Synthetic Pyrethroids Permethrin Research Articles

Acute Toxicity of Malathion, Permethrin, and Roundup on the Tropical Freshwater Shrimp Xiphocaris elongata (Guérin-Méneville, 1855)

Urban and agricultural runoffs can transport contaminants and pesticides into freshwater ecosystems, particularly in the developing tropics. For instance, organophosphate and pyrethroids pesticides, such as Roundup, Malathion, and Permethrin, have been found in tropical streams. The uncontrolled application of these pesticides has become a growing concern due to their adverse effects on various non-targeted organisms. Unfortunately, most studies have focused on a few selected model species, ignoring the effects on other non-target organisms, which may play an important role in tropical lotic ecosystems. In addition, the biological characteristics of aquatic crustaceans, including their morphology, physiology, and behavior, make them susceptible to toxic chemicals. For this reason, this study used the widely distributed freshwater shrimp Xiphocaris elongata as a model organism to determine the acute toxicity of Permethrin, Malathion, and Roundup. Our results show that the proportion of mortality of X. elongata in each concentration group became progressively higher as the concentration of exposure increased. We also found that the synthetic pyrethroid Permethrin was the most toxic pesticide tested, with a median lethal concentration (LC50) value for 96 h of 3.96 × 10−6 µg·L−1, followed by organophosphate Malathion (8.87 µg·L−1) and Roundup (748.92 µg·L−1). Experiments with this freshwater shrimp showed a good control performance and reproducibility for the tested pesticides. This study demonstrated that X. elongata is a suitable test organism that can be a representative bioindicator of pesticide toxicity in tropical streams.

Acute Toxicity of Malathion, Permethrin, and Roundup on the Tropical Freshwater Shrimp Xiphocaris elongata (Guérin-Méneville, 1855)

Urban and agricultural runoffs can transport contaminants and pesticides into freshwater ecosystems, particularly in the developing tropics. For instance, organophosphate and pyrethroids pesticides, such as Roundup, Malathion, and Permethrin, have been found in tropical streams. The uncontrolled application of these pesticides has become a growing concern due to their adverse effects on various non-targeted organisms. Unfortunately, most studies have focused on a few selected model species, ignoring the effects on other non-target organisms, which may play an important role in tropical lotic ecosystems. In addition, the biological characteristics of aquatic crustaceans, including their morphology, physiology, and behavior, make them susceptible to toxic chemicals. For this reason, this study used the widely distributed freshwater shrimp Xiphocaris elongata as a model organism to determine the acute toxicity of Permethrin, Malathion, and Roundup. Our results show that the proportion of mortality of X. elongata in each concentration group became progressively higher as the concentration of exposure increased. We also found that the synthetic pyrethroid Permethrin was the most toxic pesticide tested, with a median lethal concentration (LC50) value for 96 h of 3.96 × 10−6 µg·L−1, followed by organophosphate Malathion (8.87 µg·L−1) and Roundup (748.92 µg·L−1). Experiments with this freshwater shrimp showed a good control performance and reproducibility for the tested pesticides. This study demonstrated that X. elongata is a suitable test organism that can be a representative bioindicator of pesticide toxicity in tropical streams.

Autophagy perturbation upon acute pyrethroid treatment impacts adipogenic commitment of mesenchymal stem cells

Environmental chemical exposure can cause dysregulation in adipogenesis that can result in metabolic syndrome, which includes insulin resistance, type 2 diabetes, cardiovascular disease, as well as excessive body weight. The role of autophagy in adipocyte differentiation is debatable since both positive and negative effects have been reported. Type-I and type-II synthetic pyrethroids α-cypermethrin (CPM) and permethrin (PER), respectively, are reported to increase adipogenesis in vitro and in vivo. However, it is not known how these pyrethroids affect mesenchymal stem cells (MSCs). Thus, this study focused on evaluating the effect of pyrethroids (CPM and PER) pre-treatment (24 h) on MSC commitment and the regulatory role of autophagy in adipogenic lineage commitment. The formation of adipocytes was observed through nile red staining, perilipin expression by immunoflourescence, and adipogenic markers PPARγ, C/EBPα, and FABP4 by western blotting. It was found that the adipogenic differentiation ability of MSCs was significantly increased upon CPM or PER pre-treatment at 100 μM concentration as evident by lipid accumulation and enhanced expression of adipogenic markers. To assess the involvement of autophagy, the expression of p62 and LC3II were evaluated following pre-treatment. Immunoblotting results revealed an increased expression of p62 and LC3II in CPM or PER pretreated MSCs suggesting CPM and PER mediated inhibition of autophagy at 24 h. Further, an increase was observed in adipogenesis upon CPM or PER pre-treatment in combination with chloroquine, while use of rapamycin during pre-treatment abrogated the effect of CPM and PER. Thus, this study concludes that CPM or PER pre-treatment increases the adipogenic differentiation of MSCs. Since chloroquine also demonstrated similar adipogenic response, it further highlights that 24 h pre-treatment with autophagy modulators to inhibit basal autophagy primes MSCs towards adipogenic lineage.

Toxic effects of the synthetic pyrethroid permethrin on the hematological parameters and antioxidant enzyme systems of the freshwater fish Cyprinus carpio L.

This study investigated changes in hematological and antioxidant parameters of carp exposed to two different doses of synthetic pyrethroid permethrin (control, vehicle, 10 ppm, and 20 ppm) for two different periods (4 days and 21 days). Hematological analyses were then performed on a veterinary Ms4 (Melet Schloesing, France) blood counter using commercially available kits (Cat. No. WD1153). Buege and Aust for MDA, Luck for CAT, McCord and Frivovich for SOD, Lawrence and Burk methods for GSH-Px were used to determine antioxidant parameters. Decreases in RBC count, Hb amount, Hct value, granulocyte ratios, and increases in total WBC and lymphocyte ratios were statistically significant in both dose groups treated with permethrin compared to the control group (p < 0.05). However, there was no statistically significant difference in monocyte ratios (p > 0.05). Overall, permethrin exposure caused an increase in MDA levels in the liver and gill tissues of carp in both dose and duration groups compared to the control group. Also, no statistically significant difference between the two dose groups in the liver tissue was observed in terms of duration (p > 0.05). Nonetheless, the increase in MDA levels in PERM10 and PERM20 dose groups in the gill tissues over 21 days was statistically significant (p < 0.05). Furthermore, permethrin exposure increased CAT, SOD, and GSH-Px enzyme activities in the gill tissue, while impacting in the opposite direction the liver tissue. Finally, regarding MDA, CAT, SOD, and GSH-Px levels, the control, and control acetone dose groups of all experimental groups were observed to be similar (p > 0.05). As a result, permethrin produced a toxic effect on Cyprinus carpio, triggering changes in blood parameters and inducing the antioxidant enzyme system.

Strong insect-resist property and wash-durability exhibited by wool fabric sustainably treated with a natural diterpenoid and a synthetic pyrethroid under subcritical CO2

To conserve wool textiles from insect attack, they are frequently treated with emulsions of natural and synthetic pyrethroid in an aqueous medium. Although the treatment is highly effective, it produces toxic effluent. In this work, insect-resist wool fabrics were produced by treating them with a natural diterpene (totarol), and a synthetic pyrethroid (permethrin) in a subcritical carbon dioxide (subc-CO2) medium. The totarol treatment failed to provide any insect-resist activity but the permethrin treatment even at 0.03% on the weight of wool fiber (owf) showed excellent insect-resist properties and the mortality of the larvae was more than 98%. The wool fabrics treated with permethrin at 0.03% owf under subc-CO2 only marginally lost insect resistance after 20 washes (equivalent to 80 domestic washes) but at 0.09% owf, still, the mortality of larvae was more than 98%. However, the fabric treated with 0.05% owf by the traditional aqueous treatment completely lost its insect-resistance property after 5 washes. The Soxhlet extraction of permethrin with dichloromethane from the treated fabric and GC-MS analysis of the extracted permethrin suggest that most of the permethrin was absorbed into the wool fiber. The developed process could be a durable and sustainable treatment for the conservation of wool textiles.

Nonlethal Effects of Pesticides on Web-Building Spiders Might Account for Rapid Mosquito Population Rebound after Spray Application

Spiders are important population regulators of insect pests that spread human disease and damage crops. Nonlethal pesticide exposure is known to affect behavior of arthropods. For spiders such effects include the inability to repair their webs or capture prey. In this study, nonlethal exposure of Mabel’s orchard spider (Leucauge argyrobapta) to the synthetic pyrethroid permethrin, via web application, interfered with web reconstruction and mosquito capture ability for 1–3 days. The timing of this loss-of-predator ecosystem function corresponds to the rapid population rebound of the yellow fever mosquito (Aedes aegypti) following insecticide application to control arbovirus epidemics. We suggest this temporal association is functional and propose that follow-up study be conducted to evaluate its significance.

New drugs for horses and production animals in 2019

In 2019, one novel pharmaceutical agent for horses or food-producing animals was released on the German market: An injection suspension for horses containing chondrogenic-induced equine allogeneic peripheral blood-derived mesenchymal stem cells as the active ingredient (ArtiCell® Forte) is now available. Two established veterinary active pharmaceutical ingredients became accessible for additional species: a salicylanilide anthelmintic oxyclozanide (Distocur®) for the treatment and control of fascioliasis in sheep as well as a type-I synthetic pyrethroid permethrin (Z-Itch®), which now has additionally been authorized for donkeys. Additionally, one veterinary drug with a new combination of active ingredients (toltrazuril + gleptoferron), 2 drugs (permethrin, omeprazole) in a new pharmaceutical formulation, one drug (lidocaine) with a novel route of administration, one drug (amprolium) with a higher content of the active ingredient, as well as one active substance (butylscopolaminium bromide) in mono-preparation have been launched on the market for horses and food-producing animals.

The optimization of pyrethroid simultaneous analysis in tropical soil of Indonesian tea plantation: Preliminary study

The preliminary study for the simultaneous analysis of five synthetic pyrethroids (lambda-cyhalothrin, permethrin, cypermethrin, fenvalerate, and deltamethrin) in tropical soil of tea plantation has been performed. The objective of this study is to perform an optimum condition for simple method development, based on green analytical chemistry. The concentrations of 0.1 μg.g-1 for all pyrethroids were evaluated using ultrasonic and microwave-assisted extraction. The quantification was performed using gas chromatography-electron capture detection (GC-ECD). Based on the experiment, the 0.5 mm soils size particles and 30 minutes sonication times were set as optimal condition for ultrasonic-assisted extraction with the best recovery yields of spiked soils were from 80 to 105 % for each pyrethroid and repeatability represent by the relative standard deviation (RSD, %) ranging of 1.1 – 4.8 %. Results were comparable with those found by microwave-assisted extraction. The result shows that the reproducibility, which is represented by recoveries obtained, ranged from 151 – 276 %, and were unacceptable because the value was beyond the specific range that was proposed by the Association of Analytical Communities (AOAC) International. The ultrasonic-assisted extraction was applicable for pyrethroids analysis in the real sample, with concentration found was 0.01 to 0.12 μg.g−1.

Impact of Poultry Red Mite (Dermanyssus gallinae) Infestation on Blood Parameters of Laying Hens

The poultry red mite Dermanyssus gallinae is commonly acknowledged as a serious biological threat to global poultry breeding. This is mostly because of the inefficiency of acaricidal treatments of poultry houses, which does not eliminate the mite population, only constrains it. However, the impact of D. gallinae on poultry welfare is poorly characterized. The biochemical and cytological characteristics of infection are limited mainly to anaemia, decreased levels of triglycerides in the blood and eosinophilia. For the first time, we report the adverse effects of D. gallinae infestation of industrial poultry houses on the functional state of poultry livers. Treatment of poultry houses with acaricidal powder preparation, Wooran-dust 0.7%, containing synthetic pyrethroids (permethrin, S-fenvalerate and tetramethrin), led to the elimination of the mite population and resulted in normalization of most of the haematological and biochemical blood parameters (haemoglobin, erythrocytes, neutrophils, basophils, lymphocytes and AST). Increased eosinophils and ALT were the only indicators of infection in the blood of laying hens, and they remained above normal range until the 22nd day after the beginning of treatment with the acaricidal agent.

Assessment of insecticide resistance in primary dengue vector, Aedes aegypti (Linn.) from Northern Districts of West Bengal, India

Aedes mosquitoes are the major vectors transmitting several arboviral diseases such as dengue, zika and chikungunya worldwide. Northern districts of West Bengal is home to several epidemics vectored by mosquito including dengue infections, proper control of which depends on efficient vector control. However the onset of insecticide resistance has resulted in failure of vector control approaches. This study was carried out to unveil the level of insecticide resistance prevailing among the primary dengue vector in this dengue endemic region of India. It was observed that, field caught populations of Ae. aegypti were moderately to severely resistant to majority of the insecticide classes tested, i.e. Organochlorine (DDT), Organophosphates (temephos, malathion), Synthetic Pyrethroids (deltamethrin, lambdacyhalothrin and permethrin) and carbamate (propoxur). In majority of the populations, metabolic detoxification seemed to play the underlying role behind the development of insecticide resistance. This study seems to be the first report revealing the pattern of insecticide resistance in Ae. aegypti from Northern West Bengal. Efficient disease management in this region can only be achieved through proper insecticide resistance management. This study may help the concerned authorities in the formulation of an effective vector control strategy throughout this region incorporating the knowledge gained through this study.

Effects of synthetic pyrethroids on RTG-2 cells

The cellular and subcellular effects of some synthetic pyrethroids (permethrin, cypermethrin, tetramethrin, and deltamethrin) on RTG-2 trout cell line were assessed. Mitochondrial function/cell viability and membrane integrity were measured by MTT and LDH release assays. Major morphological changes as evaluated by light and confocal microscopy were treated cells had fragmented morphology and condensed nuclei, fragmentations with hole formation in cytoskeleton, pyknotic nuclei and micronucleus formation, shrinkage of the cells and nuclei. Generation of cytoplasmic vacuoles, prominent induction of cellular pleomorphism, and hydropic degeneration were recorded as compared with controls showing fusiform cells and central nucleus by H&E staining.

Assessment of diagnostic doses for widely used synthetic pyrethroids (Deltamethrin & Permethrin) in an endemic focus of leishmaniasis in Turkey.

BackgroundLeishmania is a group of parasitic flagellated protozoons, which are transmitted by female sand flies and produces health problems in humans and also in wild and domestic animals. So far, 25 Phlebotomus and 4 Sergentomyia species were recorded in Turkey including proven or possible vectors of Leishmania spp. As no single insecticide susceptibility test was conducted targeting the sand flies in Turkey, we aimed to determine the diagnostic dose against two commonly used synthetic pyrethroids (deltamethrin and permethrin) in a hyperendemic area for leishmaniasis.MethodsSand flies were collected from villages of Adana in 2–4 September 2013 using Centers for Disease Control and Prevention (CDC) light traps and transferred to the laboratory. The World Health Organisation tube test method was conducted using self-prepared filter papers with different concentrations. In order to determine the diagnostic dose, lethal doses (LD) were calculated by EPA Probit Analysis. Sand flies used in the experiments were dissected, mounted and identified.ResultsFor the lowest (0.025 %) and highest dose of permethrin (0.5 %), the mortality rate was recorded as 52.6 % and 100 % by the end of 24-h period and the diagnostic dose was recorded as 0.36 %. The mortality rate for lowest (0.0025 %) and highest (0.05 %) doses of deltamethrin was recorded as 54.8 % and 100 %. The diagnostic dose of deltamethrin was determined as 0.9 %.ConclusionAn insecticide susceptibility study was conducted in Turkey for the first time and effective doses were determined by calculating the LDs. According to presented results, the wild population of sand flies collected from a hyper-endemic region of Adana Province is still susceptible to deltamethrin and permethrin.

Effect of synthetic pyrethroid insecticides on N2-fixation and its mineralization in tea soil

Microorganisms degrade a great variety of chemical substances including pesticide residues in soil. By virtue of low persistence and broad-spectrum efficacy, pyrethroid insecticides are sometimes used in tea garden to combat insect pests but the residual effects of these chemicals on microbial activities in soil have rarely been studied. The present experiment has been conducted under laboratory conditions to investigate the effect of four synthetic pyrethroid insecticides, viz. cypermethrin, deltamethrin, fenvalerate and permethrin at their field application rates (225, 200, 225, 210 g a.i. ha−1, respectively), on growth and activities of microorganisms in relation to non-symbiotic N2-fixation and N mineralization in a tea garden soil of the Himalayan terai (at the lower base) region of West Bengal, India. Application of insecticides, in general, decreased growth and activities of ammonifying and nitrifying bacteria but increased proliferations of non-symbiotic N2-fixing bacteria, resulting in greater fixation of atmospheric N2, more so with permethrin (7.8%) followed by cypermethrin (5.2%). Most of the insecticides had a deleterious effect on the accumulation of oxidizable organic C and total N, more pronounced with fenvalerate and permethrin. The availability of exchangeable NH4+ was also significantly reduced, more prominently with fenvalerate (15.6%) followed by deltamethrin (11.2%), while permethrin followed by cypermethrin accentuated greater accumulation of soluble NO3− in soil. Therefore, the effects of synthetic pyrethroid insecticides on microbial activities in relation to non-symbiotic N2-fixation and its mineralization in tea soil of West Bengal can not be generalized, rather in most cases the effects were inclined more towards detrimental than a few stimulative one.

How do species, population and active ingredient influence insecticide susceptibility in Culicoides biting midges (Diptera: Ceratopogonidae) of veterinary importance?

BackgroundCulicoides biting midges are biological vectors of internationally important arboviruses of livestock and equines. Insecticides are often employed against Culicoides as a part of vector control measures, but systematic assessments of their efficacy have rarely been attempted. The objective of the present study is to determine baseline susceptibility of multiple Culicoides vector species and populations in Europe and Africa to the most commonly used insecticide active ingredients. Six active ingredients are tested: three that are based on synthetic pyrethroids (alpha-cypermethrin, deltamethrin and permethrin) and three on organophosphates (phoxim, diazinon and chlorpyrifos-methyl).MethodsSusceptibility tests were conducted on 29,064 field-collected individuals of Culicoides obsoletus Meigen, Culicoides imicola Kieffer and a laboratory-reared Culicoides nubeculosus Meigen strain using a modified World Health Organization assay. Populations of Culicoides were tested from seven locations in four different countries (France, Spain, Senegal and South Africa) and at least four concentrations of laboratory grade active ingredients were assessed for each population.ResultsThe study revealed that insecticide susceptibility varied at both a species and population level, but that broad conclusions could be drawn regarding the efficacy of active ingredients. Synthetic pyrethroid insecticides were found to inflict greater mortality than organophosphate active ingredients and the colony strain of C. nubeculosus was significantly more susceptible than field populations. Among the synthetic pyrethroids, deltamethrin was found to be the most toxic active ingredient for all species and populations.ConclusionsThe data presented represent the first parallel and systematic assessment of Culicoides insecticide susceptibility across several countries. As such, they are an important baseline reference to monitor the susceptibility status of Culicoides to current insecticides and also to assess the toxicity of new active ingredients with practical implications for vector control strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1042-8) contains supplementary material, which is available to authorized users.

Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes.

Sublethal toxicity of commercial formulations of deltamethrin and permethrin on selected biochemical constituents and enzyme activities in liver and muscle tissues of Anabas testudineus

The freshwater fish Anabas testudineus was exposed for 21days to two commercial formulations of synthetic pyrethroids deltamethrin and permethrin at sublethal concentrations of 0.007 and 0.0007mgL−1, and 0.093 and 0.0093mgL−1, that represented 10% and 1%, respectively, of the 96h LC50 of these two pesticides for this fish. The glycogen, protein and lactic acid contents, along with succinate dehydrogenase (SDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) enzyme activities in liver and muscle tissues of control and pesticide-exposed fish were estimated. When compared with those of control fish, significant depletion of glycogen content was observed in liver, and that of protein in muscle tissue of fish treated with both the pesticides at their higher as well as lower concentrations. Lactic acid reduction was significant only in fish muscle treated with deltamethrin. SDH level was reduced significantly in both liver and muscle tissues except in fish exposed to 0.0093mgL−1 permethrin. AST level was reduced significantly in liver and muscle tissues and ALT in muscle tissue of deltamethrin treated fish only. It is concluded that deltamethrin, a type-II pyrethroid, is more toxic to fish than the type-I pyrethroid permethrin and is capable of rendering toxicity at a dose as low as 1% of its LC50 value.

Proposed model for binding of permethrin and deltamethrin insecticides with ct-DNA, a structural comparative study

In this work, the interaction of two synthetic pyrethroid insecticides, permethrin (PER) and deltamethrin (DEL), with ct-DNA has been studied by cyclic voltammetry (CV), circular dichroism (CD), competitive fluorescence, atomic force microscopy (AFM), UV–vis spectroscopy, thermodynamic measurements, Fourier-transform infra-red (FT-IR), high performance liquid chromatography (HPLC) and two-layered ONIOM (our N-layered integrated molecular orbital+molecular mechanics) (DFT B3LYP, 6-31++G(d, p):UFF) molecular modeling methods. The last four methods were also utilized to study the binding of DEL with DNA. The results revealed that the PER may interact through partial intercalation and groove binding process while the PER only interacts through groove binding. Finally, the insecticides structure effect on interaction is discussed.

Pyrethroid susceptibility and behavioral avoidance in Anopheles epiroticus, a malaria vector in Thailand.

The physiological susceptibility to insecticides and the behavioral responses of four wild-caught populations of female Anopheles epiroticus to synthetic pyrethroids (deltamethrin, permethrin, and alpha-cypermethrin) were assessed. Test populations were collected from different localities along the eastern coast, Trat (TR), Songkhla (SK), and Surat Thani (ST) and one population from the western coast, Phang Nga (PN). Results showed that all four populations of An. epiroticus were susceptible to all three synthetic pyrethroids tested. Behavioral responses to test compounds were characterized for all four populations using an excito-repellency test system. TR displayed the strongest contact excitation ('irritancy') escape response (76.8% exposed to deltamethrin, 74.1% permethrin, and 78.4% alpha-cypermethrin), followed by the PN population (24.4% deltamethrin, 35% permethrin, and 34.4% for alpha-cypermethrin) by rapidly escaping test chambers after direct contact with surfaces treated with each active ingredient compared with match-paired untreated controls. Moderate non-contact repellency responses to all three compounds were observed in the TR population but were comparatively weaker than paired contact tests. Few mosquitoes from the SK and ST populations escaped from test chambers, regardless of insecticide tested or type of trial. We conclude that contact excitation was a major behavioral response in two populations of An. epiroticus, whereas two other populations showed virtually no escape response following exposure to the three pyrethroids. The explanation for these large unexpected differences in avoidance responses between pyrethroid-susceptible populations of the same species is unclear and warrants further investigation.

Knockdown and repellent effect of permethrin-impregnated army uniform cloth against Aedes aegypti after different cycles of washings

Personnel protection is one of the methods for protection from bites of mosquitoes and other arthropod vectors transmitting many dreadful diseases. Insect repellents and other plant products are normally used to ward off mosquitoes. Application of synthetic pyrethroid permethrin on cloth is adopted for repelling arthropod vectors in many countries for military and civil purposes. In the present study, attempt has been made to impregnate permethrin in the army uniform cloth and to evaluate for its knockdown and repellency against unfed female Aedes aegypti mosquitoes in laboratory condition. WHO protocols were adopted for impregnation of permethrin on cloth and evaluation for its knockdown and repellency after different cycles of washing. Results showed that 93.33% of mosquitoes were knocked down within 1 h after the first washing while its efficacy reduced gradually till the fifty-fifth washing. Landing of mosquitoes on the permethrin-treated cloth was found to increase with respect to number of washings as compared to the untreated cloth. Within 24 h, 100% mortality of all the mosquitoes exposed to permethrin-impregnated cloth was observed. SEM-EDX studies on the texture of untreated cloth and permethrin-treated cloth after different cycles of washing also revealed presence of permethrin on treated cloth.

In vivo Genotoxicity of Four Synthetic Pyrethroids with Combinations of Piperonyl Butoxide (PBO) Using the Drosophila SMART Assay

In this study, the genotoxic effects of four synthetic pyrethroids (cypermethrin, cyphenothrin, deltamethrin, and permethrin) alone and their combinations with different rates of piperonyl butoxide (PBO) were studied using the wing somatic mutation and recombination test (SMART) of the Drosophila melanogaster. In the first stage, lethal concentration values (LC 25 or LC 50 ) of the synthetic pyrethroids and concentrations of PBO used for the synthetic pyrethroids were determined. Then, Drosophila larvae were exposed to lethal concentrations of synthetic pyrethroids and combinations with different rates of PBO (1:0.25, 1:0.5, 1:0.75, 1:1, and 1:2). According to the obtained results, alone and with the PBO of the mixtures of the four synthetic pyrethroids are not genotoxic when compared with the negative control. In addition, the PBO when used alone demonstrated negative results when exposed to 1, 5, and 25 ppm concentrations, while demonstrating positive result when exposed to 50 ppm concentration. However, the PBO did not show any co-genotoxic activity with the four tested synthetic pyrethroids. Results of this study will take an important place in human and environmental health with the new results for the PBO ratios in insecticide formulations.