Insecticide susceptibility of Aedes albopictus and Ae. aegypti from Brazil and the Swiss-Italian border region

Abstract

Background Aedes aegypti and Ae. albopictus are two highly invasive mosquito species, both vectors of several viruses, including dengue, chikungunya and Zika. While Ae. aegypti is the primary vector in the tropics and sub-tropics, Ae. albopictus is increasingly under the public health watch as it has been implicated in arbovirus-transmission in more temperate regions, including continental Europe. Vector control using insecticides is the pillar of most control programmes; hence development of insecticide resistance is of great concern. As part of a Brazilian-Swiss Joint Research Programme we set out to assess whether there are any signs of existing or incipient insecticide resistance primarily against the larvicide Bacillus thuringiensis svar. israelensis (Bti), but also against currently applied and potentially alternative insecticides in our areas, Recife (Brazil) and the Swiss-Italian border region.MethodsFollowing World Health Organization guidelines, dose-response curves for a range of insecticides were established for both colonized and field caught Ae. aegypti and Ae. albopictus. The larvicides included Bti, two of its toxins, Cry11Aa and Cry4Ba, Lysinibacillus sphaericus, Vectomax CG®, a formulated combination of Bti and L. sphaericus, and diflubenzuron. In addition to the larvicides, the Swiss-Italian Ae. albopictus populations were also tested against five adulticides (bendiocarb, dichlorodiphenyltrichloroethane, malathion, permethrin and λ-cyhalothrin).ResultsShowing a similar dose-response, all mosquito populations were fully susceptible to the larvicides tested and, in particular, to Bti which is currently used both in Brazil and Switzerland. In addition, there were no signs of incipient resistance against Bti as larvae were equally susceptible to the individual toxins, Cry11Aa and Cry4Ba. The field-caught Swiss-Italian populations were susceptible to the adulticides tested but DDT mortality rates showed signs of reduced susceptibility.ConclusionsThe insecticides currently used for mosquito control in Switzerland and Brazil are still effective against the target populations. The present study provides an important reference as relatively few insecticide susceptibility surveys have been carried out with Ae. albopictus.Electronic supplementary materialThe online version of this article doi:(10.1186/s13071-017-2364-5) contains supplementary material, which is available to authorized users.

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

“…The few studies conducted on PR in Ae. albopictus from temperate areas have mostly reported full susceptibility, while first evidence of resistance to one or the other compound was recently observed in Spain, Italy and the USA …”

“…[32][33][34] The few studies conducted on PR in Ae. albopictus from temperate areas have mostly reported full susceptibility, 14,24,35,36 while first evidence of resistance to one or the other compound was recently observed in Spain, 37 Italy 38 and the USA. 39,40 Resistance mechanisms have been extensively studied in major tropical vector species, but little information is available on mechanisms underlying pyrethroid resistance in Ae.…”

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

“…Results were compared to the LC 50 and LC 95 values reported for susceptible-laboratory Ae. albopictus strains reported in other studies [36,37,38].…”

“…This is significantly lower than the recommended field doses (DU-DIM 15SC: 0.32 -0.63 mg/L), the recommended WHO dosage of DFB in potable water containers (0.25 mg/L) [41], as well as the emergence inhibition dose (EI 50 of 0.376 mg/L) previously reported for susceptible Ae. albopictus field strains [36].…”

Activation of Bacterial Cytochrome P450 in the Intestine of Larval Mosquitoes an Indication of Its Role in the Insecticide Resistance

“…Mosquitoes affect people life by inducing big impact through disease transmition such as Rift Valley Fever and West Nile virus (1,2), and their eradication difficulties are devastatingly increasing. These problems induced by different issues such as insecticide resistance (3,4). The gut microbiome (GM) in different animals has been discovered to add principle influence on the gastrointestinal tract physiology and pathology such as Alzheimer's Disease and entambiasis (5,86 Bas.J.Vet.Res.…”