High genetic diversity but no geographical structure of Aedes albopictus populations in Réunion Island

• Published in: Parasites & vectors 2019-12, Vol.12 (1), p.597-597, Article 597
• Main Authors: Latreille, Anne C, Milesi, Pascal, Magalon, Hélène, Mavingui, Patrick, Atyame, Célestine M
• Format: Article
• Language: English
• Subjects: Aedes - classification; Aedes - genetics; Aedes - physiology; Aedes albopictus; Alleles; Animals; Aquatic insects; arboviruses; Asian tiger mosquito; Chikungunya Fever - transmission; Cluster analysis; Clustering; Coastal zone; Coasts; Culicidae; dengue; Dengue - transmission; Dengue fever; Dengue virus; Deoxyribonucleic acid; Disease transmission; DNA; Eggs; Emerging diseases; Epidemics; Gene flow; Genetic diversity; Genetic structure; Genetic variance; Genetic Variation; Genotype; genotyping; Geographical distribution; Human diseases; Human health and pathology; Humans; Insect control; Islands; Laboratories; Life Sciences; Loci; Microsatellite; Microsatellite Repeats; Microsatellites; mosquito control; Mosquito Vectors - classification; Mosquito Vectors - genetics; Mosquito Vectors - physiology; Mosquitoes; Outbreaks; Pesticides; Population density; Population genetics; Population number; Population structure; Populations; Public health; Regions; Reunion; Reunion Island; Réunion Island; Software; Tropical diseases; Variance analysis; Vector-borne diseases; vectorial capacity; Viral diseases; virus transmission; Viruses; West Nile virus
• ISSN: 1756-3305; 1756-3305
• DOI: 10.1186/s13071-019-3840-x

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. 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 F 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. 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.