Mean r2 ranged from 0.073 to 0.766. In most genes and species LD decayed very rapidly with increasing inter-marker distance. Conclusions These results are of great interest for the development of large scale polymorphism studies, as LD generally falls below any useful limit. It indicates that very fine scale SNP detection will be required to give an overall view of genome-wide polymorphism. Perhaps a more feasible approach to genome wide association studies is to use targeted approaches using candidate gene selection to detect association to phenotypes of interest.

International audience; Les domaines de la santé et de l’environnement ont longtemps été considérés, tant par les décideurs que par les scientifiques, comme des réalités disjointes. Il a fallu attendre les dernières décennies pour que soit reconnu et que se concrétise le lien entre environnements et santé avec la création d’agences spécialisées.Qu’il s’agisse de foyers de maladies parasitaires ou de pollution atmosphérique, les situations d’exposition à un risque sanitaire lié à l’environnement relèvent de facteurs particuliers : épidémiologiques, géographiques, politiques, et bien évidemment sociaux.À partir de zones géographiques situées tant au Sud qu’au Nord, les auteurs de cet ouvrage présentent un large éventail de configurations dans lesquelles s’exprime la complexité des relations entre santé et environnements dans leur rapport avec les groupes humains.Ils mettent l’accent sur l’importance de la perception et de la pratique des acteurs (des décideurs aux bénéficiaires des mesures, en passant par les médecins) pour penser le risque sanitaire selon les milieux.Ils soulignent tout l’intérêt de l’apport des sciences sociales et des pratiques interdisciplinaires dès lors qu’il s’agit d’envisager les relations entre un pathogène et l’homme. Chacune des approches s’attache ainsi à éclairer les différentes facettes du risque environnemental, depuis le comportement des individus jusqu’aux politiques nationales, en invitant le le lecteur à se départir de toute vision déterministe et simplificatrice.

BackgroundMalaria and alcohol consumption both represent major public health problems. Alcohol consumption is rising in developing countries and, as efforts to manage malaria are expanded, understanding the links between malaria and alcohol consumption becomes crucial. Our aim was to ascertain the effect of beer consumption on human attractiveness to malaria mosquitoes in semi field conditions in Burkina Faso.Methodology/principal findingsWe used a Y tube-olfactometer designed to take advantage of the whole body odour (breath and skin emanations) as a stimulus to gauge human attractiveness to Anopheles gambiae (the primary African malaria vector) before and after volunteers consumed either beer (n = 25 volunteers and a total of 2500 mosquitoes tested) or water (n = 18 volunteers and a total of 1800 mosquitoes). Water consumption had no effect on human attractiveness to An. gambiae mosquitoes, but beer consumption increased volunteer attractiveness. Body odours of volunteers who consumed beer increased mosquito activation (proportion of mosquitoes engaging in take-off and up-wind flight) and orientation (proportion of mosquitoes flying towards volunteers' odours). The level of exhaled carbon dioxide and body temperature had no effect on human attractiveness to mosquitoes. Despite individual volunteer variation, beer consumption consistently increased attractiveness to mosquitoes.Conclusions/significanceThese results suggest that beer consumption is a risk factor for malaria and needs to be integrated into public health policies for the design of control measures.

International audience; Cet article s'articule autour d'un entretien sur l'entomologie médicale réalisé auprès de Didier Fontenille, directeur de recherche à l’Institut de recherche pour le développement (IRD), entomologiste médical, spécialiste de la biologie, de la génétique et du contrôle des insectes vecteurs de maladies comme le paludisme, la dengue ou le Chikungunya.

Cet article s'articule autour d'un entretien sur l'entomologie medicale realise aupres de Didier Fontenille, directeur de recherche a l’Institut de recherche pour le developpement (IRD), entomologiste medical, specialiste de la biologie, de la genetique et du controle des insectes vecteurs de maladies comme le paludisme, la dengue ou le Chikungunya.

International audience; Sugar feeding by male mosquitoes is critical for their success in mating competition. However, the facets of sugar source finding under natural conditions remain unknown. Here, evidence obtained in Western Burkina Faso indicated that the distribution of An. gambiae s.s. (M and S molecular forms) males across different peri-domestic habitats is dependent on the availability of potential sugar sources from which they obtain more favorable sites for feeding or resting. Among field-collected anophelines, a higher proportion of specimens containing fructose were found on flowering Mangifera indica (Anacardiaceae), Dolonix regia (Fabaceae), Thevetia neriifolia (Apocynaceae), Senna siamea, and Cassia sieberiana (both Fabaceae) compared to that recorded on other nearby plants, suggesting that some plants are favored for use as a sugar source over others. Y-tube olfactometer assays with newly-emerged An. gambiae s.s. exposed to odors from individual plants and some combinations thereof showed that males use odor cues to guide their preference. The number of sugar-positive males was variable in a no-choice cage assay, consistent with the olfactory response patterns towards corresponding odor stimuli. These experiments provide the first evidence both in field and laboratory conditions for previously unstudied interactions between males of An. gambiae and natural sugar sources.

Background Highland areas of Africa are mostly malaria hypoendemic, due to climate which is not appropriate for anophelines development and their reproductive fitness. In view of designing a malaria control strategy in Western Cameroon highlands, baseline data on anopheline species bionomics were collected. Methods Longitudinal entomological surveys were conducted in three localities at different altitudinal levels. Mosquitoes were captured when landing on human volunteers and by pyrethrum spray catches. Sampled Anopheles were tested for the presence of Plasmodium circumsporozoite proteins and their blood meal origin with ELISA. Entomological parameters of malaria epidemiology were assessed using Mac Donald's formula. Results Anopheline species diversity and density decreased globally from lowland to highland. The most aggressive species along the altitudinal transect was Anopheles gambiae s.s. of S molecular form, followed in the lowland and on the plateau by An. funestus, but uphill by An. hancocki. An. gambiae and An. ziemanni exhibited similar seasonal biting patterns at the different levels, whereas different features were observed for An. funestus. Only indoor resting species could be captured uphill; it is therefore likely that endophilic behaviour is necessary for anophelines to climb above a certain threshold. Of the ten species collected along the transect, only An. gambiae and An. funestus were responsible for malaria transmission, with entomological inoculation rates (EIR) of 90.5, 62.8 and zero infective bites/human/year in the lowland, on the plateau and uphill respectively. The duration of gonotrophic cycle was consistently one day shorter for An. gambiae as compared to An. funestus at equal altitude. Altitudinal climate variations had no effect on the survivorship and the subsequent life expectancy of the adult stage of these malaria vectors, but most probably on aquatic stages. On the contrary increasing altitude significantly extended the duration of gonotrophic cycle and reduced: the EIR, their preference to human blood and consequently the malaria stability index. Conclusion Malaria epidemiological rooting in the outskirts of Western Cameroon highlands evolves with increasing altitude, gradually from stable to unstable settings. This suggests a potential risk of malaria epidemic in highlands, and the need for a continuous epidemiological surveillance.

BackgroundThe time necessary for malaria parasite to re-appear in the blood following treatment (re-infection time) is an indirect method for evaluating the immune defences operating against pre-erythrocytic and early erythrocytic malaria stages. Few longitudinal data are available in populations in whom malaria transmission level had also been measured.MethodsOne hundred and ten individuals from the village of Ndiop (Senegal), aged between one and 72 years, were cured of malaria by quinine (25 mg/day oral Quinimax™ in three equal daily doses, for seven days). Thereafter, thick blood films were examined to detect the reappearance ofPlasmodium falciparumevery week, for 11 weeks after treatment. Malaria transmission was simultaneously measured weekly by night collection of biting mosquitoes.ResultsMalaria transmission was on average 15.3 infective bites per person during the 77 days follow up. The median reappearance time for the whole study population was 46.8 days, whereas individuals would have received an average one infective bite every 5 days. At the end of the follow-up, after 77 days, 103 of the 110 individuals (93.6%; CI 95% [89.0–98.2]) had been re-infected withP. falciparum. The median reappearance time ('re-positivation') was longer in subjects with patent parasitaemia at enrolment than in parasitologically-negative individuals (58 days vs. 45.9; p = 0.03) and in adults > 30 years than in younger subjects (58.6 days vs. 42.7; p = 0.0002). In a multivariate Cox PH model controlling for the sickle cell trait, G6PD deficiency and the type of habitat, the presence of parasitaemia at enrolment and age ≥ 30 years were independently predictive of a reduced risk of re-infection (PH = 0.5 [95% CI: 0.3–0.9] and 0.4; [95% CI: 0.2–0.6] respectively).ConclusionResults indicate the existence of a substantial resistance to sporozoites inoculations, but which was ultimately overcome in almost every individual after 2 1/2 months of natural challenges. Such a study design and the results obtained suggest that, despite a small sample size, this approach can contribute to assess the impact of intervention methods, such as the efficacy vector-control measures or of malaria pre-erythrocytic stages vaccines.

In much of sub-Saharan Africa, the mosquito Anopheles gambiae is the main vector of the major human malaria parasite, Plasmodium falciparum. Convenient laboratory studies have identified mosquito genes that affect positively or negatively the developmental cycle of the model rodent parasite, P. berghei. Here, we use transcription profiling and reverse genetics to explore whether five disparate mosquito gene regulators of P. berghei development are also pertinent to A. gambiae/P. falciparum interactions in semi-natural conditions, using field isolates of this parasite and geographically related mosquitoes. We detected broadly similar albeit not identical transcriptional responses of these genes to the two parasite species. Gene silencing established that two genes affect similarly both parasites: infections are hindered by the intracellular local activator of actin cytoskeleton dynamics, WASP, but promoted by the hemolymph lipid transporter, ApoII/I. Since P. berghei is not a natural parasite of A. gambiae, these data suggest that the effects of these genes have not been drastically altered by constant interaction and co-evolution of A. gambiae and P. falciparum; this conclusion allowed us to investigate further the mode of action of these two genes in the laboratory model system using a suite of genetic tools and infection assays. We showed that both genes act at the level of midgut invasion during the parasite's developmental transition from ookinete to oocyst. ApoII/I also affects the early stages of oocyst development. These are the first mosquito genes whose significant effects on P. falciparum field isolates have been established by direct experimentation. Importantly, they validate for semi-field human malaria transmission the concept of parasite antagonists and agonists., Author Summary Malaria is a parasitic infectious disease transmitted by mosquitoes. It impacts half the population of the world and kills 1 to 3 million people every year, the vast majority of whom are children aged below 5 in sub-Saharan Africa. There, the deadliest parasite is Plasmodium falciparum and its most important vector is the mosquito Anopheles gambiae. This study identifies for the first time specific A. gambiae genes that demonstrably regulate the density of mosquito infection by P. falciparum parasites circulating in malaria patients in Africa. These genes function in mosquito lipid transport and intracellular actin cytoskeleton dynamics, and act as an agonist and an antagonist, respectively, of the parasite ookinete-to-oocyst developmental transition. Importantly, our study validates for P. falciparum the concept of mosquito genes that support or hinder parasite development, a concept that we defined previously using a laboratory model system. Thus, the work constitutes a major contribution to understanding meaningful mosquito/parasite interactions in natural transmission conditions.

A comparative study between the Enzyme-Linked Immuno Sorbent Assay (ELISA-CSP) for circumsporozoitic antigen detection method, the direct observation after dissection and the polymerase chain reaction (PCR) technique used to identify Plasmodium falciparum genomic DNA markers was carried out. This to evaluate the sensibility and the specificity of the PCR, for the determination of both sporozoitic index (ICSP) and the entomological inoculation rate (EIR). The study is conducted in laboratory on eighty six specimens of Anopheles gambiae M infected after being fed with the blood of a gametocytes carrier from Dielmo (Senegal). Salivary glands of forty-eight specimens randomly selected (test A) among the infected eighty six are microscopically observed after manual dissection for the sporozoites detection. The content of these salivary glands and the crushed head/thorax of the remaining 38 specimens (test B) are tested in ELISA-CSP and PCR. The positive and negative results obtained were recorded and summarized for each method. A pair-comparison of the results obtained with each method generally revealed a good sensibility and an excellent specificity. The kappa coefficient (K) of test A indicated a "moderate" to "excellent" concordance between the three different methods performed. By using the crushed head/thorax sample, generally used to determine the transmission parameters (ICSP and EIR), the PCR / ELISA-CSP concordance was excellent. In the light of the values of sensibility and specificity obtained, this PCR is comparable to the other methods for the assessment of sporozoitic index and entomological inoculation rate.; Une étude comparative entre la méthode immuno-enzymatique de détection de l'antigène circum-sporozoïtique (ELISA-CSP), l'observation directe après dissection et la technique d'amplification en chaîne (PCR) d'un marqueur génomique de Plasmodium falciparum a été menée. Ceci pour évaluer la sensibilité et la spécificité de la PCR comme une autre méthode de détermination de l'indice sporozoïtique (ICSP) des anophèles et du taux d'inoculation entomologique (EIR). L'étude est réalisée en laboratoire sur 86 spécimens d'Anopheles gambiae M infectés après alimentation avec le sang d'un porteur de gamétocytes originaire de Dielmo (Sénégal). Les glandes salivaires de 48 spécimens pris au hasard sur les 86 sont observées au microscope pour la recherche de sporozoïtes (test A). Leurs contenus ainsi que les broyats de tête/thorax des 38 échantillons restants (test B) sont utilisés pour l'ELISA-CSP et la PCR. Les résultats positifs et négatifs obtenus avec chacune des techniques sont comparés par paires. Généralement, une bonne sensibilité et une excellente spécificité sont obtenues. Le coefficient kappa () montre une concordance, variant de modérée à excellente, entre les différentes techniques utilisées dans le test A. Avec le broyat tête/thorax, généralement utilisé pour la détermination des indicateurs de la transmission, la concordance entre la PCR et l'ELISA-CSP est excellente. Au vu des valeurs de sensibilité et de spécificité obtenues, cette PCR est comparable aux autres méthodes pour la détermination de l'indice sporozoïtique et le taux d'inoculation entomologique.

The Camargue is an extensive wetland in the southeast of France, which is highly influenced by human activities. Large ponds, marshes and irrigated fields pro- vide abundant potential breeding sites for mosquitoes. Mosquitoes, which are important in terms of the nuisance they cause to people and animals, the limitations they impose on tourism and their potential threat to human health. Several of the mosquito species present are potential vectors of malaria and West Nile virus. Therefore, the population dynamics of these species were monitored over an entire breeding season during March - October 2005. Mosquito populations were sampled in two study areas once every 2 weeks, using CDC light traps baited with CO 2 . Sixteen species were collected. The majority (98.7%) of the catch were Aedes caspius (Pallas) (Diptera: Culicidae), Culex modestus (Ficalbi), Culex pipiens L. and Anopheles hyrcanus (Pallas). The population dynamics of these species varied considerably in relation to the species ' biology, climatic conditions (rainfall, temperature and season), water management, implementa- tion of mosquito control campaigns and landscape use.

International audience; Many triggering factors for onset of emerging infectious diseases are now recognised, such as: globalisation, demographic increase, population movements, international trade, urbanisation, forest destruction, climate changes, loss in biodiversity, and extreme life conditions such as poverty, famine and war. Epidemic burden is often leading to disasters, in terms of human losses, as well as economic, political or social consequences. These outbreaks may jeopardize within a few weeks or months, industry, trade, or tourism. While dengue and its most severe forms (hemorrhagic and shock syndrome) is spreading all over the tropical world, another arbovirosis, chikungunya disease dramatically spread in Indian Ocean islands where 30 to 75% of population were infected in 2005 and 2006, and then extended its progression towards India, Sri Lanka, Indonesia, Malaysia, Maldives islands with more than a million people infected with the East-African strain, replacing the former Asian strain which was known to prevail more than 30 years ago in India. Patients experience sequelae with disability, work loss, and rarely severe outcome recently identified in La Réunion and Mayotte (French overseas territories). No country, no part of the world may consider itself as protected against such events. However, consequences of emerging or re-emerging diseases are more and more unacceptable when they impact the poorest countries of the world. Viruses, bacteria, as well as wild animals, birds, or arthropods are not stopped by borders. It is time now to promote barriers against infectious diseases, including prevention, anticipation, disease surveillance and research. This is not only for humanitarian reasons, but also for contributing to a sustainable development with equity for worldwide population. This report presents comprehensive actions taken in 2006 for tracing the epidemic and mobilise research, as requested to the task force set up by the Prime Minister by March 20, 2006.

Background Malaria is a former endemic problem in the Camargue, South East France, an area from where very few recent data concerning Anopheles are available. A study was undertaken in 2005 to establish potential malaria vector biology and dynamics and evaluate the risk of malaria re-emergence. Methods Mosquitoes were collected in two study areas, from March to October 2005, one week every two weeks, using light traps+CO2, horse bait traps, human bait catch, and by collecting females in resting sites. Results Anopheles hyrcanus was the most abundant Anopheles species. Anopheles melanoon was less abundant, and Anopheles atroparvus and Anopheles algeriensis were rare. Anopheles hyrcanus and An. melanoon were present in summer, whereas An. atroparvus was present in autumn and winter. A large number of An. hyrcanus females was collected on humans, whereas almost exclusively animals attracted An. melanoon. Based on an enzyme-linked immunosorbent assay, almost 90% of An. melanoon blood meals analysed had been taken on horse or bovine. Anopheles hyrcanus and An. melanoon parity rates showed huge variations according to the date and the trapping method. Conclusion Anopheles hyrcanus seems to be the only Culicidae likely to play a role in malaria transmission in the Camargue, as it is abundant and anthropophilic.

International audience

International audience; Triatoma infestans is the main vector of Chagas disease and target of control programmes in the Southern Cone countries. So far Bolivia is the only country where true T. infestans wild foci are documented. The dispersal ability for wild T. infestans was studied at microgeographical scale in Bolivian Andes, to assess the possibility for wild populations to actively recolonize insecticide-treated villages. Nine microsatellite loci were used to detect the extent of gene flow between neighbouring collecting sites. The detection of restricted gene flow between close but distinct sylvatic sites supports the hypothesis that wild T. infestans does not disperse by flying at high altitude (2 750 m asl). It gradually disperses over small distances by walking within a 'patch' of continuous land cover. The genetic differentiation detected between sylvatic and domestic populations suggests a limited short-term role of wild insects in the process of recolonization of insecticide-treated houses in the Andes.