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International Journal of Health Sciences 2022German cockroach is highly adapted to different environments like hospitals. This pest is an important carrier of pathogenic agents and allergic compounds. Hence, it is...
Determination of susceptibility levels of three different cockroach species including hospitals German cockroach, L. (Blattodea: Blattellidae), to common insecticides, cypermethrin, propoxur and fenitrothion.
OBJECTIVE
German cockroach is highly adapted to different environments like hospitals. This pest is an important carrier of pathogenic agents and allergic compounds. Hence, it is important to German cockroaches always be monitored and controlled. This study investigated the toxicity and resistance levels of technical-grade of cypermethrin, propoxur, and fenitrothion against adult males of four strains of the German cockroach.
METHODS
Four German cockroaches' strains including laboratory-reared susceptible strain (S) and three hospital-collected strains (B, F, and Z) were tested in this study. Adult male cockroaches were treated topically with three technical grade insecticides on the first abdominal segment of the insects using a hand micro-applicator.
RESULTS
Using topical application methods, fenitrothion showed the most toxicity to all four strains. The LD values of fenitrothion in the susceptible strain (S) and the hospital-collected strains B, F, and Z were 1.89, 21.48, 25.73, and 31.55 μg/grBW, respectively. All hospital-collected strains showed different resistant levels to all insecticides. The field-collected Z strain was the most resistant strain to cypermethrin, propoxur, and fenitrothion. The resistance ratios of strain Z to cypermethrin, propoxur, and fenitrothion were 10.9, 10.47 and 16.67, respectively.
CONCLUSION
Based on the susceptibility and resistance ratios for each insecticide, we conclude that there are high rates of insecticide resistance in from different hospitals of Sari County which can be caused by different insecticides treatment histories.
PubMed: 35949698
DOI: No ID Found -
Veterinary World Nov 2019Attempts to use the plant products are to be an appropriate option due to substantial concerns about human health and environmental problems of using synthetic...
BACKGROUND AND AIM
Attempts to use the plant products are to be an appropriate option due to substantial concerns about human health and environmental problems of using synthetic pesticides. Therefore, the cytotoxicity of essential oil was compared with propoxur against invertebrate (Sf9) and vertebrate (L929) cell lines.
MATERIALS AND METHODS
The cell lines of Sf9 and L929 which were derived from the ovary glands of fall armyworm, (Lepidoptera: Noctuidae) and mouse fibroblast cells, respectively, were obtained from the National Cell Bank of Pasteur Institute of Iran. About a number of 2 × 10 cells were placed into the wells of 96-well plate experiments. Then, appropriate concentrations of essential oil of plant and propoxur added to the wells. The cells were allowed to grow for 3-5 days and estimated the numbers of cells. The cells of control experiment wells contained only cells with dimethyl sulfoxide. All control and treatment experiments repeated at least four replicates.
RESULTS
Propoxur had negative effects on the viability of both invertebrate (Sf9) and vertebrate (L929) cell lines. The cytotoxicity of propoxur against invertebrate (Sf9) and vertebrate (L929) cell lines was gradually increased in accordance with propoxur concentrations. The cytotoxicity of essential oil against vertebrate (L929) cell line was gradually decreased in accordance with plant concentrations, while the cytotoxicity of essential oil against invertebrate (Sf9) cell line was strongly increased in accordance with plant concentrations.
CONCLUSION
Plant essential oil not only had no negative effects but also had boosting effects on vertebrate cell viability. Essential oil of plant had negative effects on invertebrate cell viability with the differences that the products derived from plants possessing of biodegradable and environmentally friendly derivatives, hydrolyzing rapidly in nature, and nearly having no destructive effects on environment, humans, or the mammals.
PubMed: 32009748
DOI: 10.14202/vetworld.2019.1698-1706 -
Insects Sep 2019Propoxur-sel strains of were derived from a lab-bred strain following 16 generations of propoxur exposure under sublethal concentrations of LC (lethal concentration of...
Propoxur-sel strains of were derived from a lab-bred strain following 16 generations of propoxur exposure under sublethal concentrations of LC (lethal concentration of 25%) and LC (lethal concentration of 50%), respectively. This resulted in resistance development in F16 with ratios of 8.8× and 6.3×, respectively, compared with F0. The fecundity, longevity, sex ratio (F/M), and hatchability of the propoxur-exposed adult survivors and their offspring were decreased, with no effect on the emergence ratio and pupa survival rate. In addition, the intrinsic rates of increase (r), the net reproduction (R), and the finite rate of increase (λ) of the offspring generations were also decreased significantly compared to F0. Correspondingly, the mean generation time (T) and the population double time (DT) in propoxur-sels were increased. Enhanced activities of cytochrome P450 monooxygenase and esterase were also observed in propoxur-sels, indicating that a detoxification mechanism might be responsible for resistance development in . Except for the three genes , , and which displayed a coincidence in some degree in different treatments, induction by different doses of propoxur and constitutive expression in different generations of propoxur-sel strains resulted in an inconsistent identification of the P450 genes probably related with resistance.
PubMed: 31500284
DOI: 10.3390/insects10090288 -
Parasites & Vectors Jun 2022The practice of agriculture in urban settings contributes to the rapid expansion of insecticide resistance in malaria vectors. However, there is still not enough...
BACKGROUND
The practice of agriculture in urban settings contributes to the rapid expansion of insecticide resistance in malaria vectors. However, there is still not enough information on pesticide usage in most urban settings. The present study aims to assess the evolution of Anopheles gambiae (s.l.) population susceptibility to insecticides and patterns of pesticide usage in agriculture in the city of Yaoundé, Cameroon.
METHODS
WHO susceptibility tests and synergist PBO bioassays were conducted on adult An. gambiae (s.l.) mosquitoes aged 3 to 5 days emerging from larvae collected from the field. Seven insecticides (deltamethrin, permethrin, DDT, bendiocarb, propoxur, fenitrothion and malathion) were evaluated. The presence of target site mutation conferring knockdown (kdr) resistance was investigated using TaqMan assay, and mosquito species were identified using SINE-PCR. Surveys on 81 retailers and 232 farmers were conducted to assess general knowledge and practices regarding agricultural pesticide usage.
RESULTS
High resistance intensity to pyrethroids was observed with a high frequency of the kdr allele 1014F and low frequency of the kdr 1014S allele. The level of susceptibility of An. gambiae (s.l.) to pyrethroids and carbamates was found to decrease with time (from > 34% in 2017 to < 23% in 2019 for deltamethrin and permethrin and from 97% in 2017 to < 86% in 2019 for bendiocarb). Both An. gambiae (s.s.) and An. coluzzii were recorded. Over 150 pesticides and fertilizers were sold by retailers for agricultural purposes in the city of Yaoundé. Most farmers do not respect safety practices. Poor practices including extensive and inappropriate application of pesticides as well as poor management of perished pesticides and empty pesticide containers were also documented.
CONCLUSIONS
The study indicated rapid evolution of insecticide resistance and uncontrolled usage of pesticides by farmers in agriculture. There is an urgent need to address these gaps to improve the management of insecticide resistance.
Topics: Agriculture; Animals; Cameroon; Insecticide Resistance; Insecticides; Mosquito Vectors; Permethrin; Pesticides; Pyrethrins
PubMed: 35655243
DOI: 10.1186/s13071-022-05321-8 -
Bulletin of the World Health... 1971Methylcarbamate insecticides undergo hydrolysis, oxidation, dealkylation, and conjugation in animals, plants, and insects to form similar or identical products. Carbaryl... (Review)
Review
Methylcarbamate insecticides undergo hydrolysis, oxidation, dealkylation, and conjugation in animals, plants, and insects to form similar or identical products. Carbaryl is hydroxylated in biological systems to form hydroxy, dihydro-dihydroxy, and N-hydroxymethyl carbaryl and is hydrolysed to form 1-naphthol. The products are conjugated, stored, or excreted. Carbofuran is hydroxylated at the 3 position and propoxur at the 5 position to form hydroxylated derivatives. N-hydroxymethyl derivatives of these two carbamates may also be formed. Hydrolysis appears to be the major metabolic pathway of carbofuran in the animal. Aldicarb is oxidized to its sulfoxide and then hydrolysed to the oxime sulfoxide in animals and plants. Plants hydrolyse the oxime sulfoxide to form the corresponding aldehyde, which is an intermediate in the formation of 2-methyl-2-(methyl-sulfinyl)propanol. Methomyl, which is structurally similar to aldicarb, is metabolized in plants to acetonitrile, carbon dioxide, and methylamine. Bux and Meobal undergo hydrolysis and hydroxylation to form N-hydroxy methylcarbamates, as well as hydroxybutylphenyl and hydroxymethylphenyl methylcarbamates. Zectran, which contains a dimethylamino group, is converted to the methylamino, amino, and methylformamido derivatives by insects and plants. In soil and water, methylcarbamate insecticides are hydrolysed to their respective phenols or oximes.
Topics: 1-Propanol; Animals; Benzofurans; Carbamates; Carbaryl; Carbon Isotopes; Cattle; Chemical Phenomena; Chemistry; Dogs; Hydrolysis; Imines; Insecta; Insecticides; Methylamines; Microsomes, Liver; Oxidation-Reduction; Oximes; Plants; Rats; Sulfides; Xylenes
PubMed: 4999481
DOI: No ID Found -
Journal of Arthropod-borne Diseases Dec 2021Among neglected zoonotic diseases, leishmaniases caused by parasite through infected female sand fly bite, are a group of diseases found in 98 countries and territories... (Review)
Review
BACKGROUND
Among neglected zoonotic diseases, leishmaniases caused by parasite through infected female sand fly bite, are a group of diseases found in 98 countries and territories representing a critical burden of disease worldwide. Vector management plays a crucial role in reducing the burden of vector-borne diseases by WHO's global plan. The objective of the current study was to assess the susceptibility status of wild phlebotomine sand flies from Esfahan Province, central Iran, to the recommended insecticides by WHO.
METHODS
Sand flies were collected by mouth aspirator in Matin Abad desert Eco-resort and were tested using WHO adult mosquito test kit against Dichlorodiphenyltrichloroethane (DDT) 4%, Deltamethrin 0.05%, Malathion 5% and Propoxur 0.1%. The number of knockdown sand flies were recorded during exposure time in ten minutes interval for DDT and Deltamethrin and they were allowed to recover for 24 hours. Knockdown Time (KD) and KD were generated for them using Probit software. They were mounted and identified by valid keys.
RESULTS
Among the tested insecticides against female , DDT, Deltamethrin, and Malathion recorded the highest mortality rate of 100%, followed by Propoxur with 92.2% mortality for a one-hour exposure. For DDT, KD and KD were calculated 21.87 and 42.93 and for Deltamethrin, they were 23.74 and 56.50 minutes respectively. Total sand flies exposed with DDT and Deltamethrin shed their leg(s).
CONCLUSION
It is concluded that from central Iran is susceptible to DDT, Deltamethrin, Malathion, and Propoxur.
PubMed: 36644307
DOI: 10.18502/jad.v15i4.10501 -
Parasites & Vectors Jan 2018Aedes albopictus (Skuse) is an invasive mosquito that has become an important vector of chikungunya, dengue and Zika viruses. In the absence of specific antiviral...
BACKGROUND
Aedes albopictus (Skuse) is an invasive mosquito that has become an important vector of chikungunya, dengue and Zika viruses. In the absence of specific antiviral therapy or a vaccine, vector management is the sole method available for reducing Aedes-induced disease morbidity. Determining the resistance status of Ae. albopictus to insecticides and exploring the resistance mechanisms is essential for future vector control planning.
METHODS
Aedes albopictus larvae and pupae were sampled from six sites (two sites each from urban, suburban and rural) in Guangzhou. The resistance bioassays were conducted against Bacillus thuringiensis israelensis (Bti): deltamethrin, propoxur and malathion for larvae; and deltamethrin, DDT, propoxur and malathion for adults. P450 monooxygenase (P450s), glutathione S-transferase (GSTs) and carboxylesterase (COEs) activities of adult mosquitoes were measured. Mutations at the knockdown resistance (kdr) gene were analyzed, and the association between kdr mutations and phenotypic resistance was tested.
RESULTS
Adult bioassays revealed varied susceptibility against DDT, deltamethrin and propoxur in the six Ae. albopictus populations. Significantly lower mortality rates were found in urban populations than suburban and rural populations. Urban mosquito populations showed resistance against DDT, deltamethrin and propoxur, while one rural population was resistant to DDT. All populations tested were susceptible to malathion. Larval bioassays results indicated that all populations of Ae. albopictus were sensitive to the larvicide Bti and malathion. Resistance to deltamethrin and propoxur was common in larval populations. The F1534S and F1534 L mutations were found to be significantly associated with deltamethrin resistance. Biochemical assays indicated elevated detoxification enzyme activities in the field mosquito populations.
CONCLUSIONS
Aedes albopictus populations in Guangzhou, especially in urban areas, have developed resistance to the commonly used insecticides, primarily DDT and deltamethrin. This finding calls for resistance management and developing counter measures to mitigate the spread of resistance.
Topics: Aedes; Animals; Bacillus thuringiensis; Carboxylesterase; China; Cytochrome P-450 Enzyme System; Glutathione Transferase; Insect Proteins; Insecticide Resistance; Insecticides; Mixed Function Oxygenases; Mosquito Vectors; Mutation
PubMed: 29298700
DOI: 10.1186/s13071-017-2581-y -
Acta Tropica Mar 2019In Colombia Aedes (Stegomyia) aegypti is the main vector of urban arboviruses such as dengue, chikungunya and Zika. This urban mosquito has a well-established capacity...
In Colombia Aedes (Stegomyia) aegypti is the main vector of urban arboviruses such as dengue, chikungunya and Zika. This urban mosquito has a well-established capacity to develop insecticide resistance to different types of insecticides (pyrethroids, organochlorides, organophosphates), using multiple resistance mechanisms. An understanding of ongoing resistance mechanisms is critical to determining the activities of vector control programs. In order to identify the biochemical and molecular mechanisms associated with pyrethroid resistance in Colombia, three laboratory-selected strains resistant to DDT, Propoxur and lambdacyhalothrin, and 7 field-collected strains were evaluated. CDC bioassays were performed to measure the susceptibility status to pyrethroid type I (permethrin) and II (deltamethrin and lambdacyhalothrin), and potential cross-resistance to different types of insecticides; organochlorine (DDT), carbamates (propoxur) and organophosphates (malathion). The enzymatic activity of esterases, glutathione S-transferases (GST) and P monooxygenases were biochemically determined. Frequencies of kdr mutations Val1016Ile and Phe1534cys were determined through real-time PCR. The Rockefeller strain of Aedes (Stegomyia) aegypti was used as the susceptible control. The laboratory-selected strains "propoxur" and "lambdacyhalothrin" and one field population (Medellín (BF) F were resistant to all evaluated pyrethroids. Six of the seven field populations as well as the laboratory- selected "DDT" strain were resistant to permethrin. All the evaluated strains were resistant to DDT. Cross-resistance between lambdacyhalothrin and propoxur was observed in the laboratory-selected strains; however, all field-collected strains were susceptible to propoxur and no evidence of malathion resistance was found. The main biochemical mechanism for resistance observed in the field-collected strains was related to the enzyme GST. Further, the frequencies of kdr mutations alleles associated with insecticide resistance were high and ranged from 0.02 to 0.72 for Ile1016 and from 0.44 to 0.99 for Cys1534. Strains with high frequencies of both kdr mutations were resistant to both type I and II pyrethroids. These results suggest that Ae. aegypti from Colombia have developed multiple resistance mechanisms associated with pyrethroid resistance; therefore a resistance management strategy against these field populations of Ae. Aegypti, incorporating these findings is strongly recommended.
Topics: Aedes; Animals; Colombia; Disease Vectors; Insecticide Resistance; Insecticides; Mosquito Vectors; Pyrethrins
PubMed: 30552882
DOI: 10.1016/j.actatropica.2018.12.021 -
EFSA Journal. European Food Safety... Jan 2021In accordance with Article 43 of Regulation (EC) No 396/2005, the European Commission requested EFSA to prepare a reasoned opinion on the toxicological properties and...
In accordance with Article 43 of Regulation (EC) No 396/2005, the European Commission requested EFSA to prepare a reasoned opinion on the toxicological properties and the existing maximum residue levels (MRLs) set for propoxur. EFSA was requested to assess the toxicological properties of propoxur and derive toxicological reference values, based on the toxicological assessment performed by Health Canada. EFSA was also requested to review the information provided by Member States and the UK on the metabolism of propoxur in plants and animals and on the current MRLs, as well as the limit of quantification (LOQ) that can be achieved with analytical methods used in MRL enforcement. Based on the information available to EFSA, toxicological reference values could not be derived for propoxur. No evidence was provided by Member States and UK that the existing EU MRLs need to be maintained as import tolerances. Information to support the current MRLs or alternative MRLs have not been provided by Member States and the UK. Codex MRLs are not in place. EFSA therefore recommended lowering of all existing EU MRLs for propoxur to the LOQ. According to the EU Reference Laboratories, sufficiently validated analytical methods are available to analyse for propoxur residues in all plant and animal commodities. Lacking toxicological reference values derived at EU level, a conclusion cannot be derived whether the setting of MRLs at the LOQs is sufficiently protective for the European consumers.
PubMed: 33488813
DOI: 10.2903/j.efsa.2021.6374