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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
Effectiveness of soap formulations containing deet and permethrin as personal protection against outdoor mosquitoes in Malaysia

Yap HH

J Am Mosq Control Assoc, 1986 Mar;2(1):63-7.
PMID: 2906963

Two soap formulations, both containing 20% deet and one each containing permethrin at 0.5 and 1.0%, respectively, were applied to exposed arms and legs of volunteers as personal protection against outdoor human biting mosquitoes in six locations on Penang Island, Malaysia. The predominant mosquito species collected from these locations were Aedes albopictus, Mansonia uniformis, Culex gelidus, Anopheles lesteri and Armigeres subalbatus. Efficacy and residual effects up to 4 hours indicated good protection against these species. Reduction in mosquito landing-biting rates in treated groups ranged from 83.8 to 100.0%. At high densities, small percentages of Ma. uniformis and An. lesteri landed or bit on treated skin. Use of the soap formulations in terms of cost-effectiveness, safety and overall vector control strategy for some tropical diseases is discussed.

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
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
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
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
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
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
Fulltext Dechlorination of polychlorobiphenyl degradation metabolites by a recombinant glutathione S-transferase from Acidovorax sp. KKS102

Shehu D, Alias Z

FEBS Open Bio, 2019 03;9(3):408-419.
PMID: 30868049 DOI: 10.1002/2211-5463.12405

A glutathione S-transferase (GST) with a potential dehalogenation function against various organochlorine substrates was identified from a polychlorobiphenyl (PCB)-degrading organism, Acidovorax sp. KKS102. A homolog of the gene BphK (biphenyl upper pathway K), named BphK-KKS, was cloned, purified and biochemically characterized. Bioinformatic analysis indicated several conserved amino acids that participated in the catalytic activity of the enzyme, and site-directed mutagenesis of these conserved amino acids revealed their importance in the enzyme's catalytic activity. The wild-type and mutant (C10F, K107T and A180P) recombinant proteins displayed wider substrate specificity. The wild-type recombinant GST reacted towards 1-chloro-2,4-dinitrobenzene (CDNB), ethacrynic acid, hydrogen peroxide and cumene hydroperoxide. The mutated recombinant proteins, however, showed significant variation in specific activities towards the substrates. A combination of a molecular docking study and a chloride ion detection assay showed potential interaction with and a dechlorination function against 2-, 3- and 4-chlorobenzoates (metabolites generated during PCB biodegradation) in addition to some organochlorine pesticides (dichlorodiphenyltrichloroethane, endosulfan and permethrin). It was demonstrated that the behavior of the dechlorinating activities varied among the wild-type and mutant recombinant proteins. Kinetic studies (using CDNB and glutathione) showed that the kinetic parameters Km, Vmax, Kcat and Km/Kcat were all affected by the mutations. While C10F and A180P mutants displayed an increase in GST activity and the dechlorination function of the enzyme, the K107T mutant displayed variable results, suggesting a functional role of Lys107 in determining substrate specificity of the enzyme. These results demonstrated that the enzyme should be valuable in the bioremediation of metabolites generated during PCB biodegradation.

Matched MeSH terms: Permethrin
Fulltext Dengue control during flood disaster in Johore,Malaysia

Shaharom, N.A., Nyamah, M.A., Norashikin, M., Zaharah, M.S., Zuhaida, A.J., Norb, H., et al.

Malaysian Journal of Community Health, 2009;15(3):104-110.
MyJurnal

The state of Johore suffered a massive flood disaster from 19th December 2006 to 1st January and from 12th January to 19th February 2007. The possible upsurge of dengue was of foremost concern and led to efforts in increasing control activities. Anyone with history of high fever with at least two symptoms of severe headache, pain behind the eyes, muscles and joint paint, rashes and petechiae were notified as dengue. Active and passive case finding was initiated at all 371 evacuation centres as well through health facilities and hospitals through an active surveillance system. Presumptive larval survey was also carried together with control activities by 46 health teams. Data were collected using the format ‘Aktiviti harian kawalan denggi di kawasan pos banjir- Lampiran E‘ and ‘Laporan aktiviti harian kawalan denggi di pusat pemindahan banjir – Lampiran D2’. Dengue serology and blood film for malaria was sent for as well as vector species identification. A total of 594 dengue cases were reported for the period of 19th December 2006 till 19th February 2007, which was an increase in comparison to the 5-year median but less than that reported in year 2006. However only 14 (2.3%) cases were from flood affected areas. During the flood phase, a total of 5,929 inspections were carried out at the evacuation centres with Aedes Index (AI) of 1.86%, while the post flood period showed a lower index. However Breteau Index (BI) and Container Index (CI) were higher. Preventive fogging were carried out at the evacuation centres using adulticides, thermal fogging was carried out at 21,959 premises (40.04% of inspected premises) and 350.6 L adulticides (malathion, fenitrothion and permethrin) were used. Dengue was expected to increase during flood as a result of increase Aedes potential breeding sites. However with intensive and integrated control activities, Johore was able to minimize the impact of flood for vector-borne diseases as seen from the low cases reported in flood related areas. A special guidelines for surveillance and control was developed during this flood as a reference for future occurrences.

Matched MeSH terms: Permethrin
Fulltext Characterization on malathion and permethrin resistance by bioassays and the variation of esterase activity with the life stages of the mosquito Culex quinquefasciatus

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

Trop Biomed, 2007 Jun;24(1):63-75.
PMID: 17568379 MyJurnal

Larvae and adults of Culex quinquefasciatus were used for the test undertaken for malathion resistant strain (F61 - F65) and permethrin resistant strain (F54 - F58). The results showed that the LC50 for both malathion (F61 - F65) and permethrin (F54 - F58) resistant Cx. quinquefasciatus increased steadily throughout the subsequent five generations, indicating a marked development of resistance. The adult female malathion resistant strain have developed a high resistance level to malathion diagnostic dosage with a resistance ratio of 9.3 to 17.9 folds of resistance compared with the susceptible Cx. quinquefasciatus. Permethrin resistance ratio remained as 1.0 folds of resistance at every generation. It was obvious that malathion resistance developed at a higher rate in adult females compared to permethrin. Enzyme-based metabolic mechanisms of insecticide resistance were investigated based on the biochemical assay principle. From the results obtained obviously shows that there is a significant difference (p < 0.05) in esterase level in both malathion and permethrin selected strains. Female malathion selected strain has the higher level of esterase activity compared to the female permethrin selected strain at (0.8 to 1.04) alpha-Na micromol/min/mg protein versus (0.15 to 0.24) alpha-Na micromol/min/mg protein respectively. This indicated increased level of non-specific esterase is playing an important role in resistance mechanism in female malathion selected strain. Permethrin selected strain exhibited non-specific esterase activity at a very low level throughout the different life stages compared to malathion selected strain. This study suggests that life stages play a predominant role in conferring malathion and permethrin resistance in Cx. quinquefasciatus.

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 Controlling Malaria in Western Pacific with Mosquito Nets Treated with Pyrethroids in Village Communities, 1979-1999

Self L

Am J Trop Med Hyg, 2016 07 06;95(1):10-4.
PMID: 26880771 DOI: 10.4269/ajtmh.15-0817

Insecticide-treated mosquito nets were first put to practical use in the Western Pacific Region. Less than a decade after conducting workshops and other promotional activities, millions of people were protected by 1989. This occurred before the availability of commercially produced pretreated nets and before global funding for mass net distribution. This paper describes the sequence of steps leading to regional control success. The beginning stages in 1979 recognized that treating torn mosquito nets was a viable control option. Basic net treatment procedures were established by 1983 and workshops were held the next 2 years in China, Cambodia, Laos, Malaysia, Papua New Guinea, Philippines, Solomon Islands, Vanuatu, and Vietnam. Malaria staff became convinced of net benefits and were motivated to impart their knowledge to others. Village inhabitants soaked the nets in washbasins containing permethrin or deltamethrin solution, then dried them horizontally on mats. By the 1990s, the population protected by nets had appreciably increased, and regional malaria cases confirmed by microscopy were markedly reduced. This coincided with commercial interest to mass-produce pretreated mosquito nets for worldwide use.

Matched MeSH terms: Permethrin
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
A preliminary proteomic study of permethrin resistant and susceptible Aedes aegypti (L.)

Rosilawati R, Nabila R, Siti Futri Farahininajua F, Nazni WA, Lee HL

Trop Biomed, 2019 Dec 01;36(4):855-865.
PMID: 33597458

The mechanism of insecticide resistance is traditionally attributed to detoxification enzymes, target site alteration, decreased penetration of insecticides and behavioural resistance. Other form of mechanisms, such as the role of protein(s) in resistance is unknown. In the present study, the protein profiling of both IMR-PSS strain (permethrin-selected) and IMR-LS strain (laboratory-susceptible) 24 hours post exposure period to permethrin was carried out via 1D-gel electrophoresis and liquid chromatography mass spectrometry (LC-MS/ MS). The bands which appeared in the gel of 1D-electrophoresis revealed an abundance of proteins. The band pattern of both strains looked macroscopically alike and differed only in band intensity. However, LC-MS/MS analysis revealed that the IMR-PSS strain produced extra 388 peptides that were not found in the IMR-LS strain, indicating that IMR-PSS strain reacted differently from IMR-LS strain as a result of persistent exposure to permethrin. Since the complex banding patterns of 1D-gel electrophoresis were difficult to interpret the significance of the protein difference between IMR-PSS and IMR-LS strain, hence LC-MS/MS analysis is ideally suited for better protein resolution and thus will allow more in-depth comparison of the complex pattern. The findings here provide the first preliminary evidence that insecticide resistance in mosquito induces up regulation of proteins that may be protective to mosquitoes against insecticide and proteins could be another mechanism that contributes to development of resistance.

Matched MeSH terms: Permethrin*
Fulltext Current insecticide susceptibility status of Malaysian Anopheles maculatus Theobald to malathion, permethrin, DDT and deltamethrin

Rohani A, Aziz I, Zurainee MN, Rohana SH, Zamree I, Lee HL

Trop Biomed, 2014 Mar;31(1):159-65.
PMID: 24862056 MyJurnal

Chemical insecticides are still considered as important control agents for malaria vector control. However, prolonged use of these chemicals may select mosquito vectors for resistance. In this study, susceptibility status of adult Anopheles maculatus collected from 9 localities in peninsular Malaysia, viz., Jeli, Temerloh, Pos Banun, Senderut, Jeram Kedah, Segamat, Kota Tinggi, Kluang and Pos Lenjang were determined using the standard WHO bioassay method in which the adult mosquitoes were exposed to standard insecticide impregnated papers malathion, permethrin, DDT and deltamethrin--at pre-determined diagnostic dosage. Deltamethrin was most effective insecticide among the four insecticides tested, with the LT50 of 29.53 min, compared to malathion (31.67 min), DDT (47.76 min) and permethrin (48.01 min). The effect of all insecticides on the laboratory strain was greater (with all insecticides demonstrated LT50 < 1 hour) than the field strains (deltamethrin 32.7, malathion 53.0, permethrin 62.0, DDT 67.4 min). An. maculatus exhibited low degree of resistance to all test insecticides, indicating that these chemical insecticides are still effective in the control of malaria vector.

Matched MeSH terms: Permethrin/pharmacology
Adulticidal Susceptibility Evaluation of Aedes albopictus Using New Diagnostic Doses in Penang Island, Malaysia

Rahim J, Ahmad AH, Ahmad H, Ishak IH, Rus AC, Maimusa HA

J Am Mosq Control Assoc, 2017 Sep;33(3):200-208.
PMID: 28854111 DOI: 10.2987/16-6607R.1

Insecticide-based vector control approaches are facing challenges due to the development of resistance in vector mosquitoes. Therefore, a proper resistance surveillance program using baseline lethal concentrations is crucial for resistance management strategies. Currently, the World Health Organization's (WHO) diagnostic doses established for Aedes aegypti and Anopheles species are being used to study the resistance status of Aedes albopictus. In this study, we established the diagnostic doses for permethrin, deltamethrin, and malathion using a known susceptible reference strain. Five field-collected populations were screened against these doses, following the WHO protocol. This study established the diagnostic dose of malathion at 2.4%, permethrin at 0.95%, and deltamethrin at 0.28%, which differ from the WHO doses for Aedes aegypti and Anopheles spp. Among the insecticides tested on the 5 wild populations, only deltamethrin showed high effectiveness. Different susceptibility and resistance patterns were observed with permethrin, malathion, and dichloro-diphenyl-trichloroethane (DDT) at 4%. This study may assist the health authorities to improve future chemical-based vector control operations in dengue-endemic areas.

Matched MeSH terms: Permethrin/pharmacology*
Differential permethrin susceptibility of head lice sampled in the United States and Borneo

Pollack RJ, Kiszewski A, Armstrong P, Hahn C, Wolfe N, Rahman HA, et al.

Arch Pediatr Adolesc Med, 1999 Sep;153(9):969-73.
PMID: 10482215 DOI: 10.1001/archpedi.153.9.969

BACKGROUND: Pediculiasis is treated aggressively in the United States, mainly with permethrin- and pyrethrin-containing pediculicides. Increasingly frequent anecdotal reports of treatment failure suggest the emergence of insecticidal resistance by these lice.

OBJECTIVE: To confirm or refute the susceptibility of head lice sampled in the United States to permethrin.

DESIGN: Survey. Head lice were removed from children residing where pediculicides are readily available and where such products are essentially unknown. Their survival was compared following exposure to residues of graded doses of permethrin in an in vitro bioassay.

SETTING: School children from Massachusetts, Idaho, and Sabah (Malaysian Borneo).

SUBJECTS: In the United States, 75 children aged 5 to 8 years. In Sabah, 59 boys aged 6 to 13 years. Virtually all sampled US children had previously been treated with pediculicides containing pyrethrins or permethrin; none of the Sabahan children were so exposed.

MAIN OUTCOME MEASURE: Survival of head lice exposed to permethrin.

RESULTS: Permethrin did not affect head lice sampled from chronically infested US children who had previously been treated for pediculiasis. The slope of the dose-response regression line for these lice did not differ significantly from zero (P = .66). This pediculicide immobilized lice sampled in Sabah. Mortality correlated closely with permethrin concentration (P = .008).

CONCLUSIONS: Head lice in the United States are less susceptible to permethrin than are those in Sabah. The pyrethroid susceptibility of the general population of head lice in the United States, however, remains poorly defined. Accordingly, these relatively safe over-the-counter preparations may remain the pediculicides of choice for newly recognized louse infestations.

Matched MeSH terms: Permethrin
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
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

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