Phenotypic and genotypic pyrethroid resistance ofAedes albopictus, with focus on the 2017 chikungunya outbreak in Italy

Abstract

BACKGROUND The highly invasive mosquito species Aedes albopictus has become a major health concern in temperate areas due to its role as vector of exotic arboviruses. Pyrethroid insecticides represent the main tools for limiting the circulation of such mosquito‐borne viruses. The present work aim to extend previous reports on phenotypic pyrethroid‐resistance in European Ae. albopictus, to identify its genetic basis and to monitor the geographical distribution of resistant genotypes, with a particular focus on sites experiencing the 2017 chikungunya outbreak in Italy. RESULTS Bioassays, performed according to World Health Organization protocols, showed full susceptibility to deltamethrin (concentration = 0.05%) and varying levels of resistance to permethrin (0.75%) and/or α‐cypermethrin (0.05%) across Italy, with highest levels in the core of the 2017 chikungunya outbreak. Partial genotyping of the VSSC gene revealed widespread distribution of V1016G mutation and confirmed its association with pyrethroid resistance. CONCLUSION The results obtained show that the condition for the spread of pyrethroid resistance in Ae. albopictus in Europe exists under strong selective pressure due to intensive insecticide spraying to control exotic arbovirus outbreak or high levels of nuisance. The results draw attention to the need for an evidence‐based implementation of mosquito nuisance control, taking insecticide resistance management into consideration. © 2019 Society of Chemical Industry

A bacterium against the tiger: preliminary evidence of fertility reduction after release of Aedes albopictus males with manipulated Wolbachia infection in an Italian urban area

“…However, the effectiveness of these interventions is limited, mostly because of the inherent difficulty in targeting all potential larval sites, as well as a lack of coordinated/synchronized implementation in public and private areas, insufficient resources and poor community participation. Therefore, in several highly infested areas, pyrethroid‐based insecticide space‐spraying is extensively carried out by public administrations and private citizens to reduce adult biting and associated nuisance, despite little evidence of long‐term effectiveness and increasing risk of the development of insecticide resistance . Notably, although pyrethroids are considered relatively safe for humans (EU Directive 528/2012.…”

“…Therefore, in several highly infested areas, pyrethroid-based insecticide space-spraying is extensively carried out by public administrations and private citizens to reduce adult biting and associated nuisance, despite little evidence of long-term effectiveness 14,15 and increasing risk of the development of insecticide resistance. [16][17][18] Notably, although pyrethroids are considered relatively safe for humans (EU Directive 528/2012. Biocidal Products Regulation 528/2012), they represent environmental contaminants toxic to non-target insect species, such as aquatic invertebrates and fishes.…”

Phenotypic and molecular analysis of insecticide resistance in Aedes albopictus populations from Greece

“…The recorded 1534C allele frequencies raised above 40% in populations from southern and central Greece, peaking in Attica (68.3%). Previous studies also reported relatively high mutation frequencies (reaching 66%) in populations sampled from the Attica region [47,48]. To date, kdr F1534C has also been recorded in Brazil [49], Singapore, Vietnam [50] and China [51], while other substitutions in the same genomic locus, F1534L and F1534S, also associated with pyrethroid resistance, have been identified in the USA, China, Vietnam and Italy [47,[50][51][52].…”

“…Genotyping of the VGSC gene for the detection of mutations associated with pyrethroid resistance revealed a widespread distribution of the kdr mutation F1534C across the country, following initial reports of the mutation in Greece [47,48]. The recorded 1534C allele frequencies raised above 40% in populations from southern and central Greece, peaking in Attica (68.3%).…”

Population dynamics, pathogen detection and insecticide resistance of mosquito and sand fly in refugee camps, Greece

“…albopictus have been recorded in Ae. albopictus populations from Italy and Greece where the mutation 1534C was detected at a frequency of 24.2% in the Athens population [19,20].…”