Invasive mosquito species Aedes albopictus and Aedes aegypti on the Black Sea coast of the Caucasus: genetics (COI, ITS2), Wolbachia and Dirofilaria infections

E. V. Shaikevich,V. М. Rakova,A. S. Bogacheva,I. V. Patraman,L. A. Ganushkina,O. Р. Zelya

doi:10.18699/vj18.397

Abstract

The area of invasive species Aedes albopictus and Aedes aegypti is expanding. Precise identification and understanding of the genetic diversity of invasive mosquito populations allows us to develop appropriate control methods. Endosymbiotic bacterium Wolbachia pipientis has different effects on their arthropod hosts and can influence the transmission and spread of the pathogens. The objective of the presented study was molecular-genetic identification of the Aedes mosquitoes collected in sampling sites on the Black Sea coast from 2007 to 2017; determination of genetic variability of Ae. aegypti , Ae. albopictus and their symbiotic bacteria Wolbachia ; assessment of mosquitoes ability to be infected and to spread parasitic Dirofilaria . Another objective was obtaining the genetic characteristic of laboratory strain Ae. aegypti IMPITM. We investigated two markers of nuclear and mitochondrial DNA from Ae. albopictus and Ae. aegypti and compared them to DNA from Ae. cretinus and Ae. korei с us sympatrically inhabiting the territory, as well as to one of Ae. aegypti from a laboratory line. The study of nuclear and mitochondrial DNA revealed a low level of variability in the invasive mosquitoes Ae. albopictus and Ae. aegypti collected at different collection sites and in different years. More than a half of Ae. albopictus were infected with Wolbachia , two strains of bacteria, w AlbA and w AlbB, occur in the Ae. albopictus population on the Black Sea coast. Total infection of Ae. aegypti and Ae. albopictus with dirofilariae was 1.8 %. Dirofilaria immitis was found only in mosquito abdomen, larvae of infective stage L3 were not found. D. repens larvae developed to the infective stage in the mosquitoes of both species.

Highlights

Инвазивные виды Aedes albopictus и Aedes aegypti на Черноморском побережье Краснодарского края: генетика (COI, ITS2), зараженность Wolbachia и Dirofilaria
Ae. aegypti had been absent in Russia for 50 years, until 2001 (Ryabova et al, 2005; Yunicheva et al, 2008) due to the special measures taken in the USSR in the 1920s and 1930s aimed at eradication of the aforementioned species (Martsinovsky, 1929)
In Russia Ae. albopictus were found only recently, in 2011, but they actively, as it is common for invasive species in a new place, have taken their niche around the Big Sochi in the wet subtropical climate zone, pressing Ae. aegypti from Adler to Lazarevskoe

Summary

Introduction

Инвазивные виды Aedes albopictus и Aedes aegypti на Черноморском побережье Краснодарского края: генетика (COI, ITS2), зараженность Wolbachia и Dirofilaria. Ae. aegypti acts as a primary carrier for yellow fever (Jeffries, Walker, 2016) Beside arboviruses, both mosquito species are able to transmit the threadworm larvae of Dirofilaria family responsible for dirofilariasis in humans and animals (Ganushkina et al, 2014a). Later in the 20th century, greater concerns aroused worldwide about the expansion of Ae. albopictus, another effective carrier of dangerous arboviruses, which started to spread beyond its natural habitat in Southeast Asia. This mosquito species expanded into areas, previously inhabited by other endemic species, like morphologically similar Ae. cretinus Edwards (Patsoula et al, 2006). The Caucasus coast of the Black Sea is the only territory in the WHO European region that geographically includes the Asian region of the Caucasus where the both mosquito species have been registered as active vectors for arbovirus infectious agents (http://www. who.int/about/regions/euro/)

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