Species Composition, Ecological Preferences, and Chromosomal Polymorphism of Malaria Mosquitoes of the Crimean Peninsula and the Black Sea Coast of the Caucasus

TL;DR

This study identifies seven malaria mosquito species in Crimea and the Caucasus, noting their habitats and chromosomal differences, which can help control malaria transmission.

Contribution

The study provides updated data on malaria mosquito species distribution and chromosomal polymorphism in a high-risk region for malaria resurgence.

Findings

Seven species of malaria mosquitoes were identified, including An. maculipennis as the dominant species.

An. plumbeus has expanded into urban areas along the Black Sea coast.

Chromosomal polymorphism in An. daciae was higher in the Caucasus compared to Crimea.

Abstract

The territories of Crimea and the Black Sea coast of the Caucasus are considered high-risk areas for the resurgence of malaria transmission. Cases of imported malaria are reported annually in these regions. Mosquito species of the genus Anopheles (Diptera, Culicidae) inhabit the Black Sea coast, and they can be effective vectors of malaria. The malaria mosquito’s habitat in this region has been affected by the development of tourist resorts over the last 20 years. To understand the current species abundance and distribution, we studied malaria mosquito breeding sites, measured the ecological parameters of water bodies, and determined larval density and species composition of mosquitoes. Seven species of malaria mosquitoes were found in the study areas: An. atroparvus, An. claviger, An. daciae, An. hyrcanus, An. maculipennis, An. plumbeus, and An. melanoon. Although the dominant species was An. maculipennis, An. plumbeus has recently spread to urbanized areas. The level of chromosomal polymorphism in An. daciae was significantly higher in the Caucasian populations than in the Crimean population. Data on the species composition and distribution of malaria mosquitoes will help in developing appropriate measures to prevent and control imported malaria and other mosquito-borne diseases.

In this study, we sampled malaria mosquito larvae in natural and artificial breeding places to study the geographical distribution, ecological preferences, and chromosomal variability of different species of the genus Anopheles in the territory of the Crimean Peninsula and the Black Sea coast of the Caucasus. Species were diagnosed using a combination of morphological, cytogenetic, and molecular markers. The ecological conditions of the larval habitats, such as dissolved oxygen content in the water, acidity, salinity, and temperature, were measured. Seven species of malaria mosquitoes were identified in the pool of 2229 individual mosquitoes collected at 56 breeding sites, including An. atroparvus, An. claviger, An. daciae (formerly identified as An. messeae s. l.), An. hyrcanus, An. maculipennis s. s., An. plumbeus, and An. melanoon. The previously recorded species of An. algeriensis, An. messeae s. s., An. sacharovi, and An. superpictus were not found in this study. Anopheles maculipennis was dominant in typical anophylogenic water bodies. Anopheles plumbeus, which used to breed mainly in tree holes in coastal forests, has spread to urban settlements along the Black Sea coast and breeds in artificial containers. Chromosomal polymorphism was studied and found in An. atroparvus and An. daciae populations. Differences in the chromosomal composition of An. daciae populations in Crimea and on the Black Sea coast of the Caucasus were revealed. The Crimean population had a low level of polymorphism in autosomal inversions. The data obtained in this study can be used to inform a better control of potential malaria vectors in the Black Sea coastal region.

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