Adverse effect of pre- and postnatal exposure to carbamate and pyrethroid pesticides on cognition in children at 4 and 6 years of age: A prospective study

Objective@#To determine the adverse effect of pre- and postnatal exposure to carbamate (propoxur) and pyrethroid pesticides on children's cognitive functions at 4 and 6 years of age. @*Method@#As part of a prospective cohort study among children with known pre- and postnatal exposure to propoxur and pyrethroids, children were examined at time points, 4 and 6 years, to determine the adverse effect of pesticide exposure on neurocognitive function, i.e., intelligence (IQ) using the WPPSI-III test. Pre- and postnatal pesticide exposures were measured by meconium and hair analysis, respectively, using gas chromatography-mass spectrometry (GCMS).@*Results@#Seven hundred twenty-four (724) maternal/children dyads were seen at four years and 717 at six years of age. Their mean (SD) full-scale IQ was low on average: 83.9 (10.2) at four years and 83.6 (8.6) at six years. Prenatal but not postnatal exposure to propoxur (-0.139, p=0.01) and pyrethroids (-0.097, p=0.05) were significantly correlated (negative) with full-scale IQ at four years but not at six years. The confounders that were significantly correlated to full-scale IQ at four and/or six years of age were maternal IQ, child’s weight, height, head circumference, socio-economic status, child environment, and stimulation at home (HOME) violence or abuse at home. Regression analysis of pesticides and confounders showed similar results, except for weight and head circumference.@*Conclusion@#We conclude that prenatal exposure to propoxur and pyrethroids had a negative effect on the children’s IQ at four years but no longer at six years. Thus, the ability of the child’s IQ to recover from the adverse effect of intrauterine pesticide insult may be attributable to the neuronal plasticity of its brain. Similarly, confounders to these outcome measures are multiple and are essential to address when evaluating the effect of pesticides on neuro-cognitive development in children.

Aplicação dos princípios do RISK21 na avaliação do risco de inseticidas da classe dos piretróides / The use of RISK21 principles in the risk assessment of pyrethroids

A avaliação do risco é um processo científico e sistemático que incorpora quantitativamente o perigo e a exposição a diversos agentes. O processo de avaliação do risco tem evoluído nos últimos anos, indo além da exposição a únicos agentes e vias de exposição para a caracterização do risco cumulativo a múltiplos agentes. As metodologias para avaliação do risco cumulativo não são harmonizadas o que pode tornar o processo complexo. Nesta linha, a abordagem do RISK21 promovida pelo Health Environmental Science Institute (HESI) pode contribuir para desmistificar o tema. A exposição combinada da ingestão de resíduos de praguicidas através da dieta e do uso residencial de produtos a base de piretróides pela população brasileira não são conhecidas. Os piretróides são praguicidas utilizados na lavoura, bem como em ambiente doméstico no controle de pragas. O mecanismo de toxicidade destes agentes é bem conhecido e de relevância para a saúde humana, pois atuam sobre a permeabilidade iônica dos canais de sódio sensíveis a voltagem (CSSV), produzindo efeitos na excitabilidade das terminações nervosas. Como os seres humanos são potencialmente expostos a estes agentes, portanto, torna-se importante compreender os riscos cumulativos da exposição a estes praguicidas pela população brasileira. O objetivo deste trabalho foi conduzir a avaliação do risco dos piretróides registrados no Brasil com base nos princípios do RISK21. A abordagem em etapas proposta pelo RISK21 demonstrou que o risco da ingestão crônica e aguda de resíduos de piretróides foi considerado aceitável. Além disso, não foi observada qualquer preocupação toxicológica decorrente da exposição residencial a estes agentes. Quando combinados os cenários da dieta aguda e residencial, também não foram observados níveis de preocupação, portanto, o risco foi considerado aceitável. A avaliação do risco dos piretróides registrados para o uso agrícola e residencial no Brasil com base nos principios do RISK21 foi uma importante etapa neste trabalho, uma vez que foi possível avaliar o risco e preocupações para cada um dos praguicidas de maneira rápida e visual. Além disso, mesmo considerando premissas altamente conservadoras, observou-se que a população exposta de maneira combinada a estes agentes não demonstrou um nível de preocupação para o cenário brasileiro

Risk assessment is a scientific and systematic approach that quantitatively incorporates hazard and exposure to agents' evaluation. The risk assessment process has evolved in recent years, going beyond exposure to single agents and pathways to characterize multiple agents' cumulative risk. Cumulative risk assessment methodologies are not harmonized, which can make the process complex. In this line, the RISK21 approach promoted by the Health Environmental Science Institute (HESI) can demystify the subject. The combined exposure of residue intake through diet and residential use of pyrethroid-based products by the Brazilian population is unknown. Pyrethroids are pesticides used in the crop as well as in a domestic environment in pest control. The mechanism of toxicity of these agents is well known and relevant to human health, as they act on the ionic permeability of voltage-sensitive sodium channels (VSSC), producing effects on the excitability of nerve endings. As human beings are potentially exposed to these agents, it is essential to understand the cumulative risks derived from the exposure to these pesticides by the Brazilian population. The objective of this research was to conduct the risk assessment based on the principles of RISK21 of pyrethroids registered in Brazil. The stepwise approach proposed by RISK21 demonstrated that the risk of chronic and acute ingestion of pyrethroid residues was considered acceptable. Furthermore, no toxicological concern stemming from residential exposure to these agents was observed. When acute and residential diet scenarios were combined, no levels of concern were also observed, so the risk was considered acceptable. The risk assessment based on the principles of RISK21 of pyrethroids registered for agricultural and residential use in Brazil was an essential step in this research since it was possible to assess the risk and concerns for each of the pesticides in a fast and visual way. Moreover, from highly conservative premises, it was observed that the population exposed in combination with these agents did not demonstrate a level of concern for the Brazilian scena

Role of novel insecticides in crop protection and their selectivity to natural enemies: A review

In the present context of pest management in major crops, as the nature of pest pressure evolves, the requirement of new research-based tactics for pest control becomes a continuous process. Insecticide chemistry plays a major, if not dominant role in these developments. In this review, the toxicological aspects of new novel insecticides against crop pests and their selectivity to natural enemies have been discussed.The progress achieved in toxicological research has introduced new insecticides in crop protection during last two decades which are quite different over the existing groups in terms of chemistry and mode of action. It is evident from their mode of action that these chemicals target alternate physiological and biochemical effect. However, it is important to maintain the diversity in chemistry of insecticides for maximizing flexibility, precision and stability in pest management. In recent years, several new insecticide groups viz., neonicotinoids, butenolides, tetronic and tetramic acid derivatives, oxadiazines, diamides, ketoenols, phenylpyrazoles, pyridines, flonicamid, mitochondrial electron transport inhibitor (METI) acaricides, diafenthiuron, tetrazines, oxazolines, and insecticides from soil microorganisms such as avermectins, milbemycins, spinosyns, pyrrole insecticides and insect growth regulators (IGRs) have been discovered and commercialized for agricultural pest management. The ability of these new groups of insecticides to be effective at low rates or doses, high level of selectivity, greater specificity to target pests along with low toxicity to non-target organisms and the environment, replaced many conventional compounds. The conservation of beneficial organisms like natural enemies and pollinators is the fundamental principle of integrated pest management (IPM). Majority of new insecticide groups are safer and fit well into IPM. It is perceived that in the process of entry of new chemical insecticides in crop protection there is a gradual shift from traditional chemicals to selective novel groups which have minimal side-effects on natural enemies of the pests. These selective insecticides have less adverse impact on the conservation and multiplication of bio agents which can be used in a compatible manner with other tools of IPM. The new chemistries are emphasizing to account separately for possible non-target effects on predators, parasitoids, and pathogens. These factors are becoming increasingly important as the agricultural sector moves away from highly persistent broad-spectrum insecticides to more selective rapidly decaying products.

Pyrethroids Exposure: Implications For Testicular Dysfunction In Rats

Pyrethroids are synthetic pesticides which at low dose of exposure are harmless to humans but at environmentallyhigh concentrations they cause debilitating effects in humans and animals alike. Lack of regulation of theinsecticide applications in agriculture and among Nigerian households is therefore a cause for health concern.The reproductive effects of these chemicals are not precisely known. Twenty healthy, sexually active male Wistarrats were randomly divided into four groups. Three groups were exposed to the insecticide in sprayed puffs fromthe aerosolized insecticide for 15, 30 and 45 seconds/day respectively in air – tight plastic housing for 60 dayswhile one group served as the untreated control. All animals were euthanized via cervical dislocation; the testeswere excised and fixed in Bouin’s fluid for routine histological studies using haematoxylin and eosin. The caudaepididymis was also excised for semen quality evaluation. Reduced body weight, alteration of testicularmicrostructure and significant increase in the proportion of abnormal and non-motile sperm cells were observedin animals exposed to pyrethroid. Exposure to pyrethroid insecticide may lead to body weight loss accompaniedwith testicular dysfunction possibly leading to sterility in the rats.

Resistance status of main malaria vector, Anopheles stephensi Liston (Diptera: Culicidae) to insecticides in a malaria Endemic Area, Southern Iran

Objective: To evaluate the susceptibility of Anopheles stephensi (An. stephensi) Liston, the main malaria vector in southern Iran, to WHO recommended insecticides. Methods: Larvae of An. stephensi were collected from three different larval habitats in both urban and rural area of Bandar Abbas city and one rural area in Rudan county southern Iran. WHO standard method was used for evaluation of adult and larval mosquito susceptibility. Bendiocarb, permethrin, lambda-cyhalothrin, deltamethrin as insecticide and temephos and chlorpyriphos as larvicide were used at the diagnostic dosages recommended by WHO. Results: Findings of this study showed all larval populations of An. stephensi were completely susceptible to temephos and candidate for resistance to chlorpyriphos. Adult mosquitoes in rural areas of Bandar Abbas city were resistant to pyrethroid and carbamate insecticides. Conclusion: Comparison of the results of this survey with previous studies indicates that the resistance to pyrethroids and carbamates in this malaria endemic region is increasing. Wide use of pesticides in agriculture is certainly effective in increasing resistance. The inter-sectoral coordination and collaboration in health and agriculture seem to be necessary to manage insecticide resistance in malaria vectors.

Role of metabolic detoxification enzyme activity and knockdown resistance gene mutations in resistance of aedes albopictus to pyrethroid insecticides / 第二军医大学学报

[Abstract] Objective To explore the role of metabolic detoxification enzyme activity and knockdown resistance (kdr) gene mutations in the pyrethroid resistance of Aedes (Ae.) albopictus. Methods From Aug. to Sep. in 2017, the Ae. albopictus samples were collected in Qianfoshan Park, Jinan City, Shandong Province (JN), Shangmaojiabu, Hangzhou City, Zhejiang Province (HZ), Baoshan Sixth Village, Baoshan District, Shanghai (BS), Gongqing Forest Park, Yangpu District, Shanghai (YP), and Meilan District Residential Area, Haikou City, Hainan Province (HK). The above five field populations were all resistant to insecticide. The activities of metabolic detoxification enzymes (glutathione-S transferase [GST] and mixed function oxidase [MFO]) were detected and compared with the Ae. albopictus susceptible strain (JS). The contribution rates of activity changes of GST and MFO and kdr mutations (I1532 and F1534) in the resistance formation were analyzed by the classification and regression trees (CART). Results The baseline enzyme activities of GST and MFO in Ae. albopictus JS were both significantly higher than those in the BS and HK resistant populations (both P0.01). There were no significant difference in the activities of GST and MFO between the BS population unexposed and exposed to deltamethrin (P0.05). After exposure to permethrin of BS population, the activities of GST and MFO were significantly increased (P0.05, P0.01). After exposure to deltamethrin, the GST activity was not significantly changed in the HK population (P0.05), while the MFO activity was significantly increased (P0.01). However, after exposure to permethrin in the HK population, there were no significant changes in the GST and MFO activities (both P0.05). In the 5 field resistant populations exposed to deltamethrin and permethrin, the changes of GST and MFO activities were irregular compared with baseline of Ae. albopictus JS strain. CART analysis showed that in the resistance formation of Ae. albopictus against deltamethrin, the contribution rates of GST activity and kdr F1534 mutation were the greatest, followed by MFO activity, and the kdr I1532 mutation was the smallest. In the resistance formation of Ae. albopictus against permethrin, the kdr F1534 mutation had the highest contribution rate, followed by the GST and MFO activities, and the kdr I1532 mutation had no contribution. Conclusion The activity levels of metabolic detoxification enzymes (GST and MFO) are not suitable as single markers for detecting the resistance of Ae. albopictus to pyrethroids. The activity changes of metabolic detoxification enzymes and kdr mutations may be two synergistic mechanisms in the resistance formation of Ae. albopictus to pyrethroid insecticides.

Resistance status of main malaria vector, Anopheles stephensi Liston (Diptera: Culicidae) to insecticides in a malaria Endemic Area, Southern Iran

Objective: To evaluate the susceptibility of Anopheles stephensi (An. stephensi) Liston, the main malaria vector in southern Iran, to WHO recommended insecticides. Methods: Larvae of An. stephensi were collected from three different larval habitats in both urban and rural area of Bandar Abbas city and one rural area in Rudan county southern Iran. WHO standard method was used for evaluation of adult and larval mosquito susceptibility. Bendiocarb, permethrin, lambda-cyhalothrin, deltamethrin as insecticide and temephos and chlorpyriphos as larvicide were used at the diagnostic dosages recommended by WHO. Results: Findings of this study showed all larval populations of An. stephensi were completely susceptible to temephos and candidate for resistance to chlorpyriphos. Adult mosquitoes in rural areas of Bandar Abbas city were resistant to pyrethroid and carbamate insecticides. Conclusion: Comparison of the results of this survey with previous studies indicates that the resistance to pyrethroids and carbamates in this malaria endemic region is increasing. Wide use of pesticides in agriculture is certainly effective in increasing resistance. The inter-sectoral coordination and collaboration in health and agriculture seem to be necessary to manage insecticide resistance in malaria vectors.

Validación de un método para la determinación del ácido 3-fenoxibenzoico en orina por QuEChERS, microextracción líquido-líquido dispersiva y cromatografía líquida de alta resolución-arreglo de diodos / Validation of a method for the determination of 3-phenoxybenzoic acid in urine using QuEChERS, microextraction liquid-liquid dispersive and high-performance liquid chromatography-diode array

Los piretroides son insecticidas ampliamente usados no sólo en el ámbito agropecuario y doméstico sino también en salud pública. Una vez absorbidos, son rápidamente metabolizados a compuestos polares eliminados por vía renal. Uno de los metabolitos común a un gran número de piretroides es el ácido 3-fenoxibenzoico (3-PBA) el cual es utilizado como marcador de exposición. Se presenta en este trabajo, la validación de una metodología analítica para la determinación del 3-PBA utilizando QuEChERS acoplado a microextracción líquido-líquido dispersiva con tricloroetileno como disolvente extractivo y cromatografía líquida de alta resolución con detector de foto-arreglo de diodos. La validación se realizó con muestras aisladas de orina de voluntarios adultos de ambos sexos sin exposición conocida y orina sintética. El método resultó lineal en el intervalo 9 μg L-1-79 μg L-1; los límites de detección y cuantificación fueron de 3 μg L-1 y 9 μg L-1, respectivamente. No se observaron señales de interferentes a los tiempos de retención del 3-PBA y del ácido 2-fenoxibenzoico (2-PBA), estándar interno, en las muestras de orina blanco. Las señales cromatográficas en las muestras enriquecidas fueron espectralmente homogéneas. Las precisiones intradiarias (RSDr%) (n= 5) para 9 μg L-1 estuvieron comprendidas entre 9,3%-9,9% y para 27 μg L-1 entre 5,9%-10,6%. Las precisiciones interdiarias (RSDint%) (n=15) para los mismos niveles de concentración fueron de 11,8% y 9,1%, respectivamente. El rango de porcentajes de recuperación para 9 μg L-1 fue de 87%-119% y para 27 μg L-1 de 70%-91%. Se evaluó la estabilidad del analito en la muestra y en el extracto. El analito resultó estable a -20 °C durante 7 días en la muestra y durante 1 día en el extracto. Los valores de incertidumbre relativa e incertidumbre expandida fueron evaluados mediante la ecuación de Horwitz, los resultados obtenidos fueron para el nivel 9 μg L-1 de 33% y 65% y para el nivel 27 μg L-1 de 28% y 55%. La aplicabilidad del método validado fue evaluada con muestras reales de personas sin exposición laboral conocida, quienes declararon haber usado insecticidas piretroides. El método resultó sensible y selectivo.

Pyrethroid insecticides are used not only in the agricultural and domestic environment, but also in public health. Once absorbed, they are rapidly metabolized into polar compounds eliminated by the kidneys. One of the metabolites common to many pyrethroids is 3-phenoxybenzoic acid (3-PBA) which are used to evaluate exposure. We present in this paper the validation of an analytical methodology for the determination of 3-PBA using QuEChERS coupled to dispersive liquid-liquid microextraction with trichloroethylene as an extractive solvent and high-performance liquid chromatography with a photodiode array detector. Validation was carried out with isolated samples of urine from adult volunteers of both sexes without exposure and synthetic urine. The method was linear in the interval 9 μg L-1-79 μg L-1; the limit of detection and quantitation were 3 μg L-1 and 9 μg L-1, respectively. Interfering signals were not observed in the blank urine samples and the chromatographic signals in the enriched samples were spectrally homogeneous. The within-run precision (RSDr%) (n = 5) for 9 μg L-1 were between 9.3%-9.9% and for 27 μg L-1 between 5.9%-10.6%. The between-run precision (RSDint%) (n = 15) for the same concentration levels were 11.8% and 9.1%, respectively. The recovery for 9 μg L-1 ranged from 87%-119% and for 27 μg L-1 from 70%-91 %. The stability of the analyte was evaluated in the sample and in the extract. The analyte in the sample was stable at -20 °C for 7 days and in the extract was stable for 1 day. The values of relative uncertainty and expanded uncertainty obtained by the Horwitz equation were 33% and 65% for 9 μg L-1, and 28% and 55% for 27 μg L-1. The applicability of the validated method was evaluated with real samples of people without known occupational exposure, who declared having used pyrethroid insecticides. The method was sensitive and selective.

Contrasting patterns of insecticide resistance and knockdown resistance (kdr) in Aedes aegypti populations from Jacarezinho (Brazil) after a Dengue Outbreak

ABSTRACT After a dengue outbreak, the knowledge on the extent, distribution and mechanisms of insecticide resistance is essential for successful insecticide-based dengue control interventions. Therefore, we evaluated the potential changes to insecticide resistance in natural Aedes aegypti populations to Organophosphates (OP) and Pyrethroids (PY) after chemical vector control interventions. After a Dengue outbreak in 2010, A. aegypti mosquitoes from the urban area of Jacarezinho (Paraná, Brazil) were collected in 2011 and 2012. Insecticide resistance to OP Temephos was assessed in 2011 and 2012 by dose–response bioassays adopting WHO-based protocols. Additionally, in both sampling, PY resistance was also investigated by the Val1016Ile mutation genotyping. In 2011, a random collection of mosquitoes was carried out; while in 2012, the urban area was divided into four regions where mosquitoes were sampled randomly. Bioassays conducted with larvae in 2011 (82 ± 10%; RR95 = 3.6) and 2012 (95 ± 3%; RR95 = 2.5) indicated an incipient altered susceptibility to Temephos. On the other hand, the Val1016IIe mutation analysis in 2011, presented frequencies of the 1016Ilekdr allele equal to 80%. Nevertheless, in 2012, when the urban area of Jacarezinho was analyzed as a single unit, the frequency of the mutant allele was 70%. Additionally, the distribution analysis of the Val1016Ile mutation in 2012 showed the mutant allele frequencies ≥60% in all regions. These outcomes indicated the necessity of developing alternative strategies such as insecticide rotations for delaying the evolution of resistance.

Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera: Culicidae) in Saudi Arabia

Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC

Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera:Culicidae) in Saudi Arabia

Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photo-microscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC50: 0.045 and 0.032 mg/L) than Actikil (0.052 and 0.038 mg/L) and Bacilod (0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin syn-thesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained (concen-tration which to inhibit the emergence of 50%of mosquito adults), the compound Dudim (0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal (0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively. Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

Clinical safety of dichlorvos (45%), cypermethrin (5%) and piperonyl butoxide (25%) administered by spray on the skin of cattle / Seguridad clínica del diclorvos (45%), cipermetrina (5%) y butóxido de piperonilo (25%) administrado por aspersión sobre la piel de bovinos

Objective. Due to the importance of controlling ectoparasites, associated with the necessity of technical knowledge on the safety of topical treatment with organophosphates, pyrethroids and piperonyl butoxide to the animal organism, this bioassay was carried out to evaluate the clinical safety of the association of dichlorvos (45%) + cypermethrin (5%) + piperonyl butoxide (25%) administered by spray on the skin of cattle, through the study of clinical parameters, biochemical, haematological and behavioral changes. Materials and methods. Sixteen crossbred animals with a mean age of 18 months, males and females grouped into two treatments with eight animals each: T1 (1:800 v/v) and T2 (1:200 v/v). Were collected blood samples at six different times: before treatment (BT), 24, 48, 72, 96 and 192 hours post treatment (HPT). Results. The antiparasitic association administered by spray on the skin did not result in changes in the enzymatic activity of ALT, AST, GGT and ALP, as well as in serum albumin, triglycerides, cholesterol, urea and creatinine, demonstrating the safety of this antiparasitic compound for maintaining hepatic and renal functionality. The erythrocyte, leukocyte and platelet studies showed no changes caused by treatments, and no clinical signs and behavioral changes were observed after treatment. Conclusions. These findings demonstrated good safety margin for spray treatment on the skin with this antiparasitic compound, even when administered at a dilution of 1:200 v/v, which is four times the dose recommended for ectoparasite control.

Objetivo. Debido a la importancia del control de ectoparásitos en bovinos, asociado a la necesidad de conocimientos técnicos sobre la seguridad del tratamiento tópico con organofosforados, piretroides y butóxido de piperonilo, se realizó este bioensayo para la evaluación de la seguridad clínica de la asociación de diclorvos (45%) + cipermetrina (5%) + butóxido de piperonilo (25%), administrado por aspersión en la piel del ganado bovino, a través del estudio de los parámetros clínicos, bioquímicos, hematológicos y comportamentales. Materiales y métodos. Dieciséis animales entre machos y hembras cruzados con edad media de 18 meses, agrupados en dos tratamientos de ocho animales cada uno: T1 (1:800 v/v) y T2 (1:200 v/v). Fueron colectadas muestras de sangre en seis momentos diferentes: antes del tratamiento (BT), 24, 48, 72, 96 y 192 horas post tratamiento (HPT). Resultados. La asociación antiparasitaria administrada por aspersión en la piel no alteró la actividad enzimática de ALT, AST, GGT y FA, así como la albúmina, triglicéridos, colesterol, urea y creatinina, que demuestra la seguridad de este compuesto antiparasitario en la función renal y hepática. El análisis de eritrocitos, leucocitos y plaquetas no mostraron cambios en los tratamientos, tampoco fueron observados signos clínicos y de comportamiento post tratamiento. Conclusiones. Estos resultados demostraron buen margen de seguridad en el tratamiento por aspersión en la piel con este compuesto antiparasitario, incluso cuando se administra en una dilución de 1:200 v/v, que es cuatro veces la dosis recomendada para el control de ectoparásitos.

Perfil do uso populacional de inseticidas domésticos no combate a mosquitos / Profile of the population use of household insecticides against mosquitoes

Esse trabalho descreve a utilização doméstica de inseticidas pela população de Picos (Piauí, Brasil),identifica quais são os tipos de inseticidas mais utilizados e descreve a incidência de intoxicação e a consciência ambiental da população. Após visitas domiciliares (n=700), notou-se que a maioria dos entrevistados foi representada por mulheres (75%), com idade entre 31-55 anos (49%), ensino fundamental incompleto (38,1%) e renda familiar entre 1-2 salários mínimos (64%). A maioria das residências tem entre 1-3 moradores (48%), 85% dos entrevistados usam inseticidas escolhidos principalmente em propagandas de TV e radio e apenas 54% leem o rótulo antes de aplicar o produto. A forma de apresentação mais usada é o aerossol (70,7%). A maioria (79%) reconhece que inseticidas são maléficos à saúde, mas 74% não usam nenhum Equipamento de Proteção Individual (EPI). Sintomas de toxicidade foram relatados por 27%dos entrevistados. Duas mulheres relataram irritação, tonturas e problemas respiratórios e necessidade de intervenção médica e internação hospitalar. Todos os entrevistados descartam as embalagens como lixo comum, uma vez que em Picos não há coleta seletiva. Em conclusão, a maioria das pessoas usam inseticidas, conhecem sobre os riscos individuais e coletivos aos quais estão expostos mas não usam EPI mesmo acreditando que sejam tóxicos. Notou-se que aquisição de conhecimentos não resulta,necessariamente, em mudanças de comportamento, uma vez que o conhecimento não se traduz em atitudes e práticas preventivas adequadas, ressaltando-se a necessidade de campanhas de conscientização quanto à toxicidade e aos riscos ambientais, capacitação de profissionais e política fiscalizatória contra a venda indiscriminada.

This study described the use of household insecticides in Picos (Piauí, Brazil), identify which are the mostused types of insecticides and describes the incidence of poisoning and environmental awareness of the population. After home visits (n = 700), it was seen that the majority of respondents was represented by women (75%), with 31-55 years-old (49%), incomplete primary education (38.1%) and income between 1-2 earnings (64%). Most homes have between 1-3 residents (48%), 85% of the persons use insecticides mainly chosen in TV and radio and only 54% of them read the label before employing the product. The most used form of presentation is the aerosol (70.7%). Majority (79%) recognizes that insecticides are harmful to health, but 74% do not use any Personal Protective Equipment (PPE). Symptoms of toxicity were reported by 27% of people interviewed. Two women reported irritation, dizziness and respiratory problems and need for medical intervention and hospitalization. All interviewed discard the package as regular trash, since Picos does not has selective collection. In conclusion, most people use insecticides, know about the individual and collective risks to which they are exposed but do not use PPE, though they believe insecticides are toxic. It was noted that acquisition of knowledge does not necessarily result in behavioral changes, since learning does not translate into appropriate preventive attitudes and practices, emphasizing the requirement for awareness campaigns about toxicity and environmental risks, preparation of professionals and surveillance policy against indiscriminate sale.

Quantitative structure-activity relationship of synthetic pyrethroids and antibody activity / 中国免疫学杂志

Objective:To research on the immune recognition mechanism of synthetic pyrethroids and generic specific antibody.Methods:We studied on quantitative structure-activity relationship ( QSAR ) of synthetic pyrethroids and their analogs as well as antibody activity ( IC50:fifty percent inhibition concentration ) using stepwise multiple linear regression method.Based on calculating structure descriptors of synthetic pyrethroids and their analogs , two-demensional QSAR ( 2D-QSAR ) model was established.The main factors affecting antibody activity were screened using 2D-QSAR,and predictive ability of QSAR models were evaluated by the method of leave-one-out( LOO) cross-validation.Meanwhile, the structure parameters of synthetic pyrethroid fragments were calculated and then analyzed using partial least squares ( PLS) assay.And then hologram QSAR ( H-QSAR) model was constructed on molecular substructure and antibody activity.The fragments contribution to antibody activity were illustrated by encoding different colors.Results:Decision coefficent (R2) of 2D-QSAR model and HQSAR model were 0.920 and 0.917 individually,cross-validation coefficient ( Q2 ) of two QSAR models were 0.875 and 0.660 respectively ,which showed two models had good predictive abil-ity.The result from 2D-QSAR model was also obtained that smaller was hydrophobicity of pyrethroids , easier was recognized by antibody.In addition,the optimum HQSAR model was constructed after we tried many combinations of these parameters .The fragment size in optimum HQSAR model was between 4 to 10,a hologram length was 61,optimum principle component was 4,and the fragment type of B/C/Ch was selected.However ,the fingerprint encoded results of synthetic pyrethroids weren′t consistent completely with exper-imental IC50 values.Conclusion:Hydrophobicity of synthetic pyrethroids is the largest correlation factors in antibody recognization .

Determination of Three Pyrethroids in Soil by Matrix Solid Phase Dispersion Extraction_Dispersed Liquid Phase Microextraction_Gas Chromatography Mass Spectrometry / 分析化学

A matrix solid phase dispersion extraction_dispersed liquid phase microextraction_gas chromatography_mass spectrometric method has been developed for the determination of three pyrethroids ( tetramethrin, permethrin and deltamethrin) in soil. The optimal conditions for the analysis were as follows. About 0. 5 g soil and 1. 5 g C18 solid phase extraction powder were grinding for 5 min. The mixture was eluted with 10 mL of acetone. The eluent was concentrated to 0. 4 mL, and then mixed with 20 μL of tetrachloromethane and 5. 0 mL of ultrapure water to form a homogeneous cloudy solution. The emulsion was broken by centrifugation. About 1 μL of sediment was injected and analyzed directly by GC_MS. Good linearities for three pyrethroids were ranged from 5 to 200 μg/kg (r2≥0. 9989), and recoveries at three spiked levels were ranged from 86 . 5% to 108 . 0% with RSDs less than 7 . 8%. The LODs of three pyrethroids were 1. 00-1. 48 μg/kg. This method can meet the determination of trace pyrethroids in soil.

Evaluación de la resistencia a insecticidas en Aedes aegypti (Diptera: Culicidae) de Argentina / Evaluation of insecticidal resistance observed in Aedes aegypti (Diptera:Culicidae) from Argentina

Introducción: a pesar de los enormes esfuerzos que realiza el Ministerio de Salud de Argentina para el control de Aedes aegypti, persisten en algunas regiones del país determinados índices de infestación que favorecen el desarrollo de epidemias o brotes de dengue. En este negativo indicador se destaca las provincias de Misiones y Buenos Aires, donde desempeña un papel importante el uso de insecticidas. Objetivos: determinar el nivel de resistencia a insecticidas químicos en cepas de Ae. aegypti de Misiones y Buenos Aires, Argentina. Métodos: se determinó en larvas el nivel de resistencia a insecticidas organofosforados (temefos y fenitrotion) y a piretroides (deltametrina y cipermetrina) a través de los bioensayos de la Organización Mundial de la Salud. En el estado adulto se evaluó los piretroides (deltametrina, lambdacialotrina y cipermetrina) y el organofosforado clorpirifos. Resultados: tanto las larvas como los adultos resultaron susceptibles a todos los insecticidas evaluados. Conclusiones: el control químico de Ae. aegypti de las localidades estudiadas, de las provincias de Misiones y Buenos Aires, puede realizarse de forma efectiva, utilizando los insecticidas en uso para el control vectorial, como son, temefos como larvicida y como adulticidas e insecticidas, piretroides y el organofosforado clorpirifos(AU)

Introduction: despite the great efforts of the Ministry of Health in Argentina for the control of Aedes Aegypti, certain significant infestation indexes persist in some regions and lead to the occurrence of dengue epidemics or outbreaks. This negative indicator is remarkable in Misiones y Buenos Aires provinces where the use of pesticides is important. Objective: to determine the levels of resistance of Aedes aegypti strains to chemical insecticidal effects in Misiones and Buenos Aires provinces in Argentina. Methods: World Health Organization bioassays determined the level of resistance in mosquito larvae to organophosphate insecticides (temephos and fenitrotion) and to pyrethroids (deltametrin and cypermetrin). In adult mosquitoes, the action of pyrethroids (deltametrin, lambdacyalotrin and cypermetrin) as well as that of organophosphate ones called chlorpiriphos was evaluated. Results: both the larvae and the adult insects were susceptible to all the insecticides. Conclusions: The chemical control of Ae aegypti in the studied areas from Misiones and Buenos Aires provinces can be effectively exerted by using the insecticides for the vector control such as temephos as larvicide and pyrethroids and the organophosphate called chlorpiriphos as adulticides(AU)

Clinical, biochemical and haemathological effects in Rhamdia quelen exposed to cypermethrin / Efeitos clínicos, bioquímicos e hematológicos em Rhamdia quelen expostos à cipermetrina

The acute intoxication of Cypermethrin in Silver Catfish (Rhamdia quelen) was evaluated. Animals weighing 56.67±4.43g and measuring 18.92±1.16cm were exposed to sublethal concentrations of Cypermethrin for the species in hydrological conditions during 96 hours. A total of 52 fish divided into three groups were used and received the following concentrations of Cypermethrin: 0 (n=12); 1.5 (n=20) and 2.5 (n=20)mg/L. The intoxicated animals suffered behavioral changes such as loss of balance, swimming alteration, dyspnea, upright swimming and sudden spiral swimming movements. As soon as the 96-hour period was over, a blood collection for hematological and biochemical analyses was performed. A complete haemogram test, plasmatic protein test, albumin, alanine transaminase (ALT), aspartate aminotransferase (AST), gamma glutamyltransferase and alkaline phosphatase (ALP) were studied. The values of erythrocytes, hematocrits, haemoglobin, total number of leukocytes, thrombocyte, ALT, AST and ALP changed according to the groups. The results have shown that the environmental contamination by Cypermethrin is toxic to the species...

Avaliou-se a intoxicação aguda da cipermetrina em jundiás (Rhamdia quelen). Jundiás que pesavam 56,67±4.43g e mediam 18,92±1,16cm foram expostos a concentrações subletais de cipermetrina para a espécie em 96 horas, via hídrica, utilizando-se 52 peixes, distribuídos em três grupos, segundo a concentração de cipermetrina: 0 (n = 12); 1,5 (n = 20) e 2,5 (n = 20)mg/L. Os animais intoxicados apresentaram alterações comportamentais, como perda de equilíbrio, dispneia, natação na posição vertical e movimentos bruscos de natação em espiral. Após 96 horas de exposição, foi coletado sangue para análises de hemograma completo, proteína plasmática, albumina, alanina aminotransferase (ALT), aspartato aminotransferase (AST), fosfatase alcalina (ALP) e gamaglutamiltransferase. Os valores de eritrócitos, hematócrito, hemoglobina, número total de leucócitos, número total de plaquetas, ALT, AST e ALP diferiram entre os grupos. Os resultados demonstraram que a contaminação ambiental por cipermetrina é tóxica para a espécie...

Development of sensitive molecular markers for detecting the genotoxicity induced by two pyrethroids insecticides, Cypermethrin and permethrin, to the Meditnerranean sole, Solea senegalensis (Kaup 1858).

The effects of two pyrethroid insecticides, cypermethrin and permethrin, on juvenile Senegalese sole, Solea senegalensis, were assessed. For this purpose, LC50 at 24 h and 72 h were determined as 500 μg L-1 and 900 μg L-1, respectively. The specimens were divided into 5 experimental groups exposed to: i) ethanol vehicle in sea water (control), ii) 1/25 of cypermethrin LC50 (20 μg L-1), iii) 1/10 of cypermethrin LC50 (50 μg L-1), iv) 1/25 of permethrin LC50 (36 μg L-1) and v) 1/10 of permethrin LC50 (90 μg L-1) during 10 days. At the end of the experiment, gill and hepatic samples were obtained for studying the expression patterns of different enzyme genes related to toxicity and osmoregulation, namely glyceraldehyde-3-phosphate dehydrogenases1 and 2 (GAPDH-1 and 2), and Na+, K+-ATPase subunits α and β (NKA α and β). Both pyrethroid insecticides enhanced gill GAPDH-1, NKA-α and NKA-β expressions. However, hepatic responses were less prominent. The low dose of cypermethrin decreased GAPDH-2 expressions. Also, the lowest permethrin dose decreased GAPDH-2 expression. These results indicate that pyrethroids induce some degree of oxidative stress in Solea senegalensis specimens led to an osmotic imbalance, activating -mainly at branchial level- different antioxidant and osmoregulatory enzyme genes.

Characterization of the pyrethroid resistance profile of Rhipicephalus (Boophilus) microplus populations from the states of Rio Grande do Sul and Mato Grosso do Sul, Brazil / Caracterização do perfil de resistência do Rhipicephalus (Boophilus) microplus a piretróides em populações dos estados do Rio Grande do Sul e Mato Grosso do Sul, Brasil

Cattle ticks Rhipicephalus (Boophilus) microplus are mainly controlled in Brazil by means of acaricide products, without any official policies in this regard. Acaricides continue to be sold indiscriminately, and this has contributed towards making the problem of resistance widespread, thus making diagnosis and monitoring of tick resistance essential. Here, bioassays (larval packet test) were performed on tick populations from the states of Rio Grande do Sul and Mato Grosso do Sul regarding their susceptibility to cypermethrin, deltamethrin and flumethrin. All the tick samples tested showed resistance to cypermethrin (10) (resistance factor (RF) ranging from 5.6 to 80.3) and deltamethrin (10) (RF ranging from 2.4 to 83.1). Six out of eight populations were resistant to flumethrin (RF ranging from 3.8 to 8.2). PCR molecular analyses did not show any T2134A mutations in the voltage-gated sodium channel gene, in any of the sampled populations. The results from this study highlight the critical status of resistance of the cattle tick to synthetic pyrethroids in the regions studied. Further studies are needed to identify the mechanisms responsible for the resistant phenotypes observed in the bioassays. This was the first detection of flumethrin resistance in Brazil.

O controle do carrapato Rhipicephalus (Boophilus) microplus no Brasil é feito principalmente com produtos acaricidas, sem uma política de controle oficial. A venda destes produtos continua ocorrendo de maneira indiscriminada, o que tem contribuído para generalizar o problema da resistência em todo o país, tornando essencial seu diagnóstico e monitoramento. Bioensaios (teste do pacote de larvas) foram conduzidos com populações de carrapatos do Rio Grande do Sul e Mato Grosso do Sul, com relação à sua suscetibilidade a três princípios ativos piretróides. Todas as amostras analisadas mostraram resistência à cipermetrina (10), com fatores de resistência (FR) de 5,6 a 80,3, e à deltametrina, com FR variando de 2,4 a 83,1. Seis das oito amostras foram resistentes à flumetrina (FR de 3,8 a 8,2). Análises moleculares utilizando PCR demonstraram que em todas as populações amostradas não foram encontrados alelos com a mutação T2134A no gene do canal de sódio controlado por voltagem. Os resultados deste estudo evidenciam a situação crítica da resistência do carrapato bovino ao grupo dos piretróides sintéticos nas regiões estudadas. Novos estudos são necessários para identificar os mecanismos responsáveis pelos fenótipos resistentes observados nos bioensaios. Este é o primeiro relato da resistência a flumetrina no Brasil.

Evaluation of Field Performance of Insecticide-Treated Mosquito Nets in North-Western Burkina Faso.

Aims: The aim of the study was to evaluate the field performance of insecticide-treated mosquito nets (ITNs) in north-western Burkina Faso. Study design: Cross-sectional survey. Place and Duration: The study took place between September and November 2008 (end of rainy season) in rural north-western Burkina Faso. Methodology: Standard WHO bioassays were performed on field-collected ITNs from three areas of different insecticide pressure: semi-urban Nouna town, three villages with cotton agriculture, and three villages without cotton agriculture. Data on age and washing frequency of ITNs was collected, and deltamethrin content was determind by HPLC. Results: The mean age of field-collected ITNs was 2.1 years. The mosquito mortality rate (Anopheles gambiae sl.) after 24 hours was 4% for the negative controls, 90% for the positive controls, and 73% for field-used ITNs. Differences in mosquito mortality between sub-areas disappeared after controlling for confounding variables. Conclusion: This study demonstrates that under real life conditions, deltamethrin still shows some level of effectiveness despite ongoing insecticide pressure. However, deltamethrin resistance has been observed in other parts of the country and thus close surveillance of ITN efficacy is needed. More frequent replacement of ITNs is also recommended.