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Pesticide Biochemistry and Physiology Jan 2024Insecticide resistance is both economically important and evolutionarily interesting phenomenon. Identification of the mutations responsible for resistance allows for...
Insecticide resistance is both economically important and evolutionarily interesting phenomenon. Identification of the mutations responsible for resistance allows for highly sensitive resistance monitoring and allows tools to study the forces (population genetics, fitness costs, etc.) that shape the evolution of resistance. Genes coding for insecticide targets have many well-characterized mutations, but the mutations responsible for enhanced detoxification have proven difficult to identify. We employed multiple strategies to identify the mutations responsible for the extraordinarily high permethrin resistance in the KS17-R strain of house fly (Musca domestica): insecticide synergist assays, linkage analysis, bulk segregant analyses (BSA), transcriptomics and long read DNA (Nanopore) sequencing. The >85,100-fold resistance in KS17-R was partially suppressed by the insecticide synergists piperonyl butoxide and S,S,S-tributylphosphorothionate, but not by diethyl maleate nor by injection. This suggests the involvement of target site insensitivity, CYP-mediated resistance, possibly hydrolase mediated resistance and potentially other unknown factors. Linkage analysis identified chromosomes 1, 2, 3 and 5 as having a role in resistance. BSA mapped resistance loci on chromosomes 3 and 5. The locus on chromosome 3 was centered on the voltage sensitive sodium channel. The locus on chromosome 5 was associated with a duplication of multiple detoxification genes. Transcriptomic analyses and long read DNA sequencing revealed overexpressed CYPs and esterases and identified a complex set of structural variants at the chromosome 5 locus.
Topics: Animals; Insecticides; Houseflies; Permethrin; Insecticide Resistance; Cytochrome P-450 Enzyme System; Genomics; Pyrethrins
PubMed: 38225095
DOI: 10.1016/j.pestbp.2023.105752 -
PloS One 2023After a decade of successful control, malaria is on the rise again. The prevalence of malaria in Tanzania has increased from 7% in 2017 to 8% in 2022 and reached 18% in... (Randomized Controlled Trial)
Randomized Controlled Trial
Factors associated with malaria infection among children after distribution of PBO-pyrethroid synergist-treated nets and indoor residual spraying in north-western Tanzania.
BACKGROUND
After a decade of successful control, malaria is on the rise again. The prevalence of malaria in Tanzania has increased from 7% in 2017 to 8% in 2022 and reached 18% in Kagera region in the North West of Tanzania. Malaria vectors in Muleba district Kagera have high level of pyrethroid resistance. The aim of this paper is to explore factors associated with malaria infection prevalence in children aged 6 months to 14 years in Muleba, where Long Lasting Insecticidal Net (LLIN) combining a pyrethroid insecticide and synergist piperonyl butoxide (PBO) that counteract resistance in the mosquitoes, was first distributed under trial conditions in 2015.
METHODS
The trial was a community randomized control in which there were two malaria prevalence cross-sectional household surveys each year (June and December) from 2015 to 2017 in Muleba. In this study we conducted a secondary data analysis of the December surveys only. Multilevel Poisson regression analysis was used to assess factors associated with malaria infection.
RESULTS
A total of 10,941 children and 4,611 households were included in this study. Overall malaria prevalence was 35.8%, 53.3% and 54.4% in the year 2015, 2016 and 2017 respectively. Living in an area with standard LLIN as opposed to the novel PBO synergist LLIN, being a male child, above 5 years of age, living in a house with open eaves, living in house without IRS, having head of household with no formal education, lower socioeconomic status and survey year were associated with increased risk of malaria infection.
CONCLUSIONS
Using PBO LLIN reduced the risk of malaria infection. However, additional measures could further reduce malaria infection in areas of insecticide resistance such as housing improvement.
Topics: Child; Animals; Humans; Male; Pyrethrins; Tanzania; Cross-Sectional Studies; Mosquito Control; Insecticide-Treated Bednets; Insecticides; Malaria; Insecticide Resistance; Mosquito Vectors
PubMed: 38127909
DOI: 10.1371/journal.pone.0295800 -
Journal of Pesticide Science Nov 2023Four nitromethylene analogues of imidacloprid (CH-IMIs) having a 4,5-dimethylated (diMe) imidazolidine ring were stereospecifically synthesized to evaluate their...
Four nitromethylene analogues of imidacloprid (CH-IMIs) having a 4,5-dimethylated (diMe) imidazolidine ring were stereospecifically synthesized to evaluate their affinity for the nicotinic acetylcholine receptors of the housefly . Among the analogues, the 4,5-diMe analogue showed the highest receptor affinity (=0.39 nM). The insecticidal activity against of the synthesized compounds was also measured under synergistic and nonsynergistic conditions. Under nonsynergistic conditions, the insecticidal activity of the 4,5-diMe analogue was the highest. The order of the insecticidal potency of the four diMe-CH-IMIs (4,5->4,5-=4,5->4,5-diMe analogues) was the same as that of the receptor affinity. Piperonyl butoxide (PBO) did not synergize with the test compounds, but both PBO and NIA16388 applications strengthened the activity of analogues other than the 4,5-diMe analogue. This suggests that the configuration of the substituents on the imidazolidine ring should influence the metabolism process of CH-IMI in houseflies.
PubMed: 38090215
DOI: 10.1584/jpestics.D23-024 -
Scientific Reports Dec 2023Barrier bednets (BBnets), regular bednets with a vertical insecticidal panel to target mosquitoes above the bednet roof, where they are most active, have the potential...
Barrier bednets (BBnets), regular bednets with a vertical insecticidal panel to target mosquitoes above the bednet roof, where they are most active, have the potential to improve existing Insecticidal Treated Bednets (ITNs), by reducing the quantity of insecticide required per net, reducing the toxic risks to those using the net, potentially increasing insecticide choice. We evaluated the performance of PermaNet 3.0 (P3) and untreated (Ut) bed nets with and without pyrethroid and piperonyl butoxide roof barriers in killing pyrethroid-resistant and susceptible Anopheles gambiae, simultaneously video-recording mosquito flight tracks. Bioassay results showed that treated roof barriers, particularly the longitudinal P3 barrier (P3L) could be an effective addition to a bed net: P3 + P3L were consistently significantly more effective than the reference P3 bednet while performance of untreated nets could be raised to equal that of the reference P3 following the addition of a P3 barrier. The BBnet's potential to augment existing bednets and enhance their performance is considered.
Topics: Animals; Humans; Insecticides; Anopheles; Insecticide-Treated Bednets; Mosquito Control; Malaria; Pyrethrins; Insecticide Resistance
PubMed: 38086842
DOI: 10.1038/s41598-023-48499-2 -
Pesticide Biochemistry and Physiology Dec 2023Solenopsis invicta is a main issue in southern China and is causing significant damage to the local ecological environment. The extensive use of insecticides has...
Solenopsis invicta is a main issue in southern China and is causing significant damage to the local ecological environment. The extensive use of insecticides has resulted in the development of tolerance in S. invicta. In our study, ten S. invicta colonies from Sichuan Province exhibited varying degrees of tolerance against flonicamid, with LC values from 0.49 mg/L to 8.54 mg/L. The sensitivity of S. invicta to flonicamid significantly increased after treatment with the P450 enzyme inhibitor piperonyl butoxide (PBO). Additionally, the activity of P450 in S. invicta was significantly enhanced after being treated with flonicamid. Flonicamid induced the expression levels of CYP4aa1, CYP9e2, CYP4C1, and CYP6A14. The expression levels of these P450 genes were significantly higher in the tolerant colonies compared to the sensitive colonies, and the relative copy numbers of CYP6A14 in the tolerant colonies were 2.01-2.15 fold. RNAi feeding treatment effectively inhibited the expression of P450 genes, thereby reducing the tolerance of S. invicta against flonicamid. In addition, the overexpression of CYP6A14 in D. melanogaster resulted in reduced sensitivity to flonicamid. Our investigations revealed hydrophobic interactions between flonicamid and seven amino acid residues of CYP6A14, along with the formation of a hydrogen bond between Glu306 and flonicamid. Our findings suggest that flonicamid can effectively control S. invicta and P450 plays a pivotal role in the tolerance of S. invicta against flonicamid. The overexpression of CYP6A14 also increased tolerance to flonicamid.
Topics: Animals; Fire Ants; Drosophila melanogaster; Ants; Insecticides
PubMed: 38072526
DOI: 10.1016/j.pestbp.2023.105651 -
Journal of Agricultural and Food... Dec 2023The citrus red mite has developed strong resistance to acaricides. Cytochrome P450 monooxygenases (P450s) can detoxify pesticides and are involved in pesticide...
The citrus red mite has developed strong resistance to acaricides. Cytochrome P450 monooxygenases (P450s) can detoxify pesticides and are involved in pesticide resistance in many insects. Here, a pyridaben-resistant strain showed cross-resistance to cyenopyrafen, bifenazate, fenpyroximate, and tolfenpyrad. Piperonyl butoxide, a P450 inhibitor, significantly increased the toxicity of pyridaben to resistant (Pyr_Rs) and susceptible (Pyr_Control) strains. P450 activity was significantly higher in Pyr_Rs than in Pyr_Control. Analyses of RNA-Seq data identified a P450 gene () that is potentially involved in pyridaben resistance. Consistently, it was up-regulated in two field-derived resistant populations (CQ_WZ and CQ_TN). RNA interference-mediated knockdown of significantly decreased the pyridaben resistance in . Transgenic expressing showed increased pyridaben resistance. Molecular docking analysis showed that pyridaben could bind to several amino acids at substrate recognition sites in CYP4CL2. These findings shed light on P450-mediated pyridaben resistance in pest mites.
Topics: Animals; Mites; Citrus; Drosophila melanogaster; Molecular Docking Simulation; Tetranychidae; Acaricides; Cytochrome P-450 Enzyme System
PubMed: 38048568
DOI: 10.1021/acs.jafc.3c06921 -
Frontiers in Plant Science 2023Crabgrass () is a common malignant weed in corn fields in China. Recently, the acetolactate synthase (ALS) inhibitor, nicosulfuron, has shown decreasing efficacy against...
Crabgrass () is a common malignant weed in corn fields in China. Recently, the acetolactate synthase (ALS) inhibitor, nicosulfuron, has shown decreasing efficacy against crabgrass. In order to elucidate the molecular basis of resistance to nicosulfuron in crabgrass, we conducted bioassays, combined with gene sequence analysis, relative expression and relative copy number analysis, to characterize resistance in crabgrass populations collected from Beijing, Heilongjiang, Jilin and Anhui provinces. Whole-plant dose-response results indicated that only population collected in Heilongjiang province (HLJ) had developed low level of resistance to nicosulfuron compared with the sensitive population (SD22). No known resistant mutation of gene was found in HLJ population. The real-time fluorescence quantitative PCR results showed that the gene copy number did not differ significantly between the HLJ and SD22 populations. However, the gene expression in the HLJ was 2.07-fold higher than that of the SD22 population at 24 h after treatment with nicosulfuron. Pretreatment with the cytochrome P450 (CYP450) inhibitor malathion, piperonyl butoxide (PBO), and the glutathione S-transferase (GST) inhibitor 4-Chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) all partially reversed HLJ resistance. Among them, the synergistic effect of PBO and nicosulfuron is the most significant. This is the first report of resistance to nicosulfuron in crabgrass through gene overexpression and possible metabolic resistance.
PubMed: 38046608
DOI: 10.3389/fpls.2023.1290600 -
Archives of Public Health = Archives... Nov 2023Pyrethroid-PBO nets have demonstrated improved impact against clinical malaria transmitted by pyrethroid resistant mosquito vectors and are being scaled up across...
Community evaluation of the physical and insecticidal durability of DuraNet® Plus, an alpha-cypermethrin and piperonyl butoxide incorporated mosquito net: protocol for a multi-country study in West, Central and East Africa.
BACKGROUND
Pyrethroid-PBO nets have demonstrated improved impact against clinical malaria transmitted by pyrethroid resistant mosquito vectors and are being scaled up across Africa. However very little is known about their physical and insecticidal durability under operational conditions. This study will investigate the attrition, fabric integrity, insecticide content and bioefficacy of DuraNet® Plus, a new WHO prequalified alphacypermethrin and PBO incorporated net developed by Shobikaa Impex Private Limited over 3 years of field use in communities in Benin, Cameroon and Tanzania.
METHODS
The study will be conducted in parallel in selected villages in Zakpota District in Benin, Mbalmayo, District in Cameroon and Muheza District in Tanzania. In each country, ~ 1800 households will be recruited and randomised to receive DuraNet® Plus or DuraNet® (a WHO prequalified alphacypermethrin-only ITN). Follow up surveys will be performed at 1 month post distribution to investigate adverse events and subsequently every 6-12 months to assess ITN attrition and fabric integrity following standard WHO procedures. A second cohort of nets will be withdrawn every 6-12 months and assessed for alpha-cypermethrin and PBO content and for entomological activity in laboratory bioassays (cone bioassays and tunnel tests). Alpha-cypermethrin bioefficacy will be monitored using the susceptible Anopheles gambiae Kisumu strain in cone bioassays while PBO bioefficacy will be monitored using pyrethroid resistant strains with overexpressed P450 enzymes in tunnel tests to determine the proportion of efficacious nets (≥ 95% knockdown, ≥ 80% mortality or ≥ 90% blood feeding inhibition in tunnels) at each time point. Nets withdrawn at 12, 24 and 36 months from each country will also be tested in experimental hut trials against wild free-flying pyrethroid resistant Anopheles gambiae sl in Côvè Benin to investigate the superiority of DuraNet® Plus over DuraNet® at each time point under semi field conditions.
CONCLUSION
This large-scale multi country trial will provide useful information on the durability of a pyrethroid-PBO net (DuraNet® Plus) in 3 different regions in sub-Saharan Africa. The methods proposed for bioefficacy testing could also contribute towards the development of new standardised guidelines for monitoring the insecticidal efficacy of pyrethroid-PBO nets under operational conditions.
PubMed: 37986195
DOI: 10.1186/s13690-023-01217-w -
Pesticide Biochemistry and Physiology Nov 2023Tuta absoluta (Meyrick) is an invasive tomato pest that occurs worldwide, including Iran. This study investigates the occurrence of resistance to indoxacarb, an...
Tuta absoluta (Meyrick) is an invasive tomato pest that occurs worldwide, including Iran. This study investigates the occurrence of resistance to indoxacarb, an oxadiazine insecticide, and the underlying mechanisms in Iranian populations of T. absoluta. Bioassays were performed on second-instar larvae using indoxacarb alone and in combination with three synergists: Piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP). The activities of the main detoxification enzymes, including glutathione S-transferases (GST), general carboxylesterases (CarEs), and P450 monooxygenases (P450s), were evaluated. In addition, the presence of known amino acid substitutions in the IV segment 6 domain of the T. absoluta sodium channel was investigated. The results showed that resistance rates to indoxacarb in Iranian populations ranged from 2.37- to 14.45-fold. However, pretreatment with synergists did not significantly increase the toxicity of indoxacarb. Enzyme assays showed that Ardabil (Ar) and Kerman (Kr) populations had the highest CarEs activity, while Ar population showed the highest P450 activity. However, the observed increases in enzyme activities were <2-fold. Two indoxacarb resistance mutations, F1845Y and V1848I, were detected. Apart from a significant and positive correlation between LC50 values of indoxacarb and thiocyclam hydrogen oxalate, no cross-resistance between indoxacarb and other insecticides was detected. Overall, these results suggest that populations of T. absoluta in Iran have developed resistance to indoxacarb, primarily through changes at the target site.
Topics: Animals; Lepidoptera; Iran; Insecticide Resistance; Insecticides; Larva; Carboxylic Ester Hydrolases; Moths
PubMed: 37945235
DOI: 10.1016/j.pestbp.2023.105633 -
Parasitology Research Dec 2023Numerous biting and nuisance insects are a noted cause of discomfort and stress to horses. Pyrethrins and pyrethroids have been used for many years in numerous...
Efficacy of topical administration of prallethrin-permethrin-piperonyl butoxide (Bronco® Equine Fly Spray) for the treatment and control of flies and other nuisance insects of horses.
Numerous biting and nuisance insects are a noted cause of discomfort and stress to horses. Pyrethrins and pyrethroids have been used for many years in numerous formulations for the control of insect pests in animals, humans and environment. There are, however, few studies reporting their field efficacy in horses. The aim of the present study was to evaluate the repellent activity of a spray formulation based on prallethrin and permethrin synergized with piperonyl butoxide (BRONCO® Equine Fly Spray, Farnam Companies, Inc., USA) against annoying and harmful insects for horses in field conditions. Nine horses of mixed breed were divided into 2 groups (treatment and control). Pre-treatment insect counts were compared to daily counts for 4 days post-treatment (pt). One minute after the administration of the product (day 0), all the horses were negative for the presence of insects. All counts up to the 6-h pt check remained negative for Hippobosca equina, tabanid flies and Simulium spp., showing 100% efficacy. This remained above 90% throughout the study. For the H. equina, the repellent efficacy remained > 99.7% for all 4 days pt, for tabanid flies > 93.3% and for Simulium spp. > 97.4%. The efficacy against Musca spp. decreased from 82.2% at day 0 to 62.2% at day 3. Treatment was well-tolerated. In conclusion, despite the low number of tested horses, Bronco® has demonstrated high insecticide and repellent efficacy and a good persistence, maintained for up to 4 days post-treatment, against the most common species of insects harmful for horses.
Topics: Humans; Horses; Animals; Permethrin; Piperonyl Butoxide; Pyrethrins; Insecticides; Muscidae; Insect Repellents; Simuliidae; Administration, Topical
PubMed: 37921904
DOI: 10.1007/s00436-023-08004-0