Liste à jour des espèces de moustiques (Diptera: Culicidae) de Madagascar

International audienceAn 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

Seroprevalence of IgG Antibodies Directed against Dengue, Chikungunya and West Nile Viruses and Associated Risk Factors in Madagascar, 2011 to 2013

Arboviruses have been shown to circulate in Madagascar, including West Nile, dengue, and chikungunya viruses, though the extent of their circulation remains poorly documented. We estimated the seroprevalence of these three arboviruses in Madagascar and determined risk factors associated with seropositivity. Serum samples obtained from 1680 individuals surrounding the Sentinel Health Centers network in all regions of the country were analyzed using ELISA and hemagglutination inhibition assays for dengue, chikungunya, and West Nile viruses IgG antibodies, and multivariate logistic regression models were run. Overall, 6.5% [IC 95% 3.2–9.9] were seropositive for dengue virus, predominantly of Dengue serotype 1, 13.7% [IC 95% 6.5–20.9] for chikungunya virus, and 12.7% [IC 95% 9.0–16.5] for West Nile virus. There was no association with age, showing that dengue and chikungunya viruses were likely recently introduced. Eastern and Northern parts were more affected by dengue and chikungunya viruses, while West Nile virus seemed to circulate in all parts of the country. Dengue and chikungunya seropositivity were notably associated with high levels of vegetation, as well as frequent work in the forest, and West Nile seropositivity with the presence of cultivated areas, as well as standard of living. This analysis gives a new insight into arboviruses circulation and transmission patterns in Madagascar

Genetic relatedness of geographically distinct WNV isolates determined by using the nucleotide sequence data from a 228 bp region of the E gene.

<p>The tree was constructed with the PAUP by using the neighbor-joining distance program of Mega 5 software. Node values were determined for 1,000 replicates. Isolates are labeled as follows: strain identification, country, date of isolation, genbank accession number.</p

Seroprevalence analysis of West Nile virus in domestic birds.

<p>(A) in the Mitsinjo district (B) in the Antsalova district. Numbers in parentheses corresponded to the number of animals in each category and in the y axis represented the percentage of animals presenting WNV antibodies. P-values were generated from the regression analysis.</p

Comprehensive Characterization of Viral Diversity of Female Mosquitoes in Madagascar

The diversity and circulation of arboviruses are not much studied in Madagascar. The fact is that arboviral emergences are rarely detected. The existing surveillance system primarily relies on serological detection and records only a few human infections annually. The city of Mahajanga, however, experienced a confirmed dengue fever epidemic in 2020 and 2021. This study aimed to characterize and analyze the virome of mosquitoes collected in Mahajanga, near patients with dengue-like syndromes to detect known and unknown viruses as well as investigate the factors contributing to the relative low circulation of arboviruses in the area. A total of 4280 mosquitoes representing at least 12 species from the Aedes, Anopheles, and Culex genera were collected during the dry and the rainy seasons from three sites, following an urbanization gradient. The virome analysis of 2192 female mosquitoes identified a diverse range of viral families and genera and revealed different patterns that are signatures of the influence of the mosquito genus or the season of collection on the composition and abundance of the virome. Despite the absence of known human or veterinary arboviruses, the identification and characterization of viral families, genera, and species in the mosquito virome contribute to our understanding of viral ecology and diversity within mosquito populations in Madagascar. This study serves as a foundation for ongoing surveillance efforts and provides a basis for the development of preventive strategies against various mosquito-borne viral diseases, including known arboviruses

Detection in and circulation of Bluetongue virus among domestic ruminants in Madagascar

International audienceSo far, no published data was available concerning the circulation of Bluetongue virus (BTV) in Madagascar. During a survey on Rift Valley Fever, we were able to detect a virus belonging to BTV. Therefore, we conducted a study aiming at characterizing molecularly the BTV isolated and assess the importance of circulation of BTV in Madagascar. A total of 4393 sera from ruminants selected randomly by stratification and sampled in 30 districts of Madagascar were tested for BTV. Moreover, 175 cattle were followed during 11 months.Phylogenetic analyses were performed from virus isolated from unfed pools of mosquitoes.Overall, the estimated mean seroprevalence of infection at the national level was 95.9% (95% CI: [95.2–96.5]) in cattle and 83.7% (95% CI: [81.4–85.9]) in small ruminants. Estimation of incidence rate was 54 per 100 cattle-years assuming that the incidence rate is constant allyear along. Phylogenetic analyses revealed that BTV detected belong to serotype 2.In conclusion, our results showed that BTV is endemic in Madagascar and highly prevalent among cattle. In our study we did not work on the vector involved in transmission of BTV in cattle. Thus, research should be conducted to better describe epidemiology of BTV in Madagascar including vectors and assess economic impact of the disease associated to BTV infections

Results of a biological inventory of the Nosy Ankao island group, Parc National de Loky-Manambato, northeastern Madagascar

International audienceUn inventaire biologique a été réalisé du 3 au 14 mars 2016 dans quatre îles de la commune d'Apisikinana, district de Vohémar: Nosy Ankao (365ha), Nosy Manampao (29ha), Nosy Ratsy (6ha) et Nosiborona (6ha). Ces îles font partie du Parc National de Loky-Manambato. Chacune des îles se distingue par sa superficie et sa distance à la côte malgache. L'investigation menée sur le terrain et présentée ici inclut les groupes suivants: plantes ligneuses, moustiques, fourmis, reptiles, amphibiens, oiseaux et petits mammifères. En outre, des informations sur d'autres groupes, tels que les escargots terrestres, ont été collectées et sont présentées