Household Insecticides Research Articles

Household expenditure on control of urban mosquitoes Aedes albopictus and Culex pipiens in Emilia-Romagna, Northern Italy.

In 2007, the first outbreak of Chikungunya in Italy generated great alarm, highlighting the health risks caused by exotic species recently introduced in Europe and the need to strengthen control actions against the vectors. Besides health risks, mosquitoes cause nuisance, and citizens are required to adopt control measures. While the economic aspects of mosquito control by public agencies have been investigated, the scientific literature on the costs of mosquito protection incurred by families is scarce. This study assessed the households' expenditure on protective measures against mosquitoes in Emilia-Romagna, a region in Northern Italy. A phone questionnaire survey was conducted to collect data on the annual expenditure incurred by households for self-protection against mosquitos in relation to the perceived level of nuisance and the household and dwelling characteristics. Univariate and multivariate analyses were conducted to identify the main determinants influencing such expenditure, which resulted affected by dwelling characteristics, presence of children under 6 years of age, and health concerns of family members. The average annual household expenditure was estimated at 84.63 euros, about 30 times higher than the expenditure per household supported by regional and local administrations for interventions against mosquitoes in public areas, as calculated in a previous study. Household expenditure is mainly aimed at providing a direct defense against mosquito bites (mosquito nets, adulticides, skin-on repellents, etc.) while spending for more effective measures addressed to reduce mosquito density results marginal: e.g., only 3.5% of the total expenditure was dedicated to larval control. Control activities that lower the mosquito density in both private and public areas could reduce the use of household insecticides in urban environments and the related costs, and the risk of spread of imported arboviruses as well.

Essential Oil with Mosquito-Repellent Potential from Plectranthus Amboinicus Leaves Against Aedes Aegypti via Human Volunteer Study

Plectranthus amboinicus(PA) is a highly aromatic perennial shrub that belongs to the Lamiaceae family. It has thick, fleshy and succulent leaves and stem. The margins of the leaves contain numerous glandular hairs that produce essential oil. The essential oil of PA(PAEO) exhibits therapeutical, nutritional, antioxidant, antimicrobial, insecticidal, and insect repellent potentials. The objective of this study was to evaluate and compare the repellent properties of PAEO and DEET against Aedes aegypti mosquitoes, which are known carriers of dengue fever. The extraction of PAEO was carried out using hydrodistillation method while the chemical profile was analysed by gas chromatography-mass spectrometry (GC-MS) technique. The bioefficacy test was conducted according to the household insecticide products personal mosquito repellent evaluation method for biological efficacy (First revision) (MS1497:2007) provided by the Standard and Industrial Research Institute of Malaysia (SIRIM) with slight modification. 10% PAEO was used as test solution while 10% DEET was used as positive control. Fabric and patches treated with 10% PAEO were tested on human volunteers. Both the fabric and the patch, treated with 10% PAEO, exhibit excellent repellency (97 - 100%) against Ae. aegypti mosquitoes for a duration of up to 240 min (4 h) post-application. In contrast, 10% DEET, which initially showed a comparable repellency (99%) 30 min after application, experiences a gradual decline in repellency over time, reaching a 51% repellency rate at the end of the test (240 min post-application). A two-way ANOVA analysis indicates significant effect for type of treatment (p = 0.016) but with no significant difference between the exposure time. Tukey’s test showed significant differences between 10% PAEO-treated patches and 10% DEET (p = 0.016), and between 10% PAEO-treated fabric and 10% DEET (p = 0.026). These findings suggest that PAEO is potentially an effective natural repellent against Ae. aegypti.

The association between prenatal pyrethroids exposure and children's health - current research.

Exposure to pyrethroids, a widely used agricultural, forestry, and household insecticide, is a major public health concern due to its potential health effects on children. The aim of this review was to summarize the current knowledge of the effects of prenatal exposure to pyrethroids on the course and outcome of pregnancy, health status, and neurobehavioural development of children. A systematic and comprehensive search of the PubMed, Web of Science, and Scopus databases was conducted during January-February 2024. The review included original articles published in peerreviewed English-language journals since 2015. Based on keywords, 198 studies were identified and screened for eligibility. Ultimately, the review analyzed 25 articles including 16 that assessed the effects of prenatal exposure to pyrethroids on children's neurobehavioural development, 3 studies that assessed the effects on the course and outcome of pregnancy, and further 3 focused on respiratory disease. In addition, 1 study analyzed the development of obesity and 2 studies examined the effects on children's growth, weight and body composition in early childhood. In conclusion, there is considerable uncertainty about the adverse effects of prenatal exposure to pyrethroids on children's health. The strongest evidence has been reported for neurobehavioural development although results are also inconsistent. Further research is needed to understand the mechanisms of action and health effects of pyrethroids in susceptible populations. Int J Occup Med Environ Health. 2024;37(4).

Exposure of Young Children to Permethrin and Cypermethrin Insecticides in the Residential Environment.

The aims of this study were to evaluate the exposure to permethrin and cypermethrin of young children aged between 2 and 5 years in Nakhon Pathom and Sing Buri provinces, Thailand. A questionnaire that included general demographic information, household characteristics, insecticide usage and exposure-related behavior in children was used to interview parents or family caregivers. Permethrin and cypermethrin concentrations on floor surfaces and children's hands, as well as their urinary metabolites, were analyzed by gas chromatography coupled with mass spectrometry. The results showed that permethrin and cypermethrin were detected in 62% and 83% of the children's hand wipe samples, with geometric mean (GM) levels of 0.02 µg and 0.04 µg, respectively. Permethrin and cypermethrin were detected in 79% and 93% of floor surface wipe samples, with GM levels of 0.90 µg/m2, and 1.49 µg/m2, respectively. For children's urine, the GM concentrations of cis- and trans-DCCA, 3-PBA, and total pyrethroid metabolites were 0.84, 0.31 and 1.23 nmol/g creatinine, respectively. This study found that household insecticide product usage and having a tile floor were associated with increased permethrin concentrations on the children's hands and floor surfaces. However, cypermethrin concentrations on floor surfaces were significantly higher in families using aerosol insecticide sprays and insecticide products in the living room and bedroom. The predictors of the total pyrethroid, DCCA and 3-PBA metabolites are permethrin on children's hands or floor surfaces and cypermethrin on floor surfaces.

Associations between residential environmental characteristics during pregnancy and birthweight and head circumference among term births: The Taiwan birth Cohort study

Exposure to environmental pollutants during pregnancy may cause adverse birth outcomes in newborns. This study examined links between exposure to various residential environmental characteristics during pregnancy and newborn birth weight/head circumference, using the Taiwan Birth Cohort Study (TBCS) database with 14,829 subjects. We conducted simple and multiple linear regression analyses to find out the associations between residential environmental characteristics (molds, environmental tobacco smoke [ETS], household insecticide use, and home renovation or painting) and birth outcomes (birthweight, head circumference), and adjusting for demographics and environmental variables. The standardized beta coefficients were calculated. We also analyzed whether the associations varied by newborn sex and maternal body mass index (BMI). The regression analysis indicated that molds on multiple walls at the residence were significantly associated with lower birthweight (standardized β = −0.025, p = 0.003) and with smaller head circumference (standardized β = −0.023, p = 0.008) than no mold on walls after adjustment. Exposure to ETS did not result in significance for birthweight reduction but a significant reduction in head circumference (standardized β = −0.018, p = 0.047). The birthweight reductions associated with molds were −0.024 SD (standard deviation) for boys and −0.028 SD for girls, whereas the head circumference reduction with molds was sex-specific, being only significant for girls (standardized β = −0.029, p = 0.021). The analysis on BMI-separated data indicated that all significance occurred to mothers having normal BMI. Mold presence correlated significantly with reduced birth weight and head circumference, while ETS exposure only reduced head circumference. Girls and mothers with normal BMI were more affected by these reductions than boys or under/overweight mothers.

Use of Household Insecticides against Mosquitoes in Dengue-Endemic Areas in Sri Lanka.

The use of household insecticides in the formulation of mosquito coils and vaporizers is common among the public to protect against mosquito-borne diseases. However, information regarding the use of these commonly practiced household insecticides is scarce in Sri Lanka. A questionnaire-based survey was directed to 600 households in Colombo, Gampaha, Kandy, Kalutara, Jaffna, and Galle districts in Sri Lanka. Household insecticides were used by the majority of the respondents (57.0%), and electric liquid vaporizers (46.7%) and mosquito coils (45.7%) were the commonly used forms. The active ingredients in mosquito coils were d-trans-allethrin (w/w 0.12%), metofluthrin (w/w 0.005%), and dimefluthrin (w/w 0.01%); in liquid vaporizers, they were prallethrin (w/v 1.24% and w/v 1.26%) and transfluthrin (w/v 0.9%). The majority of the household insecticide consumers were moderately satisfied with the effectiveness of the products (68.6%), and most of the participants used household insecticides daily (35.5%), especially during the evening (41.6%). Most of the consumers were unaware of the chemicals included in household insecticides (62.8%). Mosquito coils were abundantly used by rural area participants (75.8%), whereas liquid vaporizers were the most common among the urban participants (56.4%). The findings indicate that demographic and socioeconomic factors influence household insecticide practices. To our knowledge, this study reveals the use of household insecticides to control mosquitoes for the first time in Sri Lanka and highlights the importance of awareness programs and the proper utilization of these products.

Does aversion to insects affect insecticide use? An elusive answer calls for improved methods in biophobia research

Abstract Insecticides are commonly used to control insects and other arthropods in homes (hereafter collectively referred to as ‘insects’). Although aversion to insects might encourage the use of insecticides, it is unclear whether such feelings truly influence the decision to use insecticides. We investigated the connection between feelings of disgust towards insects and the use of household insecticides. Our aim was to uncover the unexplored emotional drivers of insecticide use, in order to provide insights that might help develop new programmes to reduce exposure to household insecticides. We conducted an online survey (n = 2500) that focussed on insecticide use and disgust feelings towards six species commonly found in homes (cockroaches, ants, spiders, mosquitoes, flies and centipedes). Respondents rated their level of disgust towards these species and reported various beliefs and practices related to household insects and insect control. Approximately 70% of respondents expressed strong disgust towards these species (ratings of 6 or 7 on a scale of 1–7). More than half (53.3%) reported using aerosol insecticides in their homes in the 6 months prior to the survey. Path analyses highlighted several factors that influenced insecticide use, including infestation level, disgust intensity, lack of knowledge about arthropods and aversion to chemicals. However, the observed effect sizes were modest, particularly regarding the influence of disgust on insecticide use, which somewhat constrains our study's contribution to the understanding of the motivators driving household insecticide use. We explain how our findings potentially reflect a critical methodological limitation in the standard methods commonly used for measuring aversion in biophobia (fear of nature) research. This limitation originates from the fact that highly aversive animals often provoke extreme reactions from most participants, resulting in a very low data variation that hinders data analysis. We address this concern in the context of our findings and propose potential solutions that could pave the way for future research on how attitudes towards highly aversive animals affect individuals, society, and the relationships between people and nature. Read the free Plain Language Summary for this article on the Journal blog.

Spatial distribution and risk assessment of pyrethroid insecticides in surface waters of East China Sea estuaries

Pyrethroid insecticides are the most commonly used household insecticides and pose substantial risks to marine aquatic organisms. many studies have detected pyrethroid insecticides in the waters and estuaries of the western United States, but their distributions within western Pacific estuaries have not been reported. Accordingly, we used high-throughput organic analyses combined with high volume solid-phase extraction to comprehensively assess 13 pyrethroid insecticides in East China Sea estuaries and the Huangpu River. The results demonstrated the presence of various ∑13pyrethroid insecticides in East China Sea estuaries (mean and median values of 8.45 ± 5.57 and 7.78 ng L−1, respectively), among which cypermethrin was the primary contaminant. The concentrations of ∑12pyrethroid insecticide detected in the surface waters at the Huangpu River (mean 6.7 ng L−1, outlet 16.4 ng L−1) were higher than those in the Shanghai estuary (4.7 ng L−1), suggesting that runoff from inland areas is a notable source of insecticides. Wetlands reduced the amount of runoff containing pyrethroid insecticides that reached the ocean. Several factors influenced pesticide distributions in East China Sea estuaries, and higher proportions were derived from agricultural sources than from urban sources, with a higher proportion of agricultural sources than urban sources, influenced by anthropogenic use in the region. Permethrin and cypermethrin were the main compounds contributing to the high ecological risk in the estuaries. Consequently, to prevent risks to marine aquatic life, policymakers should aim to reduce insecticide contaminants derived from urban and agricultural sources.

Mosquito Control Strategies and Insecticide Resistance of the Malaria Vector in Urbanized Land Use Types in Suame Municipality, Ghana.

Modified landscapes could create breeding habitats for mosquitoes and affect their community structure and susceptibility with implications for their management. Hence, in this study, household mosquito control methods in two urbanized landscapes; industrial and residential human settlements, in Ghana and insecticide susceptibility of the inhabiting Anopheles populations were assessed. Household knowledge and usage pattern of mosquito control methods in the modified landscapes were obtained using a questionnaire. Female adult Anopheles mosquitoes were also subjected to susceptibility tests using mosquito coils (0.08% meperfluthrin, 0.03% dimefluthrin, and 0.3% transfluthrin) and World Health Organization (WHO) insecticide test papers (0.05% deltamethrin, 4% DDT, 0.1% bendiocarb, 0.25% pirimiphos-methyl, and 5% malathion). Although insecticide-treated nets and aerosols were used for mosquito control, mosquito coils were the most common and widely preferred household method. The Anopheles mosquitoes were resistant to all the insecticides (mosquito coils and WHO test papers) except pirimiphos-methyl. Land use type did not affect insecticide resistance, but the insecticide type did. The findings indicate the effect of household insecticide usage practices on local mosquito populations and their implications for effective vector management and disease control in modified landscapes.

Gambaran Penggunaan Insektisida Rumah Tangga di Kelurahan Tangkerang Barat Kecamatan Marpoyan Damai, Pekanbaru

Dengue Hemorrhagic Fever (DHF) is a potentially fatal disease that threatening global health, including Indonesia. Various efforts have been made to control DHF, one of them is by means of vector control. Household based insecticides are widely used by the community in controlling insect vectors, including Ae.aegypti as the main vector of DHF. This study aimed to describe the use of household insecticides in the Tangkerang Barat Sub District, Marpoyan Damai District. This study was conducted in September-November 2022 with a total of 100 respondents. The sample selection technique used was simple random sampling from 4 RWs. Data collection was carried out using guided interviews with 4 questions to respondents who used insecticides. Data analysis was carried out using univariate analysis. This study showed that almost all respondents (98%) used household insecticides, the most widely used type of formulation was aerosol (51%), active ingredient was dimeflutrin 0.02%; cypermethrin 0.10% (25.5%), used once a day (75.5%) and used at night (98%). Improper use of household insecticides can have negative effects on the environment, humans, and the occurrence of resistance. Mosquito Nest Eradication needs to be further improved in controlling Ae.aegypti.

Pyrethrins and Pyrethroids: A Comprehensive Review of Natural Occurring Compounds and Their Synthetic Derivatives

This comprehensive scientific review provides an in-depth analysis of both the natural compounds, pyrethrins, and their synthetic derivatives, pyrethroids, focusing on their classification, biosynthesis, mechanism of action, general and pharmaceutical uses, as well as their toxicity and environmental impact. Pyrethrins, derived from certain plant species, have long been recognized for their potent insecticidal properties. The review begins by examining the classification of pyrethrins and pyrethroids, elucidating their structural characteristics and unique features within the field of natural and synthetic compounds. The biosynthetic pathways responsible for producing pyrethrins in plants are discussed, highlighting the enzymatic reactions and genetic regulation involved. In addition, the synthesis of pyrethroid derivatives is explored, including both natural and synthetic sources and potential optimization strategies. Understanding the mechanisms of action by which pyrethrins and pyrethroids exert their insecticidal effects is a crucial aspect of this review. Complex interactions with the nervous systems of target organisms are examined, providing insights into their selective toxicity and modes of action. In addition, the various applications of these compounds are explored, from their use in agriculture for pest control to their incorporation into household insecticides and potential pharmaceutical applications. The review also critically evaluates the potential toxicity of pyrethrins and pyrethroids to human health. By consolidating current knowledge and research findings, this review provides a comprehensive understanding of the properties and applications of pyrethrins and pyrethroids, highlighting their benefits and risks, and the importance of responsible and sustainable use in various areas.

Biodegradation of naphthalene – Ecofriendly approach for soil pollution mitigation

Naphthalene (NPT), a widely used household pest repellent and insecticide obtained from crude oil, serves as a toxic pollutant to non-target living matter. The stable and resistant nature of NPT makes it difficult to degrade through the physiochemical processes. The present study investigated the bacterial degradation of NPT isolated from crude oil-contaminated soil. Initially, the potent bacteria, Bacillus sp. GN 3.4, were isolated by enrichment culture method and subsequently assessed for NPT biodegradation. The optimum conditions for NPT biodegradation were pH 7.0 at 37 °C, 80 mg/L (initial NPT), 3% v/v (inoculum dose), and 7 days of treatment which showed 100% biodegradation. Furthermore, GC–MS analysis revealed the presence of degradation metabolites, namely, salicylate and hydroquinone indicating potential metabolic pathways. Considering the water-solubility and non-toxic nature of these metabolites, the results imply that Bacillus sp. GN 3.4. could potentially play a role in bioremediation by aiding in eliminating NPT from the soil.

Is a Good Sleep on Mosquito-Free Nights Worth the Risk of Lymphoma Associated with the Use of Household Insecticides? A Case-Control Study of Lymphoma Subtypes in Adults.

The evidence linking the use of household pesticides and the risk of lymphoma is scanty. We explored the hypothesis in a population-based case-control study on lymphoma conducted in Sardinia, Italy, in 1998-2004, including 325 cases and 465 population controls and data on lifetime frequency, seasonality, and years of use of household insecticides and potential confounders. We calculated the risk of lymphoma (all subtypes) and its major subtypes associated with using household insecticides in three time windows (up to 1978, from 1979-2001, and 2002 onwards) with unconditional logistic regression adjusting by age, sex, education, and occupational exposure to pesticides. Household insecticides did not increase risk of lymphoma (all subtypes), Hodgkin's lymphoma, B-cell lymphoma, and the major B-cell lymphoma subtypes. The risk of multiple myeloma (MM) but not the other subtypes showed a non-significant upward trend (p = 0.203) with increasing quartiles of days of use in the time window when propoxur was the most popular household insecticide. Our results suggest no association between the household use of insecticides and the risk of lymphoma. Further studies are warranted to confirm or discard an association between MM risk and the use of propoxur.

Exposure of the general French population to herbicides, pyrethroids, organophosphates, organochlorines, and carbamate pesticides in 2014-2016: Results from the Esteban study.

Esteban is a nationwide cross-sectional study conducted in France in 2014-2016, including 2503 adults aged 18-74 years old and 1104 children aged 6-17 years old, as part of the French Human Biomonitoring programme. The present paper describes the biological levels of five families of pesticides analysed on random sub-samples of 900 adults and 500 children for urine concentrations, and 759 adults and 255 children for serum concentrations, and the determinants of exposure. Organophosphates, carbamates and herbicides were measured in urine by UPLC-MS/MS; chlorophenols and pyrethroids were measured in urine by GC-MS/MS; specific organochlorines were measured in serum by GC-HRMS. Multivariate analyses were performed to identify the determinants of exposure using a generalized linear model. Pyrethroid metabolites were quantified in 99% of adults and children, with the exeption of F-PBA, which was quantified in 31% of adults and 27% of children, respectively. Carbamates and some specific organophosphates were barely or not quantified. DMTP was quantified in 82% of adults and 93% of children, and γ-HCH (lindane) was quantified in almost 50% of adults and children. Concentration levels of pesticide biomarkers were consistent with comparable international studies, except for β-HCH, DMTP, and the deltamethrin metabolite Br2CA, whose levels were sometimes higher in France. Household insecticide use and smoking were also associated with higher levels of pyrethroids. All pyrethroids concentration levels were below existing health-based HBM guidance values, HBM-GVsGenPop, except for 3-PBA, for which approximately 1% and 10% of children were above the lower and upper urine threshold values of 22μg/L and 6.4μg/L, respectively. Esteban provides a French nationwide description of 70 pesticide biomarkers for the first time in children. It also describes some pesticide biomarkers for the first time in adults, including glyphosate and AMPA. For the latter, urine concentration levels were overall higher in children than in adults. Our results highlight a possible beneficial impact of existing regulations on adult exposure to organochlorine and organophosphate pesticides between 2006 and 2016, as concentration levels decreased over this period.

Frequency of urinary pesticides in children: a scoping review.

Pesticides are any mix of ingredients and substances used to eliminate or control unwanted vegetable or animal species recognized as plagues. Its use has been discussed in research due to the scarcity of strong scientific evidence about its health effects. International literature is still insufficient to establish a global recommendation through public policy. This study aims to explore international evidence of the presence of pesticides in urine samples from children and their effects on health through a scoping review based on the methodology described by Arksey and O'Malley. The number of articles resulting from the keyword combination was 454, and a total of 93 manuscripts were included in the results and 22 were complementary. Keywords included in the search were: urinary, pesticide, children, and childhood. Children are exposed to pesticide residues through a fruit and vegetable intake environment and household insecticide use. Behavioral effects of neural damage, diabetes, obesity, and pulmonary function are health outcomes for children that are commonly studied. Gas and liquid chromatography-tandem mass spectrometry methods are used predominantly for metabolite-pesticide detection in urine samples. Dialkylphosphates (DAP) are common in organophosphate (OP) metabolite studies. First-morning spot samples are recommended to most accurately characterize OP dose in children. International evidence in PubMed supports that organic diets in children are successful interventions that decrease the urinary levels of pesticides. Several urinary pesticide studies were found throughout the world's population. However, there is a knowledge gap that is important to address (public policy), due to farming activities that are predominant in these territories.

Fluralaner systemic treatment of chickens results in mortality in Triatoma gerstaeckeri, vector of the agent of Chagas disease

BackgroundChagas disease remains a persistent vector-borne neglected tropical disease throughout the Americas and threatens both human and animal health. Diverse control methods have been used to target triatomine vector populations, with household insecticides being the most common. As an alternative to environmental sprays, host-targeted systemic insecticides (or endectocides) allow for application of chemicals to vertebrate hosts, resulting in toxic blood meals for arthropods (xenointoxication). In this study, we evaluated three systemic insecticide products for their ability to kill triatomines.Methods Chickens were fed the insecticides orally, following which triatomines were allowed to feed on the treated chickens. The insecticide products tested included: Safe-Guard® Aquasol (fenbendazole), Ivomec® Pour-On (ivermectin) and Bravecto® (fluralaner). Triatoma gerstaeckeri nymphs were allowed to feed on insecticide-live birds at 0, 3, 7, 14, 28 and 56 days post-treatment. The survival and feeding status of the T. gerstaeckeri insects were recorded and analyzed using Kaplan–Meier curves and logistic regression.ResultsFeeding on fluralaner-treated chickens resulted 50–100% mortality in T. gerstaeckeri over the first 14 days post-treatment but not later; in contrast, all insects that fed on fenbendazole- and ivermectin-treated chickens survived. Liquid chromatography tandem mass spectrometry (LC-QQQ) analysis, used to detect the concentration of fluralaner and fenbendazole in chicken plasma, revealed the presence of fluralaner in plasma at 3, 7, and 14 days post-treatment but not later, with the highest concentrations found at 3 and 7 days post-treatment. However, fenbendazole concentration was below the limit of detection at all time points.ConclusionsXenointoxication using fluralaner in poultry is a potential new tool for integrated vector control to reduce risk of Chagas disease.Graphical

Acute respiratory distress after metofluthrin insecticide ingestion in a 19-month-old girl

Metofluthrin is a volatile pyrethroid insecticide. Despite being widely used as a safe household insecticide, it could cause severe systemic symptoms. A 19-month-old girl was taken to the emergency department after ingesting 1 mL of a mosquito repellent containing metofluthrin. After the arrival, the girl developed respiratory distress, which worsened progressively despite the administration of oxygen with nebulized salbutamol and budesonide. Additionally, she underwent application of high-flow nasal cannula, and administration of activated charcoal and systemic steroids. Her dyspnea gradually improved, and she was thus discharged on day 4 with oral prednisolone. All medications were discontinued 10 days after the discharge without any complication. Respiratory distress can develop after the ingestion of even a small amount of metofluthrin. Symptomatic and adjunctive steroid therapies can be effective therapeutic options.

Assessing the knowledge, attitude, and practices of using household insecticides among residents and factors related to practices in Vinh Linh District, Quang Tri Province, 2022

Objectives: To describe the current status of knowledge, attitude, and practices of using household insecticides among residents and some factors related to practices in Vinh Linh District, Quang Tri Province in 2022. Methods: This was a cross-sectional study, interviewing 412 people over 18 years old in three towns and one commune in Vinh Linh District, Quang Tri Province in 2022. Results: Research results showed that 79.1% of households used spraying insecticides and 20.9% used ant-killing powder, mosquito scent, and mosquito repellant cream. 77.3%, 79.8% and 73.3% had good knowledge, positive attitude and appropriate practices for using household insecticides, respectively. When using insecticides, 86.3% of people wore masks/face coverings, 71.8% followed the instructions for use, and 53.7% did not follow the instructions when mixing chemicals. Appropriate practices of participants who had access to information about household insecticides, with appropriate knowledge and positive attitude were 2.8 times (95% CI: 1.5-5.2), 2.2 times (95% CI: 1.2-3.7), and 1.8 times (95% CI: 1.0-3.17) higher than those who did not have access to information, with inappropriate knowledge and inappropriate attitudes about using household insecticides, respectively. Conclusions: Approximately three-fourths of the people had good knowledge, positive attitude and appropriate practices for using household insecticides. Education, years of use, knowledge, attitude, and receiving information about household insecticides were related to the practice of using household insecticides. People should go to the shops selling licensed household insecticides for advice and instructions on the safe use and purchase of chemicals. It is also important to carefully read and follow the instructions for insecticide use and not buy insecticides of unknown origin. The Department of Health should strengthen the inspection and supervision at the points of sale of insecticides and communicate about the safe and effective use of household insecticides.

Improving the efficiency of aerosolized insecticide testing against mosquitoes

Developing robust and standardised approaches for testing mosquito populations against insecticides is vital for understanding the effectiveness of new active ingredients or formulations. Methods for testing mosquito susceptibility against contact insecticides or products, such as those delivered through public health programmes, are well-established and standardised. Nevertheless, approaches for testing volatile or aerosolized insecticides used in household products can be challenging to implement efficiently. We adapted WHO guidelines for household insecticides to develop a standardised and higher-throughput methodology for testing aerosolized products in a Peet Grady test chamber (PG-chamber) using caged mosquitoes and an efficient decontamination method. The new approach was validated using insecticide resistant and susceptible Aedes and Anopheles mosquito colonies. An added feature is the inclusion of cage-facing cameras to allow real-time quantification of knockdown following insecticide exposure. The wipe-based decontamination method was highly effective for removing pyrethroids' aerosolized oil-based residues from chamber surfaces, with < 2% mortality recorded for susceptible mosquitoes tested directly on the surfaces. There was no spatial heterogeneity for knockdown or mortality of caged mosquitoes within the PG chamber. The dual-cage approach we implement yields eight-times the throughput compared to a free-flight protocol, allows simultaneous testing of different mosquito strains and effectively discriminates susceptible and resistant mosquito colonies tested side-by-side.

Transfluthrin- and prallethrin-based insecticides elicit specific enzymatic antioxidant responses in different tissue of zebrafish

Pyrethroids prallethrin (P-BI) and transfluthrin (T-BI) are among the most commonly used molecules with insecticide action. These molecules comprise different formulations of insecticides largely used in household, agricultural, and animal production fields. However, the increased use of these molecules has led to concerns regarding their safety in animals and humans. Oxidative stress (OS) is believed to be easily established by xenobiotic contacts, such as pyrethroids. We aimed to evaluate and understand the impact of two household insecticides and two doses applied to different tissues of the antioxidant system of zebrafish (Danio rerio). We observed that the effect on the antioxidant system differed between tissues. The muscle was the most affected tissue in the body, the antioxidant enzymes were activated, and a mechanism of non-enzymatic antioxidants was activated; however, it could still cause cellular damage. The observed effect on muscle may be related to the progression of neurodegenerative conditions. In addition, in the brain, these compounds can inactivate the first line of enzymatic antioxidant defense, which is compensated for by the second line, avoiding cellular damage. Ultimately, the gill tissue did not appear to suffer lipid damage, but heme group formation was largely affected by the compounds.