Pyrethroid insecticides are generally considered to have low mammalian toxicity; however, severe toxicity may occur following high-dose or intentional ingestion. Pyrethroids are classified into two types, Type Ⅰ and Type Ⅱ, with permethrin belonging to Type Ⅰ, which is typically associated with tremor. Laryngeal edema associated with pyrethroid poisoning has been rarely reported and is usually acute and self-limited. We report a case of delayed-onset and prolonged laryngeal edema following permethrin ingestion that required extended airway management and tracheostomy. A 73-year-old woman attempted suicide by ingesting a permethrin-based insecticide. She was intubated on admission for airway protection, showing no evidence of laryngeal edema at that time. Seizures occurred on hospital days two and three, likely attributed to pyrethroid neurotoxicity. Although her neurological status improved, extubation on day eight resulted in inspiratory stridor. Laryngoscopy revealed marked laryngeal edema, necessitating reintubation. Despite corticosteroid therapy, the edema persisted for more than two weeks, and a tracheostomy was performed on day 16. The patient was decannulated on day 30 and discharged without sequelae. This case demonstrated that pyrethroid poisoning can induce delayed-onset and prolonged laryngeal edema, even in the absence of initial airway findings. Clinicians should remain vigilant as airway compromise may evolve beyond the acute phase; consequently, extended monitoring of the upper airway is warranted in cases of severe pyrethroid toxicity.

Malaria remains a significant public health concern in Ko Chang, an island in Trat Province, eastern Thailand. The island has historically experienced low to moderate malaria transmission, particularly in forested and coastal zones. Transmission is driven by local Anopheles vectors such as Anopheles epiroticus Linton & Harbach. In this study, we employed the excito-repellency (ER) assay system to evaluate behavioral responses of laboratory and field strains of An. epiroticus to four synthetic and two natural repellent agents. Mosquito escape responses (% escape) were recorded under contact and non-contact conditions to determine irritant and repellent properties. For the laboratory strain, deltamethrin (42%) and permethrin (35%) at LC50 levels induced the highest escape responses in contact trials. In contrast, alpha-cypermethrin (4-14%) induced limited irritancy and repellency. Citronella oil (>50%) at 5.0% (v/v) elicited the strongest non-contact repellency, outperforming DEET (18-26%) and vetiver oil (26-40%). However, the field strain showed a different pattern: DEET (64%) and deltamethrin (60%) were most effective in contact trials, while citronella and vetiver oils (both ∼14%) had minimal non-contact effects. Our findings indicate differences in excito-repellency between field and laboratory strains of An. epiroticus in Ko Chang. Deltamethrin, permethrin, and DEET were more effective as contact irritants against the field population, whereas citronella oil demonstrated greater efficacy as non-contact repellents against the laboratory strain. These results indicate the need to account for behavioral variation when designing vector control strategies and inform both malaria prevention for travelers and local control programs in coastal Thailand.

The widespread use of household insecticides represents a potential but often overlooked source of selection pressure contributing to insecticide resistance in malaria vectors. In Côte d'Ivoire, resistance to pyrethroids is widespread; however, the role of domestic insecticide practices in shaping metabolic resistance mechanisms remains poorly documented. A cross-sectional household survey was conducted in 3 urban localities of Côte d'Ivoire (Abengourou, Daloa, and Gagnoa) to characterize insecticide use patterns, frequencies, and application practices. In parallel, larvae of Anopheles gambiae s.l. were collected from the same localities, reared to adulthood, and analyzed for the expression of 8 detoxification genes (CYP6P3, CYP6M2, CYP9K1, CYP6P4, CYP6Z1, GSTE2, CYP6P1, and CYP4G16) using quantitative real-time PCR. Gene expression levels were compared with those of the insecticide-susceptible reference strain Anopheles gambiae Kisumu using REST software. Overall, 63.0% of households reported regular use of insecticides, with marked heterogeneity between sites Pyrethroid-based formulations, predominantly permethrin-transfluthrin combinations, were the most commonly used products. Household insecticide consumption was highest in Abengourou, exceeding 2 aerosol cans (300 ml) per week. Molecular analyses revealed significant overexpression of CYP6P1 in An. gambiae s.l. from Abengourou and CYP6Z1 in populations from Daloa and Gagnoa compared with the Kisumu reference strain. The intensive and recurrent use of household insecticides is associated with the presence of metabolic resistance markers; however, causality cannot be established. These findings highlight the need to integrate domestic insecticide practices into national insecticides resistance management strategies.

Permethrin, a widely used pyrethroid insecticide, impairs male reproductive function through oxidative stress and endocrine disruption. This study evaluated the protective effects of quercetin against permethrin-induced testicular toxicity in adult male Wistar rats. Thirty rats were divided into five groups (n = 6): control, DMSO vehicle, permethrin (35 mg/kg/day orally), permethrin + quercetin (15 mg/kg/day orally), and quercetin alone, for 60 days. Permethrin exposure induced severe ultrastructural damage including mitochondrial swelling, nuclear chromatin condensation, and Sertoli cell detachment from the basement membrane-along with seminiferous tubule disorganization, reduced sperm motility and viability, increased sperm morphological abnormalities, and suppressed serum testosterone, FSH, and LH levels. Co-administration of quercetin significantly attenuated these adverse effects, preserving testicular cellular integrity, improving sperm quality, and partially restoring gonadotropin and testosterone levels. These findings demonstrate that quercetin exerts multifaceted protection against permethrin-induced testicular injury at hormonal, functional, histological, and ultrastructural levels, highlighting its potential as a protective agent in mitigating pesticide-associated male reproductive dysfunction.

Honey bees are recognized as keystones of terrestrial ecosystems, being responsible for about 80% of human crop pollination. Unfortunately, bee populations have significantly declined over the past years due to various factors including pesticide use. Although pyrethroid insecticides have been intensively used since the 70 s and recognized for their high toxicity to bees, their possible deleterious effects on honey bee cognition have received little attention. Here, we investigated the impact of sublethal doses of two pyrethroids (permethrin and cypermethrin) on honey bee perception, learning and memory. We used a battery of cognitive tests of increasing complexity, all based on the conditioning of the proboscis extension response (PER). This protocol replicates in the Lab the final phase of bees' foraging behavior, in which they learn to associate odorants with sucrose rewards. Topical exposure to pyrethroids impaired both non-associative learning (habituation) and associative learning (olfactory learning and discrimination performances). Using in vivo calcium imaging, we then assessed odor-induced activity in the antennal lobe, the primary olfactory center of the insect brain. Surprisingly, cypermethrin treatment showed no effect on odor representation within the antennal lobes, neither in terms of signal intensity nor in the separability of glomerular activity patterns. This suggests that pyrethroid effects may be located in higher-order centers of the honey bee brain. These results show although they are widely used, sublethal doses of pyrethroids gravely affect bees' cognitive abilities. More generally, our test battery can be used for a more thorough systematical assessment of cognitive effects of insecticides in pollinators.

Scabies is a contagious skin infestation of ongoing public health concern. This retrospective, descriptive study analyzed the epidemiological trends, clinical characteristics, and treatment outcomes of pediatric scabies in a tertiary care setting in Ankara, covering both pre- and post-earthquake periods between September 2019 and December 2023. Among 848 patients, representing 25% of all parasitic infections, case numbers showed a steady increase over the four-year period. The majority of patients (95.8%) resided in Central Anatolia, and 49% reported symptomatic household contacts. Pruritus (90.5%) and rash (78.3%) were the dominant symptoms, while secondary bacterial complications were rare (0.7%). Permethrin was the primary treatment (62.2%), yielding an 87.2% favorable clinical response. Recurrence occurred in 12.7% of cases. These descriptive findings highlight the steadily increasing burden of pediatric scabies in Central Anatolia and underscore the need for enhanced public health surveillance and comprehensive household-level management in urban settings.

Intensive insecticide use has been repeatedly employed to prevent the spread of mosquito-borne Chikungunya fever, but poses potential exposure risks to ecosystems and environments. Herein, we developed a dual mass spectrometric (MS) strategy for on-site monitoring of typical insecticides in different environmental media and for assessing associated exposure risks during the Chikungunya epidemics. The dual MS strategy demonstrated good analytical performance for on-site analysis, including sensitivity (at parts per billion level), reproducibility (<20%, n = 7), and analytical speed (within 10 min). It was found that the main active compounds, such as permethrin and allethrin, persist in water and soil, whereas volatile auxiliaries such as toluene and isooctyl alcohol rapidly volatilize into ambient air immediately after spraying. Particularly, sawtooth-shaped accumulation effects of non-volatile insecticides were found after repeated applications. Furthermore, a successive five-day monitoring revealed that health exposure risks would be significantly increased due to the cumulative effects of repeated insecticide spraying. Overall, this study not only provides a promising strategy for the on-site monitoring of insecticides but also offers valuable insights into their cumulative effects and associated exposure risks across different environmental media.

Sarcoptic mange and tick infestations caused by Sarcoptes scabiei and Rhipicephalus microplus are growing veterinary and economic concerns globally. Resistance against traditional acaricides, coupled with growing concern for the environment, calls for the development of alternative control strategies. The current study aimed to develop and evaluate the acaricidal activity of silver nanoparticles (AgNPs) synthesized using a green methodology that involved the leaf extracts of Punica granatum. The AgNPs were characterized using UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. The synthesized AgNPs were also tested for their acaricidal activities using Adult Immersion Test (AIT), Larval Packet Test (LPT), contact bioassays, and molecular docking to determine the possible binding interactions of the bioactive metabolites with the respective target proteins. The results revealed the successful synthesis of crystalline AgNPs with a diameter of 25 to 80 nm, coupled with a strong signal for silver in the EDX analysis. The AgNPs also showed a promising bio efficacy and acaricidal activity against R. microplus and S. scabiei. In the contact bioassays, the acaricidal activity of the AgNPs extract was concentration dependent, with significant 100% mortality even at 2 mg/mL. The extract was even more active than the positive control, permethrin. In contact bioassays, prolonged exposure demonstrated an improvement in the LC50 and LC90 values, while the Adult Immersion Test showed a remarkable inhibition of oviposition. At a concentration of 40 mg/mL, 100% mortality rate, and 71.93% inhibition of egg-laying were observed with the AgNPs extract. This demonstrates significant suppression of tick reproduction. Computational analyses supported these findings. Structural homology of target proteins was validated using Ramachandran plots, ERRAT, and CASTp, while molecular docking showed that the most active compounds, benzene dicarboxylic acid and 3-amino-N-(pyridin-4-yl) propanamide had the highest binding affinities to the aspartic proteases of S. scabiei and R. microplus, thus aligning with the observed bioactivity. In silico studies underscored novel phytocompounds with strong inhibitory potential as the extract and the as-synthesized AgNPs exhibited potent acaricidal activity, underscoring them as promising candidates to replace synthetic acaricides.

In response to rising insecticide resistance among malaria vector species, countries are implementing long-lasting insecticide treated nets (LLINs) coformulated with piperonyl butoxide (PBO), which can restore susceptibility to pyrethroid-based nets. In mid-2021, Kenya National Malaria Program rolled out PBO-LLINs in Bungoma County. We evaluated the susceptibility of wild-collected vectors to new versus used PBO-LLINs using the WHO cone bioassays. Results were confirmed with the WHO susceptibility assay. A total of 2,020 female Anopheles were tested, of which 1,480 were wild-collected and 540 were a Kilifi-susceptible strain. Mortality after exposure to new PBO-LLINs was only 68% in the wild-collected mosquitoes and as low as 34% when mosquitoes were exposed to used, 24-month old PBO-LLINs. Anopheles arabiensis was the main vector species that survived exposure. Susceptibility tests confirmed very low mortality after exposure to permethrin with or without PBO. Reduced sensitivity can be attributed partly to the aging of the net but also to very high levels of resistance in the local vector population.