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1
Ecker, János, and László Fülöp. "Molecular modeling of DDT's and it's major metabolites adsorption in the interlaminar space of montmorillonite." Journal of Universal Science Online 1, no. 1 (2014): 12–19. http://dx.doi.org/10.17202/juso.2014.1.12.
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A simple adsorption mechanism of the organochloride insecticide DDT and it's most common metabolites DDD and DDE in the interlaminar layer of montmorillonite mineral is discussed in this paper, based on the results of molecular modeling. A model of a simple fragment of the montmorillonite crystal with the interlaminar layer was created and used. The interlaminar layer contained water as a solvent and the ionic forms of sodium or calcium as exchangeable cations along with the molecules of DDT/DDD/DDE. The molecular interactions were simulated by force fields and the results of the simulation could be explained by the physical characteristics of the models which were studied with bioinformatics tools as well. Based on the observed mechanisms, the adsorption of DDT and it's metabolites in the interlaminar layer of montmorillonite is possible and it is partly responsible for the persistent nature of these insecticides.
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Nazaire Aïzoun, Guévara Nonviho, Frédéric Aïzoun, and Faustin Assongba. "Current insecticide resistance status in malaria vector populations from Dogbo district in South-western Republic of Benin, West Africa." World Journal of Advanced Research and Reviews 13, no. 2 (February 28, 2022): 225–31. http://dx.doi.org/10.30574/wjarr.2022.13.2.0135.
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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 of Anopheles 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.
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Moin, Sarmad. "Contemporary Resistance Status of Anopheles Stephensi against Insecticides in District Dungarpur, Rajasthan, India." Journal of Communicable Diseases 53, no. 03 (September 30, 2021): 153–58. http://dx.doi.org/10.24321/0019.5138.202151.
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Pyrethroids are powerful insecticides used in the vector control program with impregnated mesh, and residual indoor sprays. However, resistance to insecticide reduces the effectiveness. The present susceptibility study carried out against theAnopheles Stephensi to monitor the sensitivity conditions of An. Stephensi vector, which raises the need to understand the state of vector resistance in the Dungarpur region of Rajasthan, India in order to better report vector-based interventions. The sensitivity study was carried out by the WHO standard method using recommended diagnostic doses of DDT, alpha-cypermethrin, permethrin, and deltamethrin. An. Stephensi showed resistance to DDT from the entire study while sensitive to alpha-cypermethrin, permethrin, and deltamethrin. The study looks at the selection and circulation of the appropriate insecticide’s molecule for a vector control program as insecticide need constant monitoring to develop effective vector control strategies such as improving insecticide by applying integrated biological and ecological methods.
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Uddin, M. Amin, Md Abdur Rahman, M. Alamgir Zaman Chowdhury, Md Harunur Rashid, Zeenath Fardous, and Meherun Nesha. "Analysis of organochlorine DDT residue along with its metabolites in dry fishes from some selected markets of Dhaka city." Asian-Australasian Journal of Food Safety and Security 5, no. 2 (November 30, 2021): 79–84. http://dx.doi.org/10.3329/aajfss.v5i2.56959.
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A study was investigated to estimate the current status of health hazardous organochlorine insecticide DDT and its metabolites DDE and DDD in different species of dry fish. To achieve the goal of this experiment, ten different sun-dried fish samples were collected from different markets of Dhaka city. The concentration of DDT, DDE and DDD was determined using the capillary column coupled to Gas Chromatograph with Electron Captured Detector (GC-ECD). Most of the dry fishes, seven out of ten samples, were found to be contaminated with DDT along with its metabolites DDE and DDD ranging from 0.029-1.22 mg/kg which is a serious concern because of the nature of long persistency and bioaccumulation of DDT in the environment. The highest concentration of DDT (1.22 mg/kg) was observed in Pampus chinensis dry fish whereas low concentration was detected in Otolithoides pama (0.029 mg/kg). Asian Australas. J. Food Saf. Secur. 2021, 5 (2), 79-84
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Clarke, Sabine, and Richard J. E. Brown. "Pyrethrum and the Second World War: Recontextualising DDT in the Narrative of Wartime Insect Control." HoST - Journal of History of Science and Technology 16, no. 2 (December 1, 2022): 89–112. http://dx.doi.org/10.2478/host-2022-0017.
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Abstract Historians have long recognised that DDT’s fame began with extraordinary propaganda late in the Second World War, yet heroic narratives that centre the chemical still shape historical understanding. Two false assumptions inform much of the existing scholarship on wartime insect control: one is that without DDT the Allies had no protection from malaria and typhus; the other is that DDT was significantly more toxic than any alternative insecticide available. This paper tells a very different story of wartime insecticides. We recontextualise DDT in the wider wartime technological landscape and in so doing show the enduring significance of the natural insecticide, pyrethrum. DDT was never solely responsible for protecting troops and civilians from malaria and typhus and its deployment did not render all existing insecticides obsolete. Claims about the significance of DDT often work by writing out the existence of alternative methods of controlling vectors or by downplaying the efficacy of existing materials and practices.
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Kalinina, Tatiana, Vladislav Kononchuk, Lyubov Klyushova, and Lyudmila Gulyaeva. "Effects of Endocrine Disruptors o,p′-Dichlorodiphenyltrichloroethane, p,p′-Dichlorodiphenyltrichloroethane, and Endosulfan on the Expression of Estradiol-, Progesterone-, and Testosterone-Responsive MicroRNAs and Their Target Genes in MCF-7 Cells." Toxics 10, no. 1 (January 7, 2022): 25. http://dx.doi.org/10.3390/toxics10010025.
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Many studies have shown that dichlorodiphenyltrichloroethane (DDT) exposure raises breast cancer risk. Another insecticide with similar properties is endosulfan, which has been actively used in agriculture after DDT prohibition. Previously, we have identified some estradiol-, progesterone-, and testosterone-sensitive microRNAs (miRNAs, miRs). Because DDT and endosulfan have estrogenic, antiandrogenic, and antiprogesterone properties, we hypothesized that these miRNAs are affected by the insecticides. We quantified relative levels of miRNAs and expression levels of their target genes in breast cancer MCF-7 cells treated with p,p′-DDT, o,p′-DDT, or endosulfan. We also quantified miR-19b expression, which, as previously shown, is regulated by estrogen. Here, we observed that miR-19b expression increased in response not only to estradiol but also to testosterone and progesterone. Treatment of MCF-7 cells with p,p′-DDT or endosulfan decreased the protein levels of apoptosis regulators TP53INP1 and APAF1. In cells treated with o,p′-DDT, the TP53INP1 amount decreased after 24 h of incubation, but increased after 48 h of incubation with insecticide. OXTR expression, which is known to be associated with breast carcinogenesis, significantly diminished under the exposure of all insecticides. In cells treated with p,p′-DDT or o,p′-DDT, the observed changes were accompanied by alterations of the levels of hormone-responsive miRNAs: miR-324, miR-190a, miR-190b, miR-27a, miR-193b, and miR-19b.
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O'Reilly, Andrias O., Bhupinder P. S. Khambay, Martin S. Williamson, Linda M. Field, B. A. WAllace, and T. G. Emyr Davies. "Modelling insecticide-binding sites in the voltage-gated sodium channel." Biochemical Journal 396, no. 2 (May 15, 2006): 255–63. http://dx.doi.org/10.1042/bj20051925.
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A homology model of the housefly voltage-gated sodium channel was developed to predict the location of binding sites for the insecticides fenvalerate, a synthetic pyrethroid, and DDT an early generation organochlorine. The model successfully addresses the state-dependent affinity of pyrethroid insecticides, their mechanism of action and the role of mutations in the channel that are known to confer insecticide resistance. The sodium channel was modelled in an open conformation with the insecticide-binding site located in a hydrophobic cavity delimited by the domain II S4-S5 linker and the IIS5 and IIIS6 helices. The binding cavity is predicted to be accessible to the lipid bilayer and therefore to lipid-soluble insecticides. The binding of insecticides and the consequent formation of binding contacts across different channel elements could stabilize the channel when in an open state, which is consistent with the prolonged sodium tail currents induced by pyrethroids and DDT. In the closed state, the predicted alternative positioning of the domain II S4-S5 linker would result in disruption of pyrethroid-binding contacts, consistent with the observation that pyrethroids have their highest affinity for the open channel. The model also predicts a key role for the IIS5 and IIIS6 helices in insecticide binding. Some of the residues on the helices that form the putative binding contacts are not conserved between arthropod and non-arthropod species, which is consistent with their contribution to insecticide species selectivity. Additional binding contacts on the II S4-S5 linker can explain the higher potency of pyrethroid insecticides compared with DDT.
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Moin, Sarmad. "Status of Insecticide Resistance of Malaria Vector Anopheles stephensi towards Insecticides in Alwar District of Rajasthan, India." Journal of Communicable Diseases 53, no. 01 (March 31, 2021): 58–61. http://dx.doi.org/10.24321/0019.5138.202109.
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Pyrethroids have been developed as a powerful insecticide that is widely used for space spray and residual indoor spraying, with impregnated nets included in the vector control programme. Insecticide resistance reduces the effectiveness of pesticides. Therefore, the vector susceptibility condition of the Anopheles stephensi is monitored in order to select the active ones. The current study is being conducted in a malaria-ridden area in various parts of the Alwar region of Rajasthan, India, against the malaria vector An. stephensi. The Susceptibility study was conducted by the WHO standardized method using the diagnostic doses of DDT, Alpha-cypermethrin and Deltamethrin. An. stephensi showed intermediate resistance to DDT from all over the study while susceptible to Alpha-cypermethrin and Deltamethrin.
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Mishra, Ashok K., Praveen K. Bharti, Gyan Chand, Aparup Das, Himanshu Jayswar, Manju Rahi, and Kamaraju Raghavendra. "Monitoring of Insecticide Resistance in Anopheles culicifacies in Twelve Districts of Madhya Pradesh, Central India (2017–2019)." Journal of Tropical Medicine 2022 (January 5, 2022): 1–8. http://dx.doi.org/10.1155/2022/4404027.
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Background. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are malaria vector control measures used in India, but the development of insecticide resistance poses major impediments for effective vector control strategies. As per the guidelines of the National Vector Borne Disease Control Programme (NVBDCP), the study was conducted in 12 districts of Madhya Pradesh to generate data on insecticide resistance in malaria vectors. Methods. The susceptibility tests were conducted on adult An. culicifacies as per the WHO standard technique with wild-caught mosquitoes. The blood-fed female mosquitoes were exposed in 3 to 4 replicates on each occasion to the impregnated papers with specified discriminating dosages of the insecticides (DDT: 4%, malathion: 5%, deltamethrin: 0.05%, and alphacypermethrin: 0.05%), for one hour, and mortality was recorded after 24-hour holding. Results. An. culicifacies was found resistant to DDT 4% in all the 12 districts and malathion in 11 districts. The resistance to alphacypermethrin was also observed in two districts, and possible resistance was found to alphacypermethrin in seven districts and to deltamethrin in eight districts, while the vector was found susceptible to both deltamethrin and alphacypermethrin in only 3 districts. Conclusion. An. culicifacies is resistant to DDT and malathion and has emerging resistance to pyrethroids, alphacypermethrin, and deltamethrin. Therefore, regular monitoring of insecticide susceptibility in malaria vectors is needed for implementing effective vector management strategies. However, studies to verify the impact of IRS with good coverage on the transmission of disease are required before deciding on the change of insecticide in conjunction with epidemiological data.
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Sindhania, Ankita, Himanshu P. Lohani, Madhavinadha Prasad Kona, Taranjeet Kaur, B. R. Kaushal, and Om P. Singh. "Molecular forms of the Indian Anopheles subpictus complex differ in their susceptibility to insecticides and the presence of knockdown resistance (kdr) mutations in the voltage-gated sodium channel." PLOS ONE 18, no. 2 (February 2, 2023): e0280289. http://dx.doi.org/10.1371/journal.pone.0280289.
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Objectives To investigate the differential insecticide-susceptibility of two molecular forms of Anopheles subpictus complex (A and B) against DDT and pyrethroids, the occurrence of knockdown resistance (kdr) mutations in these forms, and the association of kdr mutations with insecticide resistance. Methods Insecticide susceptibility tests of An. subpictus s.l., collected from coastal and inland areas of mainland India, were performed against DDT, permethrin and deltamethrin using the WHO standard insecticide susceptibility test kit. The mosquitoes were characterized for molecular forms using a diagnostic PCR developed in this study. Representative samples of An. subpictus molecular forms A and B were sequenced for a genomic region encompassing the IIS4-5 linker to the IIS6 segments of the voltage-gated sodium channel to identify kdr mutations. A common PIRA-PCR was developed for identifying L1014F-kdr mutation and used for genotyping in both molecular forms of An. subpictus. Results Molecular form A of An. subpictus was resistant to all three insecticides, i.e., DDT, Permethrin and deltamethrin, whereas Form B was categorized as ‘possibly resistant’ to these insecticides. Significantly higher mortalities in WHO insecticide susceptibility tests were recorded in Form B compared to Form A in sympatric populations. Molecular characterization of the IIS4-5 linker to IIS-6 segments of the voltage-gated sodium channel revealed the presence of two alternative nucleotide transversions at L1014 residue in Form A, both leading to the same amino acid change, i.e., Leu-to-Phe; however, such mutations could not be observed in Form B. PIRA-PCR-based kdr-genotyping of field populations revealed high frequencies of L1014F-kdr mutations in Form A and the absence of this mutation in Form B. The proportion of L1014F mutation was significantly higher in resistant mosquitoes following insecticide-bioassay with DDT (p<0.0001), permethrin (p<0.001) and deltamethrin (p<0.01) as compared to their susceptible counterparts. Conclusions Significant differences in insecticide susceptibility were found between two molecular forms of An. subpictus complex in sympatric populations. The L1014F-kdr mutation was observed in Form A only, which was found to be associated with DDT, permethrin and deltamethrin resistance.
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Orjuela, Lorena I., Juliana A. Morales, Martha L. Ahumada, Juan F. Rios, John J. González, Johana Yañez, Angelo Rosales, et al. "Insecticide Resistance and Its Intensity in Populations of Malaria Vectors in Colombia." BioMed Research International 2018 (August 29, 2018): 1–12. http://dx.doi.org/10.1155/2018/9163543.
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Insecticide resistance in malaria vectors threatens malaria prevention and control efforts. In Colombia the three primary vectors, Anopheles darlingi, An. nuneztovari s.l., and An. albimanus, have reported insecticide resistance to pyrethroids, organophosphates, carbamates, and DDT; however, the insecticide resistance monitoring is not continuous, and the data on the prevalence of resistance is scarce and geographically limited. We describe the resistance levels and intensity of previously detected resistant populations among primary malaria vectors from the most endemic malaria areas in Colombia. The study was carried out in 10 localities of five states in Colombia. Bioassays were carried out following the methodology of CDC Bottle Bioassay using the discriminating concentration and in order to quantify the intensity the specimens were exposed to 2, 5, and 10X discriminating concentrations. Five insecticides were tested: deltamethrin, lambda-cyhalothrin, alpha-cypermethrin, permethrin, and DDT. The results provide evidence of low resistance intensity and resistance highly localized to pyrethroids and DDT in key malaria vectors in Colombia. This may not pose a threat to malaria control yet but frequent monitoring is needed to follow the evolution of insecticide resistance.
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Oboh, Mary Aigbiremo. "Susceptibility and fecundity of Bedbugs (Cimex hemipterus) from Yaba College of Technology Lagos exposed to Selected Classes of Insecticides: A short report." Pan African Journal of Life Sciences 6, no. 2 (August 31, 2022): 472–76. http://dx.doi.org/10.36108/pajols/2202/60.0250.
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Background: Tropical bed bug, Cimex hemipterus, is a nocturnal obligate blood-sucking ectoparasite of humans that is highly prevalent in Nigeria. Bed bug controls heavily rely on the application of several insecticide-based formulations. Insecticide resistance in bed bug populations has been widely reported. In this study, we assessed the mortality of bed bugs following exposure to different classes of insecticides. Methodology: Active adult female bed bugs were collected from students’ halls of residence and exposed to DDT (4%), permethrin (0.75), bendiocarb (0.1) and malathion (4%) insecticide-impregnated papers. Mortality and number of eggs laid by each exposed group were recorded at 90 minutes, 24hrs, 48hrs and 72hrs. Results: The impact of the different assays on bugs mortality revealed DDT to produce a time-dependent outcome with the highest mortality rate [(36.7% (Cl 32.7±38.9)], this was followed by Bendiocarb [31.6% (CI 27.2±35.1)]. In comparison, permethrin and malathion produced the same effect [26.7% (CI 23±30.5)] 24 hours post-exposure. In contrast, malathion and bendiocarb impacted the most mortality [53.3% (49.3±58.7) and 46.6%(42.2±49.5)], followed by permethrin [18.9% (CI 44.6±56.8) after 72 hours. The relative numbers of eggs produced by bedbugs in the DDT, bendiocarb and malathion assays were lower than what was observed in the control and permethrin group 24 hours after exposure. The highest reduction in egg production was observed in the malathion exposed group 48- and 72-hours post-exposure compared to the other insecticides and the control group. Conclusion: This study revealed suspected insecticide resistance to all classes of insecticide used on bed bug populations in Lagos State, Nigeria.
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Hancock, Penelope A., Antoinette Wiebe, Katherine A. Gleave, Samir Bhatt, Ewan Cameron, Anna Trett, David Weetman, et al. "Associated patterns of insecticide resistance in field populations of malaria vectors across Africa." Proceedings of the National Academy of Sciences 115, no. 23 (May 21, 2018): 5938–43. http://dx.doi.org/10.1073/pnas.1801826115.
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The development of insecticide resistance in African malaria vectors threatens the continued efficacy of important vector control methods that rely on a limited set of insecticides. To understand the operational significance of resistance we require quantitative information about levels of resistance in field populations to the suite of vector control insecticides. Estimation of resistance is complicated by the sparsity of observations in field populations, variation in resistance over time and space at local and regional scales, and cross-resistance between different insecticide types. Using observations of the prevalence of resistance in mosquito species from the Anopheles gambiae complex sampled from 1,183 locations throughout Africa, we applied Bayesian geostatistical models to quantify patterns of covariation in resistance phenotypes across different insecticides. For resistance to the three pyrethroids tested, deltamethrin, permethrin, and λ-cyhalothrin, we found consistent forms of covariation across sub-Saharan Africa and covariation between resistance to these pyrethroids and resistance to DDT. We found no evidence of resistance interactions between carbamate and organophosphate insecticides or between these insecticides and those from other classes. For pyrethroids and DDT we found significant associations between predicted mean resistance and the observed frequency of kdr mutations in the Vgsc gene in field mosquito samples, with DDT showing the strongest association. These results improve our capacity to understand and predict resistance patterns throughout Africa and can guide the development of monitoring strategies.
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Poniman, Tri Retnaningsih Soeprobowowati, and Muhammad Helmi. "Geospatial distributions of organochlorine insecticide in shallot agriculture land at Wanasari sub-district, Brebes regency, Central Java, Indonesia." E3S Web of Conferences 202 (2020): 06009. http://dx.doi.org/10.1051/e3sconf/202020206009.
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The organochlorine insecticide is a POPs compound that was monitored according to the Stockholm convention in 2003 because it can cause environmental damage and threaten human health. The study of the distribution of organochlorine insecticides on onion farms has been carried out in the village area in Wanasari sub-District and Brebes Regency. This study was conducted in March-June 2019, with the scope of soil sampling, organochlorine insecticide residue analysis, and spline interpolation. To determine the number of organochlorine insecticide residues using the SNI 06-6991.1-2004 method, while to determine the distribution pattern using the Spline interpolation method with the ArcGIS 10.4. In preparing geospatial residues, we use the ratio of the maximum residual limit (MRLs) of each organochlorine active ingredient. These research sites can be categorized as severe pollution of OCPs insecticides. In this study OCPs residues (Aldrin, Lindane, and Heptachlor, DDT, Endrin, and Dieldrin) can be found with concentrations above the MRLs requirements. OCPs residues with very high range characteristics are shown by Aldrin, DDT, Endrin, and Dieldrin each of more than 50% of the total observed land area. Point numbers six detected all OCPs residues were observed with concentrations exceeding MRLs.
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Krishnan, Jayalakshmi. "Monitoring of Insecticide Resistance and Exploring the Presence of Virus in Field Populations of Culex gelidus at Thiruvarur District of Tamil Nadu, India." Journal of Communicable Diseases 53, no. 04 (December 31, 2021): 76–83. http://dx.doi.org/10.24321/0019.5138.202177.
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Introduction: The introduction of potent synthetic insecticides into public health programmes has since beginning posed the challenge of development of resistance among the insect vectors against the insecticides. Culex (Cx.) gelidus is one of the vectors of JE which is abundantly found in southern India. Its breeding habitats are similar to the vishnui subgroup of Culex mosquitoes, the major vectors for transmission of JE. The present study was aimed to assess the susceptibility status of adult Culex (Cx.) gelidus, to insecticides, namely DDT (Dichlorodiphenyltrichloroethane), Deltamethrin, and Malathion. Method: The field-collected mosquito larvae from ten villages of Thiruvarur district from December 2018 to May 2019 were reared in the laboratory until F1 generation and the emerged adults identified as Cx. gelidus were exposed to insecticide-impregnated papers supplied through World Health Organization (WHO). The adult susceptibility tests were carried out as per the protocol of WHO. Further, an attempt was made to check the presence of JE virus in Cx. gelidus and the virus detection was done by RT-PCR. Results: The results indicated that the adult Cx. gelidus populations were susceptible to DDT, whereas they were resistant to Malathion and Deltamethrin. The possible reason of DDT susceptibility may be that DDT has not been used in Tamil Nadu since the year 1980 (about 40 years). Conclusion: JE virus was not detected in the tested mosquitoes. The study suggests that insecticide resistance monitoring from time to time is required to facilitate vector control programmes in focusing on appropriate vector control measures.
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Maulianawati, Diana, Adi Setyo Purnomo, and Ichiro Kamei. "Biodegradation of DDT by Co-cultures of Pleurotus eryngii and Pseudomonas aeruginosa." HAYATI Journal of Biosciences 28, no. 3 (August 25, 2021): 240. http://dx.doi.org/10.4308/hjb.28.3.240.
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Dichloro-diphenyl-trichloroethane (DDT) is a synthetic insecticide that widely used around the world, which has a negative effect on human health and the environment. The objective of this research was to investigate the ability of bacterium Pseudomonas aeruginosa in co-culturing with white-rot fungus Pleurotus eryngii to degrade DDT. The various volume of P. aeruginosa (1 ml ≈ 1.5 x 109 CFU) were added into 10 ml of P. eryngii culture for a 7-days of incubation. Approximately 82% of degradation of DDT were obtained from co-cultures with the adjunct of 10 ml of P. aeruginosa during the 7-day incubation period, which had the best ratio of optimization of 0.57. The confrontational assay showed that P. aeruginosa gave no effect on the growth of P. eryngii (0.39 cm/day). DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene) were detected as metabolic products from the DDT degradation by co-cultures bacterium P. aeruginosa and fungus P. eryngii. This study indicated that bacterium P. aeruginosa can be used to enhance DDT degradation by whire-rot fungus P. eryngii.
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JUNG, Junho. "DDT Resistance Korean Body Lice and Development of Insecticide Resistance Knowledge during Korean War." Korean Journal of Medical History 31, no. 3 (December 31, 2022): 757–91. http://dx.doi.org/10.13081/kjmh.2022.31.757.
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DDT exemplifies success and failure of modern science and technology. Once it was heralded as technological wonder that will deliver human from misery of insect-borne infectious disease. However DDT took dramatic downturn after failure in global malaria eradication program initiated by World Health Organization, with advent of DDT-resistant strain of mosquitoes. Although insecticide resistance has been know since late 19th century, the definitions and mythologies for finding resistance has not been settled until 1950s. This paper argues that discovery of DDT-resistant strain of body lice in prisoners of war camp in Korea during the Korean War provided essential knowledge and opportunity for advancing insecticide resistance studies.</br>Since 1945 to the end of Korean War, US Army sprayed thousands of tonnes of DDT on Korean body and soil. DDT was only went into wide field application since 1943, was still a very new technology. The ways to deliver and utilize DDT was still under the investigation. And Korea, especially during the War, was ideal place to construct such knowledge and place it in the application. The main focus was to control public health threats, such as louse-borne typhus fever. Korean soldiers and prisoners of war exposed to regular dose of DDT, which soon gave rise to DDT-resistant strain of body lice. It was the first major outbreak of insecticide-resistance appeared in insect that has major public health importance. Until early 1950s, mechanisms of resistance, or even definition of insecticide resistance was unclear. Researchers in US Army and Department of Agriculture rushed to find the ways to quantify insecticide resistance. Network of laboratories, connecting Korea-Japan-US, had to devise new laboratory methods to rear, and test body lice. These body lice later migrate to laboratories in US, providing valuable asset for future insecticide resistance research in US. At the same time, laboratory methods of testing resistance in body louse became a standard across the globe, setting new research agenda through World Health Organization. This shows flow of knowledge, along with migration of body louse, during the Korean War. At the same time, this case show who new knowledge is constructed through the expense of involvement of minority populations, such as natives, soldiers, and prisoners of war.
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Long, Austin R., Michael D. Crouch, and Steven A. Barker. "Multiresidue Matrix Solid Phase Dispersion (MSPD) Extraction and Gas Chromatographic Screening of Nine Chlorinated Pesticides in Catfish (Ictalurus punctatus) Muscle Tissue." Journal of AOAC INTERNATIONAL 74, no. 4 (July 1, 1991): 667–70. http://dx.doi.org/10.1093/jaoac/74.4.667.
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Abstract A multiresidue technique for extraction and gas chromatographic screening of 9 insecticide (lindane, heptachlor, aldrin, heptachlor epoxide, p,p-DDE, dieldrin, endrin, p,p- TDE, and p,p'-DDT) residues In catfish {Ictalurus punctatus) muscle tissue is presented. The 9 Insecticides, plus dibutyl chlorendate internal standard, were fortified into catfish muscle tissue (0.5 g) and blended with 2 g C18 (octadecylsilyl derlvatized silica reverse-phase material). The C18/muscle tissue matrix blend was fashioned into a column by adding the blend to a 10 mL syringe barrel containing 2 g activated Florisil. The insecticides were then eluted from the column with acetonitrlle (8 mL), and a portion (2 μL) of the acetonitrile eluate was then directly analyzed by gas chromatography with electron capture detection. Unfortified blank controls were treated similarly. The resultant extracts contained pesticide analytes (31.25-500 ng/g) free of interfering compounds when analyzed. Correlation coefficients for the 9 extracted pesticide standard curves (linear regression analysis, n = 5) ranged from 0.9967 (± 0.0018) to 0.9999 (± 0.0001). Average percentage recoveries (82 ± 4.8% to 97 ± 3.6%, n = 25 for each Insecticide), Interassay (5.0 ± 2.7% to 16.9 ± 6.5%, n = 25 for each insecticide) and intraassay (1.8 to 4.7%, n = 5 for each Insecticide) variabilities were Indicative of an acceptable methodology for the analysis and screening of these residues in catfish muscle tissue.
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Mamane Salé, Noura, Rabiou Labbo, Ibrahim Maman Laminou, Ibrahima Issa Arzika, Ali Djibo Souley, Wilfried Zoulkifouly Hounkarin, Halima Zamanka Naroua, et al. "Insecticide resistance in Anopheles gambiae sensu lato (Diptera: Culicidae) across different agroecosystems in Niamey, Niger." African Journal of Tropical Entomology Research 3, no. 1 (May 2, 2024): 30–40. http://dx.doi.org/10.58697/ajter030105.
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Malaria vector control in Niger is currently based on the distribution of insecticide treated nets. However, vectors resistance to insecticides represents a major threat to the current national strategy against malaria. This study aims to characterize the impact of agroecosystems on insecticide resistance in Anopheles gambiae s.l. at Niamey. Larvae collected were reared until emergence. Adults aged 2-5 days were used to assess susceptibility to insecticides (pyrethroids, DDT and bendiocarb) after pre-exposure to piperonyl butoxide (PBO) synergist according to WHO protocols. PCRs were performed to identify the sibling species of An. gambiae complex and characterization resistance mutations (Kdr and ace-1). Overall, An. gambiae s.l. was resistance to pyrethroids and DDT (mortality rates from 1% to 55%) and susceptible to bendiocarb at most sites. Pre-exposure to the PBO synergist resulted in partial restoration of pyrethroid susceptibility. Two species of An. gambiae complex were found: An. arabiensis and An. coluzzii. The presence of An. coluzzii was strongly correlated with agricultural practices (99% in rice cultivation sites). Kdr mutations were found at all sites with kdr-w ranging from 45% to 70% in mosquitoes collected in unirrigated and rice field, respectively, and kdr-e found at 37% to 47% at each type of site, respectively. The ace-1 mutation was detected at low frequency (1%) and only from two rice cultivation sites. The high levels of pyrethroid and DDT resistance detected in Niamey had a strong link with rice cultivation, shown that agriculture is a driver of resistance that can compromise control malaria efforts. Keywords: Anopheles gambiae sensu lato, insecticide, resistance, agroecosystem, vector control, Niamey, Niger..
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Nkemngo, Francis N., Leon M. J. Mugenzi, Ebai Terence, Abdoulaye Niang, Murielle J. Wondji, Micareme Tchoupo, Nguiffo D. Nguete, et al. "Elevated Plasmodium sporozoite infection and multiple insecticide resistance in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon." Wellcome Open Research 5 (June 23, 2020): 146. http://dx.doi.org/10.12688/wellcomeopenres.15818.1.
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Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a village located 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F1 adult progeny. Bioassays were performed to assess resistance profile to insecticides. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having a similar sporozoite rate. Both species exhibited high levels of resistance to pyrethroids (<40% mortality). An. gambiae s.s. was also resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively. Furthermore, the high pyrethroid/DDT resistances in An. gambiae s.s. corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the high Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Nkemngo, Francis N., Leon M. J. Mugenzi, Ebai Terence, Abdoulaye Niang, Murielle J. Wondji, Micareme Tchoupo, Nguiffo D. Nguete, et al. "Multiple insecticide resistance and Plasmodium infection in the principal malaria vectors Anopheles funestus and Anopheles gambiae in a forested locality close to the Yaoundé airport, Cameroon." Wellcome Open Research 5 (November 5, 2020): 146. http://dx.doi.org/10.12688/wellcomeopenres.15818.2.
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Background: Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, Plasmodium infection rate, insecticide resistance profiles and underlying resistance mechanisms. Methods: Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a locality situated 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F 1 adults. Bioassays were performed to assess resistance profile to the four insecticides classes. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and Plasmodium infection rates were investigated. Results: Anopheles funestus s.s. was the most abundant species in Elende (85%) followed by Anopheles gambiae s.s. (15%) with both having similar sporozoite rate. Both species exhibited high levels of resistance to the pyrethroids, permethrin and deltamethrin (<40% mortality). An. gambiae s.s. was resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. An. funestus s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S ace-1 resistance allele (15%) were detected in An. funestus s.s. and An. gambiae s.s., respectively. Furthermore, the high pyrethroid/DDT resistances in An. gambiae corresponded with an increase frequency of 1014F kdr allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of CYP6P5, CYP6P9a and CYP6P9b. Conclusion: The resistance to multiple insecticide classes observed in these vector populations alongside the significant Plasmodium sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
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Long, Austin R., Maher M. Soliman, and Steven A. Barker. "Matrix Solid Phase Dispersion(MSPD) Extraction and Gas Chromatographic Screening of Nine Chlorinated Pesticides in Beef Fat." Journal of AOAC INTERNATIONAL 74, no. 3 (May 1, 1991): 493–96. http://dx.doi.org/10.1093/jaoac/74.3.493.
Full textAbstract:
Abstract A multiresldue technique Is presented for the extraction and quantitative gas chromatographic screening of 9 insecticides (lindane, heptachlor, aldrin, heptachlor epoxide, p.p'-DDE, dleldrln, endrin, p,p'-TDE, and p.p'-DDT) as residues In beef fat. Beef fat was fortified by adding the 9 Insecticides, plus dlbutyl chlorendate as Internal standard, to 0.5 g portions of beef fat and blending with 2 g C18 (octadecylsllyl)-derivatlzed silica. The C18/fat matrix blend was fashioned into a column by adding the blend to a 10 mL syringe barrel containing 2 g activated Florisll. The insecticides were then eluted from the column with 8 mL acetonitrile, and a 2μL portion of the acetonitrile eluate was then directly analyzed by gas chromatography with electron capture detection. Unfortified blank controls were treated similarly. The acetonitrile eluate contained all of the pesticide analytes (31.25-500 ng/g) and was free of interfering co-extractants. Correlation coefficients for the 9 extracted pesticide standard curves (linear regression analysis, n = 5) ranged from 0.9969 (±0.0021) to 0.9999 (±0.0001). Average relative percentage recoveries (85 ± 3.4% to 102 ± 5.0%, n = 25 for each insecticide), inter-assay variability (6.0 ± 1.0% to 14.0 ± 6.7%, n = 25 for each insecticide), and intra-assay variability (2.5-5.1%, n = 5 for each insecticide) indicated that the methodology is acceptable for the extraction, determination, and screening of these residues in beef fat.
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Ifeoluwa Kayode, Fagbohun, Idowu Emmanuel Taiwo, Adeogun Adedapo O, Olagundoye Olalekan, Ikebaku Precious Chimdalu, Orisaheyi Iyanuoluwa Olayilola, Oyeniyi Tolulope Amos, et al. "Low frequency of knockdown resistance mutation (L1014F) and the efficacy of PBO synergist in multiple insecticide-resistant populations of Anopheles gambiae in Ikorodu, Lagos State, Nigeria." African Health Sciences 23, no. 1 (April 6, 2023): 255–61. http://dx.doi.org/10.4314/ahs.v23i1.27.
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Objective: We evaluated the susceptibility status of Anopheles gambiae in two communities of Ikorodu, Lagos, Nigeria to DDT, deltamethrin, lambda cyhalothrin and bendiocarb.
Methods: Anopheles immature stages were collected from their habitats in the surveyed community and allowed to emerge before exposure adult females to discriminating doses of WHO insecticides including DDT, deltamethrin, lambda cyhalothrin, bendiocarb and malathion. PBO synergistic bioassay was conducted for insecticides where the mosquito samples showed resistance. PCR assay was used for the detection of kdr mutation in the mosquitoes.
Results: Resistance to DDT (40% and 86%) and lambda cyhalothrin (75% and 84%) in Oke-Ota and Majidun respectively. Suspected resistance to deltamethrin (94.9%) and bendiocarb (93.5%) was recorded in Oke-Ota community and the mosquitoes were susceptible to malathion in both communities. KDR mutation (L1014F) from resistance samples from both locations though with a low frequency that significantly departs from Hardy-Weinberg’s probability (P> 0.01). PBO synergized bioassay was able to increase knockdown, percentage mortality and restore full susceptibility to deltamethrin and bendiocarb.
Conclusion: Results from this study indicates that the metabolic resistance mechanism is highly implicated in the resistance to different classes of insecticide in Ikorodu and this should be taken into consideration when implementing vector control activities in this area.
Keywords: Malaria; Anopheles gambiae; insecticide resistance; knockdown resistance; metabolic resistance.
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Kampango, Ayubo, Emma F. Hocke, Helle Hansson, Peter Furu, Khamis A. Haji, Jean-Philippe David, Flemming Konradsen, et al. "High DDT resistance without apparent association to kdr and Glutathione-S-transferase (GST) gene mutations in Aedes aegypti population at hotel compounds in Zanzibar." PLOS Neglected Tropical Diseases 16, no. 5 (May 16, 2022): e0010355. http://dx.doi.org/10.1371/journal.pntd.0010355.
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Global efforts to control Aedes mosquito-transmitted pathogens still rely heavily on insecticides. However, available information on vector resistance is mainly restricted to mosquito populations located in residential and public areas, whereas commercial settings, such as hotels are overlooked. This may obscure the real magnitude of the insecticide resistance problem and lead to ineffective vector control and resistance management. We investigated the profile of insecticide susceptibility of Aedes aegypti mosquitoes occurring at selected hotel compounds on Zanzibar Island. At least 100 adults Ae. aegypti females from larvae collected at four hotel compounds were exposed to papers impregnated with discriminant concentrations of DDT (4%), permethrin (0.75%), 0.05 deltamethrin (0.05%), propoxur (0.1%) and bendiocarb (0.1%) to determine their susceptibility profile. Allele-specific qPCR and sequencing analysis were applied to determine the possible association between observed resistance and presence of single nucleotide polymorphisms (SNPs) in the voltage-gated sodium channel gene (VGSC) linked to DDT/pyrethroid cross-resistance. Additionally, we explored the possible involvement of Glutathione-S-Transferase gene (GSTe2) mutations for the observed resistance profile. In vivo resistance bioassay indicated that Ae. aegypti at studied sites were highly resistant to DDT, mortality rate ranged from 26.3% to 55.3% and, moderately resistant to deltamethrin with a mortality rate between 79% to and 100%. However, genotyping of kdr mutations affecting the voltage-gated sodium channel only showed a low frequency of the V1016G mutation (n = 5; 0.97%). Moreover, for GSTe2, seven non-synonymous SNPs were detected (L111S, C115F, P117S, E132A, I150V, E178A and A198E) across two distinct haplotypes, but none of these were significantly associated with the observed resistance to DDT. Our findings suggest that cross-resistance to DDT/deltamethrin at hotel compounds in Zanzibar is not primarily mediated by mutations in VGSC. Moreover, the role of identified GSTe2 mutations in the resistance against DDT remains inconclusive. We encourage further studies to investigate the role of other potential insecticide resistance markers.
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Saingamsook, Jassada, Jintana Yanola, Nongkran Lumjuan, Catherine Walton, and Pradya Somboon. "Investigation of Relative Development and Reproductivity Fitness Cost in Three Insecticide-Resistant Strains of Aedes aegypti from Thailand." Insects 10, no. 9 (August 22, 2019): 265. http://dx.doi.org/10.3390/insects10090265.
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Knockdown resistance (kdr) and detoxification enzymes are major resistance mechanisms in insecticide-resistant Aedes aegypti throughout the world. Persistence of the resistance phenotype is associated with high fitness of resistance alleles in the absence of insecticide pressure. This study determined the relative fitness cost of three insecticide-resistant strains of Aedes aegypti—PMD, PMD-R, and UPK-R—and a hybrid under similar laboratory conditions in the absence of insecticide. The PMD strain is resistant to DDT with no kdr alleles; the PMD-R is resistant to DDT and permethrin with 1534C homozygous kdr alleles; and UPK-R is resistant to DDT, permethrin, and deltamethrin with 989P + 1016G homozygous alleles. The DDT-resistant PMD strain had the highest fitness compared with the two DDT/pyrethroid-resistant strains (PMD-R and UPK-R) and hybrid. Consistent fitness costs were observed in the DDT/pyrethroid-resistant strains and hybrid, including shorter wing length, reduced egg hatchability, shorter female lifespan, and shorter viability of eggs after storage, whereas no effect was observed on blood feeding rate. In addition, reduced egg production was observed in the PMD-R strain and prolonged developmental time was seen in the UPK-R strain. The corresponding hybrid that is heterozygous for kdr alleles was fitter than either of the homozygous mutant genotypes. This is in accordance with the high frequency of heterozygous genotypes observed in natural populations of Ae. aegypti in Chiang Mai city.
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Djiappi-Tchamen, Borel, Mariette Stella Nana-Ndjangwo, Konstantinos Mavridis, Abdou Talipouo, Elysée Nchoutpouen, Idene Makoudjou, Roland Bamou, et al. "Analyses of Insecticide Resistance Genes in Aedes aegypti and Aedes albopictus Mosquito Populations from Cameroon." Genes 12, no. 6 (May 28, 2021): 828. http://dx.doi.org/10.3390/genes12060828.
Full textAbstract:
The emergence of insecticide resistance in Aedes mosquitoes could pose major challenges for arboviral-borne disease control. In this paper, insecticide susceptibility level and resistance mechanisms were assessed in Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) from urban settings of Cameroon. The F1 progeny of Aedes aegypti and Aedes albopictus collected in Douala, Yaoundé and Dschang from August to December 2020 was tested using WHO tube assays with four insecticides: deltamethrin 0.05%, permethrin 0.75%, DDT 4% and bendiocarb 0.1%. TaqMan, qPCR and RT-qPCR assays were used to detect kdr mutations and the expression profiles of eight detoxification genes. Aedes aegypti mosquitoes from Douala were found to be resistant to DDT, permethrin and deltamethrin. Three kdr mutations, F1534C, V1016G and V1016I were detected in Aedes aegypti populations from Douala and Dschang. The kdr allele F1534C was predominant (90%) in Aedes aegypti and was detected for the first time in Aedes albopictus (2.08%). P450s genes, Cyp9J28 (2.23–7.03 folds), Cyp9M6 (1.49–2.59 folds), Cyp9J32 (1.29–3.75 folds) and GSTD4 (1.34–55.3 folds) were found overexpressed in the Douala and Yaoundé Aedes aegypti populations. The emergence of insecticide resistance in Aedes aegypti and Aedes albopictus calls for alternative strategies towards the control and prevention of arboviral vector-borne diseases in Cameroon.
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Kouamo, Mersimine F. M., Sulaiman S. Ibrahim, Jack Hearn, Jacob M. Riveron, Michael Kusimo, Magellan Tchouakui, Terence Ebai, et al. "Genome-Wide Transcriptional Analysis and Functional Validation Linked a Cluster of Epsilon Glutathione S-Transferases with Insecticide Resistance in the Major Malaria Vector Anopheles funestus across Africa." Genes 12, no. 4 (April 13, 2021): 561. http://dx.doi.org/10.3390/genes12040561.
Full textAbstract:
Resistance is threatening the effectiveness of insecticide-based interventions in use for malaria control. Pinpointing genes associated with resistance is crucial for evidence-based resistance management targeting the major malaria vectors. Here, a combination of RNA-seq based genome-wide transcriptional analysis and RNA-silencing in vivo functional validation were used to identify key insecticide resistance genes associated with DDT and DDT/permethrin cross-resistance across Africa. A cluster of glutathione-S-transferase from epsilon group were found to be overexpressed in resistant populations of Anopheles funestus across Africa including GSTe1 [Cameroon (fold change, FC: 2.54), Ghana (4.20), Malawi (2.51)], GSTe2 [Cameroon (4.47), Ghana (7.52), Malawi (2.13)], GSTe3 [Cameroon (2.49), Uganda (2.60)], GSTe4 in Ghana (3.47), GSTe5 [Ghana (2.94), Malawi (2.26)], GSTe6 [Cameroun (3.0), Ghana (3.11), Malawi (3.07), Uganda (3.78)] and GSTe7 (2.39) in Ghana. Validation of GSTe genes expression profiles by qPCR confirmed that the genes are differentially expressed across Africa with a greater overexpression in DDT-resistant mosquitoes. RNAi-based knock-down analyses supported that five GSTe genes are playing a major role in resistance to pyrethroids (permethrin and deltamethrin) and DDT in An. funestus, with a significant recovery of susceptibility observed when GSTe2, 3, 4, 5 and GSTe6 were silenced. These findings established that GSTe3, 4, 5 and 6 contribute to DDT resistance and should be further characterized to identify their specific genetic variants, to help design DNA-based diagnostic assays, as previously done for the 119F-GSTe2 mutation. This study highlights the role of GSTes in the development of resistance to insecticides in malaria vectors and calls for actions to mitigate this resistance.
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Hemingway, J., S. W. Lindsay, G. J. Small, M. Jawara, and F. H. Collins. "Insecticide susceptibility status in individual species of the Anopheles gambiae complex (Diptera: Culicidae) in an area of The Gambia where pyrethroid impregnated bednets are used extensively for malaria control." Bulletin of Entomological Research 85, no. 2 (June 1995): 229–34. http://dx.doi.org/10.1017/s0007485300034301.
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AbstractPyrethroid-impregnated bednets are being used nationwide in The Gambia. The future success of this malaria control programme depends partly on the vectors remaining susceptible to those insecticides used for treating the nets. The present study was carried out on the south bank of the river Gambia, during the first large scale trial of nets in this country. Thus this area represents a sentinel site for detecting insecticide resistance in local vectors. This study gives an example of how a system of early detection for resistance problems can be set up in a relatively complex situation where multiple vectors and non-vectors are present. Samples of the Anopheles gambiae complex were caught indoors using light traps in twelve villages used in the bednet study. In all villages A. gambiae sensu stricto Giles was the predominant member of the complex as determined using the rDNA-PCR diagnostic assay. Limited bioassays with DDT and permethrin, and biochemical assays for a range of insecticide resistance mechanisms suggest that the A. gambiae complex remains completely susceptible to all major classes of commonly used insecticides including pyrethroids. Biochemical assays suggest that a low frequency of DDT resistance may occur in A. melas Theobald. This is based on elevated glutathione S-transferase levels coupled with increased levels of DDT metabolism and does not involve cross-resistance to pyrethroids. Therefore we do not envisage a decline in the efficacy of treated nets against malaria vectors in the study area in the immediate future, although monitoring should be continued whilst wide-scale use of impregnated bednets is operational.
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T E Cusack, Paul. "Cresol & Insecticide DDT: A Cause of Autism & Alzheimer’s." Cancer Research and Cellular Therapeutics 7, no. 4 (September 27, 2023): 01–02. http://dx.doi.org/10.31579/2640-1053/154.
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Based on my previous paper on Autism, I wonder if it wasn’t caused in Danny M by DDT (dichloro, di methyl trichloroethane) which was used as an insecticide. Danny M grew up in a faming area which may have Refer to: Cusack PTE. On Autism: One Case. Adv Clin Toxicol 2021, 6(2): 000214 Acetylcholine is replaced by a chlorine from DDT. Autism therefore may have been caused by DDT spraying. I think it is worth fit for someone to explore the connection. The report states that at least 5.7 million kg of DDT were sprayed on New Brunswick forests between 1952 and 1968. In comparison, Quebec used less than one million kg during the same time period.
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Intan Nur Laili Izzah, Selviani Eka Suci, Yuliani Dewi, and Nia Yuniarsih. "The Potential of Natural Ingredients as Anti Pediculosis capitis: A Narrative Review." Archives of The Medicine and Case Reports 3, no. 4 (June 20, 2022): 300–303. http://dx.doi.org/10.37275/amcr.v3i4.217.
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Head louse (Pediculus humanus capitis) is a small parasite that feeds itself by sucking human blood, which causes infection of the scalp so that it becomes inflamed. The most common way to kill fleas is through the use of pharmaceutical insecticides. Some insecticide products contain permethrin, lindane, and DDT which are toxic to the body and are not easily biodegradable in the environment. Uncontrolled use of insecticides can make ticks resistant to these insecticides. Lemon, kirinyuh leaves, pandan wangi, Srikaya leaves, garlic, jarak pagar, citronella leaves, papaya, and lime have potential as anti-parasitic head lice.
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Bamou, Roland, Edmond Kopya, Leslie Diane Nkahe, Benjamin D. Menze, Parfait Awono-Ambene, Timoléon Tchuinkam, Flobert Njiokou, Charles S. Wondji, and Christophe Antonio-Nkondjio. "Increased prevalence of insecticide resistance in Anopheles coluzzii populations in the city of Yaoundé, Cameroon and influence on pyrethroid-only treated bed net efficacy." Parasite 28 (2021): 8. http://dx.doi.org/10.1051/parasite/2021003.
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In Cameroon, pyrethroid-only long-lasting insecticidal nets (LLINs) are still largely used for malaria control. The present study assessed the efficacy of such LLINs against a multiple-resistant population of the major malaria vector, Anopheles coluzzii, in the city of Yaoundé via a cone bioassay and release-recapture experimental hut trial. Susceptibility of field mosquitoes in Yaoundé to pyrethroids, DDT, carbamates and organophosphate insecticides was investigated using World Health Organization (WHO) bioassay tube tests. Mechanisms of insecticide resistance were characterised molecularly. Efficacy of unwashed PermaNet® 2.0 was evaluated against untreated control nets using a resistant colonised strain of An. coluzzii. Mortality, exophily and blood feeding inhibition were estimated. Field collected An. coluzzii displayed high resistance with mortality rates of 3.5% for propoxur (0.1%), 4.16% for DDT (4%), 26.9% for permethrin (0.75%), 50.8% for deltamethrin (0.05%), and 80% for bendiocarb (0.1%). High frequency of the 1014F west-Africa kdr allele was recorded in addition to the overexpression of several detoxification genes, such as Cyp6P3, Cyp6M2, Cyp9K1, Cyp6P4 Cyp6Z1 and GSTe2. A low mortality rate (23.2%) and high blood feeding inhibition rate (65%) were observed when resistant An. coluzzii were exposed to unwashed PermaNet® 2.0 net compared to control untreated net (p < 0.001). Furthermore, low personal protection (52.4%) was observed with the resistant strain, indicating reduction of efficacy. The study highlights the loss of efficacy of pyrethroid-only nets against mosquitoes exhibiting high insecticide resistance and suggests a switch to new generation bed nets to improve control of malaria vector populations in Yaoundé.
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Adefia, Almeira Putri, Astri Rinanti, Melati Ferianita Fachrul, Astari Minarti, Sarah Aphirta, Lutfia Rahmiyati, Sheilla Megagupita Putri Marendra, and Thalia Sunaryo. "Dichloro Diphenyl Trichloroethane (DDT) Insecticide Polluted Soil Remediation by Bacteria Consortium with Co-Substrate Utilization." E3S Web of Conferences 500 (2024): 02009. http://dx.doi.org/10.1051/e3sconf/202450002009.
Full textAbstract:
Dichloro Diphenyl Trichloroethane (DDT) is an organochlorine insecticide that are largely used on agriculture and health sectors. DDT is an organic pollutant that are difficult to be dissolved and tend to survive in the environment for a long time because it is highly stable and persistent. DDT insecticide residue is still discovered in the soil even though its utilization has been stopped years ago and still negatively impacting human life and the environment through bio accumulation and bio magnification. Bioremediation is a potential method to remove recalcitrance compound such as DDT. The objective of this study is to gather and analyze information on DDT degradation by bacteria consortium with co-substrate addition. Pseudomonas putida and Pseudomonas stutzeri bacteria consortium were utilized to remediate DDT with glucose, sucrose, and yeast extract as cosubstrates. During 72 hours of observation, the three co-substrates namely yeast extract, glucose, and sucrose are able to degrade 75%, 56% and 39.55% of 10 ppm DDT. Yeast is the most ideal co-substrate to assist bacteria consortium growth and to degrade DDT. The implementation of pilot scale land treatment bioremediation is planned to be at 50m3, with dimension of 20m length, 5m wide, and 0.5m high. The efficiency of the removal reached 90% with 67 hours of detention time.
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Wan-Norafikah, Othman, Narimah Abdul Hamid Hasani, Abu Bakar Nabila, Ibrahim Najibah, Abdul Hadi Hazirah Nurjuani, Muhamad Masliana, Sharifah Aliah-Diyanah, et al. "Insecticide Susceptibility Tests of Aedes albopictus Skuse in Geothermal Hot Springs, Malaysia." Chiang Mai Journal of Science 51, no. 1 (January 31, 2024): 1–13. http://dx.doi.org/10.12982/cmjs.2024.011.
Full textAbstract:
Dengue fever is a major public health concern, including more than 20,000 reported dengue cases annually in Malaysia. Aedes albopictus is the primary vector of chikungunya and secondary vector of dengue and Zika viruses. The susceptibility to dichlorodiphenyltrichloroethane (DDT), dieldrin, fenitrothion, pirimiphos-methyl, propoxur and bendiocarb of Ae. albopictus from four hot springs in Selangor, Malaysia was ascertained in accordance with World Health Organization guidelines. Threeto fi ve-day old female mosquitoes which were reared from eggs collected by ovitraps were exposed to discriminating dosages of insecticides for 1 hr recommended exposure period, and the 24 h mortality was recorded. The Kerling Hot spring (KERL) population was susceptible to six insecticides. All four fi eld populations were susceptible to pirimiphos-methyl 0.25% indicating it could be considered as a replacement insecticide for future vector control operations. Propoxur is the second in line as an alternative insecticide based on mortality > 80.0%. Nevertheless, it is necessary to confi rm their crossresistance to pyrethroids and other organophosphates before using them in rotation in the management of insecticide resistance.
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Mishra, Ashok K., Mrigendra P. Singh, Aparup Das, and Kamaraju Raghavendra. "First Report on Intensity Bioassays for Pyrethroid Resistance in Anopheles culicifacies s.l in District Dindori of Madhya Pradesh State and Districts Kanker and Bastar of Chhattisgarh State, India." Journal of Tropical Medicine 2022 (September 20, 2022): 1–8. http://dx.doi.org/10.1155/2022/1595604.
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Background. The major malaria vector in India is Anopheles culicifacies, and indoor residual spraying (IRS) and distribution of long-lasting insecticidal nets (LLINs) are the two main vector control measures in the national program. This species has shown resistance to dichlorodiphenyltrichloroethane (DDT), malathion, and synthetic pyrethroids (SP). The study was carried out in three districts, that is, Dindori of Madhya Pradesh and Kanker and Bastar from Chhattisgarh state to know the range of resistance phenotypes and to assess the strength of resistance in An. culicifacies. Methods. An. culicifacies collected from the field was tested to determine the susceptibility status to the discriminating concentration (DC) of different insecticides, that is, DDT 4.0%, malathion 5.0%, alphacypermethrin 0.05%, and deltamethrin 0.05% following the World Health Organization (WHO) procedures. Further, intensity bioassays of the resistant An. culicifacies to 1X discriminating concentration (DC) of alphacypermethrin and deltamethrin were conducted by exposing 5X and 10X concentrations of 1X DC. Results are interpreted as per the WHO criterion. Results. The overall result of susceptibility status in An. culicifacies in districts Dindori, Kanker, and Bastar revealed confirmed resistance to DDT, malathion, alphacypermethrin, and deltamethrin registering mortality of 15% (10–20%), 70% (65–75%), 78.6% (77–82.5%), and 87% (84.8–91.3%), respectively. Further, in district Dindori and Baster, the intensity bioassay test at 5X DC of alphacypermethrin and deltamethrin revealed 99% and 100%, respectively, while in district Kanker, the species registered moderate resistance with 92.5% and 95% mortality, respectively, in 5X DC of alphacypermethrin and deltamethrin. However, in 10X DC, the An. culicifacies was susceptible to both pyrethroids (100%) in district Kanker. Conclusion. The results of the intensity bioassay tests with SP-resistant An. culicifacies suggested no change of insecticide is required in the ongoing intervention. However, regular monitoring of insecticide susceptibility and intensity bioassays in malaria vectors in view of continued use of these interventions may increase resistance and for implementing effective vector management strategies.
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Sadia, Christabelle G., France-Paraudie A. Kouadio, Behi K. Fodjo, Sebastien K. Oyou, Adepo-Gourene A. Beatrice, Benjamin G. Koudou, and Chouaïbou S. Mouhamadou. "Short-term metabolic resistance inductive effect of different agrochemical groups on Anopheles gambiae mosquitoes." Wellcome Open Research 6 (October 28, 2021): 147. http://dx.doi.org/10.12688/wellcomeopenres.16876.2.
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Background: In order to assess the impact of the different groups of agricultural pesticides used in Côte d'Ivoire on the increase of mosquitoes resistance to insecticides, the expression profiles of 7 P450 cytochromes and one GSTE2 of Anopheles gambiae involved in mosquito resistance to insecticides were studied. The goal of this study was to determine the effect of short exposure of mosquito larvae to different groups of agricultural pesticides on mosquito resistance. Methods: Three groups of pesticides were selected: (i) agricultural insecticide solutions, (ii) non-insecticide pesticide solutions (a mixture of herbicides and fungicides), and (iii) a mixture of the first two. A fourth non-pesticide solution was used as a control. Four groups of each stage 2 larvae (strain Kisumu, male and female) were exposed to 20% concentrated solution for 24 hours. Susceptibility tests for dichlorodiphenyltrichloroethane (DDT) and Deltamethrin were carried out on adults aged 2-5 days. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was performed to quantify the expression of eight metabolic genes involved in mosquito resistance to insecticides. Results: Susceptibility to DDT showed a similar increase in the time required to knock down 50% of mosquitoes (kdt50) in l colonies exposed to insecticides and non-insecticides compared to the control colony. As for deltamethrin, kdt50 was higher in the colonies exposed to insecticides and the pesticide mixture compared to the colony exposed to non-insecticides. Of all the genes studied in all colonies, except for CYP6P1 induced only in the colony consisting of the pesticide mixture, no genes were induced. Conclusions: This study confirmed that induction is influenced by the duration, the concentration of the solution and the type of xenobiotic used as an inducer. The overexpression of CYP6P1 confirmed the inductive effect that a short exposure of mosquito larvae to agricultural pesticides could have.
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Sadia, Christabelle G., France-Paraudie A. Kouadio, Behi K. Fodjo, Sebastien K. Oyou, Adepo-Gourene A. Beatrice, Benjamin G. Koudou, and Chouaïbou S. Mouhamadou. "Short-term metabolic resistance inductive effect of different agrochemical groups on Anopheles gambiae mosquitoes." Wellcome Open Research 6 (June 11, 2021): 147. http://dx.doi.org/10.12688/wellcomeopenres.16876.1.
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Background: In order to assess the impact of the different groups of agricultural pesticides used in Côte d'Ivoire on the increase of mosquitoes resistance to insecticides, the expression profiles of 7 P450 cytochromes and one GSTE2 of Anopheles gambiae involved in mosquito resistance to insecticides were studied. The goal of this study was to determine the effect of short exposure of mosquito larvae to different groups of agricultural pesticides on mosquito resistance. Methods: Three groups of pesticides were selected: (i) agricultural insecticide solutions, (ii) none-insecticide pesticide solutions (a mixture of herbicides and fungicides), and (iii) a mixture of the first two. A fourth non-pesticide solution was used as a control. Four groups of each stage 2 larvae (strain Kisumu, male and female) were exposed to 20% concentrated solution for 24 hours. Susceptibility tests for dichlorodiphenyltrichloroethane (DDT) and Deltamethrin were carried out on adults aged 2-5 days. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was performed to quantify the expression of eight metabolic genes involved in mosquito resistance to insecticides. Results: Susceptibility to DDT showed a similar increase in the time required to knock down 50% of mosquitoes (kdt50) in l colonies exposed to insecticides and none-insecticides compared to the control colony. As for deltamethrin, kdt50 was higher in the colonies exposed to insecticides and the pesticide mixture compared to the colony exposed to none-insecticides. Of all the genes studied in all colonies, except for CYP6P1 induced only in the colony consisting of the pesticide mixture, no genes were induced. Conclusions: This study confirmed that induction is influenced by the duration, the concentration of the solution and the type of xenobiotic used as an inducer. The overexpression of CYP6P1 confirmed the inductive effect that a short exposure of mosquito larvae to agricultural pesticides could have.
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Jones, Aaryn D., Andrew T. Morehead, and Yu Yang. "Degradation and Extraction of Organochlorine Pollutants from Environmental Solids under Subcritical Water Conditions." Molecules 28, no. 14 (July 16, 2023): 5445. http://dx.doi.org/10.3390/molecules28145445.
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A subcritical water degradation and extraction method was developed to remediate environmental soils contaminated by highly recalcitrant organochlorine pollutants. Hydrogen peroxide was used to effectively decompose organochlorine pollutants under subcritical water conditions. As a method optimization study, the static wet oxidation of chlorophenols was first performed in subcritical water with and without added hydrogen peroxide. Complete oxidation was achieved using an added oxidant, and thus, the oxidation and extraction of chlorophenols from a sand matrix was then attempted. Complete oxidation and extraction with added oxidant were achieved within 30 min at 100 °C. We then investigated the subcritical water degradation and extraction of dieldrin, mirex, and p,p′-DDD. These organochlorine pesticides were not as easily oxidized as the chlorophenols, and the benefit of adding hydrogen peroxide was only clearly observed at 200 °C. Approximately a 20% increase in degradation was noted for each pesticide and insecticide at this temperature. Unfortunately, this difference was not observed with an increase in temperature to 250 °C, except in some cases, where the amount of degradation byproducts was reduced. Dieldrin and p,p′-DDD were essentially destroyed at 250 °C, while all the pesticides and the insecticides were completely removed from the sand at this temperature. The proposed method was then used to remediate a soil sample highly contaminated with DDT. The soil was obtained from the grounds of an old DDT mixing facility in Virginia and has been aging for several decades. Not only was 100% removal of DDT from this soil achieved using the proposed method at 250 °C, but also, the extracted DDT was completely destroyed during the process. The proposed remediation method, therefore, demonstrates a high potential as an efficient and environmentally sound technique for the detoxification of soils.
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El-Sayed, S., J. Hemingway, and R. P. Lane. "Susceptibility baselines for DDT metabolism and related enzyme systems in the sandfly Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae)." Bulletin of Entomological Research 79, no. 4 (November 1989): 679–84. http://dx.doi.org/10.1017/s0007485300018836.
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AbstractDDT metabolism in Phlebotomus papatasi (Scopoli) was investigated and compared to that in DDT-resistant and susceptible strains of Culex quinquefasciatus Say and Anopheles gambiae Giles with the objective of establishing baselines for sandfly studies. P. papatasi produced eight metabolites of DDT, with DDE predominating, as in the two mosquito species. Both oxidases and glutathione transferases were found to be involved in DDT metabolism in insecticide-susceptible adults of P. papatasi. The activity level of glutathione transferases and the reduced and oxidized difference spectra of cytochrome P-450 were measured spectrophotometrically. The level of glutathione transferase activity in P. papatasi was lower than that in susceptible C. quinquefasciatus adults when expressed in terms of the activity per milligram of soluble protein but, in contrast, the cytochrome P-450 was slightly higher in both the reduced and oxidized states.
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Djègbè, Innocent, Romaric Akoton, Genevieve M. Tchigossou, Koffi Mensah Ahadji-Dabla, Seun Michael Atoyebi, Razack Adéoti, Francis Zeukeng, Guillaume Koffivi Ketoh, and Rousseau Djouaka. "First report of the presence of L1014S Knockdown-resistance mutation in Anopheles gambiae s.s and Anopheles coluzzii from Togo, West Africa." Wellcome Open Research 3 (March 19, 2018): 30. http://dx.doi.org/10.12688/wellcomeopenres.13888.1.
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Background: To optimize the success of insecticide-based malaria control intervention, knowledge of the distribution of Anopheles gambiae species and insecticide resistance mechanisms is necessary. This paper reported an updated data on pyrethroids/DDT resistance in the An. gambiae s.l population from Togo. Methods: From December 2013 to April 2015, females of indoor-resting An. gambiae s.l were captured in three locations belonging to three different ecological zones. Resistance to DDT, permethrin and deltamethrin was screened in F1 progeny of collected mosquitoes using WHO susceptibility tests. The identification of species of An. gambiae complex and the detection of kdr and ace.1R allele were carried out using DNA-based molecular techniques. Results: An. gambiae from Kovié and Nangbéto were highly resistant to DDT and permethrin with mortalities rate ranging from 0.83% to 1.58% for DDT and zero to 8.54% for permethrin. Mosquitoes collected in Nangbéto displayed 81.53% mortality with deltamethrin. An. coluzzii and An. gambiae s.s were found in sympatry in Nangbéto and Mango. The allelic frequency of L1014F was high, ranging from 66 to 100% in both An. coluzzii and An. gambiae s.s. For the first time we detected the L1014S allele in both An. coluzzii and An. gambiae s.s. from Togo at the frequency ranging from 5% to 13% in all the sites. The kdr N1575Y was present at various frequencies in both species ranging from 10% to 45%. Both An. gambiae s.s. and An. coluzzii shared the ace1R mutation in all investigated sites with allelic frequency ranging from 4% to 16%. Conclusion: These results showed that multiple mutations are involved in insecticides resistance in An. gambiae populations from Togo including the kdr L1014F, L1014S, and N1575Y and ace.1R G119S mutations.
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Scott, Jeffrey G. "Life and Death at the Voltage-Sensitive Sodium Channel: Evolution in Response to Insecticide Use." Annual Review of Entomology 64, no. 1 (January 7, 2019): 243–57. http://dx.doi.org/10.1146/annurev-ento-011118-112420.
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The voltage-sensitive sodium channel (VSSC) is a critical component of the insect nervous system. Pyrethroids and DDT are insecticides that have been widely used, and they kill insects by perturbations of the VSSC. Decades of insecticide use selected for mutations in Vssc that give rise to resistance in almost all pest insects. However, the mutations responsible for the resistance are not always the same, and some unusual patterns have emerged. This review focuses on what pyrethroid/DDT selection has done, in terms of Vssc changes that have occurred, using four well-studied species as examples of the differences that have evolved. Information is provided about the mutations that occur, potential pathways by which alleles with multiple mutations arose, the relative fitness of the alleles, the levels of resistance conferred, and the geographic distribution of the mutations. The lessons learned and exciting new areas of research are discussed.
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Galván-Portillo, Marcia, Carlos Jiménez-Gutiérrez, Luisa Torres-Sánchez, and Lizbeth López-Carrillo. "Food consumption and adipose tissue DDT levels in Mexican women." Cadernos de Saúde Pública 18, no. 2 (April 2002): 447–52. http://dx.doi.org/10.1590/s0102-311x2002000200009.
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This article analyzes food consumption in relation to levels of DDE (the principal metabolite of DDT) in the adipose tissue of 207 Mexican women residing in States with high and low exposure to DDT. Data on the women's dietary habits and childbearing history were obtained from a personal interview. Adipose tissue DDE levels were measured by gas-liquid chromatography and compared by analysis of variance (ANOVA) and multiple linear regression. Adipose tissue DDE levels increased significantly with age (p = 0.005) and residence in coastal areas (p = 0.002) and non-significantly with the consumption of onion, cauliflower, prickly pear, squash blossoms, sweet corn, broad beans, chili pepper sauce, ham, and fish. Even so, during breastfeeding there was a non-significant reduction in these levels. The findings suggest that certain foods serve as vehicles for DDE residues and confirm that breastfeeding is a mechanism for the elimination of this insecticide, which accumulates over the years in the human body.
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Agbor, Okemena V., Taiwo E. Idowu, Kayode I. Fagbohun, Amos T. Oyeniyi, Romoke T. Jimoh, and Adetoro O. Otubanjo. "Molecular Identification and Insecticide Resistance Status of Culex mosquitoes collected from blocked drainages in Lagos State, Nigeria." Pan African Journal of Life Sciences 4, no. 1 (April 1, 2020): 1–6. http://dx.doi.org/10.36108/pajols/0202/40(0110).
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Background: Culex mosquitoes are important vectors of several human pathogens causing infections such as lymphatic filariasis and several viruses. Poor and blocked drainage system can lead to impediment in water flow, leading to the artificial creation of larval habitats for Culex mosquitoes. Culex mosquitoes has the ability to breed in organically polluted water bodies and exhibit high resistance to insecticides. Therefore, this study assessed the species and insecticides susceptibility status of Culex breeding in blocked drainages in Lagos State. Methods: Culex mosquito larvae were collected from blocked drainages in three Local Government Areas (LGAs) of Lagos State, Nigeria, using standard WHO technique. The physicochemical parameters of the larval habitats were also recorded. Collected mosquito larvae were raised to adult, 2-3 days old. Glucose fed adults female mosquitoes were exposed to permethrin (0.75%) and DDT (4.0%) WHO insecticide test papers. Morphological identification was carried out using standard keys and molecular identification of Culex pipiens sub-species and kdr genotyping was carried out using PCR Results: High level of resistance was recorded with mortality r ate after 24 hour s for DDT ranging from 20% to 32% while permethrin ranges from 14% to 36%. The pH of the all the Culex mosquito larva habitats ranges from 7.38±0.11 to 7.62±0.29, while TDS ranges from 592.6±79.1 to 655±68.1. A total of 1113 Culex pipiens mosquitoes that were identify morphologically, some were selected for molecular identification using PCR assays, out of which 96.2% were identified as Culex p. quinquefasciatus while 3.7% were unidentified. Knockdown mutation (L1014F) was not detected in DDT and pyrethroids resistant Cx. quinquefasciatus in this study. Conclusion: Unplanned ur banization, inadequate w ater su pply and inefficient solid w aste and sewage management practices can result in the creation artificial larval habitats for Culex mosquitoes leading to potential outbreak of Culex mosquito borne diseases. The resistance to DDT and permethrin insecticides in Cx. quinquefasciatus in Lagos State may represent a threat towards the efficacy of ITNs and other forms of vector control such as indoor residual spraying in the future.
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Hajibeygi, Ramtin, Seyed Zia Hejripour, Nader Taghavi, Hamzeh Shahali, Saeed Zarei, Majid Nouri, Hadi Mirahmadi, Seyed Mahdi Tabatabaie, Rahmat Solgi, and Mohammad Darvishi. "Evaluation of the knockdown resistance locus (kdr) in Anopheles stephensi (Diptera: Culicidae) in southeastern Iran." Journal of Vector Borne Diseases 60, no. 4 (2023): 444–48. http://dx.doi.org/10.4103/0972-9062.383648.
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Background & objectives: The resistance to insecticide among Anopheles stephensi population due to insecticide selection pressure has been previously reported from Iran. The current study was performed to evaluate the susceptibility of different insecticide reagents against An. stephensi by bioassay and molecular methods in Saravan County, a malaria-endemic area in southeastern Iran. Methods: An. stephensi mosquitoes were collected from different larval habitats in Saravan City, southeastern Iran in 2022. At first, the susceptibility of collected samples for DDT, permethrin, and deltamethrin were evaluated by bioassay test. The collected mosquitoes were then evaluated for the presence of different kdr mutations. Results: Insecticide susceptibility tests were conducted on the field population of An. stephensi from Saravan, revealing its potential resistance to pyrethroids and DDT. Of the 150 An. stephensi samples, 4 % carried the kdr L1014F mutation as heterozygous and the rest of them were homozygous L1014 wild type. Interpretation & conclusion: The current study revealed the presence of L1014F mutation for the first time in Iran. So, further monitoring of kdr mutations in the VGSC gene and resistance phenotypes should be performed.
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Smith, Graham. "1,1,1-Trichloro-2,2-bis(4-iodophenyl)ethane." Acta Crystallographica Section E Structure Reports Online 68, no. 8 (July 21, 2012): o2504. http://dx.doi.org/10.1107/s1600536812032254.
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In the structure of the title compound, C14H9Cl3I2, which is the 4-iodophenyl analogue of the insecticide DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], isomorphism between the two compounds has been confirmed. In the molecule, the dihedral angle between the planes of the two benzene rings is 65.8 (4)° which compares with 64.7 (7)° in DDT.
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Yan, Guiyun, Dave D. Chadee, and David W. Severson. "Evidence for Genetic Hitchhiking Effect Associated With Insecticide Resistance in Aedes aegypti." Genetics 148, no. 2 (February 1, 1998): 793–800. http://dx.doi.org/10.1093/genetics/148.2.793.
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Abstract Information on genetic variation within and between populations is critical for understanding the evolutionary history of mosquito populations and disease epidemiology. Previous studies with Drosophila suggest that genetic variation of selectively neutral loci in a large fraction of genome may be constrained by fixation of advantageous mutations associated with hitchhiking effect. This study examined restriction fragment length polymorphisms of four natural Aedes aegypti mosquito populations from Trinidad and Tobago, at 16 loci. These populations have been subjected to organophosphate (OP) insecticide treatments for more than two decades, while dichlor-diphenyltrichlor (DDT) was the insecticide of choice prior to this period. We predicted that genes closely linked to the OP target loci would exhibit reduced genetic variation as a result of the hitchhiking effect associated with intensive OP insecticide selection. We also predicted that genetic variability of the genes conferring resistance to DDT and loci near the target site would be similar to other unlinked loci. As predicted, reduced genetic variation was found for loci in the general chromosomal region of a putative OP target site, and these loci generally exhibited larger FST values than other random loci. In contrast, the gene conferring resistance to DDT and its linked loci show polymorphisms and genetic differentiation similar to other random loci. The reduced genetic variability and apparent gene deletion in some regions of chromosome 1 likely reflect the hitchhiking effect associated with OP insecticide selection.
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Ibrahim, Sulaiman S., Muhammad M. Mukhtar, Helen Irving, Jacob M. Riveron, Amen N. Fadel, Williams Tchapga, Jack Hearn, Abdullahi Muhammad, Faruk Sarkinfada, and Charles S. Wondji. "Exploring the Mechanisms of Multiple Insecticide Resistance in a Highly Plasmodium-Infected Malaria Vector Anopheles funestus Sensu Stricto from Sahel of Northern Nigeria." Genes 11, no. 4 (April 22, 2020): 454. http://dx.doi.org/10.3390/genes11040454.
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The Nigerian Government is scaling up the distribution of insecticide-treated bed nets for malaria control, but the lack of surveillance data, especially in the Sudan/Sahel region of the country, may hinder targeting priority populations. Here, the vectorial role and insecticide resistance profile of a population of a major malaria vector Anopheles funestus sensu stricto from Sahel of Nigeria was characterised. An. funestus s.s. was the only vector found, with a high human blood index (100%) and a biting rate of 5.3/person/night. High Plasmodium falciparum infection was discovered (sporozoite rate = 54.55%). The population is resistant to permethrin (mortality = 48.30%, LT50 = 65.76 min), deltamethrin, DDT (dichlorodiphenyltrichloroethane) and bendiocarb, with mortalities of 29.44%, 56.34% and 54.05%, respectively. Cone-bioassays established loss of efficacy of the pyrethroid-only long-lasting insecticidal nets (LLINs); but 100% recovery of susceptibility was obtained for piperonylbutoxide (PBO)-containing PermaNet®3.0. Synergist bioassays with PBO and diethyl maleate recovered susceptibility, implicating CYP450s (permethrin mortality = 78.73%, χ2 = 22.33, P < 0.0001) and GSTs (DDT mortality = 81.44%, χ2 = 19.12, P < 0.0001). A high frequency of 119F GSTe2 mutation (0.84) was observed (OR = 16, χ2 = 3.40, P = 0.05), suggesting the preeminent role of metabolic resistance. These findings highlight challenges associated with deployment of LLINs and indoor residual spraying (IRS) in Nigeria.
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Idowu, ET, IK Fagbohun, OS Agosu, TA Oyede, and OA Otubanjo. "Susceptibility Status of Anopheles Gambiae S.I. to DDT and Permethrin in Lagos State, Nigeria." NIGERIAN ANNALS OF PURE AND APPLIED SCIENCES 3, no. 1 (July 19, 2020): 8–13. http://dx.doi.org/10.46912/napas.152.
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Malaria is of public health importance in Nigeria and may retain its status, if new intervention methods are not introduced or the current ones monitored. This study was carried out in Alimosho, Kosofe, Ibeju-Lekki and Badagry Local Government Areas (LGAs) of Lagos State to assess the susceptibility status of Anopheles gambiae s.l., a dominant malaria vector in the localities to DDT 4% and Permethrin 0.75%. Anopheles larvae were collected from larva habitats in both LGAs, reared to adults and fed with 10% sucrose solution. Nonblood fed 2-5 days old female mosquitoes were exposed to discriminating doses of DDT and permethrin according to the standard WHO procedures. The knockdown effect was recorded at interval of 10 minutes and mortality scored 24hours after exposure. Species identification was done by morphological characteristics. Results from the study showed that Anopheles gambiae s.l. are resistant to DDT (4%) and permethrin (0.75%) with 24hr post exposure mortality ranging from 15.00-24.0% and 4.25-22.0% respectively. The Knockdown Time (KDT) ranged from 30.8-941.95minutes for DDT and 12.6-85.51minutes for permethrin. KDT95 50 ranges from 117.49-27524.22 minutes and 117.49-412.1 minutes for DDT and permethrin respectively. All the LGAs showed high level of resistance to DDT and permethrin. The high level of insecticide resistance recorded in this study could be detrimental to the elimination of malaria. Therefore, integrated vector management is needed to effectively carry out to manage the development of insecticide resistance.
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Matowo, Nancy S., Givemore Munhenga, Marcel Tanner, Maureen Coetzee, Wim F. Feringa, Halfan S. Ngowo, Lizette L. Koekemoer, and Fredros O. Okumu. "Fine-scale spatial and temporal heterogeneities in insecticide resistance profiles of the malaria vector, Anopheles arabiensis in rural south-eastern Tanzania." Wellcome Open Research 2 (October 2, 2017): 96. http://dx.doi.org/10.12688/wellcomeopenres.12617.1.
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Background: Programmatic monitoring of insecticide resistance in disease vectors is mostly done on a large scale, often focusing on differences between districts, regions or countries. However, local heterogeneities in residual malaria transmission imply the need for finer-scale data. This study reports small-scale variations of insecticide susceptibility in Anopheles arabiensis between three neighbouring villages across two seasons in Tanzania, where insecticidal bed nets are extensively used, but malaria transmission persists. Methods: WHO insecticide susceptibility assays were conducted on female and male An. arabiensis from three proximal villages, Minepa, Lupiro, and Mavimba, during dry (June-December 2015) and wet (January-May 2016) seasons. Adults emerging from wild-collected larvae were exposed to 0.05% lambda-cyhalothrin, 0.05% deltamethrin, 0.75% permethrin, 4% DDT, 4% dieldrin, 0.1% bendiocarb, 0.1% propoxur, 0.25% pirimiphos-methyl and 5% malathion. A hydrolysis probe assay was used to screen for L1014F (kdr-w) and L1014S (kdr-e) mutations in specimens resistant to DDT or pyrethroids. Synergist assays using piperonly butoxide (PBO) and triphenol phosphate (TPP) were done to assess pyrethroid and bendiocarb resistance phenotypes. Results: There were clear seasonal and spatial fluctuations in phenotypic resistance status in An. arabiensis to pyrethroids, DDT and bendiocarb. Pre-exposure to PBO and TPP, resulted in lower knockdown rates and higher mortalities against pyrethroids and bendiocarb, compared to tests without the synergists. Neither L1014F nor L1014S mutations were detected. Conclusions: This study confirmed the presence of pyrethroid resistance in An. arabiensis and showed small-scale differences in resistance levels between the villages, and between seasons. Substantial, though incomplete, reversal of pyrethroid and bendiocarb resistance following pre-exposure to PBO and TPP, and absence of kdr alleles suggest involvement of P450 monooxygenases and esterases in the resistant phenotypes. We recommend, for effective resistance management, further bioassays to quantify the strength of resistance, and both biochemical and molecular analysis to elucidate specific enzymes responsible in resistance.
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Wipf, Nadja C., Wandrille Duchemin, France-Paraudie A. Kouadio, Behi K. Fodjo, Christabelle G. Sadia, Chouaïbou S. Mouhamadou, Laura Vavassori, et al. "Multi-insecticide resistant malaria vectors in the field remain susceptible to malathion, despite the presence of Ace1 point mutations." PLOS Genetics 18, no. 2 (February 10, 2022): e1009963. http://dx.doi.org/10.1371/journal.pgen.1009963.
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Insecticide resistance in Anopheles mosquitoes is seriously threatening the success of insecticide-based malaria vector control. Surveillance of insecticide resistance in mosquito populations and identifying the underlying mechanisms enables optimisation of vector control strategies. Here, we investigated the molecular mechanisms of insecticide resistance in three Anopheles coluzzii field populations from southern Côte d’Ivoire, including Agboville, Dabou and Tiassalé. All three populations were resistant to bendiocarb, deltamethrin and DDT, but not or only very weakly resistant to malathion. The absence of malathion resistance is an unexpected result because we found the acetylcholinesterase mutation Ace1-G280S at high frequencies, which would typically confer cross-resistance to carbamates and organophosphates, including malathion. Notably, Tiassalé was the most susceptible population to malathion while being the most resistant one to the pyrethroid deltamethrin. The resistance ratio to deltamethrin between Tiassalé and the laboratory reference colony was 1,800 fold. By sequencing the transcriptome of individual mosquitoes, we found numerous cytochrome P450-dependent monooxygenases – including CYP6M2, CYP6P2, CYP6P3, CYP6P4 and CYP6P5 – overexpressed in all three field populations. This could be an indication for negative cross-resistance caused by overexpression of pyrethroid-detoxifying cytochrome P450s that may activate pro-insecticides, thereby increasing malathion susceptibility. In addition to the P450s, we found several overexpressed carboxylesterases, glutathione S-transferases and other candidates putatively involved in insecticide resistance.
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Antunes-Madeira, M. C., and Vítor M. C. Madeira. "Membrane fluidity as affected by the organochlorine insecticide DDT." Biochimica et Biophysica Acta (BBA) - Biomembranes 1023, no. 3 (April 1990): 469–74. http://dx.doi.org/10.1016/0005-2736(90)90141-a.
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