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Evidence of habitat structuring Aedes albopictus populations in Reunion Island.

ABSTRACT: 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.

SUBMITTER: Delatte H

PROVIDER: S-EPMC3605158 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Evidence of habitat structuring Aedes albopictus populations in Réunion Island.

Delatte Hélène H Toty Céline C Boyer Sébastien S Bouetard Anthony A Bastien Fanny F Fontenille Didier D

PLoS neglected tropical diseases 20130321 3

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 ...[more]

PMID: 23556012

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Project description:BACKGROUND:In recent years, the Asian tiger mosquito Aedes albopictus has emerged as a species of major medical concern following its global expansion and involvement in many arbovirus outbreaks. On Réunion Island, Ae. albopictus was responsible for a large chikungunya outbreak in 2005-2006 and more recently an epidemic of dengue which began at the end of 2017 and is still ongoing at the time of writing. This dengue epidemic has seen a high number of human cases in south and west coastal regions, while few cases have been reported in the north and east of the island. To better understand the role of mosquito populations in such spatial patterns of dengue virus transmission in Réunion Island, we examined the genetic diversity and population structure of Ae. albopictus sampled across the island. RESULTS:Between November 2016 and March 2017, a total of 564 mosquitoes were collected from 19 locations in three main climatic regions (West, East and Center) of Réunion Island and were genotyped using 16 microsatellite loci. A high genetic diversity was observed with 2-15 alleles per locus and the average number of alleles per population varying between 4.70-5.90. Almost all FIS values were significantly positive and correlated to individual relatedness within populations using a hierarchical clustering approach based on principal components analyses (HCPC). However, the largest part of genetic variance was among individuals within populations (97%) while only 3% of genetic variance was observed among populations within regions. Therefore, no distinguishable population structure or isolation by distance was evidenced, suggesting high rates of gene flow at the island scale. CONCLUSIONS:Our results show high genetic diversity but no genetic structure of Ae. albopictus populations in Réunion Island thus reflecting frequent movements of mosquitoes between populations probably due to human activity. These data should help in the understanding of Ae. albopictus vector capacity and the design of effective mosquito control strategies.

Project description:BackgroundAedes (Stegomyia) albopictus (Skuse) is an indigenous species and the predominant vector of dengue fever in China. Understanding of genetic diversity and structure of the mosquito would facilitate dengue prevention and vector control. Sympatric cryptic species have been identified in the Ae. albopictus subgroup in Southeast Asia; however, little is known about the presence and distribution of cryptic species in China. This study aimed to examine the genetic diversity, evaluate potential new cryptic sibling species, and assess the prevalence of Wolbachia infections in field populations.MethodsAedes adult female specimens were collected from five provinces in southern and central China during 2015-2016. Morphological identification was performed under dissection microscope. The mitochondrial DNA cytochrome c oxidase subunit 1 (cox1, DNA barcoding) locus and the ribosomal DNA internal transcribed spacer region 2 (ITS2) marker were used to examine the genetic variation, evaluate cryptic sibling species, and population structure in the field populations. Screening for the presence of Wolbachia was performed using multiplex PCR.ResultsA total of 140 individual specimens with morphological characteristics similar to Ae. albopictus were sequenced for DNA barcoding. Among these, 129 specimens (92.1%) were confirmed and identified as Ae. albopictus. The remaining 11 specimens, from 2 provinces, were identified as 2 distinct sequence groups, which were confirmed by ITS2 marker sequencing, suggesting the existence of potential cryptic species of Ae. albopictus. In Ae. albopictus, we found significant genetic differentiation and population structure between populations collected from different climate zones. Medium to high frequencies of Wolbachia infections were observed in natural Ae. albopictus populations, whereas Wolbachia was infrequent or absent in cryptic species populations.ConclusionsOur findings highlight the population differentiation by climate zone and the presence of novel, cryptic Aedes species in China. The low prevalence of Wolbachia infections in cryptic species populations could reflect either a recent invasion of Wolbachia in Ae. albopictus or different host immune responses to this symbiont in the cryptic species. The study provides useful information for vector control and host-symbiont coevolution. Further study is needed to investigate the potential for arbovirus infection and disease transmission in the emerged cryptic species.

Project description:BackgroundReunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect-borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) are the vectors of bluetongue (BTV) and epizootic hemorrhagic disease (EHDV) viruses. In a previous study, statistical models based on environmental and meteorological data were developed for the five Culicoides species present in the island to provide a better understanding of their ecology and predict their presence and abundance. The purpose of this study was to couple these statistical models with a Geographic Information System (GIS) to produce dynamic maps of the distribution of Culicoides throughout the island.MethodsBased on meteorological data from ground weather stations and satellite-derived environmental data, the abundance of each of the five Culicoides species was estimated for the 2214 husbandry locations on the island for the period ranging from February 2016 to June 2018. A large-scale Culicoides sampling campaign including 100 farms was carried out in March 2018 to validate the model.ResultsAccording to the model predictions, no husbandry location was free of Culicoides throughout the study period. The five Culicoides species were present on average in 57.0% of the husbandry locations for C. bolitinos Meiswinkel, 40.7% for C. enderleini Cornet & Brunhes, 26.5% for C. grahamii Austen, 87.1% for C. imicola Kieffer and 91.8% for C. kibatiensis Goetghebuer. The models also showed high seasonal variations in their distribution. During the validation process, predictions were acceptable for C. bolitinos, C. enderleini and C. kibatiensis, with normalized root mean square errors (NRMSE) of 15.4%, 13.6% and 16.5%, respectively. The NRMSE was 27.4% for C. grahamii. For C. imicola, the NRMSE was acceptable (11.9%) considering all husbandry locations except in two specific areas, the Cirque de Salazie-an inner mountainous part of the island-and the sea edge, where the model overestimated its abundance.ConclusionsOur model provides, for the first time to our knowledge, an operational tool to better understand and predict the distribution of Culicoides in Reunion Island. As it predicts a wide spatial distribution of the five Culicoides species throughout the year and taking into consideration their vector competence, our results suggest that BTV and EHDV can circulate continuously on the island. As further actions, our model could be coupled with an epidemiological model of BTV and EHDV transmission to improve risk assessment of Culicoides-borne diseases on the island.

Project description:BACKGROUND:The Asian tiger mosquito, Aedes albopictus, is a highly dangerous invasive vector of numerous medically important arboviruses including dengue, chikungunya and Zika. In four decades it has spread from tropical Southeast Asia to many parts of the world in both tropical and temperate climes. The rapid invasion process of this mosquito is supported by its high ecological and genetic plasticity across different life history traits. Our aim was to investigate whether wild populations, both native and adventive, also display transcriptional genetic variability for functions that may impact their biology, behaviour and ability to transmit arboviruses, such as sensory perception. RESULTS:Antennal transcriptome data were derived from mosquitoes from a native population from Ban Rai, Thailand and from three adventive Mediterranean populations: Athens, Greece and Arco and Trento from Italy. Clear inter-population differential transcriptional activity was observed in different gene categories related to sound perception, olfaction and viral infection. The greatest differences were detected between the native Thai and the Mediterranean populations. The two Italian populations were the most similar. Nearly one million quality filtered SNP loci were identified. CONCLUSION:The ability to express this great inter-population transcriptional variability highlights, at the functional level, the remarkable genetic flexibility of this mosquito species. We can hypothesize that the differential expression of genes, including those involved in sensory perception, in different populations may enable Ae. albopictus to exploit different environments and hosts, thus contributing to its status as a global vector of arboviruses of public health importance. The large number of SNP loci present in these transcripts represents a useful addition to the arsenal of high-resolution molecular markers and a resource that can be used to detect selective pressure and adaptive changes that may have occurred during the colonization process.

Dataset Information

Evidence of habitat structuring Aedes albopictus populations in Reunion Island.

Publications

Evidence of habitat structuring Aedes albopictus populations in Réunion Island.

Similar Datasets

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