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The influence of permethrin-impregnated bednets and mass drug administration on the incidence of Plasmodium falciparum malaria in children in Sabah, Malaysia

Hii JL, Vun YS, Chin KF, Chua R, Tambakau S, Binisol ES, et al.

Med Vet Entomol, 1987 Oct;1(4):397-407.
PMID: 2979556

A small-scale trial was carried out in the Upper Kinabatangan district of Sabah, Malaysia, to determine the effect of using permethrin-impregnated bednets on malaria transmission. A total of 306 nylon bednets with cotton borders, impregnated at a dose estimated to have been 0.062 g permethrin/m2 of nylon netting, were distributed to 139 households in five villages. At the time of distributing bednets, mass drug administration with Fansidar plus primaquine was also administered to the human population to clear all parasitaemias due to Plasmodium falciparum Welch. In another village, for comparison, mass drug administration was the only intervention. After intervention measures in December 1984 and January 1985, the parasite rates in children declined in all villages during the first month, significantly more in the villages with impregnated bednets than in the control, thus proving that the nets had an impact on malaria. However, after about 2 months, parasite rates started to increase again. After 4-6 months, parasite rates in the villages with bednets approached the rate in the control village without nets. The increase in parasite rates was paralleled by a significant deterioration in the quality, physical condition and the degree of non-utilization of bednets. Entomological evaluation proved the efficacy of permethrin-impregnated nets for controlling Anopheles balabacensis Baisas and other anophelines. Bioassays (1 h exposure) of permethrin-impregnated bednets gave 100% mortality initially and 44-61% mortality after 85-106 days. Mosquito collections in treated bednets were significantly reduced for at least 217 days. The project failed to achieve prolonged suppression of malaria transmission for a combination of entomological, sociological and practical reasons which are discussed in relation to the objectives and implementation of future bednet studies.

Matched MeSH terms: Permethrin
Fulltext The impact of permethrin impregnated bednets on the malaria vector Anopheles maculatus (Diptera: Culicidae) in aboriginal villages of Pos Betau Pahang, Malaysia

Vythilingam I, Foo LC, Chiang GL, Chan ST, Eng KL, Mahadevan S, et al.

Southeast Asian J. Trop. Med. Public Health, 1995 Jun;26(2):354-8.
PMID: 8629075

The effect of permethrin impregnated bednets on Anopheles maculatus Theobald was studied in four villages in Pos Betau, Pahang, Malaysia from August 1990 to July 1992. Collections of mosquitos were carried out indoors and outdoors from 1900 to 0700 hours. All mosquitos were dissected for sporozoites and parity. In May 1991 two villages received bednets impregnated with permethrin at 0.5 g/m2 and two villages received placebo bednets. There was a significant difference in the sporozoite and parous rates between the treated and control villages after the distribution of bednets (p < 0.05). There was no significant difference in the bites/man/night of An. maculatus between the pre and post treatment periods in the control villages. However there was a significant difference in bites/man/night between pre and post treatment in the treated villages (p < 0.001).

Matched MeSH terms: Permethrin
Fulltext The effectiveness of permethrin-impregnated bed nets for malaria control in Kg. Ganoh, an Orang Asli area of Rompin District, Pahang

Amal NM, Yussof S

Med J Malaysia, 1996 Dec;51(4):491-3.
PMID: 10968043
Matched MeSH terms: Permethrin
The Efficacy of a Pyrethroid-impregnated Mattress Liner on Multiple International Strains of Cimex lectularius (Hemiptera: Cimicidae) and Cimex hemipterus (Hemiptera: Cimicidae)

Leong XY, Lee CY, Veera Singham G, Chong Shu-Chien A, Naylor R, Naylor A, et al.

J Econ Entomol, 2023 Feb 10;116(1):19-28.
PMID: 35640206 DOI: 10.1093/jee/toac067

Modern bed bugs are resistant to multiple insecticide classes, particularly the pyrethroids. The efficacy of pyrethroid-impregnated mattress liners marketed for bed bug management has been variable. This study evaluated the efficacy of a permethrin-impregnated mattress liner, ActiveGuard, against 24 bed bug strains, consisting of both Cimex hemipterus (F.) and Cimex lectularius L. A 'mat assay', employing an allethrin-impregnated mat, was used to establish the pyrethroid resistance profile of all strains. Three experiments were conducted to evaluate the effect of ActiveGuard exposure on bed bug knockdown: 1) exposing the bed bugs continuously on the liner for up to 24 d, 2) holding the bed bugs on the liner for either 4 or 6 h, and 3) placing a noninsecticide treated fabric above the liner with the bed bugs held continuously on top. Our results indicated that all modern strains (collected within the last 15 years during the current resurgence) were pyrethroid-resistant, although the magnitude of resistance was highly variable between strains. In the continuous exposure study, an incomplete knockdown was recorded for most modern bed bug strains, with some having no knockdown even up to 7 d of constant exposure. In the 4 or 6 h exposure study, the level of knockdown was reduced even further, and very few bed bugs were knocked down in the double fabric study. The results of this study indicate that pyrethroid-impregnated mattress liners are not likely to be effective in the management of most modern bed bug infestations involving either C. hemipterus or C. lectularius.

Matched MeSH terms: Permethrin
Fulltext Species composition and pyrethroid susceptibility status of Anopheles mosquitoes from two different locations in Malaysia

Ho LY, Zairi J

Trop Biomed, 2013 Mar;30(1):125-30.
PMID: 23665718 MyJurnal

A 14-months survey was carried out to identify the species composition of Anopheles mosquitoes from Kampung Bongor, Grik, Perak. Adding to that, a preliminary one month mosquito population screening was done at Kampung Tepin, Serian, Sarawak. Consequently, the insecticide susceptibility status of a pyrethroid was tested against two selected species of Anopheles collected from these two locations in Malaysia. A total of 4,497 Anopheles from 11 species were identified from collections in Kampung Bongor, whereas 2,654 An. letifer were collected from Kampung Tepin. The An. maculatus of Kampung Bongor and An. letifer of Kampung Tepin were then selected and tested using WHO standard diagnostic test kits and impregnated papers with 0.75% permethrin. The response values of KT50 and KT95 for An. maculatus were recorded at 28.09 minutes and 62.98 minutes respectively. Anopheles letifer recorded much slower response values of KT50 and KT95, which was at 35.09 minutes and 73.03 minutes respectively. Both An. maculatus and An. letifer showed 100% mortality after 24 hours holding period. The results indicate that both species were still susceptible to the tested pyrethroid. For effective vector control and resistance management, accurate and periodic insecticide resistance monitoring should be undertaken especially in rural areas with agricultural usage of insecticides.

Matched MeSH terms: Permethrin/pharmacology
Fulltext Resistance development and insecticide susceptibility in Culex quinquefasciatus against selection pressure of malathion and permethrin and its relationship to cross-resistance towards propoxur

Selvi S, Endah MA, Nazni WA, Lee HL, Azahari AH

Trop Biomed, 2005 Dec;22(2):103-13.
PMID: 16883275

To determine resistance level and characterize malathion and permethrin resistance in Culex quinquefasciatus, two methods were used namely: WHO procedures of larval bioassay to determine the susceptibility of lethal concentration (LC) and adult bioassay to determine the lethal time (LT) which are resistant to malathion and permethrin. These mosquito strains were bred in the Insectarium, Division of Medical Entomology, IMR. Thousands of late fourth instar larvae which survived the selection pressure to yield 50% mortality of malathion and permethrin were reared and colonies were established from adults that emerged. Larvae from these colonies were then subjected to the subsequent 10 generations in the test undertaken for malathion resistant strain (F61 - F70) and permethrin resistant strain (F54 - F63). Selection pressure at 50% - 70% mortality level was applied to the larvae of each successive generation. The rate of resistance development and resistance ratio (RR) were calculated by LC5 0 for larval bioassay and LT50 value for adult bioassay. The lab bred Cx. quinquefasciatus was used as a susceptible strain for comparison purpose. The adult bioassay test was carried out by using diagnostic dosages of malathion 5.0%, permethrin 0.75% and with propoxur 0.1%. All bioassay results were subjected to probit analysis. The results showed that LC5 0 for both malathion (F61 - F70) and permethrin (F54 - F63) resistant Cx. quinquefasciatus increased steadily to the subsequent 10 generations indicating a marked development of resistance. The adult female malathion resistant strain have developed high resistance level to malathion diagnostic dosage with resistance ratio 9.3 to 9.6 folds of resistance. Permethrin resistance ratio remained as 1.0 folds of resistance at every generation. It was obvious that malathion resistance developing at a higher rate in adult females compared to permethrin. Female adults exposed to 2 hours of exposure period for propoxur 0.1% showed presence of cross-resistance among the both strains of mosquitoes towards propoxur and it was indicated by 70%-100% mortality at 24 hours post-recovery period.

Matched MeSH terms: Permethrin/pharmacology*
Fulltext Rate of resistance development in wild Culex quinquefasciatus (Say) selected by malathion and permethrin

Nazni WA, Lee HL, Sa'diyah I

Southeast Asian J. Trop. Med. Public Health, 1998 Dec;29(4):849-55.
PMID: 10772575

Wild caught female Culex quinquefasciatus (Say) from Kuala Lumpur were blood fed and reared in the insectarium. The late third stage of the F1 larvae which survived the high selection pressure of malathion and permethrin were reared and colonies were established from adults that emerged. Larvae from these colonies were then subjected in the subsequent 9 generations to higher selection pressure. The rate of resistance development were measured by LC50 value of larval bioassay, LT50 value of adult bioassay and the frequency of the elevated esterase levels. In another set of experiments using the same batch of Culex mosquitos, the larvae were not exposed to any insecticides and the decrease in resistance rate was monitored in each subsequent 9 generations by using similar methods. The heterozygous standard laboratory strain was selected for susceptibility using the single raft sib-selection method. The result showed that the field collected F1 generation was 96.0 and 6.3 fold more resistant to malathion and permethrin, respectively. After selection for about 9 generations the resistance ratio to malathion and permethrin was 6.2 and 767.3 fold more compared to the LC50 values of F1 generations, respectively. Esterase in F1 larvae was 6.0 fold more than the standard laboratory strain.

Matched MeSH terms: Permethrin
Fulltext Quantitative proteomics analysis of permethrin and temephos-resistant Ae. aegypti revealed diverse differentially expressed proteins associated with insecticide resistance from Penang Island, Malaysia

Shettima A, Ishak IH, Lau B, Abu Hasan H, Miswan N, Othman N

PLoS Negl Trop Dis, 2023 Sep;17(9):e0011604.
PMID: 37721966 DOI: 10.1371/journal.pntd.0011604

Synthetic insecticides are the primary vector control method used globally. However, the widespread use of insecticides is a major cause of insecticide-resistance in mosquitoes. Hence, this study aimed at elucidating permethrin and temephos-resistant protein expression profiles in Ae. aegypti using quantitative proteomics. In this study, we evaluated the susceptibility of Ae. aegypti from Penang Island dengue hotspot and non-hotspot against 0.75% permethrin and 31.25 mg/l temephos using WHO bioassay method. Protein extracts from the mosquitoes were then analysed using LC-ESI-MS/MS for protein identification and quantification via label-free quantitative proteomics (LFQ). Next, Perseus 1.6.14.0 statistical software was used to perform differential protein expression analysis using ANOVA and Student's t-test. The t-test selected proteins with≥2.0-fold change (FC) and ≥2 unique peptides for gene expression validation via qPCR. Finally, STRING software was used for functional ontology enrichment and protein-protein interactions (PPI). The WHO bioassay showed resistance with 28% and 53% mortalities in adult mosquitoes exposed to permethrin from the hotspot and non-hotspot areas. Meanwhile, the susceptibility of Ae. aegypti larvae revealed high resistance to temephos in hotspot and non-hotspot regions with 80% and 91% mortalities. The LFQ analyses revealed 501 and 557 (q-value <0.05) differentially expressed proteins in adults and larvae Ae. aegypti. The t-test showed 114 upregulated and 74 downregulated proteins in adult resistant versus laboratory strains exposed to permethrin. Meanwhile, 13 upregulated and 105 downregulated proteins were observed in larvae resistant versus laboratory strains exposed to temephos. The t-test revealed the upregulation of sodium/potassium-dependent ATPase β2 in adult permethrin resistant strain, H15 domain-containing protein, 60S ribosomal protein, and PB protein in larvae temephos resistant strain. The downregulation of troponin I, enolase phosphatase E1, glucosidase 2β was observed in adult permethrin resistant strain and tubulin β chain in larvae temephos resistant strain. Furthermore, the gene expression by qPCR revealed similar gene expression patterns in the above eight differentially expressed proteins. The PPI of differentially expressed proteins showed a p-value at <1.0 x 10-16 in permethrin and temephos resistant Ae. aegypti. Significantly enriched pathways in differentially expressed proteins revealed metabolic pathways, oxidative phosphorylation, carbon metabolism, biosynthesis of amino acids, glycolysis, and citrate cycle. In conclusion, this study has shown differentially expressed proteins and highlighted upregulated and downregulated proteins associated with insecticide resistance in Ae. aegypti. The validated differentially expressed proteins merit further investigation as a potential protein marker to monitor and predict insecticide resistance in field Ae. aegypti. The LC-MS/MS data were submitted into the MASSIVE database with identifier no: MSV000089259.

Matched MeSH terms: Permethrin/pharmacology
Fulltext Pyrethroid resistance status of Aedes (Stegomyia) aegypti (Linneaus) from dengue endemic areas in Peninsular Malaysia

Rosilawati, R., Lee, H.L., Nazni, W.A., Nurulhusna, A.H., Roziah, A., Khairul Asuad, M., et al.

International Medical Journal Malaysia, 2017;16(2):73-78.
MyJurnal

Vector control is still the principal method to control dengue and chemical insecticides, especially the
pyrethroids such as permethrin are the forerunners of mosquito control agent. Intensive and extensive use
of pyrethroids often result in resistance, thereby hampering control efforts. The present study was
conducted to evaluate the susceptible status of Aedes aegypti, the primary vector of dengue against
permethrin. A nationwide mosquito sampling via ovitrapping was conducted in 12 dengue hotspots across 5
states in Peninsular Malaysia. Field collected Aedes eggs were hatched and reared until L3 larval and further
identified it species. Adult F0 Aedes aegypti were reared until F1 progeny and the female were used in
adult assay, performed according to World Health Organization (WHO) protocol as to determine the
resistance level. The laboratory strain maintained for more than 1000 generations that were susceptible to
permethrin served as the control strain. Evaluation of resistance ratio was assessed by comparing the
knockdown rate with laboratory susceptible strain. In this present study, 70% ofAe. aegypti population from
dengue hotspots was highly resistance to permethrin. The study clearly demonstrated that widespread of
permethrin resistant Ae. aegypti in Malaysian mosquito’s population, indicating the need of implementing
an efficient pyrethroid resistance management.

Matched MeSH terms: Permethrin
Fulltext Profiling Insecticide Susceptibility of Aedes Albopictus From Hot Springs in Selangor, Malaysia

Wan-Norafikah O, Hasani NAH, Nabila AB, Najibah I, Nurjuani AHH, Masliana M, et al.

J Am Mosq Control Assoc, 2023 Sep 01;39(3):183-191.
PMID: 37796735 DOI: 10.2987/23-7125

The present study establishes insecticide susceptibility profiles of Aedes albopictus adult populations from 4 hot springs in Selangor, Malaysia, against 7 pyrethroids through an adult mosquito susceptibility bioassay. All Ae. albopictus populations were subjected to a 1-h exposure to each pyrethroid following the World Health Organization. The mortalities were recorded at 60 min of exposure to bifenthrin, 30 min for other pyrethroids, and 24 h posttreatment for all pyrethroids. Complete mortalities were observed upon exposures to the pyrethroids under 60 min and at 24 h posttreatment, excluding permethrin 0.25%, alpha-cypermethrin 0.05%, and bifenthrin 0.2%. These findings indicated that permethrin, deltamethrin, lambda-cyhalothrin, cyfluthrin, and etofenprox possess the recommended pyrethroid adulticide active ingredients that could be applied in vector control programs at these hot springs in the future. Nevertheless, the application of pyrethroids should be carefully monitored in rotation with other insecticide classes, including organophosphates and carbamates to avoid the development of insecticide resistance among mosquito vectors towards all insecticides. Although there were no reported cases of Aedes-borne pathogens at these hot springs to date, the current study results could still assist the Malaysian health authorities in determining approaches to control Aedes populations in these hot springs, if required in the future.

Matched MeSH terms: Permethrin
Permethrin resistance in Aedes albopictus (Diptera: Culicidae) and associated fitness costs

Chan HH, Zairi J

J Med Entomol, 2013 Mar;50(2):362-70.
PMID: 23540125

Insecticide resistance has become a serious issue in vector management programs. Information on insecticidal resistance and its associated mechanisms is important for successful insecticide resistance management. The selection of a colony of permethrin-resistant Aedes albopictus (Skuse) (Diptera: Culicidae), originating from Penang Island, Malaysia, yielded high larval-specific resistance to permethrin and cross-resistance to deltamethrin. Synergism assays showed that the major mechanism underlying this resistance involves cytochrome P450 monooxygenase. The resistance is autosomal, polygenically inherited and incompletely dominant (D = 0.26). Resistant larvae were reared under different conditions to assess the fitness costs. Under high larval density, larval development time of the resistant SGI strain was significantly longer than the susceptible VCRU strain. In both high- and low-density conditions SGI showed a lower rate of emergence and survival compared with the VCRU strain. Resistant larvae were more susceptible to predation by Toxorhynchites splendens (Wiedemann) (Diptera: Culicidae) larvae. The body size of SGI females reared under high-density conditions was larger compared with females of the susceptible strain. SGI females survived longer when starved than did VCRU females. The energy reserve upon eclosion was positively correlated with the size of the adults.

Matched MeSH terms: Permethrin/pharmacology*
Pediculosis among rural school children in Kelang, Selangor, Malaysia and their susceptibility to malathion, carbaryl, perigen and kerosene

Sinniah B, Shekhar C, Ramphal L, Senan P

J R Soc Health, 1984 Jun;104(3):114-5, 118.
PMID: 6431096
Matched MeSH terms: Permethrin
Observations of human behavior influencing the use of insecticide-impregnated bednets to control malaria in Sabah, Malaysia

Leake DW, Hii JL

Asia Pac J Public Health, 1994;7(2):92-7.
PMID: 7946656

Observational and survey methodologies were used to probe human behavioral factors influencing the use of insecticide-impregnated bednets to control malaria in rural Sabah, Malaysia. One aim was to investigate why a field trial of such nets in an interior area yielded disappointing results. A second aim was to gather baseline data prior to a field trial proposed for a coastal area. Interior villagers reported a significantly higher net usage rate than that observed directly, suggesting that subject self-reports need to be validated in some way. The poor results of the interior field trial appeared related to reluctance to regularly use nets, which were not in wide use previously. Prospects for reducing malaria transmission through bednets appeared better for the coastal area since nearly half of observed villagers were sleeping in them. However, significantly more coastal than interior villagers were observed watching television at night, an activity that may increase malaria risk by keeping villagers awake and out of bednets.

Matched MeSH terms: Permethrin
Multiple Mechanisms Conferring Broad-Spectrum Insecticide Resistance in the Tropical Bed Bug (Hemiptera: Cimicidae)

Dang K, Doggett SL, Leong XY, Veera Singham G, Lee CY

J Econ Entomol, 2021 12 06;114(6):2473-2484.
PMID: 34693975 DOI: 10.1093/jee/toab205

The modern resurgence of the common (Cimex lectularius L.) and tropical bed bugs (C. hemipterus [F.]) is thought to be primarily due to insecticide resistance. While there are many reports on insecticide resistance mechanisms in C. lectularius, such information in C. hemipterus is limited. We examined dichloro-diphenyl-trichloroethane (DDT), malathion, deltamethrin, permethrin, lambda-cyhalothrin resistance, and the underlying mechanisms in several C. hemipterus strains (Australia: Queensland [QLD-AU]; Malaysia: Kuala Lumpur [KL-MY], Tanjung Tokong [TT-MY], Christian [CH-MY], and Green Lane [GL-MY]). We used a surface contact method, synergism studies (utilizing piperonyl butoxide [PBO], S,S,S-tributyl phosphorotrithioate [DEF], and diethyl maleate [DEM]), and molecular detection of kdr mutations. Results demonstrated that all C. hemipterus strains possessed high resistance to DDT and the pyrethroids and moderate to high resistance to malathion. Synergism studies showed that deltamethrin resistance in all strains was significantly (P < 0.05) inhibited by PBO. In contrast, deltamethrin resistance was not affected in DEF or DEM. Similar findings were found with lambda-cyhalothrin resistance. Malathion resistance was significantly (P < 0.05) reduced by DEF in all strains. Resistance to DDT was not affected by DEM in all strains. Multiple kdr mutations (M918I, D953G, and L1014F) were detected by molecular analyses. TT-MY strain was found with individuals possessing three kdr mutation combinations; D953G + L1014F (homozygous susceptible: M918), M918I + D953G + L1014F (heterozygous resistant: I918), and M918I + D953G + L1014F (homozygous resistant: I918). Individuals with M918I + D953G + L1014F (homozygous resistant: I918) survived longer on deltamethrin (>12 h) than those (≤1 h) with other combinations. M918I + L1014F mutations most likely conferred super-kdr characteristic toward pyrethroids and DDT in C. hemipterus.

Matched MeSH terms: Permethrin
Mosquito Control Workers in Malaysia: Is Lifetime Occupational Pesticide Exposure Associated With Poorer Neurobehavioral Performance?

Yusof MZ, Cherrie JW, Samsuddin N, Semple S

Ann Work Expo Health, 2022 10 11;66(8):1044-1055.
PMID: 35661855 DOI: 10.1093/annweh/wxac038

BACKGROUND: Use of pesticides has been linked to neurobehavioral deficits among exposed workers. In Malaysia, organophosphate and pyrethroid pesticides are commonly used to control mosquito-borne diseases.
OBJECTIVES: This study aims to assess workers' lifetime occupational pesticide exposure and examine the relationship with neurobehavioral health.
METHODS: A cross-sectional study was conducted on 158 pesticide-exposed and 176 non-exposed workers. To collect historical exposure and job tasks, a questionnaire and an occupational history interview were used. Pesticide exposure was measured in a subgroup of workers via inhalation and skin contact. The total pesticide intake of each worker was assessed using inhalation and dermal exposure models. CANTAB® computerised neurobehavioral performance assessments were used.
RESULTS: The participants' mean age was 31 (8) years. Pirimiphos-methyl (median = 0.569 mg/m3, Interquartile range [IQR] = 0.151, 0.574) and permethrin (median = 0.136 mg/m3, IQR = 0.116, 0.157) had the highest measured personal inhalation concentrations during thermal spraying. The estimated total lifetime pesticide intake for exposed workers ranged from 0.006 g to 12800 g (median = 379 g and IQR = 131, 794 g). Dermal exposure was the predominant route of pesticide intake for all workers. Compared to controls, workers with high lifetime pesticide intake had lower Match to Sample Visual (adjusted B = -1.4, 95% Confidence Interval (CI) = -2.6, 0.1), Spatial Recognition Memory (adjusted B = -3.3, 95% CI = -5.8, 0.8), Spatial Span (SSP) (adjusted B = -0.6, 95% CI = -0.9, 0.3) scores. Workers with low pesticide intake performed worse than controls (adjusted B = -0.5, 95% CI = -0.8, -0.2) in the SSP test, but scored higher in the Motor Screening test (adjusted B = 0.9, 95% CI = 0.1, 1.6). Higher Paired Associates Learning test scores were observed among higher (adjusted B = 7.4, 95% CI = 2.3, 12.4) and lower (adjusted B = 8.1, 95% CI = 3, 13.2) pesticide intake groups. There was no significant difference between the Reaction Time and Pattern Recognition Memory tests with lifetime pesticide intake after adjusting for confounders.
CONCLUSION: Pesticide exposure has been linked to poorer neurobehavioral performance. As dermal exposure accounts for a major fraction of total intake, pesticide prevention should focus on limiting dermal exposure.

Matched MeSH terms: Permethrin
Managing wastes as green resources: cigarette butt-synthesized pesticides are highly toxic to malaria vectors with little impact on predatory copepods

Murugan K, Suresh U, Panneerselvam C, Rajaganesh R, Roni M, Aziz AT, et al.

Environ Sci Pollut Res Int, 2018 Apr;25(11):10456-10470.
PMID: 28913784 DOI: 10.1007/s11356-017-0074-3

The development of novel mosquito control tools is a key prerequisite to build effective and reliable Integrated Vector Management strategies. Here, we proposed a novel method using cigarette butts for the synthesis of Ag nanostructures toxic to young instars of the malaria vector Anopheles stephensi, chloroquine (CQ)-resistant malaria parasites Plasmodium falciparum and microbial pathogens. The non-target impact of these nanomaterials in the aquatic environment was evaluated testing them at sub-lethal doses on the predatory copepod Mesocyclops aspericornis. Cigarette butt-synthesized Ag nanostructures were characterized by UV-vis and FTIR spectroscopy, as well as by EDX, SEM and XRD analyses. Low doses of cigarette butt extracts (with and without tobacco) showed larvicidal and pupicidal toxicity on An. stephensi. The LC50 of cigarette butt-synthesized Ag nanostructures ranged from 4.505 ppm (I instar larvae) to 8.070 ppm (pupae) using smoked cigarette butts with tobacco, and from 3.571 (I instar larvae) to 6.143 ppm (pupae) using unsmoked cigarette butts without tobacco. Smoke toxicity experiments conducted against adults showed that unsmoked cigarette butts-based coils led to mortality comparable to permethrin-based positive control (84.2 and 91.2%, respectively). A single treatment with cigarette butts extracts and Ag nanostructures significantly reduced egg hatchability of An. stephensi. Furthermore, the antiplasmodial activity of cigarette butt extracts (with and without tobacco) and synthesized Ag nanostructures was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. The lowest IC50 values were achieved by cigarette butt extracts without tobacco, they were 54.63 μg/ml (CQ-s) and 63.26 μg/ml (CQ-r); while Ag nanostructure IC50 values were 72.13 μg/ml (CQ-s) and 77.33 μg/ml (CQ-r). In MIC assays, low doses of the Ag nanostructures inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi. Finally, the predation efficiency of copepod M. aspericornis towards larvae of An. stephensi did not decrease in a nanoparticle-contaminated environment, if compared to control predation assays. Overall, the present research would suggest that an abundant hazardous waste, such as cigarette butts, can be turned to an important resource for nanosynthesis of highly effective antiplasmodials and insecticides.

Matched MeSH terms: Permethrin
Fulltext Insecticide resistance development in Culex quinquefasciatus (Say), Aedes aegypti (L.) and Aedes albopictus (Skuse) larvae against malathion, permethrin and temephos

Hamdan H, Sofian-Azirun M, Nazni W, Lee HL

Trop Biomed, 2005 Jun;22(1):45-52.
PMID: 16880753

Laboratory-bred females of Culex quinquefasciatus, Aedes aegypti and Aedes albopictus from the insectarium, Unit of Medical Entomology, Institute for Medical Research were used in the experiment. The late third stage of the F0 larvae which survived the high selection pressure of malathion, permethrin and temephos were reared and colonies were established from adults that emerged. Cx. quinquefasciatus larvae were subjected to selection by malathion and permethrin for 40 generations, Ae. aegypti larvae to malathion, permethrin and temephos for 32 generations and Ae. albopictus larvae were selected against malathion and permethrin for 32 generations and 20 generations against temephos. The rate of resistance development was measured by LC50 value. Cx. quinquefasciatus larvae developed higher resistance to malathion and permethrin compared to Ae. aegypti and Ae. albopictus. On the whole, permethrin resistance developed at a faster rate than malathion and temephos.

Matched MeSH terms: Permethrin/pharmacology
Functional Role of Tyr12 in the Catalytic Activity of Novel Zeta-like Glutathione S-transferase from Acidovorax sp. KKS102

Shehu D, Alias Z

Protein J, 2018 06;37(3):261-269.
PMID: 29779193 DOI: 10.1007/s10930-018-9774-x

Glutathione S-transferases (GSTs) are a family of enzymes that function in the detoxification of variety of electrophilic substrates. In the present work, we report a novel zeta-like GST (designated as KKSG9) from the biphenyl/polychlorobiphenyl degrading organism Acidovorax sp. KKS102. KKSG9 possessed low sequence similarity but similar biochemical properties to zeta class GSTs. Functional analysis showed that the enzyme exhibits wider substrate specificity compared to most zeta class GSTs by reacting with 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrobenzyl chloride (NBC), ethacrynic acid (EA), hydrogen peroxide, and cumene hydroperoxide. The enzyme also displayed dehalogenation function against dichloroacetate, permethrin, and dieldrin. The functional role of Tyr12 was also investigated by site-directed mutagenesis. The mutant (Y12C) displayed low catalytic activity and dehalogenation function against all the substrates when compared with the wild type. Kinetic analysis using NBC and GSH as substrates showed that the mutant (Y12C) displayed a higher affinity for NBC when compared with the wild type, however, no significant change in GSH affinity was observed. These findings suggest that the presence of tyrosine residue in the motif might represent an evolutionary trend toward improving the catalytic activity of the enzyme. The enzyme as well could be useful in the bioremediation of various types of organochlorine pollutants.

Matched MeSH terms: Permethrin
Evaluation of pyrethroids lambda-cyhalothrin, deltamethrin and permethrin against Aedes albopictus in the laboratory

Sulaiman S, Omar B, Jeffery J, Busparani V

J Am Mosq Control Assoc, 1991 Jun;7(2):322-3.
PMID: 1895095

Three pyrethroids were evaluated in the laboratory against Aedes albopictus females by exposure to insecticide impregnated papers, and to 4th instar Ae. albopictus larvae as insecticide solutions. Lambda-cyhalothrin was found to be the most effective pyrethroid when tested against Aedes albopictus adult females and larvae compared with that of deltamethrin and permethrin.

Matched MeSH terms: Permethrin
Efficacy of three pyrethroids against Leptotrombidium fletcheri (Acari: Trombiculidae) infected and noninfected with scrub typhus

Ho TM, Ismail S

J Med Entomol, 1991 Nov;28(6):776-9.
PMID: 1770512

Toxicities of three pyrethroids, d-phenothrin, decamethrin, and permethrin, were evaluated in the laboratory against Leptotrombidium fletcheri (Womersley & Heaslip). The susceptibilities between populations of the species infected and noninfected with scrub typhus were investigated. The three pesticides exhibited different toxicities to the chiggers. D- phenothrin was the most toxic, followed by decamethrin, then permethrin. There were no significant differences between susceptibilities of the infected and noninfected populations. Log-probit regression lines indicated that the species was most sensitive to increasing concentrations of d-phenothrin and least sensitive to permethrin. The results show that the three pesticides are potential candidates for chemical control of L. fletcheri. It may be possible in the future to conduct similar bioassays only with the noninfected population, thus reducing risk of infection to workers conducting the bioassays. Similarly, there may not be a need to separate field-collected chiggers into the two populations before performing the bioassays.

Matched MeSH terms: Permethrin

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