Search

This study was aimed to investigate thecurrent insecticide resistance status in malaria vector mosquitoes from Dogbo district in South-western Benin, West Africa. Larvae and pupae ofAnopheles gambiae s.l.populations were collected from the breeding sites from March to July 2020 during the first rainy season in Couffo department using the dipping method. WHO susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. WHO bioassays were performed with impregnated papers of permethrin (0.75%), deltamethrin (0.05%), cyfluthrin (0.15%), lambdacyhalothrin (0.05%) and dichlorodiphenyltrichloroethane (DDT) (4%).An. gambiaes.l.populations from Dogbo district were resistant to permethrin, deltamethrin, cyfluthrin, lambdacyhalothrin and DDT. There is cross-resistance to both pyrethroid and DDT insecticides. However, the physical barrier of Long Lasting Insecticidal Nets (LLINs) which are regularly distributed free by Beninese National Malaria Control Programme throughout the entire country to increase coverage of LLINs is still important despite the insecticide resistance observed.

Current-use pesticides (CUP) are extensively applied in both agricultural and urban settings. Exposure occurs mainly via the dietary pathway; however, other pathways such as inhalation or skin contact are also important. In this study, urinary levels of 12 CUP metabolites were investigated among 110 parent-child pairs during two seasons of 2020. Metabolites of pyrethroids (3-PBA, t/c-DCCA), chlorpyrifos (TCPY), and tebuconazole (TEB-OH) were detected in more than 60% of the samples. Chlorpyrifos metabolite was found at the highest concentration and tebuconazole was detected in almost all samples. CUP urinary metabolite levels were significantly higher in children in comparison to adults, except for tebuconazole, which was similar in both groups. In children, winter samples had significantly higher concentrations of pyrethroid and chlorpyrifos metabolites in comparison to the summer samples, but in adults, only chlorpyrifos metabolite concentrations were higher in the winter. No association between CUP urinary metabolite levels and proximity/surface of agricultural areas around residences was observed. Based on our findings, we suspect that CUP exposure is mainly driven by diet and that the effect of environmental exposure is less significant. Daily Intakes were estimated with three possible scenarios considering the amount of the metabolite excreted in urine and were compared to Acceptable Daily Intake values. Using a realistic scenario, exposure to chlorpyrifos exhibited the highest health risk, but still within a safe level. The Acceptable Daily Intake was exceeded only in one child in the case of cypermethrin. The cumulative risk assessment of pesticide mixtures having an effect on the nervous system, based on the total margin of exposure calculations, did not indicate any risk. The overall risk associated with pesticide exposure in the observed population was low. However, the risk observed using the worst-case scenario suggests the need for continuous evaluation of human exposure to such compounds, especially in children.

Pyrethroids are widely applied insecticides in agriculture, but their frequent use has provoked many cases of resistance, in which mutations in the voltage-gated sodium channel (VGSC), the pyrethroid target-site, were shown to play a major role. However, for the spider mite Tetranychus urticae, it has also been shown that increased detoxification contributes to resistance against the pyrethroid bifenthrin. Here, we performed QTL-mapping to identify the genomic loci underlying bifenthrin resistance in T. urticae. Two loci on chromosome 1 were identified, with the VGSC gene being located near the second QTL and harboring the well-known L1024V mutation. In addition, the presence of an L925M mutation in the VGSC of a highly bifenthrin-resistant strain and its loss in its derived, susceptible, inbred line indicated the importance of target-site mutations in bifenthrin resistance. Further, RNAseq experiments revealed that genes encoding detoxification enzymes, including carboxyl/choline esterases (CCEs), cytochrome P450 monooxygenases and UDP-glycosyl transferases (UGTs), were overexpressed in resistant strains. Toxicity bioassays with bifenthrin (ester pyrethroid) and etofenprox (non-ester pyrethroid) also indicated a possible role for CCEs in bifenthrin resistance. A selection of CCEs and UGTs were therefore functionally expressed, and CCEinc18 was shown to metabolize bifenthrin, while teturUGT10 could glycosylate bifenthrin-alcohol. To conclude, our findings suggest that both target-site and metabolic mechanisms underlie bifenthrin resistance in T. urticae, and these might synergize high levels of resistance.

Publisher Copyright: © 2022 The Author(s) Long-lasting insecticide-treated nets (LLINs) are widely distributed to communities where malaria is a major cause of mortality, especially to those under the age of 5 years-old. To protect people from this illness, LLINs provide physical and chemical barriers by containing insecticides within the matrix of the polymer fibers or on the surface. Synthetic polymers including polyethylene and polyester are common material choices for these nets, and pyrethroids, along with other additives, are the insecticides of choice for this application. Many studies have shown the effectiveness of these nets on the impact of malaria is highly significant, but there is a demand for more durable nets that last longer than only a few years as the available products are rated for 2–3 years of use. Improvements in this area would increase cost effectiveness, because better durability would reduce the frequency of manufacturing and worldwide shipping. Additionally, due to the plastic fibers, the waste can build quickly, damaging the environment. To deal with the sustainability and durability issues, biodegradable and renewable materials should be chosen as an alternative.

Pyrethroid resistance of thrips has been reported in many countries, and knockdown resistance (kdr) has been identified as a main mechanism against pyrethroids in many insects. To characterize pyrethroid resistance in Megalurothrips usitatus from the Hainan Province of China, we conducted a biological assay and sequenced the voltage-gated sodium channel gene domain II from M. usitatus field populations. It showed high resistance to the pyrethroids for 2019 and 2020, in which LC50 to lambda-cyhalothrin of M. usitatus was 1683.521 mg/L from Sanya in 2020. The LC50 value of deltamethrin was lower in Haikou than in other locations, which mean the south of Hainan has higher resistance than the north of Hainan. Two mutations of I873S and V1015M were detected in the domain II region of the sodium channel in M. usitatus; however, the mutation frequency of V1015M was only 3.33% and that of I873S was 100%. One is homozygous and the other is a heterozygous mutant type. The three thrips-sensitive strains of sodium channel 873 are highly conserved in amino acids (isoleucine), while the M. usitatus pyrethroid-resistant strains are all serine, so I873S may be related to the resistance of M. usitatus to pyrethroids. The present study will contribute to the understanding of the evolution of pyrethroids resistance and contribute to the development of resistance management of M. usitatus in Hainan.

BACKGROUND Aedes aegypti is a remarkably effective mosquito vector of epidemiologically important arboviral diseases including dengue fever, yellow fever and Zika. The present spread of resistance against pyrethroids, the primary insecticides used for mosquito control, in global populations of this species is of great concern. The voltage‐gated sodium channel (VGSC) in the nervous system is the known target site of pyrethroids in insects. Past studies have revealed several amino‐acid substitutions in this channel that confer pyrethroid resistance, which are known as knockdown resistance (kdr) mutations. RESULTS This study investigated a laboratory colony of Ae. aegypti, MCNaeg, established from larvae collected in Rio de Janeiro, Brazil in 2016. The MCNaeg colony showed strong resistance against pyrethroids without laboratory selection. Of the two VGSC gene haplotypes present within this colony, one harbored three known kdr mutations, V410L, V1016I, and F1534C, and the other harbored only the known F1534C mutation. In latter haplotype, we also found novel amino‐acid substations including V253F. Previous molecular modeling and electrophysiological studies suggest that this residue serves a pyrethroid‐sensing site in the second receptor, PyR2. Our genetical analysis showed that the haplotype harboring V253F and F1534C is associated with equal or slightly stronger resistance than the other triple kdr haplotype to both Type I and Type II pyrethroids. CONCLUSION The novel substitution V253F is potentially involved in pyrethroid resistance in Ae. aegypti. Further studies are needed to elucidate the role of this substitution in the pyrethroid susceptibility of VGSC. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., We found a novel amino‐acid substitution V253F in the voltage‐gated sodium channel in Aedes aegypti which is potentially involved in pyrethroid resistance of this vector mosquito

Background: In low- and middle-income countries (LMICs), pesticides are widely used in agricultural and residential settings. Little is known about how pesticides affect child growth. Objectives: To systematically review and synthesise the evidence on the associations between pesticide exposure and adverse birth outcomes and/or impaired postnatal growth in children up to 5 years of age in LMICs.Methods: We searched 10 databases from inception through November 2021. We included cohort and cross-sectional studies investigating associations between self-reported or measured prenatal or postnatal pesticide exposure and child growth (postnatal child linear/ponderal growth, and/or birth outcomes). Two researchers screened studies, extracted data, and assessed certainty using GRADE. The protocol was preregistered with PROSPERO (CRD42021292919).Results: Of 939 records retrieved, 31 studies met inclusion criteria (11 cohort, 20 cross-sectional). All studies assessed prenatal exposure. Twenty-four studies reported on birth weight. Four found positive associations with organochlorines (0.01 to 0.25 standardised mean difference (SMD)) and two found negative associations (-0.009 SMD to -55 g). Negative associations with organophosphates (-170 g, n=1) and pyrethroids (-97 to -233 g, n=2) were also documented. Two (out of 15) studies reporting on birth length found positive associations with organochlorines (0.21 to 0.25 SMD) and one found negative associations (-0.25 to -0.32 SMD). Organophosphate exposure was negatively associated with birth length (-0.37 cm, n=1). Organophosphate exposure was also associated with higher risk/prevalence of low birth weight (2 out of nine studies) and preterm birth (2 out of six studies). Certainty of the evidence was “very low” for all outcomes.Conclusion: The limited literature from LMICs shows inconclusive associations between prenatal pesticide exposure, child growth, and birth outcomes. Studies with accurate quantitative data on exposure to commonly used pesticides in LMICs using consistent methodologies in comparable populations are needed to better understand how pesticides influence child growth

Background Pyrethroids are associated with adverse health consequences, even at low-dose exposures. However, there is limited evidence on pyrethroids exposure levels among vulnerable elder population and on their exposure sources. Objective We tried to determine pyrethroids exposure levels among Korean elders and their exposure sources. Methods We measured levels of 3-phenoxybenzoic acid (3-PBA), a pyrethroids metabolite, in urines repeatedly collected from 1239 Korean rural and urban elders; we also explored exposure sources for pyrethroids using questionnaire data. Results Our participants had high levels of 3-PBA with 446 (36.0%) of elders with 3-PBA level over 2 ng/mL of 95th percentile of the German representative populations. After adjustment for sex, age, smoking status, visit episode, and surveyed season using linear mixed effect models, household insecticide spray use was significantly associated with 3-PBA level (β = 0.03 and p = 0.02) and the association was apparent only for females (β = 0.03 and p = 0.03). In the analyses for nonlinear relationships using generalized additive mixed models, there was a J-shape change in 3-PBA level by insecticide spray use (p Significance Household insecticide spray was a predominant exposure source for pyrethroids at community level among Korean elders, warning more stringent control for frequently exposed environmental factors for pyrethroids including insecticide spray.

Pyrethroids like permethrin have been used as topical formulations for their ectoparasiticidal effects since the 1970s. There are numerous efficacy studies in dogs and livestock animals that indicate a fast spread of pyrethroids after topical administration onto rather confined areas of the skin. Some studies correlate the efficacy against ticks, fleas or lice with concentrations of pyrethroids in hair and, less frequently, stratum corneum samples. It is often stated that lateral transport is responsible for the distribution of the pyrethroids over the body surface. With this review, we attempt to demonstrate evidence for lateral transport of pyrethroids after topical administration in dogs, cattle and sheep and to present data gaps that should be addressed in follow‐up studies.

The South American tomato pinworm, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is a leafminer species currently considered as one of the major pests of fresh tomatoes around the world. The species settled in north Africa in 2007, before being observed in the entire continent. Widespread insecticide use has led to the emergence of resistant populations in South America and Europe, but no large-scale insecticide resistance assessment has been performed in Sub-Saharan Africa so far. In this study, we collected T. absoluta larvae from locations widely distributed in Burkina Faso, where the pest was first detected in 2016. Acute toxicity of the all available molecules in Burkina Faso was evaluated in the laboratory on F1 individuals,including acetamiprid, abamectin, spinosad, cypermethrin, chlorpyrifos, λ-cyhalothrin, deltamethrin, and Bacillus thuringiensis. No LC50 differences among T. absoluta populations were highlighted, except for Bacillus thuringiensis. Insects were still highly susceptible to abamectin [LC50 < 0.4 mg/L; Control failure likelihood (CFL) =−25%], spinosad (LC50 < 0.6 mg/L; CFL = 25%) and chlorpyrifos-ethyl (LC50 between 254 and 458 mg/L; CFL = −15%), but were less susceptible to acetamiprid (CFL ranging from 72% to 91%), cypermethrin (CFL = 80%), λ-cyhalothrin (CFL =79%), and deltamethrin (CFL ranging from 51% to 66%), with LC50 values for these insecticides ranging between 100 and 525 mg/L. Pending a proper communication strategy, we hope this work could help producers avoiding the most inefficient active substances.

Microtransplantation of rat brain neurolemma into the plasma membrane of Xenopus laevis oocytes is an ex vivo method used to study channels and receptors in their native state using standard electrophysiological approaches. In this review, we show that oocytes injected with adult rat brain neurolemma elicited tetrodotoxin-sensitive inward ion currents upon membrane depolarization, which were increased in a concentration-dependent manner by treatment with the pyrethroid insecticides permethrin and deltamethrin. Under our initial protocols, oocyte health was reduced over time and neurolemma incorporation varied between batches of oocytes from different frogs, limiting the usefulness of the assay for regulatory issues. A collection of changes to the assay procedure, data acceptance criteria, and analysis method yield substantially improved precision and, hence, assay performance. These changes established this ex vivo approach as a toxicologically relevant assay to study the toxicodynamic action of pyrethroids on ion channels in their native state using neurolemma fragments prepared from juvenile and adult rat brains.

The blood-brain barrier (BBB) is a structural and functional interface between the plasma and the human brain. Predictive BBB in-vitro models like immortalized human capillary microvascular endothelial cells (HCMEC/D3) can be used to explore the BBB disruption potential of daily exposed chemicals. The present study was focused on investigating the human BBB permeation potential of one organophosphate pesticide, chlorpyrifos (CPF), and two pyrethroids, permethrin (PMT) and cyfluthrin (CFT). HCMEC/D3 cells were exposed to the chemical and the time-dependent pass across BBB along with permeation coefficient (Papp) was calculated. Transendothelial electrical resistance (TEER) was measured for the cells to check the monolayer formation and later to check the reduction in integrity after chemical exposure. Real time PCR was conducted to investigate the effect of chemicals on the expression BBB´s tight and adherens junction proteins. Calculated Papp value for three chemicals was in the following order: CPF>CFT>PMT, where CPF showed the highest permeation coefficient. TEER calculation showed that the integrity decreased after CPF exposure which was in concordance with Papp value whereas for other chemicals, no change in TEER after exposure was observed. In addition, the transwell study showed a higher efflux ratio (ER) (>2) of CFT indicating that CFT could be a substrate for active transport. For CPF and PMT, ER was less than 2, so no active transport seems to be involved. The evaluation of the mRNA expression analysis revealed a statistically significant decrease in Occludin (OCLN) gene expression for CPF, VE-Cadherin (CDH5) for PMT and Zonula Occludens (ZO1) expression for CFT. Our study showed that CPF has the highest potential for inducing cell death, higher permeation, and capability to induce BBB dysfunction than among the above-mentioned chemicals. Additionally, the results of the permeation study could be useful to build a human PBPK model using in vitro-to-in vivo extrapolation approach., This study was financially supported by Marie Skłodowska-Curie “Neurosome Project” under the grant agreement No. 766251. This publication reflects only the authors' views. The Community and other funding organizations are not liable for any use made of the information contained therein.

17 p.-3 fig.-2 tab. This article belongs to the Special Issue Impact of Environmental Factors and Management Practices on Bee Health, Systemic insecticides are recognized as one of the drivers of the worldwide bee decline as they are exposed to them through multiple pathways. Specifically, neonicotinoids, some of which are banned for outdoor use in the European Union (EU), have been pointed out as a major cause of bee collapse. Thus, farmers have had to look for alternatives for pest control and use known insecticides or new substances reportedly less harmful to bees. We evaluated the oral acute toxicity of six insecticides (three of them systemic: imidacloprid, thiacloprid and sulfoxaflor) with four different modes of action on buff-tailed bumblebee workers (Bombus terrestris): two banned neonicotinoids (imidacloprid, thiacloprid), two pyrethroids (deltamethrin, esfenvalerate), one sulfoximine (sulfoxaflor) and a microbial insecticide based on Bacillus thuringiensis toxins, present in genetically modified (Bt) maize. The microbial insecticide only caused mortality to bumblebee workers at extremely high concentrations, so it is expected that Bt maize does not pose a risk to them. The toxicity of the other five insecticides on bumblebees was, from highest to lowest: imidacloprid, sulfoxaflor, deltamethrin, esfenvalerate and thiacloprid. This outcome suggests that certain insecticides in use are more toxic to B. terrestris than some banned neonicotinoids. Further chronic toxicity studies, under realistic conditions, are necessary for a proper risk assessment., This research was funded by the Spanish Ministry of Science and Innovation (grant number PID2019-104578RB-I00) and the Spanish Ministry of Economy and Competitiveness (grant number AGL2015-64825-R). G.C. was funded by a predoc fellowship (BES-2016-077782) by the Spanish Ministry of Economy, Industry and Competitiveness.

Pyrethroids are insecticides most commonly used for insect control to boost agricultural production. The aim of the present research was to determine the effect of permethrin and cypermethrin on cultured and non-cultivated bacteria and fungi and on the activity of soil enzymes, as well as to determine the usefulness of Zea mays in mitigating the adverse effects of the tested pyrethroids on the soil microbiome. The analyses were carried out in the samples of both soil not sown with any plant and soil sown with Zea mays. Permethrin and cypermethrin were found to stimulate the multiplication of cultured organotrophic bacteria (on average by 38.3%) and actinomycetes (on average by 80.2%), and to inhibit fungi growth (on average by 31.7%) and the enzymatic activity of the soil, reducing the soil biochemical fertility index (BA) by 27.7%. They also modified the number of operational taxonomic units (OTUs) of the Actinobacteria and Proteobacteria phyla and the Ascomycota and Basidiomycota phyla. The pressure of permethrin and cypermethrin was tolerated well by the bacteria Sphingomonas (clone 3214512, 1052559, 237613, 1048605) and Bacillus (clone New.ReferenceOTU111, 593219, 578257), and by the fungi Penicillium (SH1533734.08FU, SH1692798.08FU) and Trichocladium (SH1615601.08FU). Both insecticides disturbed the growth and yielding of Zea mays, as a result of which its yield and leaf greenness index decreased. The cultivation of Zea mays had a positive effect on both soil enzymes and soil microorganisms and mitigated the anomalies caused by the tested insecticides in the microbiome and activity of soil enzymes. Permethrin decreased the yield of its aerial parts by 37.9% and its roots by 33.9%, whereas respective decreases caused by cypermethrin reached 16.8% and 4.3%.

A regional-scale survey was conducted to assess the occurrence, distribution, and risk of two extensively used pesticides (organophosphate pesticides and pyrethroids) in agricultural soils from the Pearl River Delta (PRD), South China. All target organophosphate pesticides (OPPs) and pyrethroids (PYs) were detected in the soil samples and both with a detection rate of 100%. The residues of the sum of six OPPs and the sum of four PYs were in the range of LOD–991 ng/g and 8.76–2810 ng/g, respectively. Dimethoate was the dominant OPPs, and fenpropathrin was the predominant PYs in the soils of the PRD region. With intensive agricultural activities, higher residues of OPPs and PYs in soils were detected closer to the seaside, among which Zhuhai city and Huizhou city suffered more serious combined pesticide pollution. The vertical compositional profiles showed that dimethoate could be detected through each soil layer in the PRD region’s nine cities. The human exposure estimation of OPPs showed insignificant risks to the local population. In contrast, cypermethrin and fenpropathrin showed a potential ecological risk of 2.5% and 3.75% of the sampling sites, respectively. These results can facilitate those commonly used pesticide controls and promote sustainable soil management.

Monitoring the trend of insecticide resistance and understanding associated genetic mechanisms is important for designing efficient malaria vector control strategies. This study was conducted to provide temporal data on insecticide resistance status and mechanisms in the major malaria vector Anopheles gambiae s.l. from Ebolowa, Southern Cameroon. Methods: Larvae of An. gambiae s.l. were collected from typical breeding sites throughout the city and reared to adulthood. Emerging adults were morphologically identified and WHO tube assays were performed to determine their susceptibility to carbamate, organophosphate and pyrethroid insecticides at diagnostic doses. When resistance was observed, its intensity was determined by performing WHO tube tests using 5 and 10 times the concentration of the diagnostic dose. Metabolic resistance mechanisms were investigated using insecticide-synergist assays. Sibling species of the An. gambiae complex were identified using SINE-PCR protocol. TaqMan assay was used to genotype the L1014F and L1014S kdr mutations, and the N1575Y mutation, an amplifier of the resistance conferred by the L1014F mutation. Results: Anopheles coluzzii was by far the dominant (99%) member of the An. gambiae s.l. complex in Ebolowa. The species was fully susceptible to carbamates and organophosphates, but resistant to all pyrethroid insecticides tested. Resistance was of moderate intensity for deltamethrin (mortality: 37%, 70% and 99% for 1×, 5× and 10× insecticide concentration, respectively) but rather of high intensity for permethrin (5% for 1×; 62% for 5× and 75% for 10×) and for alphacypermethrin (4.4% for 1×; 57% for 5× and 80% for 10×). Pre-exposure to the synergist PBO resulted in a full recovery of the susceptibility to delthametrin, but this was not observed for the other two pyrethroids tested. L1014S (kdr-East) and the N1575Y mutations were absent, whereas the L1014F (kdr-West) mutation was present at a high frequency (75%), showing a significant association with resistance to permethrin (OR = 3.8; 95%; CI [1.9–7.4]; p < 0.0001) and alphacypermethrin (OR = 3; 95%; CI [1.6–5.4]; p = 0.0002). Conclusion: The increased resistance of An. gambiae s.l. to pyrethroid insecticides as observed in Ebolowa poses a threat to the efficacy of LLINs used to protect populations from the bites of Anopheles mosquitoes that transmit malaria parasites. The present study further highlights the urgent need to implement resistance management strategies in order to maintain the effectiveness of insecticide-based vector control interventions and prevent a rebound in malaria-related mortality.

ObjectiveThis cross-sectional study aimed to examine farmers' knowledge, awareness, practices regarding pesticide use, and prevalence of health symptoms related to pesticides exposure among farmers who applied organophosphates (OP) and pyrethroids (PY).MethodsData regarding demographic variables and health symptoms pertinent to pesticide use was collected from 67 farmers who applied OP and 50 farmers who applied PY using interviews from January to March 2021.ResultsThe farmers who applied OP had lower knowledge, awareness, and prevention practices regarding pesticide use than those who applied PY. After adjustment of covariate variables, the farmers who applied OP had a significantly higher prevalence of respiratory conditions (OR = 8.29 for chest pain, OR = 6.98 for chest tightness, OR = 27.54 for dry throat, and OR = 5.91 for cough), neurological symptoms (OR = 10.62 for fatigue and OR = 6.76 for paresthesia), and neurobehavioral symptoms (OR = 13.84 for poor concentration, OR = 3.75 for short term memory, and OR = 8.99 for insomnia) related to pesticide exposure than those who applied PY.ConclusionOur findings suggest that OP had a more adverse effect on human health than PY, resulting in a higher prevalence of pesticide-related symptoms. The outcomes of this study have the benefit of providing vital information for all stakeholders with regard to the implementation of safe practices in the utilization of personal protective equipment (PPE) and pesticide use in a health intervention and health promotion program.

Accumulation of pesticides has a harmful impact on the environment and human health. The main goal of this work was to develop a method to determine and quantify the residues of thirteen pesticides in edible fish and bivalves such as parati (Mugil curema), seabass (Centropomus ssp.), mullet (Mugil brasiliensis), clams (Anomalocardia brasiliana) and mussel (Mytilus galloprovincialis) collected from Sepetiba Bay and Parnaiba River Delta (Brazil) between 2019 and 2020. Matrix solid-phase dispersion (MSPD) was used for extraction and quantification through gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). The method was validated (linearity, accuracy and precision) for fatty fish (Salmo salar), lean fish (Mugil curema) and bivalves (Mytilus edulis). The survey found linear correlation coefficients (r) equal to or greater than 0.9 for almost all analytes. The relative standard deviations (RSD) of five replicates were less than 20% for almost all analytes at different concentrations in lean fish, fatty fish and bivalves. Most analytes showed satisfactory accuracy. Alachlor herbicide was found in samples of seabass, mussels, clams and parati with levels ranging between 0.55 to 420.39 μg kg−1 dw. Ethion was found in parati (maximum 211.22 μg kg−1 dw), mussels (15.1 μg kg−1 dw) and clams (maximum 44.50 μg kg−1 dw). Alachlor was found in clams (maximum 93.1 μg kg−1 dw), and bifenthrin was found in parati (maximum 43.4 μg kg−1 dw) and clams (maximum 42.21 μg kg−1 dw). The validated method was satisfactory for the determination of eleven pesticides in the fatty fish matrix, and thirteen pesticides in the samples of lean fish and bivalves. The presence of alachlor, ethion and bifenthrin stands out.

Deltamethrin (DLT) is a type-II pyrethroid ester insecticide used in agricultural and domestic applications as well as in public health. However, transmembrane ionic channels perturbed by this compound remain largely unclear, although the agent is thought to alter the gating characteristics of voltage-gated Na+ (NaV) channel current. In this study, we reappraised whether and how it and other related compounds can make any further modifications on voltage-gated Na+ current (INa) in pituitary tumor (GH3) cells. Cell exposure to DLT produced a differential and dose-dependent stimulation of peak (transient, INa(T)) or sustained (late, INa(L)) INa; consequently, the EC50 value required for DLT-stimulated INa(T) or INa(L) was determined to be 11.2 or 2.5 μM, respectively. However, neither the fast nor slow component in the inactivation time constant of INa(T) activated by short depolarizing pulse was changed with the DLT presence; conversely, tefluthrin (Tef), a type-I pyrethroid insecticide, can accentuate INa with a slowing in inactivation time course of the current. The INa(L) augmented by DLT was attenuated by further application of either dapagliflozin (Dapa) or amiloride, but not by chlorotoxin. During pulse train (PT) stimulation, with the Tef or DLT presence, the cumulative inhibition of INa(T) became slowed; moreover, following PT stimuli, a large tail current with a slowly recovering process was observed. Alternatively, during rapid depolarizing pulse, the amplitude of INa(L) and tail INa (INa(Tail)) for each depolarizing pulse became progressively increased by adding DLT, not by Tef. The recovery time constant following PT stimulation with continued presence of Tef or DLT was shortened by further addition of Dapa. The voltage-dependent hysteresis (Hys(V)) of persistent INa was differentially augmented by Tef or DLT. Taken together, the magnitude, gating, frequency dependence, as well as Hys(V) behavior of INa exerted by the presence of DLT or Tef might exert a synergistic impact on varying functional activities of excitable cells in culture or in vivo.

Indoor environmental exposure to pesticides has become one of the major concerns that might adversely affect human health and development. People spend most of their lifetime in enclosed indoor environments where they might inhale harmful toxic chemicals, such as pesticides, dispersed either in particulate or in a gas phase. In this study, an assessment of pesticide contamination in indoor environments was conducted. The study covered nine houses during one year, starting from February 2016 and ending in February 2017, in which both air and dust samples were assessed for their potential contamination with 50 pesticides. The results showed that all the assessed houses were contaminated by several pesticides, especially with the allethrin pesticide (detection frequency (DF) = 100%). The highest pesticide contamination was detected in the spring/summer season when it reached an average of around 185 ng g−1 and 186.4 ng sampler−1 in the collected dust and air samples, respectively. The potential contamination of pyrethroid insecticides within all the targeted samples revealed by this study stresses the importance of minimizing the use of such indoor treatments as part of the efficient prevention and control of human exposure to pesticides.

The encapsulation of pesticides within nanoparticles is a promising approach of advanced technology in sustainable agriculture. Lambda-cyhalothrin (LC) was encapsulated by the ionotropic gelation technique into chitosan (CS)/tripolyphosphate (TPP) and CS/alginate (ALG) matrixes. CS-LC nanoparticles were characterized, and their efficacy was then evaluated against the key pest of soft fruits in Europe and the United States, Drosophila suzukii. The encapsulation efficiency (74%), nanoparticle yield (80%), polydispersity index (0.341), zeta potential (−23.1 mV) and particle size (278 nm) were determined at the optimum conditions. FTIR confirmed the cross-linkage between CS and TPP/ALG in the nanoparticles. The optimum formula recommended by the fractional factorial design was associated with the formulation variables of CS of high or low molecular weight, cross-linking agent (TPP), LC concentration (1.5% w/v) and stirring rate (1500 rpm), showing the highest desirability value (0.5511). CS-LC nanoparticles of the lowest particle size (278 nm) exhibited the highest percent mortality of D. suzukii males (86%) and females (84%), exceeding that caused by the commercial product (Karate-zeon® 10% CS) at 2 HAT. This is the first work to use the ionic gelation technique to make LC nanoparticles, to the best of our knowledge. The encapsulation of chemical pesticides within biodegradable polymeric nanoparticles could be helpful for establishing a sustainable IPM strategy with benefits for human and environmental health and the lifetime of pesticides.

In recent years, pyrethroids have emerged as a less toxic alternative to eliminate insect pests. However, some animal studies and studies with children show that these pesticides are toxic and lead to neurobehavioral effects similar to other pesticides, such as organophosphates. The purpose of this review was to systematize the epidemiological scientific evidence about the neurobehavioral, neuromotor, and neurocognitive effects in agricultural workers and their children exposed to pyrethroid pesticides. We conducted two searches (with different terms) in PubMed and Scopus databases, including articles in Spanish and English language on the effects of occupational exposure to pyrethroid pesticides associated with neurobehavioral, neuromotor, and neurocognitive functioning of agricultural workers and their children. There were no filters by year, and the search included studies till march 2021. To develop the search, we followed the recommendations contained in the PRISMA guidelines and the PICO strategy. The results show that in 66.6% of the studies reviewed (8 of 12 studies), agricultural workers or their children occupationally exposed to pyrethroid pesticides have a higher risk of presenting difficulties in their neurocognitive, neuromotor, or neurobehavioral performance, mainly associated with attention, processing speed (linked to hand-eye coordination), and motor coordination. There are still few studies that address this issue. However, the quality of most of the research conducted (83% intermediate or high quality) confirms the risk for neurobehavioral health in agricultural workers due to occupational exposure to pyrethroids. More research is required evaluating the exposure to pyrethroids, including biomarkers and validated neurobehavioral and neuromotor tests, in addition to evaluating the effect of simultaneous exposure to other hazardous pesticides. Assuming that the use of pyrethroids is increasing considerably and faster than the scientific evidence, it is suggested as a precautionary principle to regulate, more strictly, the sale of pyrethroids and other pesticides.

Orientador: Angelo Pires do Prado Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia Resumo: Entre os ectoparasitos dos animais bovinos, o carrapato ¿ Boophilus microplus (Acari: Ixodidae) - continua sendo uma das principais causas das perdas econômicas na pecuária do Estado de São Paulo. A situação atual do controle do carrapato caracteriza-se por uma crise na produção de novas moléculas de parasiticidas e o desenvolvimento acelerado da resistência dos parasitas aos produtos usados. O presente trabalho teve por objetivo verificar o perfil de sensibilidade do carrapato B. microplus nas fazendas localizadas em alguns municípios do Vale do Ribeira e no município de Pindamonhangaba e propor um sistema de tratamento carrapaticida com base na infestação de paternóginas. Foram realizados testes de larvas - LPT (larval packet test) adotado pela FAO - teste de imersão com a fêmea adulta e o levantamento sobre as práticas de controle adotadas nas duas regiões. Os resultados de resistência para as fazendas de Pindamonhangaba mostraram que, para cipermetrina 15,4% das fazendas foram classificadas como sensível; 7,7% com resistência nível I; 69,2% com resistência nível II e 7,7% com resistência nível III. Para a deltametrina 23% sensível; 38,5% com resistência nível II e 38,5% com resistência nível III. Para o organofosforado clorpirifós 54% mostraram-se sensível; 38,4% com resistência nível I e 7,6% com resistência nível II. A região do Vale do Ribeira apresenta uma média de eficácia inferior a 20% para os piretróides; eficácia entre 49% e 72% para as associações piretróides e organofosforados; 66,83% para o amitraz e acima de 90% para as associações entre os organosfosforados. Para o teste de larvas a cipermetrina apresentou uma porcentagem de 42,85% de amostras sensível; 14,3% com resistência nível I e 42,85% com resistência nível II. Deltametrina, 50% sensível; 25% com resistência nível II e 25% com resistência nível III. O organofosforado clorpirifós mostrou uma porcentagem de 50% de amostras sensível; 25% com resistência nível I e 25% com resistência nível II. Constatouse, para as duas regiões estudadas, a falta de conhecimento dos principais grupos químicos usados no controle dos carrapatos. O produto amitraz é o mais usado e a maioria das fazendas usam o método de pulverização na aplicação dos carrapaticidas. Experimento realizado no ano de 2001 a 2003 num sítio localizado no município de Ibiúna mostrou que a avaliação de infestação de paternóginas do carrapato B. microplus na área do úbere ou escroto e baixo períneo é um critério que pode ser empregado para se determinar a aplicação de carrapaticidas. Quando se realiza a aplicação de carrapaticidas nos animais infestados com bastante paternóginas diminui a infestação de larvas no campo. Testes de bioensaios, usando fêmeas adultas, realizados num intervalo de três meses, e teste de larvas no período de seis meses servem como orientação para o proprietário na avaliação da sensibilidade dos carrapatos aos produtos químicos Abstract: The cattle tick - Boophilus microplus (Acari: Ixodidae) ¿ is one of the principal causes of economic losses in the cattle farms in São Paulo state. The current situation of the tick control is characterized by a crisis in the production of new molecules with acaricidal properties and by an increasing in the parasites resistance to the products used to control them. The current study aimed to verifying the sensibility profile of tick B. microplus in farms located in the municipalities of Vale do Ribeira and in the region of Pindamonhangaba, and propose a tick control treatment system based on nymph infestation. The resistance diagnosis tests have been carried by the larval bioassay (Larval packet test), adult immersion test and the survey of the tick control practices applied in both regions. The results for the farms at Pindamonhangaba show that to Cypermethrin 15,4% of the farms were classified as sensible, 7,7% resistance level I, 69,2% resistance level II and 7,7% resistance level III. To deltamethrin 23% were considered sensible, 38,5% Resistance level II, and 38,5% resistance level III. To organophosphate chlorpyriphos 54% presented a sensible frame, 38,4% resistance level I and 7,6% resistance level II. The Vale do Ribeira region presents an average efficacy lower than 20% for all pyrethroids; efficacy between 49% and 72% to associations with pyrethroids and organophosphates; 66,83% to amitraz, and over 90% to organophosphates associations. For the larval test, the cypermethrin presented a percentage of 42,85% from samples sensible; 14,3% resistance level I and 42,85% resistance level II. Deltamethrin, 50% sensible; 25% resistance level II and 25% resistance level III. The organophosphate chlorpyriphos presented a percentage of 50% from samples sensible; 25% resistance level I and 25% resistance level II. It has been proved, that for both regions under this study, there is a lack of knowledge concerning the main chemical groups used in the tick control. The amitraz is the most used and most farms apply the pulverization method when performing the tick control. An experiment taken from 2001 to 2003 in a little farm located in the municipality of Ibiúna has shown the evaluation in the infestation of tick B. microplus in the udder area or escrotum and low perineum is a good criteria to be applied in order to determine the application of anti-ticks. When the application of anti-ticks is undertaken on infested animals full of pathenogens, the field larvae infestation is diminished. Bioassay, using engorged female ticks, undertaken at three months intervals and larval packet test undertaken at six months intervals serve as orientation for the owners for the evaluation of ticks¿ sensibility to the chemical products Doutorado Entomologia Doutor em Parasitologia

As part of malaria control programs, many countries spray dichlorodiphenyltrichloroethane (DDT) or pyrethroid insecticides inside dwellings in a practice called indoor residual spraying that results in high levels of exposure to local populations. Gestational exposure to these endocrine- and metabolism-disrupting chemicals may influence child cardiometabolic health.MethodsWe measured the serum concentration of DDT and dichlorodiphenyldichloroethylene (DDE) and urinary concentration of pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA) in peripartum samples collected between August 2012 and December 2013 from 637 women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study based in Limpopo, South Africa. We applied marginal structural models to estimate the relationship between biomarker concentrations and child-size (height and weight), adiposity (body mass index [BMI], body fat percentage, waist circumference) and blood pressure at 5 years of age.ResultsMaternal concentrations of all four pyrethroid metabolites were associated with lower adiposity including reduced BMI z-scores, smaller waist circumferences, and decreased body fat percentages. Reductions in BMI z-score were observed only among children of mothers with sufficient energy intake during pregnancy (βcis-DCCA, trans -DCCA=-0.4, 95% confidence interval (CI) = -0.7,-0.1; pinteraction=0.03 and 0.04, respectively) but there was no evidence of effect modification for the other measures of adiposity. Maternal p,p'-DDT concentrations were associated with a reduction in body fat percentage (β = -0.4%, 95% CI = -0.8,-0.0).ConclusionsGestational exposure to pyrethroids may reduce adiposity in children at 5 years of age.

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs.

Pyrethroid insecticides contain natural pyrethrins extracted from pyrethrum flowers, and their synthetic derivatives, pyrethroids. The present article provides an overview of the structure of natural pyrethrins, and the discovery and development of pyrethroids with an emphasis on the background of selected compounds. The stereochemical relationships among pyrethroid secondary alcohols, and toxicologic and environmental effects of pyrethroids are also discussed. Finally, the pyrethroid resistance of mosquitoes and future aspects of pyrethroids are addressed.

This study aimed to compare the toxicity for fish of two active ingredients (lambda-cyhalothrin-20 g L −1, a pyrethroid, and acetamiprid-15 g L −1, a neonicotinoid) which are components of a commercial insecticide (Acer 35 EC) used in cotton crop in many West African countries. The juveniles of Oreochromis niloticus (4.01 ± 0.34 g, mean body weight) were exposed for 96 h to increasing concentrations of active ingredients (lambda-cyhalothrin and acetamiprid) or a mixture similar to Acer 35 EC (composed by 20 g of chemical compound lambda-cyhalothrin and 15 g of acetamiprid dissolved in 1 L of acetone). The experiments were carried out under controlled conditions in aquaria according to OECD Guidelines. During the experiments, the behavioral responses (loss of balance, color change, hyperactivity, etc.) that usually precede death were observed in exposed fish. Mortalities were recorded in each aquarium and the LC 50-96h of each chemical was determined. The LC 50-96h obtained were respectively 0.1268, 0.0029, 182.9 and 0.5685 ppm for Acer 35 EC, lambda-cyhalothrin, acetamiprid and mixture. All insecticides used in this study had profound impact on Nile tilapia behavior which may confirm the neurotoxicity of each single active compound as well as of their mixture.

The European red mite Panonychus ulmi (Koch) is a major pest of apple trees worldwide and causes significant damage to apple orchards in Iran. Pyrethroid insecticides/acaricides, such as fenpropathrin and fenvalerate, are widely used to control P. ulmi, but their long-term use may lead to low efficacy. Earlier studies investigating pyrethroid resistance in closely related mites such as Tetranychus urticae revealed that pyrethroid resistance was associated with point mutations in the voltage-gated sodium channel gene (vgsc). The aim of this study was to investigate the biochemical and molecular mechanisms of fenpropathrin and fenvalerate resistance in Iranian populations of P. ulmi. Pyrethroid toxicity bioassays were carried out on different P. ulmi field populations. Marand (resistance ratio, RR = 149), Maracieh (RR = 90) and Mianeh2 (RR = 71) populations exhibited high levels of resistance to fenpropathrin, compared to a susceptible field population (Shahin Dej). Resistance was also observed for fenvalerate with resistance ratio's ranging from 2- to 20-fold. Synergism experiments and enzyme activity assays predicted a minor role for classical detoxification enzymes. In contrast, two amino acid substitutions in the VGSC, L1024V and F15381, that were previously shown to confer pyrethroid resistance, were detected in all three resistant P. ulmi populations and point towards target-site insensitivity as the most likely resistance mechanism. Furthermore, sequencing after cloning of vgsc fragments from single haploid males revealed the presence of multiple copies of vgsc in a highly resistant strain. The link between resistance mutations and vgsc copy number variation should be the subject of future study, as this might be used to develop molecular markers for monitoring pyrethroid resistance of P. ulmi in the field.

The oriental fruit fly, Bactrocera dorsalis, is one of the most destructive fruit insect pests. β-cypermethrin has been widely used in the orchard to control this major insect. Based on the resistance monitoring in 2011, B. dorsalis developed significant resistance against β-cypermethrin in fields. This indicated that the B. dorsalis has been exposed to sublethal concentrations of β-cypermethrin in the field for a long time. Thus, it is urgent to understand the sublethal effects of β-cypermethrin on this fly to guide the rational use of an insecticide. According to the olfactory preference assays and electroantennogram (EAG) recording, the B. dorsalis after β-cypermethrin exposure (LD30 = 10 ng/fly) severely decreased the ability to perceive the tested odorants. Moreover, we then performed quantitative real-time PCR and found the chemosensory genes including odorant receptor co-receptor (BdorORco) and ionotropic receptor co-receptors (BdorIRcos) were obviously suppressed. Our results demonstrated that the sublethal dose of β-cypermethrin impairs the olfaction of the pest insects by suppressing the expression of chemosensory genes (BdorORco and BdorIRcos), which expanded our knowledge of the sublethal effects of the pesticide on insects.

Simple Summary Extensive research has been carried out to assess the effects of sublethal pyrethroid doses on mosquito fitness and behaviour. Although pyrethroids are mainly used as insecticides, they can also act as repellents, depending on the dosage and/or exposure time. Females and males of two laboratory-reared mosquito species (Culex pipiens and Aedes albopictus) were exposed to five treatments in the laboratory: three doses of the pyrethroid prallethrin, as well as an untreated and a negative control. Effects on mosquito fitness, mosquito biting behaviour, and human and environmental health were evaluated. Sublethal prallethrin doses were found to decrease mosquito population size, longevity, and biting rate while posing low risks to human and environmental health. Such changes in adult mosquito fitness and behaviour could reduce the ability of mosquitoes to transmit diseases and, consequently, help limit public health risks. Although these promising results suggest sublethal insecticide doses could offer a new approach to controlling species that transmit diseases, more work is needed to identify the proper balance among regulatory requirements, contexts of usage, and human and environmental health benefits. Abstract Worldwide, pyrethroids are one of the most widely used insecticide classes. In addition to serving as personal protection products, they are also a key line of defence in integrated vector management programmes. Many studies have assessed the effects of sublethal pyrethroid doses on mosquito fitness and behaviour. However, much remains unknown about the biological, physiological, demographic, and behavioural effects on individual mosquitoes or mosquito populations when exposure occurs via spatial treatments. Here, females and males of two laboratory-reared mosquito species, Culex pipiens and Aedes albopictus, were exposed to five different treatments: three doses of the pyrethroid prallethrin, as well as an untreated and a negative control. The effects of each treatment on mosquito species, sex, adult mortality, fertility, F1 population size, and biting behaviour were also evaluated. To compare knockdown and mortality among treatments, Mantel–Cox log-rank tests were used. The results showed that sublethal doses reduced mosquito survival, influencing population size in the next generation. They also provided 100% protection to human hosts and presented relatively low risks to human and environmental health. These findings emphasise the need for additional studies that assess the benefits of using sublethal doses as part of mosquito management strategies.

Production and application of pesticides have risen remarkably in the last few decades. Even if they provide many benefits, they can be hazardous for humans and ecosystems when they are not used cautiously. Human exposure to pesticides is well documented, but new approaches are needed to boost the available information. This work proposes a new application of wastewater-based epidemiology (WBE) to assess the exposure of the general population to organophosphate and triazine pesticides (pyrethroid pesticides have already been validated). Several human urinary metabolites tested as WBE biomarkers, were suitable. Untreated wastewater samples from different European countries were analyzed by liquid chromatography-tandem mass spectrometry. Biomarker concentrations were converted to mass loads and used to back-calculate the local population's exposure to the parent pesticides, using specific correction factors developed in this study. Exposure to organophosphates and pyrethroids showed spatial and seasonal variations. Finally, pesticide exposure was estimated in twenty cities of ten European countries and compared with the acceptable daily intake, concluding that some populations might face health risks. The study confirms WBE as a suitable approach for assessing the average community exposure to pesticides and is a valuable complementary biomonitoring tool. WBE can provide valuable data for public health.

Background The growing threat of vector-borne diseases and environmental pollution with conventional pesticides has led to the search for nanotechnology applications to prepare alternative products. Methods In the current study, four pyrethroid insecticides include alpha-cypermethrin, deltamethrin, lambda-cyhalothrin, and permethrin were incorporated into stable nanoemulsions. The optimization of nanoemulsions is designed based on the active ingredient, solvent, surfactant, sonication time, sonication cycle, and sonication energy by factorial analysis. The nanoscale emulsions’ droplet size and morphology were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The toxicity of nanoemulsions against Culex pipiens larvae was evaluated and compared with the technical and commercial formulations. The in vitro assay of adenosine triphosphatase (ATPase), carboxylesterase (CaE), and glutathione-S-transferase (GST) were also investigated. Furthermore, molecular docking was examined to assess the binding interactions between the tested pyrethroids and the target enzymes. Also, an ecotoxicological assessment of potential effects of the tested products on the freshwater alga Raphidocelis subcapitata was determined according to OECD and EPA methods. The emulsifible concentration (EC50) and NOEC (no observed effect concentration) values were estimated for each insecticide and graded according to the GHS to determine the risk profile in aquatic life. Results The mean droplet diameter and zeta potential of the prepared pyrethroid nanoemulsions were found to be in the range of 72.00–172.00 nm and − 0.539 to − 15.40 mV, respectively. All insecticides’ nanoemulsions showed significantly high toxicity (1.5–2-fold) against C. pipiens larvae compared to the technical and EC. The biochemical activity data proved that all products significantly inhibited ATPase. However, GST and CaE were significantly activated. Docking results proved that the pyrethroids exhibited a higher binding affinity with CaE and GST than ATPase. The docking scores ranged from − 4.33 to − 10.01 kcal/mol. Further, the biosafety studies of the nanopesticides in comparison with the active ingredient and commercial EC were carried out against the freshwater alga R. subcapitata and the mosquitocidal concentration of nanopesticides was found to be non-toxic. Conclusion The mosquitocidal efficacy of nano-pyrethroids formulated in a greener approach could become an alternative to using conventional pesticide application in an environmentally friendly manner.

The evolution of resistance to insecticides threatens the sustainable control of many of the world’s most damaging insect crop pests and disease vectors. To effectively combat resistance, it is important to understand its underlying genetic architecture, including the type and number of genetic variants affecting resistance and their interactions with each other and the environment. While significant progress has been made in characterizing the individual genes or mutations leading to resistance, our understanding of how genetic variants interact to influence its phenotypic expression remains poor. Here, we uncover a mechanism of insecticide resistance resulting from transposon-mediated insertional mutagenesis of a genetically dominant but insecticide-susceptible allele that enables the adaptive potential of a previously unavailable recessive resistance allele to be unlocked. Specifically, we identify clones of the aphid pest Myzus persicae that carry a resistant allele of the essential voltage-gated sodium channel (VGSC) gene with the recessive M918T and L1014F resistance mutations, in combination with an allele lacking these mutations but carrying a Mutator-like element transposon insertion that disrupts the coding sequence of the VGSC. This results in the down-regulation of the dominant susceptible allele and monoallelic expression of the recessive resistant allele, rendering the clones resistant to the insecticide bifenthrin. These findings are a powerful example of how transposable elements can provide a source of evolutionary potential that can be revealed by environmental and genetic perturbation, with applied implications for the control of highly damaging insect pests.

Triatominae (kissing bugs) are the vectors of Chagas disease. Chemical control of these insects is the main tool for reducing the incidence of the disease. Pyrethroids are the main insecticides used for triatomine control in all endemic countries. The evolution of insecticide resistance renders a successful chemical control strategy ineffective. In Argentina, different foci of resistance have been detected in Triatoma infestans—the most important vector in the Southern Cone of South America, which are associated with control deficiencies. The studies conducted on this species show that resistance is a complex problem because it has evolved in several areas of the species’ geographical distribution. Different resistance mechanisms have been identified. Resistance is associated with changes in various biological processes and linked to environmental changes. There is a lack of control alternatives. This paper is a review of the knowledge on pyrethroid resistance in T. infestans in Argentina. Los insectos triatominos son los vectores de la enfermedad de Chagas. El control químico de estos insectos es la principal herramienta utilizada para reducir la incidencia de la enfermedad. Los piretroides son los principales insecticidas utilizados para el control de los triatominos en todos los países endémicos. La evolución de resistencia a insecticidas convierte en ineficiente una exitosa estrategia de control químico. En Argentina se han detectado diferentes focos de resistencia en Triatoma infestans, el vector más importante en el Cono Sur de Sudamérica, asociados a deficiencias en el control. Los estudios realizados sobre esta especie muestran que la resistencia es un problema complejo, ya que evolucionó en varias zonas de la distribución geográfica de la especie, se identificaron diferentes mecanismos de resistencia, está asociada a modificaciones en diversos procesos biológicos, está vinculada a variaciones ambientales y hay escasez de alternativas de control. En este manuscrito presentamos una revisión del conocimiento sobre la resistencia a piretroides en T. infestans en Argentina. Os insetos triatomíneos são os vetores da doença de Chagas. O controlo químico desses insetos é a principal ferramenta utilizada para reduzir a incidência da doença. Os piretróides são os principais inseticidas usados para controlar os triatomíneos em todos os países endémicos. A evolução da resistência aos inseticidas converte em ineficiente uma estratégia de controlo químico eficiente. Na Argentina foram detetados diferentes focos de resistência em Triatoma infestans, o vetor mais importante do Cone Sul da América do Sul, associados a deficiências de controlo. Os estudos realizados nesta espécie mostram que a resistência é um problema complexo, visto que evoluiu em várias áreas da distribuição geográfica da espécie. Foram identificados diferentes mecanismos de resistência, associados a modificações em vários processos biológicos e ligados a variações ambientais, havendo uma escassez de alternativas de controlo. Neste manuscrito é apresentada uma revisão do conhecimento sobre a resistência aos piretróides em T. infestans na Argentina.

In recent years, the worldwide prevalence of overweight and obesity among adults and children has dramatically increased. The conventional model regarding the onset of obesity is based on an imbalance between energy intake and expenditure. However, other possible environmental factors involved, such as the exposure to chemicals like pesticides, cannot be discarded. These compounds could act as endocrine-disrupting chemicals (EDC) that may interfere with hormone activity related to several mechanisms involved in body weight control. The main objective of this study was to systematically review the data provided in the scientific literature for a possible association between prenatal and postnatal exposure to pesticides and obesity in offspring. A total of 25 human and 9 animal studies were analyzed. The prenatal, perinatal, and postnatal exposure to organophosphate, organochlorine, pyrethroid, neonicotinoid, and carbamate, as well as a combined pesticide exposure was reviewed. This systematic review reveals that the effects of pesticide exposure on body weight are mostly inconclusive, finding conflicting results in both humans and experimental animals. The outcomes reviewed are dependent on many factors, including dosage and route of administration, species, sex, and treatment duration. More research is needed to effectively evaluate the impact of the combined effects of different pesticides on human health. This study was supported by grants from the Spanish Government (Ministerio de Economía y Competitividad and Instituto Mixto de Investigación-Escuela Nacional de Sanidad (IMIENS)) and the Fondo Europeo de Desarrollo Regional (MINECO-FEDER) Grant numbers: PSI2017-90806-REDT, PSI2017-83038-P, PSI2017-83893-R, PSI2017-86396-P, PSI2017-86847-C2-2-R MINECO-FEDER, and IMIENS: PIC-IMIENS-2018-003. Sí

Objective Pyrethroids-containing products are widely used as commercial and household insecticides. While animal studies and clinical case reports have shown acute cardiovascular outcomes of pyrethroids exposure, little has been known on the effect of chronic pyrethroid exposure on cardiovascular disease (CVD). We aimed to examine the associations between chronic pyrethroid exposure and CVD in the US adults. Methods Cross-sectional data from the National Health and Nutrition Examination Survey 1999–2002 and 2007–2012 were analyzed. The exposure to pyrethroids was determined as the urinary level of 3-phenoxybenzoic acid (3-PBA), and CVD was ascertained based on self-reported physician diagnoses. Multivariable logistic regression models were fitted to evaluate associations of pyrethroid exposure with CVD, coronary heart disease (CHD), and stroke. Results Included were 6,471 participants with a mean age of 44.77 years (standard error, 0.39) for final analyses. The weighted prevalence of CVD, CHD, and stroke was 6.85%, 4.57% and 2.27%, respectively. With adjustments for major confounders, participants in the highest tertile of urinary 3-PBA had higher odds of CVD (odds ratio, 1.58; 95% confidence interval: 1.12, 2.23) and CHD (OR, 1.75; 95% CI: 1.17, 2.61) compared to those in the lowest tertile. There were linear associations for CVD (P for trend = 0.04) and CHD (P for trend = 0.02). However, no significant association was noted for stroke (1.29; 0.78, 2.16) in the main analyses. Conclusions 3-PBA was adversely associated with CVD and CHD in the US adults. Our findings highlight potential cardiovascular risk of chronic exposure to pyrethroids, and should be validated in large prospective studies in different populations in future.

Pyrethroid pesticide exposures may be associated with the onset of depression in later life via disruption of dopaminergic, serotonergic, and neurological functioning. We sought to investigate the association between living near agricultural pyrethroid pesticide applications and depression measures in central California, using two waves (PEG 1&2, total N = 1,654) of a case control study of Parkinson's disease (PD). At enrollment, participants self-reported history of use of depression medications and dates of MD-diagnosed depression and anxiety. Participants also completed a Geriatric Depression Scale-Short Form upon enrollment. We used the California Pesticide Use Registry to assign estimated ambient pyrethroid pesticide exposures at participant's home addresses over the 5 years before the index date (date of outcome, or an age-matched year for participants without the outcome). We used logistic and linear regression to evaluate associations between living near any pyrethroid applications over the 5-year index period and measures of depression and anxiety. We also evaluated modification by study wave and PD status. We observed associations of pyrethroids with depression, depression medications, and anxiety (adjusted odds ratio [aOR] depression = 1.54, 95% confidence interval [CI] 1.14, 2.07; aOR depression medications = 1.68, 95% CI 1.25, 2.25; aOR anxiety = 1.60, 95% CI 1.17, 2.18). However, we observed no associations with mild/moderate depressive symptoms according to the GDS score at enrollment (aOR = 1.04, 95% CI 0.77, 1.42). We did not observe a consistent modification of the pyrethroid-depression associations by study wave and PD status. Ambient pyrethroid pesticide exposures may be associated with measures of depression in later life.

Bed bugs, Cimex lectularius and C. hemipterus, are common blood-sucking ectoparasites of humans with a large geographical distribution, worldwide. In France, little is known about the status of bed bugs’ infestation and their resistance to insecticides, particularly, pyrethroids. Here, we aimed to find mutations in the kdr gene, known to be involved in resistance to insecticides. We gathered bed bugs from various infested locations, including 17 private houses, 12 HLM building complex, 29 apartments, 2 EHPAD, and 2 immigrants’ residences. A total of 1211 bed bugs were collected and morphologically identified as C. lectularius. Two fragments of the kdr gene, encompassing codons V419L and L925I, were successfully amplified for 156 specimens. We recorded sense mutation in the first amplified fragment (kdr1) in 89 out of 156 (57%) samples, in which in 61 out of 89 (68.5%) sequences, a change of valine (V) into leucine (L) V419L was observed. Within the second fragment (kdr2), a homozygous mutation was recorded in 73 out of 156 (46.7%) specimens at the codon 925. At this position, 43 out of 73 (58.9%) specimens had a sense mutation leading to the replacement of leucine (L) by isoleucine (I). Among 162 mutant sequences analyzed (89 for the kdr1 fragment and 73 for the kdr2 one), we detected single point mutation in 26.6%, while 73.4% presented the mutation in both kdr1 and kdr2 fragments. All modifications recorded in bed bug populations of Paris are described to be involved in the knockdown resistance (kdr) against pyrethroids.

Blue orchard bees, [Osmia lignaria (Say) (Hymenoptera: Megachilidae)], have been developed as an important pollinator for orchard crops in North America over the last 40 years. The toxicity of several pesticides to O. lignaria and other Osmia species has been previously reported. However, the field-realistic toxicity of formulated premix insecticides comprised of multiple active ingredients (each with a different mode of action) to O. lignaria has not been assessed. Here, we use a customized spray tower in a laboratory setting to assess adult male and female whole-body direct contact exposure to four formulated pesticide mixtures: thiamethoxam + lambda-cyhalothrin (TLC), imidacloprid + beta-cyfluthrin (IBC), chlorantraniliprole + lambda-cyhalothrin (CLC) and methoxyfenozide + spinetoram (MS) by directly spraying anesthetized bees in Petri dishes. Separately, adult male and female whole-body direct contact exposure to formulated imidacloprid (I), beta-cyfluthrin (BC) and their 1:1 binary combination (IBC) was assessed using the same experimental method. Resulting mortality in each study was screened up to 96 h post-treatment to determine acute whole-body contact toxicity. In the first study, TLC and IBC resulted in statistically higher mortality at 24 and 48 h than the two other insecticide combinations tested. The CLC and MS combinations were slower acting and the highest mortality for O. lignaria exposed to these mixtures was recorded at 96 h. We did observe significant differences in toxicity between CLC and MS. In the second study, exposure to the 1:1 binary combination of IBC caused overall significantly higher mortality than exposure to I or BC alone. Both active ingredients alone, however, demonstrated equivalent levels of mortality to the 1:1 binary combination treatment at the 96 h observation reading, indicating increased speed of kill, but not necessarily increased toxicity. Significant differences in the onset of mortality following acute contact whole-body exposure to the formulated insecticide mixtures and individual active ingredients tested were consistently observed across all experiments in both studies.

BackgroundPyrethroid pesticide use is increasing worldwide, although the full extent of associated health effects is unknown. An epigenome-wide association study (EWAS) with exploratory pathway analysis may help identify potential pyrethroid-related health effects.MethodsWe performed an exploratory EWAS of chronic ambient pyrethroid exposure using control participants' blood in the Parkinson's Environment and Genes Study in the Central Valley of California (N=237). We estimated associations of living and working near agricultural pyrethroid pesticide applications in the past 5 years (binary) with site-specific differential methylation, and used a false discovery rate (FDR) cut off of 0.05 for significance. We controlled for age, sex, education, cell count, and an ancestral marker for Hispanic ethnicity. We normalized methylation values for Type I/II probe bias using Beta-Mixture Quantile (BMIQ) normalization, filtered out cross-reactive probes, and evaluated for remaining bias with Surrogate Variable Analysis (SVA). We also evaluated the effects of controlling for cell count and normalizing for Type I/II probe bias by comparing changes in effect estimates and p-values for the top hits across BMIQ and GenomeStudio normalization methods, and controlling for cell count. To facilitate broader interpretation, we annotated genes to the CpG sites and performed gene set overrepresentation analysis, using genes annotated to CpG sites that were associated with pyrethroids at a raw p&nbsp

Background: There is growing concern about children’s chronic low-level pesticide exposure and its impact on health. Green building practices (e.g. reducing leakage of the thermal and pressure barrier that surrounds the structure, integrated pest management, improved ventilation) have the potential to reduce pesticide exposure. However, the potential impact of living in green housing on children’s pesticide exposure is unknown. Objective: To address this question, a longitudinal study of pyrethroid metabolites (3-phenoxybenzoic acid [3-PBA], 4-fluoro-3-phenoxybenzoic acid [4-F-3-PBA], trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid [trans-DCCA]) in first morning void urine, collected from 68 children from New Orleans, Louisiana residing in green and non-green housing was conducted. Methods: Children were followed for one year with three repeated measures of pesticide exposure. Generalized Estimating Equations examined associations between housing type (green v non-green) and urinary pyrethroid metabolite concentrations adjusting for demographic and household factors over the year. Results: Ninety-five percent of samples had detectable concentrations of 3-PBA (limit of detection [LOD]: 0.1 μg/L); 8% of 4-F-3-PBA (LOD: 0.1 μg/L), and 12% of trans-DCCA (LOD: 0.6 μg/L). In adjusted models, green housing was not associated with statistically significant differences in children’s 3-PBA urinary concentrations compared to non-green housing. Significance: In this study, green building practices had no impact on children’s pyrethroid urinary concentrations. Further studies with larger sample sizes are needed to confirm these findings.

Lyme disease is the most common vector-borne disease in the United States with hotspots in the Northeast and Midwest. Integrated vector control for mosquito-borne disease prevention is often organized at the community level, but tick control is primarily coordinated at the household and individual level. Management of the blacklegged tick, Ixodes scapularis (Say), the vector of the causative agent of Lyme disease in the Midwest and eastern United States in peridomestic environments may be critical as many tick encounters are reported to occur in the yard. Therefore, we assessed the effectiveness of a widely available and low-cost pesticide that targets common lawn pests and is labeled for use against ticks. In June 2019, we evaluated a granular form of gamma-cyhalothrin in a placebo-controlled residential backyard study (n = 90) in two communities in Wisconsin. The product applied by the research team reduced nymphal blacklegged ticks in plots established in the lawn part of the ecotone by 97% one week after application at both communities and by 89–97% three to four weeks postapplication. The proportion of homes with at least one nymphal tick postapplication was significantly lower at acaricide-treated homes and ranged from 4.2 to 29.2% compared with placebo homes where at least one nymphal tick was found at 50–81.5% of homes. These results support the efficacy of a low-cost do-it-yourself strategy for homeowners seeking to reduce blacklegged ticks in the yard.

The effects of tetramethrin and prallethrin exposure on plasma total proteins, free amino acids, albumins, urea, urea nitrogen, uric acid, creatinine were tested. Serum SGOT, SGPT and lipid profile, antioxidants super oxide dismutase (SOD), catalase, GSH, G-Px, phospholipids, cholesterol, C/P ratio in membranes of erythrocyte and membrane fluidity were analyzed. The reason of the study were analyzed to examine the possessions of mosquito repellent pyrethroid (MRP) based compounds tetramethrin and prallethrin exposure on plasma profile, antioxidant status of erythrocyte membrane, membrane fluidity in male Wistar rats. We tested chronically for three months exposure every day (continuously for 8-10 hours per day by inhalation) of tetramethrin and prallethrin markedly available (MRP) repellents treated on male Wistar rats. Our results confirmed that tetrarmethrin and prallethrin treatment effect of plasma profile alterations, and lipid homeostasis mechanism in Red Blood cells (RBCs). Tetramethrin and prallethrin treatment significantly increased in erythrocyte membrane phospholipids and decreased levels of cholesterol with no change of protein content, increased C/P ration levels. Inhalation of tetramethrin and prallethrin stimulate plasma biophysical and biochemical modify SGOT, SGPT, erythrocyte membrane cholesterol and phospholipid levels, individual phospholipids and membrane fluidity of exposure rats compared to controls.

A novel ultrasensitive nanobody-based electrochemical immunoassay was prepared for assessing human exposure to pyrethroid insecticides. 3-Phenoxybenzoic acid (3-PBA) is the common human urinary metabolite for numerous pyrethroids which broadly served as a biomarker for following the human exposure to these pesticides group. The 3-PBA detection was via a direct competition for binding to alkaline phosphatase-embedded nanobodies between free 3-PBA and a 3-PBA-bovine serum albumin conjugate covalently immobilized onto citric acid decorated Nylon nanofibers, which were incorporated on a screen-printed electrode (SPE). Electrochemical impedance spectroscopy (EIS) was utilized to support the advantage of the employment of nanofibrous membranes and the success of the immunosensor assembly. The coupling between the nanofiber and nanobody technologies provided an ultra-sensitive and selective immunosensor for 3-PBA detection in a range of 0.8 to 1000 pg mL(−1), with a detection limit of 0.64 pg mL(−1). Moreover, when the test for 3-PBA was applied to real samples, the established immunosensor proved to be a viable alternative to the conventional methods for 3-PBA detection in human urine even without sample cleanup. It showed excellent properties and stability over time.

Head lice infestation caused by Pediculus humanus capitis de Geer, 1767 is one of the most common public health problems. the relationship between humans and head lice dates back millions of years ago that differentiated into different phylogenetic clades. Treatment of head lice infestation usually based on insecticide-based products, which promotes the resistance in the head lice populations. in the present study, we aimed to screen the presence of permethrin resistance among collected P. h. capitis specimens in Turkey. Three mutation sites (T917I, L920F, and M815I) were screened using real-time PCR and resistance was identified by melt analysis. of the studied specimens, resistance allele frequency (RAF) was found 0.98 for T917I, 0.99 for L920F, and 1.00 for M815I. the phylogenetic study revealed that Clade A and Clade B are present and overlap in Turkey. the present study is first to screen the resistance among Turkish head lice specimens. To not stimulate the pyrethroids resistance in head lice populations, early detection of resistance is crucial and will help the health professionals to choose suitable formula in the treatment. We suggest that the resistance status needs to be screened in randomly selected populations before any treatment application is given., Scientific Research Project Fund of the University of Health Sciences [2018/067], We thank Dr. Suha Kenan Arserim, Prof. Dr. Seray Toz and Prof. Dr. Yusuf Ozbel for their valuable helps. This study is supported by the Scientific Research Project Fund of the University of Health Sciences under project number 2018/067.

The burden of organophosphate (OP) pesticides in pregnant women from Tarragona (n = 157), a Mediterranean area of intense agricultural activity, has been assessed from the study of hydroxylated organic metabolites in urine samples in the three trimesters of pregnancy. 2-Diethylamino-6-methylpyrimidin-4-ol (DEAMPY), a metabolite of pirimiphos, was the compound found in higher concentration, medians 0.66–2.8 μg/g creatinine. 4-Nitrophenol (PNP), a metabolite of parathion, medians 0.24–0.41 μg/g creatinine, was the second most abundant compound. 2-Isopropyl-6-methyl-4-pyrimidol (IMPY), a metabolite of diazinon, was also present but in lower concentrations. Except for DEAMPY, the concentrations found in this cohort were lower than those reported in studies from other countries. Intraclass correlation coefficients (ICCs) were calculated for the compounds found in more than the 35% of the samples, the reliability between trimesters was poor (, This paper was supported by funding from the European Union projects: HEALS (FP7-ENV-2013- 603946), Neurosome (H2020-MSCA-ITN-2017 SEP-210411486) and EDC-MET (H2020-HEALTH/0490–825762). J. Rovira received funds from the Health Department of Catalonia Government trough “Pla Estratègic de Recerca i Innovació en salut” (PERIS 2016–2020).

Humans have used insecticides since ancient times. The spectrum and potency of available insecticidal substances has greatly expanded since the industrial revolution, resulting in widespread use and unforeseen levels of synthetic chemicals in the environment. Concerns about the toxic effects of these new chemicals on non-target species became public soon after their appearance, which eventually led to the restrictions of use. At the same time, new, more environmentally-friendly insecticides have been developed, based on naturally occurring chemicals, such as pyrethroids (derivatives of pyrethrin), neonicotinoids (derivatives of nicotine), and insecticides based on the neem tree vegetable oil (Azadirachta indica), predominantly azadirachtin. Although these new substances are more selective toward pest insects, they can still target other organisms. Neonicotinoids, for example, have been implicated in the decline of the bee population worldwide. This review summarises recent literature published on non-target toxicity of neonicotinoids, pyrethroids, and neem-based insecticidal substances, with a special emphasis on neonicotinoid toxicity in honeybees. We also touch upon the effects of pesticide combinations and documented human exposure to these substances.

Pyrethroid pesticides are synthetic products derived from natural pyrethrins isolated from the flowers. It has extensive applications in horticulture, agriculture, and pest control. Pyrethroids are a highly toxic and expeditious insecticide exhibiting tremor-type syndrome, allergic reactions, and ataxia. Regular use of synthetic pyrethroids affects a helpful microbial community and reduces soil fertility. Due to environmental concerns linked with the accumulation of pyrethroids pesticides in groundwater and food products, there is an urgent need to develop rapid, economical and reliable methods amenable to on-site applications. Here, we review recently developed analytical techniques used for estimating pyrethroids and their metabolites, focusing on their removal from environmental specimens, mechanisms, and kinetics. Biodegradation offers an efficient option to mineralize pyrethroid pesticides either into less toxic compounds or useful by-products. Herein we investigate more on their biodegradability by native microbial species by exploring the genes involved in the degradation of pyrethroid pesticides and assessing the mathematical modeling for pyrethroid degradation. We discuss toxicological effects, environmental issues, analytical techniques for estimation, and approaches for efficient biodegradation, which will offer an alternative and affordable option to get noxious pesticides.

Colorado potato beetle (Leptinotarsa decemlineata, CPB) is considered one of the most persistent crop pests because it is highly adaptable and can rapidly develop insecticide resistance. Nowadays, this beetle is resistant to over 54 different insecticides. In the absence of competitive alternatives, the answer of farmers to the high degree of pest adaptability is to increase the number of pesticide treatments or apply chemicals with different modes of action. Such a strategy increases the risk of intoxication in non-target organisms and leads to environmental pollution, augmenting the carbon footprint. Furthermore, these strategies are also unsustainable and inefficient for pest management in the long-term. The time has thus come to reform existing agriculture practices, for which the implementation of an integrated pest management strategy would be a more feasible tool. Applying a sustainable pest management strategy is indispensable for a better understanding of the status and mechanisms of insecticide resistance. Effective pest management requires monitoring the resistance of pests and developing a well-programmed pesticide treatment to simultaneously reduce the insecticide selection pressure and environmental pollution. In this context, here we present a review on the difficulties of potato pest control using as a case study the resistance of CPB to pyrethroids.