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Amblyomma ticks pose a significant public health threat due to their potential to transmit pathogens associated with rickettsial diseases. (E)-2-octenal, a compound found in donkeys (Equus asinus), exhibits strong repellent properties against Amblyomma sculptum nymphs under laboratory conditions. This study assessed the effectiveness of the (E)-2-octenal in wearable slow-release devices for personal human protection against Amblyomma ticks under natural conditions. Slow-release devices treated with (E)-2-octenal and untreated controls were prepared and tested on two volunteers walking through a tick-infested area in Goiania, Brazil. The experiment was conducted twice daily for three series of 10 days, with each volunteer wearing two devices attached to each leg, one on the ankle and one just above the thigh. Volunteers with control and treated devices exchanged them between rounds. Also, the daily release rate of (E)-2-octenal from the slow-release devices was determined in the laboratory, increasing significantly from 0.77 ± 0.14 µg/day on the first day to 9.93 ± 1.92 µg/day on the 4th day and remaining constant until the 16th day. A total of 5409 ticks were collected from both volunteers. Treated devices resulted in recovering fewer ticks (n = 1,666; 31%) compared to untreated devices (control: n = 3,743; 69%). (E)-2-octenal effectively repelled Amblyomma spp. larvae, A. sculptum adults, and exhibited pronounced repellency against A. dubitatum nymphs and adults. These findings suggest the potential of (E)-2-octenal delivered by wearable slow-release devices as a green-based repellent. Further improvements, however, are necessary to provide better protection for humans against A. sculptum and A. dubitatum in field conditions.

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The serpent study involves physiological, behavioral and interaction factors with an extremely dynamic and complex environment. The relation of these animals with biodiversity is still quite preliminary, little studied and sustained by popular practices related to traditional medicine, esoteric and mystical currents. Therefore, this study proposed to know about the effect of 80% crude alcoholic extract of Petiveria alliacea L., popularly known as Tipi Herb, and its effects associated with the repellency of the Bothrops moojeni serpent. A complex of boxes was built for the observation of the snake's displacement, carried out for a total period of six days, the first three for defining the exploratory pattern and the other two for testing the alcoholic extract of Tipi, and finally on the sixth day, one cycle with the presence of a live attractant as bait. It was observed that the animal had no inhibition behavior and moved through the complex in a way like what occurs in nature and showed behavior to avoid remaining in the presence of the extract both with the presence of a live attractant or without it, preferring to move in the other compartments. The results show that this proposed tool is valid for the study of displacement of Bothrops moojeni snakes, in the same way that it added values on the importance of cerrado biome biodiversity and on the popular medicine practices of Tipi Herb, since the repellent effect on the snake was significant in the two tests performed.

O estudo das serpentes envolve fatores fisiológicos, comportamentais e de interação com um ambiente extremamente dinâmico e complexo. A relação destes animais com a biodiversidade ainda é bastante preliminar, pouco estudada e muito alimentada por práticas populares ligadas a medicina tradicional, correntes esotéricas e místicas. Nessa linha que este estudo propôs conhecer sobre o efeito do extrato bruto alcoólico a 80% da Petiveria alliacea L, popularmente conhecida como Erva Tipi, e seus efeitos associados à repelência da serpente Bothrops moojeni. Foi construído um complexo de caixas para a observação do deslocamento da serpente, realizado por um período total de seis dias, sendo os três primeiros para definição do padrão exploratório e os outros dois para o teste ao extrato alcóolico de Tipi e finalmente no sexto dia um ciclo com presença de um atrativo vivo. Foi observado que o animal não teve comportamento de inibição e se deslocou pelo complexo de forma análoga ao que ocorre na natureza e demonstrou comportamento de evitar se manter na presença do extrato tanto com a presença de um atrativo vivo como sem ele, preferindo se deslocar nos outros compartimentos. Os resultados mostram que essa ferramenta proposta é valida para estudo de deslocamento das serpentes Bothrops moojeni, da mesma maneira que agregou valores na importância da biodiversidade do Cerrado e sobre as práticas populares da Erva Tipi, uma vez que o efeito repelente sobre a serpente foi significativo nos dois testes realizados.

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In this work, it was studied the role of faeces in the location and permanence in a shelter in susceptible and pyrethroid-resistant individuals of Blattella germanica (Linnaeus 1767). Additionally, the effect of different concentrations of palmitic acid on the modulation of these behaviours was tested. A shelter constituted by a square cardboard structure was offered to susceptible as well as to resistant specimens. The shelter bases were treated with faecal extracts obtained from susceptible or resistant cockroaches, or with solutions of palmitic acid. The behaviour of susceptible as well as resistant specimens was analysed using infrared videography software. Susceptible's faecal extract attracted both specimens since the time spent by cockroaches to locate the treated shelters was lower, whereas the faecal extract from resistant insects did not elicit any effect on both strains. Faecal extracts showed an arrestant effect on both strains, suggested by the time spent inside the shelter that was significantly higher in their presence. On the other hand, treatment with palmitic acid produced an attractant or a repellent effect depending on the concentration and strain. The tested lower concentration was attractant to susceptible insects, but did not produce any effect on resistant ones. In addition, the higher concentrations did not produce any effect on susceptible individuals, but resulted repellent for resistant ones. Palmitic acid did not produce an arrestant effect on the strains as there was not an increase in time spent inside the shelter in the presence of this substance. An increase in the number of visits to the shelter and to the periphery was also observed in shelters treated with the faecal extract and with the lower concentration of palmitic acid. These results show that compounds of the susceptible faeces were attractant to cockroaches of both strains, while faecal extracts from resistant insects were not. Moreover, a dual effect of palmitic acid was observed, being attractant at low concentrations and repellent as concentration increased. Additionally, a difference in the concentration threshold at which the effect of this substance changes was observed between strains.

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Among the efforts to reduce mosquito-transmitted diseases, such as malaria and dengue fever, essential oils (EOs) have become increasingly popular as natural replacements for the repellant DEET. In this study, seven commercially available plant EOs against Aedes species mosquitoes were evaluated for their complete protection time (CPT, min) in vivo using human-hand in cage tests (GB2009/China and WHO2009). Among the EOs with the highest efficacy in repelling mosquitoes, Aedes albopictus (Skuse) were clove bud oil and patchouli oil. Both were further assessed according to the in vivo method recommended by the WHO, to determine their minimum effective dose and CPT. A comparison of the ED50 values (dose yielding a 50% repellent response) of these two EOs against Aedes aegypti(L.) showed that the ED50 (2.496 µg/cm2) of patchouli oil was 1248 times higher than that of clove bud oil (0.002 µg/cm2), thus demonstrating them greater efficacy of the latter in repelling Ae. aegypti mosquitoes. For the 2 EOs, eugenol was the major component with higher than 80% in relative amount of the clove bud oil. The patchouli oil had more than 30% of character chemical patchouli alcohol along with α-bulnesene (10.962%), α-guaiene (9.227%), and seychellene (7.566%). Clove bud oil was found to confer longer complete protection than patchouli oil against a common species of mosquito. These results suggest use of EOs as safe, highly potent repellents for use in daily life and against mosquito-transmitted diseases, such as malaria and dengue fever.

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Mosquito-borne diseases affect millions of people worldwide each year, and the use of a topically applied insect repellent is an economically viable preventative health practice. The general objective of this work was to encapsulate citronella oil (CO) in a nanostructured lipid carrier (NLC) to formulate a topical repellent with a long duration of efficacy on the skin and a good safety profile based on minimizing skin penetration. In the studied CO, the main chemical constituents of geraniol, citronellal, and citronellol were identified and subsequently used as markers for the in vitro skin permeation testing (IVPT). An optimal NLC encapsulating CO formulation was developed and had an average particle size of 350 nm. The NLC was then formulated in combination with CO at ratios of 2:1, 1:1, and 1:2 CO:NLC-CO as oil-in-water (O/W) emulsions and compared to CO in the same O/W emulsion base (all at 10% CO in the final O/W topical formulation). The markers geraniol, citronellol, and citronellal were detected in all samples tested F1 (10% CO in O/W emulsion) and F3 (10% CO/NLC-CO 1:1 in O/W emulsion). Even the percentages of F3 markers were higher than F1. The recovery of the percentage balance (based on the total remaining on the skin surface, on the skin, and penetrated through the skin to the receptor) of geraniol, citronellol, and citronellal markers for F1 and F3 was 7.70% and 11.96%; 25.51% and 31.89%; and 5.09% and 4.40%, respectively. The nanoparticle lipid solid forms a repellent reservoir on the skin surface, releasing the active ingredients slowly through volatilization, extending the repellent action, and reducing permeation through the skin. It is possible to assume that the remaining 92.30% and 88.03%; 74.49% and 68.11%; and 94.10% and 95.60% of geraniol, citronellol, and citronellal markers of F1 and F3, respectively, were lost to evaporation. In the in vivo efficacy test carried out with the Aedes aegypti mosquito, F3 was the optimal formulation, providing the greatest repellent action compared to free oil in O/W emulsion. Thermal analysis showed that the NLC-CO raised the boiling point of the encapsulated CO compared to the free oil, suggesting that the controlled release of the CO was a possible mechanism for its prolonged effect. We concluded that the nanocarriers developed with CO were stable and provided improved mosquito-repellent efficacy with minimal skin penetration of the CO actives over 24 h. Indeed, regardless of whether the CO was applied as free oil, a 1:1 mixture of CO (pure/free oil) or NLC-CO applied in an O/W emulsion can be considered safe for topical application due to minimal skin penetration.

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Mosquito-borne diseases such as dengue, malaria, yellow fever, chikungunya and Zika virus affect millions of people worldwide each year. Vector control and personal protection are very important to minimize the spread of diseases, and the use of repellent is an economic practice to prevent them. The application of repellent, which acts on the skin to form a vapor layer with a repellent odor to mosquitos, is recommended as an economic prevention and practice. The natural botanical product Citronella is an effective mosquito repellent due to the high concentrations of active chemical constituents present, notably terpenic alcohols. However, citronella tends to evaporate quickly from the skin surface, resulting in a rapid loss of activity. Strategies to increase repellency time, while at the same time minimizing toxicity, are major focuses of research and development in natural repellent products. Here we highlight the role of extended-release systems (ERS) of citronella oil in this approach.

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Este artigo teve como objetivo avaliar os efeitos do uso de repelentes na população brasileira. Para alcançar o objetivo proposto, foram utilizadas as metodologias da revisão de literatura e a pesquisa documental junto à ANVISA referentes aos repelentes registrados e comercializados no Brasil. De acordo com a RDC nº 7 de 2015 da ANVISA, os repelentes são classificados como produtos de Grau 2, compostos por Produtos de Higiene Pessoal, Cosméticos e Perfumes. Nessa categoria, constatou-se a existência de 113 produtos registrados para comercialização no Brasil. Verificou-se que, apesar do aumento do consumo devido às doenças causadas por picada dos mosquitos Aedes aegypti, a maioria dos repelentes comercializados possuem como princípio ativo as substâncias DEET, Icaridina ou IR3535, não resultando em reações tóxicas relevantes para a população, visto que, essas substâncias são de baixa toxicidade ou atóxicas, como é o caso do IR3535. Faz-se necessário considerar que o uso desses produtos deve seguir rigorosamente as orientações dos fabricantes disponíveis nos rótulos das embalagens no que tange à aplicação, reaplicação, frequência e uso específico para crianças, gestantes e lactantes. No que se refere à eficácia, a Icaridina apresenta-se como mais eficaz que o IR3535 quando considerados os fatores tempo de proteção versus concentração do princípio ativo. Entretanto, a Icaridina, em alguns casos, pode apresentar moderada toxicidade, enquanto que, o IR3535 é atóxico. Observa-se ainda, que mesmo diante desse cenário, o DEET é o mais comercializado e amplamente estudado no país.

This article aimed to evaluate the effects of the use of repellents in the Brazilian population. To achieve the proposed objective, the methodologies of literature review and documentary research with ANVISA regarding repellents registered and marketed in Brazil were used. According to ANVISA's RDC No. 7 of 2015, repellents are classified as Grade 2 products, composed of Personal Hygiene Products, Cosmetics and Perfumes. In this category, it was found the existence of 113 products registered for commercialization in Brazil. It was found that, despite the increased consumption due to diseases caused by bites from Aedes aegypti mosquitoes, most repellents marketed have as active ingredients the substances DEET, Icaridin or IR3535, not resulting in toxic reactions relevant to the population, since these substances are of low toxicity or non- toxic, as is the case of IR3535. It is necessary to consider that the use of these products should strictly follow the manufacturers' guidelines available on the packaging labels regarding application, reapplication, frequency and specific use for children, pregnant and lactating women. With regard to efficacy, Icaridin is more effective than IR3535 when considering the factors protection time versus concentration of the active ingredient. However, Icaridin, in some cases, may present moderate toxicity, while IR3535 is non- toxic. It is also observed that, even in this scenario, DEET is the most marketed and widely studied in the country.

artículo tuvo como objetivo evaluar los efectos del uso de repelentes en la población brasileña. Para alcanzar el objetivo propuesto, se utilizaron las metodologías de revisión bibliográfica e investigación documental con ANVISA sobre repelentes registrados y comercializados en Brasil. De acuerdo con el CDR nº 7 de 2015 de ANVISA, los repelentes se clasifican como productos de Grado 2, compuesto por Productos de Higiene Personal, Cosméticos y Perfumes. En esta categoría, se constató la existencia de 113 productos registrados para comercialización en Brasil. Se constató que, a pesar del aumento del consumo debido a las enfermedades causadas por picaduras de mosquitos Aedes aegypti, la mayoría de los repelentes comercializados tienen como principios activos las sustancias DEET, Icaridina o IR3535, no resultando en reacciones tóxicas relevantes para la población, ya que estas sustancias son de baja toxicidad o no tóxicas, como es el caso del IR3535. Es necesario considerar que el uso de estos productos debe seguir estrictamente las directrices de los fabricantes disponibles en las etiquetas de los envases en cuanto a aplicación, reaplicación, frecuencia y uso específico para niños, mujeres embarazadas y lactantes. En cuanto a la eficacia, la Icaridina es más eficaz que el IR3535 si se consideran los factores tiempo de protección frente a concentración del principio activo. Sin embargo, la Icaridina, en algunos casos, puede presentar una toxicidad moderada, mientras que el IR3535 no es tóxico. También se observa que, incluso en este escenario, el DEET es el más comercializado y ampliamente estudiado en el país.

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To control urban pests, especially cockroaches of the Periplaneta americana species, various pesticides have been developed that are increasingly potent and effective. However, the unrestrained application of pesticides has had negative consequences, such as the disappearance of some useful insect species and, consequently, the appearance of new pests, both in the countryside and cities. Due to the current scenario, it was necessary to search for new alternatives for the control of these insects. Among the species studied, Copaíba stood out. The oils were analyzed using GC-MS, b-caryophyllene and a-bergamotene being the predominant compounds. Repellency tests were performed with three different concentrations of C. officinalis and C. reticulata, 500 µg/mL, 250 µg/mL and 125 µg/mL, in triplicate. It can be observed that the oil of C. officinalis was more repellent to the nymphs at concentrations of 500 µg/mL and 250 µg/mL, however, when the behavior in nymphs exposed to the concentration of 125 µg/mL was compared, it was noted that C. reticulata oil was more repellent at this concentration. Copaifera has shown promising activity as a repellent against arthropods owing to the complex chemical composition of its oils

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Dengue, yellow fever, Chinkungunya, Zika virus, and West Nile fever have infected millions and killed a considerable number of humans since their emergence. These arboviruses are transmitted by mosquito bites and topical chemical repellents are the most commonly used method to protect against vector arthropod species. This study aimed to develop a new generation of repellent formulations to promote improved arboviruses transmission control. A repellent system based on polycaprolactone (PCL)-polymeric nanoparticles was developed for the dual encapsulation of IR3535 and geraniol and further incorporation into a thermosensitive hydrogel. The physicochemical and morphological parameters of the prepared formulations were evaluated by dynamic light scattering (DLS), nano tracking analysis (NTA), atomic force microscopy (AFM). In vitro release mechanisms and permeation performance were evaluated before and after nanoparticles incorporation into the hydrogels. FTIR analysis was performed to evaluate the effect of formulation epidermal contact. Potential cytotoxicity was evaluated using the MTT reduction test and disc diffusion methods. The nanoparticle formulations were stable over 120 days with encapsulation efficiency (EE) of 60% and 99% for IR3535 and geraniol, respectively. AFM analysis revealed a spherical nanoparticle morphology. After 24 h, 7 ± 0.1% and 83 ± 2% of the GRL and IR3535, respectively, were released while the same formulation incorporated in poloxamer 407 hydrogel released 11 ± 0.9% and 29 ± 3% of the loaded GRL and IR3535, respectively. GRL permeation from PCL nanoparticles and PCL nanoparticles in the hydrogel showed similar profiles, while IR3535 permeation was modulated by formulation compositions. Differences in IR3535 permeated amounts were higher for PCL nanoparticles in the hydrogels (36.9 ± 1.1 mg/cm2) compared to the IR3535-PCL nanoparticles (29.2 ± 1.5 mg/cm2). However, both active permeation concentrations were low at 24 h, indicating that the formulations (PCL nanoparticles and PCL in hydrogel) controlled the bioactive percutaneous absorption. Minor changes in the stratum corneum (SC) caused by interaction with the formulations may not represent a consumer safety risk. The cytotoxicity results presented herein indicate the carrier systems based on poly-epsilon caprolactone (PCL) exhibited a reduced toxic effect when compared to emulsions, opening perspectives for these systems to be used as a tool to prolong protection times with lower active repellent concentrations.

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U.S. military troops are exposed to mosquito-borne pathogens when deployed to endemic regions. Personal protective measures such as permethrin-treated uniforms and dermal repellents are the cornerstones of mosquito-borne disease prevention for the U.S. military. These measures have limitations and additional personal protection tools, such as spatial repellent devices to decrease the risk of vector-borne pathogen transmission, are required. Novel spatial repellent controlled-release devices formulated with metofluthrin were evaluated in an outdoor setting in the northern Amazon of Peru to evaluate performance under field conditions. The metofluthrin emitting devices lowered the number of mosquitoes captured in protected human landing collections (HLC) compared to blank devices, although there were effect differences between Anopheles spp. and species in other mosquito genera. A computational-experimental model was developed to correlate HLC and active ingredient (AI) concentrations as a function of time and space. Results show a strong correlation between the released AI and the decrease in HLC. This model represents the first effort to obtain a predictive analytical tool on device performance using HLC as the entomological endpoint.