No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Repellent efficacy of DEET, Icaridin, and EBAAP against Ixodes ricinus and Ixodes scapularis nymphs (Acari, Ixodidae)
Abstract
Repellent efficacy of 10% EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester) and 10% Icaridin ((2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester)) were evaluated against 20% DEET (N,N-diethyl-3-methylbenzamide) in human subject trials against ticks. Responses of host-seeking nymphs of the European castor bean tick (Ixodes ricinus L.; Acari: Ixodidae) and the North American blacklegged tick (I. scapularis Say; Acari: Ixodidae) were compared. Tests were carried out according to the US-EPA standard protocol with ethanolic solutions of the active ingredients of repellents being applied to the forearm of 10 volunteers. The upward movement of ticks was monitored until repellent failure taking up to 12.5h. Application of 20% DEET resulted in median complete protection times (CPT; Kaplan-Meier median) between 4 and 4.5h, while 10% EBAAP yielded CPTs of 3.5-4h. No significant differences were found between the efficacies of two repellents nor between the two species tested. The median of the CPT of a 10% Icaridin solution was 5h in nymphs of I. scapularis, but 8h in those of I. ricinus (P<0.01). Based on these studies, EBAAP and Icaridin are efficacious alternatives to DEET in their repellent activity against nymphs of the two Ixodes ticks with Icaridin demonstrating particularly promising results against I. ricinus. Future research should investigate whether similar results occur when adult Ixodes ticks or other tick species are tested.
Copyright © 2015 Elsevier GmbH. All rights reserved.
... Вирусы, в принципе, являются довольно изменчивыми микроорганизмами, особенно это касается РНК-содержащих. На примере высоко изменчивого вируса гриппа, в частности, было прослежено, что РНК мутирует в миллионы раз быстрее, чем ДНК [56]. Помимо этого важным фактором, влияющим на эволюцию возбудителя, считают и противоэпидемические мероприятия, включая вакцинацию, что наиболее актуально для управляемых, в частности детских, инфекций [4], а также применение антибиотиков. ...
... Одной из причин подобного распространения ВКЭ может являться способность птиц переносить ВКЭ. Ранее было показано, что мигрирующие птицы могут переносить клещей на большие расстояния, и в их крови обнаруживаются ВКЭ и антитела против него [55][56][57][58][59]. Таким образом, можно предположить, что птицы во время своих миграций обеспечивают «пошаговую» передачу клещей, инфицированных ВКЭ, через места их стоянок, что приводит к образованию локальных очагов ВКЭ. ...
... Это может быть связано как с временными, так и с географическими различиями исследованных выборок штаммов. Интересно, что 19 из 26 изолятов группы «Заусаев» географически происходят с Байкальского тракта -территории с наибольшей степенью риска заражения для жителей Иркутска по литературным данным и результатам наших исследований [56]. Причем в этой группе оказались 6 из 7 изолятов с участков, расположенных ближе всего к областному центру (17-й и 23-й км Байкальского тракта) -территории с большой концентрацией садоводств и рекреационных зон. ...
The book is a collection of articles devoted to the current viral infection for Russia and some countries of the world; – tick-borne encephalitis. The monograph deals with evolution; the current epidemiological situation and during the period of study of tickborne encephalitis in certain endemic territories. The accumulated data on the genetic heterogeneity of virus; the subtype change phenomenon; clinical manifestations of acute and chronic tick-borne encephalitis; pathomorphosis and pathogenesis of disease; deaths caused by the Siberian subtype virus; which dominates in the most of Russia; as well as the role of mixed tick-borne infections in the structure of infectious pathology are presented in detail. Great attention is paid to the effectiveness of vaccine prophylaxis of tick-borne encephalitis for the Siberian and Far Eastern subtypes of pathogen; analysing the causes of morbidity among the vaccinated; understanding the mechanism of the preservation of the virus in the immune organism; the features of laboratory diagnosis of acute and chronic tick-borne encephalitis in vaccinated individuals and to questions of specific and non-specific prevention. The book is intended for epidemiologists; virologists; infectious disease specialists; neurologists; as well as other specialists interested in the problem of tick-borne encephalitis. It can be used as a teaching aid in the training and advanced training of medical specialists; senior students of biological; medical faculties and graduate students.
... We suppose that our study is the first one to confirm the high efficacy of several repellents against this tick species. Büchel et al. (13) stated that application of 20% DEET resulted in median complete protection times between 4 and 4,5 h againts Ixodes ricinus and Ixodes scapularis nymphs. On the other hand Žákovská (14) used 7% DEET in their experience, and this product efficiently repelled 74% of the Ixodes ricinus nymphs. ...
... Otherwise, Büchel et al. (13) reported that the application of 10% of Icaridin solution resulted in complete protection time: for Ixodes scapularis nymph that was 5 h and 8 h for Ixodes ricinus nymph respectively. Pomimo tego, że DEET jest uważany przez wielu autorów za "złoty standard" związku odstraszającego stawonogi, w piśmiennictwie nie znaleziono danych dotyczących jego działania na kleszcze Dermacentor reticulatus. ...
... Buchel i wsp. (13) stwierdzili, że zastosowanie 20% DEET powodowało całkowite odstraszanie kleszczy Ixodes ricinus i I. scapularis odpowiednio po 4 i 4,5 godzinach. Żakowska (14) po zastosowaniu 7% DEET uzyskała 74% odstraszania nimf Ixodes ricinus. ...
Introduction:
Ticks are vectors of human and animal diseases.
Materials and methods:
The aim of this study was to investigate the efficacy of four different formulations containing DEET, Icaridin, IR3535 and mix of three compounds: DEET, IR3535 and geraniol, against Dermacentor reticulatus ticks.
Results:
The repellent effectiveness of these products to adult ticks was different. At 90 minutes after application the repellent A (DEET 30%), repellent D (DEET 30%, IR3535 20%, geraniol 0.1%) and repellent G (IR3535 12%) exhibited a 100% effectiveness in protection against ticks, but the efficacy of repellent C (Icaridin 20%) dropped to 95%.
Discussion:
DEET is considered by many authors to be the ‘gold’ standard of insect repellents, and we have also confirmed this in our studies with Dermacentor reticulatus. DEET expressed the higher repellency after 7 hours of application (90%) comparing to other formulation - repellent D containing DEET 30%, IR3535 20% and geraniol 0.1%, whose effectiveness dropped to 60%. Repellents C (Icaridin 20%) and G (IR3535 12%) were effective only up to four hours after application (the efficacy was 85% and 40%, respectively).
Conclusions:
DEET has proven to be the most effective repellent against Dermacentor reticulatus ticks.
... The frozen and invisibility rates were not modified ( Fig. 3F and H, n = 50 ticks, p > 0.05). These results confirmed the repellent effect of 20% DEET on the tick I. ricinus, as found in several studies (Buchel et al., 2015;Carroll et al., 2004). ...
... In the first set of experiments, we demonstrated that FLU, which belongs to the butenolide family, did not have a repellent effect on I. ricinus, in contrast to when DEET was applied. Although 10% DEET did not alter the explorative behavior, 20% DEET had a significant repellent effect, consistent with previous studies demonstrating that products containing 30% DEET or less provided an adequate protection (Buchel et al., 2015;Diaz, 2016;Katz et al., 2008;Soutar et al., 2019). Moreover, when using a combination of 10% DEET and FLU, we obtained a tick repellent effect which was higher than those observed for each compound alone at this concentration, demonstrating that the mixture was more efficient in terms of tick avoidance behavior. ...
Ticks are vectors of many human and animal pathogens, and represent a major threat to public health. In recent years, an increase in tick-borne diseases has been observed, and new strategies are therefore needed in order to control tick numbers and reduce human tick bites. In the present study, we adapted the previous tick repellency bioassay based on the exploration behavior of the tick, using the ToxTrac software and video-tracking, to compare the repellent effect of two compounds on the tick Ixodes ricinus: N,N-diethyl-methyl-m-toluamide (DEET), and butenolide, flupyradifurone (FLU). We found that when applied alone, 10% DEET or FLU have no/or low repellency effect. But, the combination of both 10% DEET and FLU demonstrated a significant repellency effect against I. ricinus, similar to the repellency of 20% DEET. Using membrane microtransplantation, we evaluated the effect of DEET and FLU on native acetylcholine receptors expressed on the tick synganglion. We found that DEET has no effect on acetylcholine-evoked currents, but significantly reduced nicotine-induced current amplitudes. FLU induced an ionic current but was not able to reduce acetylcholine or nicotine evoked currents. The combination of both DEET and FLU strongly reduced nicotine-evoked currents. Finally, we demonstrated that our recording device for repellency, as well as the use of membrane microtransplantation, could be used as methods to study the mode of action of active compounds on ticks.
... Actuellement des produits ciblés contre les tiques se développent pour prévenir la transmission de maladies . Dans le cas de la protection individuelle contre les tiques, l'utilisation de produits de type répulsifs est largement répandue et particulièrement efficace (Diaz 2016 (Buchel et al. 2015;Soutar, Cohen, and Wall 2019). ...
... Etude in vivo du comportement d'évitement chez la tique Ixodes ricinus 1 -Comportement d'évitement des tiques face au DEET L'utilisation du DEET pour se protéger des tiques est largement répandue et de nombreuses formulations de répulsifs, contenant entre 10 et 30% deDEET, sont commercialisées (Katz, Miller, and Hebert 2008;Diaz 2016). Également, une solution de DEET à 20% est généralement utilisée comme contrôle positif lors des tests d'efficacité de molécules répulsives potentielles(Carroll et al. 2004;Buchel et al. 2015;Soutar, Cohen, and Wall 2019). L'objectif des tests mis en place dans ce travail de thèse, est de tester l'efficacité d'un mélange DEET/FLU sur le comportement de la tique. ...
L’augmentation des populations de tiques dans le monde, due au changement climatique et au développement de résistance aux acaricides, met en évidence le besoin de nouvelles méthodes de contrôle. La caractérisation de nouvelles cibles moléculaires aux acaricides est donc nécessaire. Les récepteurs à l’acétylcholine de type nicotinique (ou nAChRs) sont des cibles pour les pesticides (comme les néonicotinoïdes) chez les arthropodes et sont peu étudiés chez la tique. Ce sont des protéines transmembranaires formées de cinq sous-unités et qui sont impliquées dans la neurotransmission synaptique rapide. Les objectifs de cette thèse sont de caractériser les profils pharmacologiques des nAChRs neuronaux chez la tique Ixodes ricinus et d’identifier de nouvelles molécules acaricides qui pourront être utilisées dans la prévention et la lutte contre les tiques. Pour accomplir ces objectifs de thèse, une nouvelle technique a été mise au point sur cette espèce de tique, la microtransplantation de membranes purifiées provenant du cerveau (ou synganglion) de la tique et leur expression en système hétérologue. Cette technique inédite a permis pour la première fois de caractériser les nAChRs natifs de la tique I. ricinus. Nous avons démontré la sensibilité des nAChRs à différents agonistes (acétylcholine et nicotine), antagonistes (alpha-bungarotoxine et méthyllycaconitine), ainsi que la faible sensibilité à des néonicotinoïdes. Néanmoins, l’utilisation d’un modulateur allostérique positif (le PNU-120596) a permis d’augmenter la sensibilité des nAChRs natifs à ces molécules. De plus, nous avons identifié plusieurs sous-unités de nAChRs chez la tique I. ricinus. En particulier, nous avons réalisé le clonage de sous-unité de nAChRs. En complément de ces études in-vitro, nous avons mené de nouvelles expériences comportementales sur des tiques adultes pour observer l’effet répulsifs de composés. Pour conclure, ces travaux ont mis en évidence la présence de nAChRs au sein du synganglion de la tique I. ricinus. Les résultats obtenus grâce à leur caractérisation moléculaire, électrophysiologique ainsi que l’approche comportementale sont encourageant pour le développement de nouvelles molécules acaricides et répulsives contre I. ricinus.
... In laboratory and field experiments involving human subjects, the use of DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), p-methane-3,8-diol (PMD, the synthetic active ingredient in oil of lemon eucalyptus), 2-undecanone, and permethrin reduced the number of ticks detected crawling on or attached to subjects compared with controls [85][86][87][88][89][90] (Table 5). Other commercially available products, including botanical agents and essential oils (eg, essential oils of rosemary, cinnamon leaf, lemongrass, geraniol [91], nootkatone, and carvacrol [92]) cannot be recommended due to insufficient evidence. ...
... Different concentrations and preparations affect their efficacy and duration of activity. In general, products with higher concentrations provide greater and/or longer periods of efficacy compared with lower concentrations [85][86][87][88][89][90], although products containing >50% DEET [93] do not offer a meaningful increase in protection time over lower concentrations. Permethrin (0.5%) kills ticks on contact but must be applied to clothing. ...
This evidence-based clinical practice guideline for the prevention, diagnosis, and treatment of Lyme disease was developed by a multidisciplinary panel representing the Infectious Diseases Society of America (IDSA), the American Academy of Neurology (AAN), and the American College of Rheumatology (ACR). The scope of this guideline includes prevention of Lyme disease, and the diagnosis and treatment of Lyme disease presenting as erythema migrans, Lyme disease complicated by neurologic, cardiac, and rheumatologic manifestations, Eurasian manifestations of Lyme disease, and Lyme disease complicated by coinfection with other tick-borne pathogens. This guideline does not include comprehensive recommendations for babesiosis and tick-borne rickettsial infections, which are published in separate guidelines. The target audience for this guideline includes primary care physicians and specialists caring for this condition such as infectious diseases specialists, emergency physicians, internists, pediatricians, family physicians, neurologists, rheumatologists, cardiologists and dermatologists in North America.
... N,N-diethyl-3-methylbenzamide (DEET) is a gold standard repellent against a large spectrum of arthropods, including several tick species (e.g. I. ricinus, Ixodes scapularis, Amblyomma americanum, Amblyomma sculptum, R. sanguineus and R. microplus) (Carrol et al., 2014;Büchel et al., 2015;Lima et al., 2016;Ferreira et al., 2017). Recently, Ferreira et al. (2019) found that the compound (E)-2-octenal produced by an A. sculptum-resistant host (Equus asinus) repels this tick species in a Y-olfactometer. ...
... DEET is a standard repellent for some tick species, such as A. sculptum, R. sanguineus s.l. (Ferreira et al., 2017), A. americanum (Carrol et al., 2014), I. ricinus, I. scapularis (Büchel et al., 2015) and R. microplus (Lima et al., 2016). The concentration of DEET tested in the present study differed from the concentration tested in previous studies (0.5 m DEET = 9.6%). ...
The present study aimed to evaluate the behaviour of larvae of Rhipicephalus microplus exposed to different stimuli. A Y‐olfactometer was positioned vertically and R. microplus larvae were exposed to environmental air, CO2 alone, N,N‐diethyl‐3‐methylbenzamide (DEET) alone, and CO2 combined with the repellents DEET and (E)‐2‐octenal. Tests were also conducted with the olfactometer positioned horizontally; in this case, however, only CO2 was tested. In all tests conducted with the Y‐olfactometer positioned vertically, CO2 activated R. microplus larvae even in the presence of DEET and (E)‐2‐octenal, although activation was lower when these repellents were used. In the absence of CO2, larval behaviour against DEET was similar to that of the larvae in the control group. In the tests performed with the olfactometer positioned horizontally, the larvae had no significant response to the presence of CO2. The larvae were not attracted to or repelled by any compound tested in either the vertical or horizontal position of the olfactometer. The lack of horizontal displacement, attraction or repellence may have been a result of the ambush behaviour of this tick species. However, when larvae were exposed to stimuli and the olfactometer was positioned vertically, the interference of attractant and repellent stimuli in larval behaviour was assessed. CO2 was a strong stimulus activating Rhipicephalus microplus larvae when the olfactometer was positioned vertically. The activation promoted by CO2 was decreased in the presence of the repellents N,N‐diethyl‐3‐methylbenzamide and (E)‐2‐octenal. Rhipicephalus microplus larvae were not attracted to or repelled by any compound tested when the olfactometer was positioned either vertically or horizontally.
... In a laboratory setting, Büchel et al. (2015) tested three synthetic repellents, DEET, icaridin and 3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester (EBAAP) against I. ricinus and I. scapularis ticks. For each repellent, 10 volunteers were tested. ...
... Statistical differences between different test substances can be tested by a multiple-sample test such as generalized Wilcoxon test and/or the log-rank test. Büchel et al. (2015) compared two treatments using the Cox's F-test and the Wilcoxon matched paired test to compare the proportion of ticks displaying certain behaviours. For acaricidal studies, dose-response data should be analysed using the probit method (Finney, 1971). ...
Ticks are haematophagous arthropods which rank closely with mosquitoes in their capacity to transmit disease pathogens of importance to animals and humans. Current control of ticks is based on the routine use of synthetic chemicals administered to animals or their environment. However, years of use and overuse of these chemicals have resulted in the development of resistance in these parasites and negative environmental impacts, hence the need for cheaper, safer and more environmentally friendly alternatives with alternate modes of action. There has been a large interest in using plants for these purposes. Peer-reviewed articles on plants evaluated for their tick repellent and/or acaricidal activities against immature and adult stages of ticks were collected from nine scientific databases with the aim of reviewing the bioassays employed. Search words included “acaricidal” “tick repellent” “antitick assays” and “phytomedicine”. Many different methods were used to determine repellency and acaricidal activity. These include, among a few others, petri dish, tick climbing, olfactometer, larval packet and immersion bioassays. Tick climbing repellency and adult immersion bioassays were most commonly used. Ethanol was the most widely used solvent and Rhipicephalus (Boophilus) microplus was the most commonly studied tick across all the reviewed papers. It is unclear whether the outcome of these experiments on a one-host tick can be applied to other species of ticks that infest animals and humans. Also, most of the assays on repellency did not discriminate between olfaction and tactile chemoreception-based repellency and though some of the observed methods were similar, results differ significantly. These aspects will need further evaluation. Standardized laboratory methods are required to enable the valid comparisons between results from different laboratories.
... On the other hand, Icaridin is meanwhile found in low mg L À1 concentrations in European lakes and rivers (Knepper, 2004a). Although the use of EBAAP has increased as well (Büchel et al., 2015), reports on its concentrations in surface waters are lacking (Nendza et al., 2013). Due to this lack of published data, it is unclear whether EBAAP occurs in similar environmental concentrations as reported for the other two repellents or if its concentrations are typically below the analytical detection limit due to biodegradation or adsorption to organic surfaces. ...
... This may not only affect aquatic insects (or their aquatic larval stages), but potentially as well crustaceans, which are phylogenetically much more closely related to insects than e.g. ticks, which are major target organisms for repellents (Büchel et al., 2015). Obviously, the validity of this hypothesis depends on the specific mode of action of the repellents on the molecular level. ...
Synthetic insect repellents are compounds applied to surfaces to discourage insects, mainly mosquitoes, from landing on those surfaces. As some of these repellents have repeatedly been detected in surface waters at significant concentrations, they may also exert repellent effects on aquatic non-target organisms. In running water systems, aquatic invertebrates actively enter downstream drift in order to avoid unfavourable environmental conditions. We thus tested the hypothesis that the widely used insect repellents DEET (N,N-Diethyl-m-toluamide), EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester) and Icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropyl ester) induce downstream drift behaviour in the aquatic invertebrates Gammarus pulex (Crustacea, Amphipoda) and Cloeon dipterum (Insecta, Ephemeroptera), using a laboratory-scale drift assay. We found no clear increase in the drift behaviour of both invertebrate species across a concentration gradient of eight orders of magnitude and even beyond maximum environmental concentrations for any of the three repellents. We found no evidence for a direct drift-inducing activity of insect repellents on aquatic non-target organisms.
... Research has shown that the presence of DEET can be detected in various water bodies worldwide, including surface water, groundwater, streams, and sewage systems [2]. Although DEET was previously considered almost harmless to human health at low exposure levels, with neurotoxic effects and even fatalities associated only with high concentrations, the increasing environmental exposure and detection rates of DEET still sparked concerns [4,5]. Recent studies have indicated a positive correlation between DEET and its metabolites in the human body and the incidence of cardiovascular disease, hyperuricemia, and obesity [6][7][8], suggesting that even at safe dosages, chronic DEET exposure might increase the risk of these related ailments. ...
Background
DEET (N, N-diethyl-m-toluamide) is a widely used insect repellent with potential neurotoxic effects. However, its impact on mental health in the general population remains unclear. This study investigates the association between DEET exposure and depression and sleep disorders, exploring the mediating roles of obesity indicators and serum albumin.
Methods
Data from the National Health and Nutrition Examination Survey (NHANES) 2007–2016 were analyzed. Urinary levels of 3-(diethylaminoformyl) benzoic acid (DCBA), a DEET metabolite, were used as an exposure marker. Depression was defined according to the scores of Patient Health questionnaire-9 (PHQ-9), and sleep disorders were diagnosed according to participants' self-reports. Multivariate logistic regression and restricted cubic spline analysis were employed to assess the associations of DCBA with depression and sleep disorders. Mediating analyses explored the roles of obesity indicators and serum albumin. Subgroup analysis further explored the differences among different populations.
Results
Higher DCBA levels were positively associated with depression and sleep disorders. Mediating analysis revealed that body mass index (BMI), waist circumference (WC), and serum albumin mediated 11.16%, 12.66%, and 7.04% of the association between DEET exposure and depression, respectively. Subgroup analysis identified increased susceptibility among women and individuals of other races. Sensitivity analysis enhanced the robustness of the results.
Conclusion
DEET exposure is associated with an increased risk of depression and sleep disorders, mediated by obesity and liver function indicators. These findings highlight the need for public health measures to reduce DEET exposure and further research into its mechanisms of action on mental health.
... In this study, 70 unfed nymphs were used for each test. Ethanol (95%) was used as the solvent for 20% DEET, 10% icaridin, 10% IR3535, and 2% cinnamaldehyde [18,21,37,38]. Ticks exposed to each repellent comprised experimental groups, with 95% ethanol serving as the control treatment. ...
Background
Ticks can transmit a wide range of pathogens that endanger human and animal health. Although repellents are commonly used for tick control, understanding their mechanisms aren't complete.
Methods
The repellent effects of N, N-diethyl-meta-toluamide (DEET); sec-butyl 2-(2-hydroxyethyl) piperidine-1-carboxylate (icaridin); N, N-diethyl-3-methylbenzamide (IR3535); and cinnamaldehyde on the parthenogenetic tick Haemaphysalis longicornis at the nymph stage were assessed using Y-tubes. The involvement of transient receptor potential (HL-TRP) channel molecules in the repellent mechanism was investigated through in situ hybridization, subcellular localization, real-time fluorescence quantitative polymerase chain reaction (PCR), RNA interference, and electroantennography. In addition, the binding affinity of HL-TRP molecules to repellents was predicted using AlphaFold3.
Results
DEET, icaridin, IR3535, and cinnamaldehyde have been shown to effectively repel nymphs. HL-TRP channel is shared among various arthropods, particularly several species of ticks. It is localized to the cell membrane and Haller’s organ. Moreover, microinjection of double-stranded RNA elicited tick repellency behavior, and the electroantennogram responses to those repellents were significantly decreased. The TYR783 site was proposed as an essential binding site to establish hydrogen bonds with icaridin, DEET, and cinnamaldehyde.
Conclusions
This exploration of ticks and repellents found that HL-TRP channel functions as a chemosensory receptor for repellents and, thereby, mediates avoidance behavior.
Graphical Abstract
... Установлена зависимость чувствительности клещей к репеллентам от вида, фазы развития и физиологического возраста [10,11,14,15,17,19,23,24]: самая высокая -у личинок, у нимф -ниже, еще ниже она у самцов, а самая низкая -у самок. Чувствительность к репеллентам, безусловно, связана и с экологическими особенностями клещей разных родов и соответствующими сенсорными системами. ...
Проведен анализ научной литературы по применению репеллентов для индивидуальной защиты людей от иксодовых клещей – переносчиков возбудителей опасных болезней человека. В историческом плане рассмотрены проведенные в нашей стране и за рубежом исследования репеллентов. Рекомендации по их применению в разных странах неодинаковы и обусловлены различной чувствительностью к репеллентам клещей разных видов и фаз развития эпидемиологически значимых иксодид на их территориях. Изложены требования к современным средствам защиты от иксодовых клещей в России.
The analysis of the scientific literature on the use of repellents for the individual protection of people from ixodid ticks — vectors of pathogens of dangerous human diseases is carried. In historical terms, studies of repellents conducted in our country and abroad, the current state of protection against ixodid ticks with repellents are considered. Recommendations on the use of repellents to protect against in different countries are not the same and are due to different susceptibility to repellents of species and phases of the most epidemiologically significant ixodids inhabiting there. In Europe and North America, various substances are used to protect humans from ticks when applied to skin and clothing, which does not comply with the recommendations in our country: the use of treatments with a high concentration of DEET when applied to clothing.
... This insect repellent has recently become one of the most widely used types. Numerous studies have established that DEET-containing solutions are among the most effective insect repellents in the market right now (Büchel et al., 2015;Rodriguez et al., 2015). Approximately 225 insect-repellent products that contained DEET were available in the marketplace. ...
N,N-Diethyl-3-toluamide (DEET) is a commonly used insect repellent, which acts as an organic chemical contaminant in water and considered as an emerging contaminant which has been observed worldwide. It gets discharged into the environment through sewage waste. The various methods have been used to degrade DEET, such as UV based, ozonation, photocatalytic degradation, and biodegradation (based on the metabolic activity of fungi and bacteria). However, less research has been done on the degradation of DEET by deploying nanoparticles. Therefore, biodegradation and nanotechnology-based methods can be the potential solution to remediate DEET from the environment. This review is an attempt to analyze the routes of entry of DEET into the atmosphere and its environmental health consequences and to explore physical, chemical, and biological methods of degradation. Furthermore, it focuses on the various methods used for the biodegradation of the DEET, including their environmental consequences. Future research is needed with the application of biological methods for the degradation of DEET. Metabolic pathway for biodegradation was explored for the new potent microbial strains by the application of physical, chemical, and microbial genomics; molecular biology; genetic engineering; and genome sequencing methods.
Graphical Abstract
... DEET is a gold standard repellent used against a large spectrum of arthropods, including several tick species (e.g., I. ricinus, Ixodes scapularis, Amblyomma americanum, A. sculptum, R. sanguineus, and R. microplus) (Carrol et al. 2014;Büchel et al. 2015;Lima et al. 2016;Ferreira et al. 2017). Owing to problems associated with the use of DEET and its potential risk to human health, safer and more effective alternatives are being investigated by the scientific community. ...
The repellent activity of Chinese cinnamon oil (Cinnamomum cassia) on nymphal ticks (Haemaphysalis longicornis Neumann, Rhipicephalus haemaphysaloides Supino, and Hyalomma asiaticum Schulze and Schlottke) was evaluated in a sample Y-tube bioassay. The results were based on the vertical migration of ticks during the host-seek phase and showed a dose-dependent repellent effect of Chinese cinnamon oil on the tested nymphs after 6 h. For H. longicornis, R. haemaphysaloides, and H. asiaticum at the concentrations (vol/vol) of 3, 3, and 1.5%, the repellent percentages over time were 68–97, 69–94, and 69–93%, respectively, which indicated strong repellent activities against ticks, similar to the positive control DEET (N,N-diethyl-3-methylbenzamide). Chinese cinnamon oil exerted the strongest effect on H. asiaticum nymphs. To our knowledge, this is the first study to investigate the repellent effects of Chinese cinnamon oil on ticks. Chinese cinnamon oil has considerable potential and should be developed as a practical tick repellent.
... Icaridin is another compound that has been evaluated for its ability to repel arthropod pests. One study suggested that Icaridin could be a very good substitute to DEET, since it repelled two species of ticks in a laboratory experiment [31]. We chose to include DEET and Icaridin in our studies as mite repellents because they are safe for humans, they are not natural products and thus are included as comparisons to natural products, and they have not been evaluated as repellents for stored product pests. ...
Simple Summary
The ham mite is the major pest of dry-cured hams, aged cheeses, and specialty pet foods that are high in fats and proteins. Ham mites are also known to cause allergies in some cases for humans. The toxic fumigant gas methyl bromide had been used for years to control this mite pest, but it is being phased out of use due to its impact on the protective ozone layer of the earth’s upper atmosphere. Ham producers now require alternatives to methyl bromide for controlling mites. We conducted laboratory experiments with food-safe synthetic and plant-derived chemical repellents to keep mites away from dry cured hams. Our results showed that several of these repellents could effectively prevent ham mites from contacting and staying on treated pieces of ham, and that they would readily go to untreated ham pieces when given a choice. Further experiments found that mites would not feed on nor produce offspring when held on ham pieces coated with oils from thyme, lemon grass, rose, or a mixture of naturally occurring fat molecules. Our experiments suggest that these food-safe repellents might protect dry-cured hams from mites during their time in aging rooms by application to racks on which hams are aged or to the nets and packaging in which hams are held.
Abstract
The fumigant pesticide methyl bromide (MB) was used for stored products, but it is now banned for most uses in many countries as an ozone-depleting substance. MB was the only pesticide used to manage the ham mite, Tyrophagus putrescentiae, which is the most significant pest of dry cured hams. Effective alternatives to MB are needed to develop integrated pest management (IPM) programs for this pest. This study evaluated plant essential oils and food-safe compounds as repellents to directly protect hams from infestation. Experiments to assess the repellency to orientation, oviposition, and population growth of mites on pieces of aged country hams were conducted. Test compounds at different concentrations were dissolved in respective solvents and compared to the solvent control. Results showed that C8910, a mixture of three short-chain fatty acids, and the sesquiterpene ketone nootkatone had repellency indices of (RI) of 85.6% and 82.3%, respectively, at a concentration of 0.1 mg/cm², when applied to a Petri dish arena. DEET and icaridin were also tested but performed poorly with RIs below 70% even at 0.1 mg/cm².The monoterpene alcohol geraniol had the highest RI of 96.3% at 0.04 mg/cm². Ham pieces dipped in C8910 and nootkatone at 150 ppm each had RIs of 89.3% and 82.8%, respectively. In general, as the concentrations of test compounds increased, the numbers of eggs that were laid on these treated ham cubes decreased after the 48 h exposure time. Ham pieces dipped in different concentrations of test compounds and then inoculated with 20 adult mites showed a significant decrease in mite population growth compared to control pieces after 14 days. The results of these experiments suggest that some plant secondary metabolites and synthetic food-safe compounds could serve as potential alternatives for managing mites on hams.
... Although actions promoting TBE prophylaxis and prevention have been undertaken, education about this issue is still incomplete. Personal protection and special safety measures against tick bites, such as proper clothing or use of repellents, have limited efficiency [9], and a skin inspection ('tick check') is not always attainable after exposure [10]. ...
Introduction:
Tick-borne encephalitis (TBE) is a neurotropic, tick-transmitted infection. Clinical presentation ranges from mild aseptic meningitis to severe encephalitis, and may result in long-term neurological sequels.
Objective:
The aim of the study is to present the clinical features of TBE in children, and the laboratory findings, in order to identify neurological sequels and the risk of cognitive deficits in long-term TBE infections.
Material and methods:
The study included eight children with serologically-confirmed TBE, hospitalized in the Paediatric Centre in Kielce, Poland.
Results:
Despite the more benign clinical course of TBE infections in children compared to adults, the potential for long-term cognitive sequels can be serious. It is hypothesized that a developing CNS is more susceptible to long-term infection effects.
Conclusions:
Paediatric TBE should be considered in children with unexplained acute CNS-related symptoms. The long-term consequences may occur with permanent impairment of the quality of life due to neurological consequences.
... As expected, both nymphs and females proved to be sensitive to higher concentrations of deet as was described by Büchel et al. (2015) and Semmler et al. (2011). Therefore, the highest concentration of 5.0% used in the experiment stopped a majority of the tested ticks regardless of their stage. ...
The use of repellents is a unique measure of personal protection, which can avoid tick attachment and thus reduce the risk of tick-borne infections. In the European Union, the efficacy of the repellents coming onto the market has to be evaluated according to the guidelines published by the European Chemical Agency before registration. The United States Environmental Protection Agency has a similar role. Despite obvious differences in morphology and behavior, both these guidelines allow the use of nymph or adult female ticks for laboratory testing. Here, we provide evidence that sensitivity to diethyltoluamide (deet) ( P < 0.0001) of Ixodes ricinus nymphs within the in vitro trial was significantly higher than in adult females. In the experiment, we also observed that feral ticks were less sensitive to repellent than were laboratory-reared ticks ( P < 0.01) and that mobility decreased when the trial was repeated ( P < 0.05). This study showed that the results of efficacy tests could vary significantly even when the protocol was conducted in accordance with the recommended methods. To refine the results of efficacy tests, we recommend a reevaluation of the guidelines, with emphasis on the developmental stage and origin of ticks.
... Theoretically, reduction of exposure is the first line of defense, but the options for tick avoidance at best have a limited effect [17]. Repellents offer no more than a moderate effectiveness [18]. Although battle-dress uniforms impregnated with permethrin reduced the tick-bite incidence by 98%, clothing covering so much of the body would be associated with minimal compliance at leisure [19,20]. ...
Tick-borne Encephalitis (TBE) is an arboviral infection widespread in Europe and northern parts of Asia. Ticks transmit the associated flavivirus usually between March and November to people with outdoor activities in the countryside, in gardens or, rarely, in urban parks. The clinical picture of TBE has two phases: after an uncharacteristic febrile illness and a brief interval in which neurological symptoms occur in a minority of the infected patients. In children, meningitis is the predominant syndrome, whereas the proportion of patients with more severe encephalitis and encephalomyelitis increases with growing age. Consequently, children may suffer from cognitive defects and adults from neurological defects after the acute phase. As there is no therapy for TBE, prevention is of paramount importance. The first line of defense is to avoid tick “bites” (actually stings). Various effective and well-tolerated vaccines are marketed in Europe, all parts of Russia, and in China.
... Reduction of risk (Reduction of exposure to tick bites) theoretically is the first line of defense, but the options for tick avoidance at best have a limited effect (Bogovic and Strle, 2015). Repellents offer no more than moderate effectiveness (Buchel et al., 2015;Kosina et al., 2008;Kunze et al., 2004;Staub et al., 2002). While battle-dress uniforms impregnated with permethrin reduced the tick-bite incidence by 98% (Faulde et al., 2015), clothing covering so much of the body is impractical for leisure activities. ...
Tick-borne encephalitis (TBE) vaccination recommendations for children residing in high-endemicity countries in Europe vary from universal recommendations to none at all. Such differences may result in uncertainty about the value of such prevention among public health authorities, healthcare professionals and parents. We conducted a systematic review of publications and data from the European Centres for Disease Prevention and Control focusing on the epidemiology, clinical characteristics, and outcomes of TBE in a pediatric population. TBE can affect children of any age, occasionally even before the first birthday. Overall, the clinical course of disease is milder compared to adults, and there are fewer neurologic sequelae persisting after the infection. However, recent follow-up surveys identified a substantial proportion of children with long-term cognitive impairment subsequent to TBE infection. Fortunately, two vaccines against western TBE are available, and both are effective and safe. It is an overly simplistic perception that TBE is severe in adults and mild in children, and to therefore conclude that vaccination is important mainly in older age groups. Even if TBE infection is less dramatic in pediatric populations, TBE often results in long-standing cognitive damage. Based on guidance from the World Health Organization, authorities in countries with high endemicity should either offer or recommend TBE vaccination to children at 1-3 years of age.
... -diol). Ils permettent de se protéger durant plusieurs heures (environ 4 heures voire 8 heures pour l'Icaridin chez I. ricinus)(Dautel et al. 2013;Pages et al. 2014;Büchel et al. 2015). Exposure toTicks on Your Property, Kirby C. Stafford III, The Connecticut Agricultural Experiment Station, 20 ...
Les maladies à tiques posent un problème majeur que se soit du point de vue de la santé animale ou de la santé humaine. Parmi ces pathologies, la borréliose de Lyme est la maladie à transmission vectorielle la plus fréquente de l’Hémisphère Nord et, en France, l’Alsace représente l’une des régions avec la plus forte incidence. Ce travail de thèse a eu pour objectif d’évaluer les densités en nymphes ainsi que les taux d’infection à Borrelia burgdorferi sl et Anaplasma phagocytophilum dans cette région. Nous avons comparé nos résultats à ceux établis dans cette même région en 2003 et 2004. De plus nous avons étudié les facteurs environnementaux potentiellement responsables de la variabilité inter-site de la densité en nymphes et également cartographié le risque de borréliose de Lyme en Alsace. Notre travail, qui pour l’instant a été conduit en Alsace, tend à s’étendre à d’autres régions de France. Il nous paraît pertinent de poursuivre les études de terrains sur certains sites pris en compte dans ce travail de façon à objectiver les tendances observées dans notre région.
... DEET has been detected in ground and surface waters in concentrations up to 3 μg L −1 in Europe and even 33 μg L −1 in the USA (Nendza et al. 2013). While the use of DEET has strongly declined in Europe in the last decade, it is frequently replaced by icaridin and EBAAP (Büchel et al. 2015). This has led to increased detection of icaridin in lowmicrogramme per litre concentrations in European lakes and rivers (Bernhard et al. 2006;Knepper 2004b;Nendza et al. 2013), while there are no reports on environmental EBAAP concentrations (Nendza et al. 2013). ...
Insect repellents are widely applied to various materials and to both human and animal skin to deter mosquitoes and ticks. The most common deterrent compounds applied are DEET, EBAAP and icaridin (picaridin, Bayrepel). Due to their extensive application, these repellents are frequently detected in surface waters in considerable concentrations. As these compounds are designed to alter invertebrates’ behaviour rather than to intoxicate them, we hypothesised that insect repellents have the potential to modify the natural behaviour of non-target invertebrates in natural freshwater bodies. To test this, we used a well-established laboratory assay designed to quantify the odour-mediated foraging behaviour of freshwater gastropods and the great pond snail Lymnaea stagnalis (Linnaeus, 1758) as a model organism to test for potential deterrent effects of insect repellents on aquatic snails. Using a wide concentration range from the picogramme per litre to microgramme per litre range (and by far exceeding the range of concentrations reported from natural waters), we found no evidence for a deterrent effect of either of the three repellents on foraging L. stagnalis. Our data and other recent studies give no indication for undesirable behavioural alterations by common insect repellents in surface waters.
... 26 By comparison, the synthetic neurotoxin diethyltoluamide (DEET) only repels ticks, and has the distinct disadvantages of dissolving various synthetic fibers, having its absorption increased by sunscreen (thus necessitat-ing it being applied 15 minutes or more after oxybenzone sunscreen is applied), has more toxic risk than permethrin, and has a disagreeable odor. 27,28 Unfortunately, permethrin resistance has begun to develop in dog ticks in the United States, and other tick species will likely follow, given the widespread use of this chemical and the inevitable history of resistance developing to prior single chemicals in various disease vectors. 29 Numerous natural acaricides have been researched and may be a reasonable alternative to the failing single molecular entity approach that permethrin and DEET represent (see Table 3 for recent examples, though many others could have been cited). ...
Numerous tick-borne infections cause problems for humans and animals worldwide. Lyme disease is the best known, but babesiosis, bartonellosis, anaplasmosis, ehrlichiosis, Rocky Mountain spotted fever, and many others are also serious problems. Many studies have confirmed that herbs and herbal extracts can help to repel the several types of ticks (as can non-chemical means such as wearing long pants and tucking them into socks) that spread these diseases, as well as inhibit their reproduction. Corymbia citriodora (lemon eucalyptus) and its compound para-menthane-3,8-diol (PMD) have most convincingly been shown to be effective. 2-Undecanone and nootkatone with carvacrol have also shown some promise. Despite many claims of efficacy, no published clinical research could be located on any herb or herbal constituent to treat any tick-borne illness and thereby validate these claims. Dipsacus fullonum (fuller's teasel) is used as a case study to show a promising herb that has simply no research on whether it helps people with Lyme disease or any tick-borne infection. In vitro and animal studies show some promise for herbs and herbal compounds such as Brucea javanica (Java brucea) and artemisinin, but they have not been studied in clinical trials. There remains a black hole in terms of supported herbal treatments for these infections that urgently needs to be filled with credible clinical trials.
... Laboratory assays with I. scapularis have demonstrated repellency for synthetic chemical compounds (e.g., deet, EBAAP [IR3535], icaridin [also known as picaridin], AI3-37220, and SS220) as well as natural product compounds in the form of plant essential oils or their components (e.g., amyris essential oil, callicarpenal, carvacrol, Chinese juniper essential oil, Chinese weeping cedar essential oil, common juniper essential oil, elemol, geraniol, intermedeol, isolongifolenone, nootkatone, and 2-undecanone from wild tomato plants; Carroll et al. 1989Carroll et al. , 2004Carroll et al. , 2005Carroll et al. , 2007Carroll et al. , 2010Carroll et al. , 2011Dietrich et al. 2006;Carroll 2008;Bissinger et al. 2009Bissinger et al. , 2014Feaster et al. 2009;Zhang et al. 2009;Dolan and Panella 2011;Bü chel et al. 2015). Several of these compounds can be applied to skin and clothing and have been evaluated for repellent efficacy against I. scapularis in the field (Table 1). ...
In the 1980s, the blacklegged tick, Ixodes scapularis Say, and rodents were recognized as the principal vector and reservoir hosts of the Lyme disease spirochete Borrelia burgdorferi in the eastern United States, and deer were incriminated as principal hosts for I. scapularis adults. These realizations led to pioneering studies aiming to reduce the risk for transmission of B. burgdorferi to humans by attacking host-seeking ticks with acaricides, interrupting the enzootic transmission cycle by killing immatures infesting rodent reservoirs by means of acaricide-treated nesting material, or reducing deer abundance to suppress tick numbers. We review the progress over the past three decades in the fields of: 1) prevention of human-tick contact with repellents and permethrin-treated clothing, and 2) suppression of I. scapularis and disruption of enzootic B. burgdorferi transmission with environmentally based control methods. Personal protective measures include synthetic and natural product-based repellents that can be applied to skin and clothing, permethrin sprays for clothing and gear, and permethrin-treated clothing. A wide variety of approaches and products to suppress I. scapularis or disrupt enzootic B. burgdorferi transmission have emerged and been evaluated in field trials. Application of synthetic chemical acaricides is a robust method to suppress host-seeking I. scapularis ticks within a treated area for at least 6-8 wk. Natural product-based acaricides or entomopathogenic fungi have emerged as alternatives to kill host-seeking ticks for homeowners who are unwilling to use synthetic chemical acaricides. However, as compared with synthetic chemical acaricides, these approaches appear less robust in terms of both their killing efficacy and persistence. Use of rodent-targeted topical acaricides represents an alternative for homeowners opposed to open distribution of acaricides to the ground and vegetation on their properties. This host-targeted approach also provides the benefit of the intervention impacting the entire rodent home range. Rodent-targeted oral vaccines against B. burgdorferi and a rodent-targeted antibiotic bait have been evaluated in laboratory and field trials but are not yet commercially available. Targeting of deer-via deer reduction or treatment of deer with topical acaricides-can provide area-wide suppression of host-seeking I. scapularis These two deer-targeted approaches combine great potential for protection that impacts the entire landscape with severe problems relating to public acceptance or implementation logistics. Integrated use of two or more methods has unfortunately been evaluated in very few published studies, but additional field evaluations of integrated tick and pathogen strategies are underway.
... In Germany, the DEET concentrations in water bodies have decreased constantly since 1999, when DEET was substituted by Icaridine (Knepper, 2004); meanwhile Icaridine has been detected in low mg/L concentrations in European surface waters (Nendza et al., 2013;Bernhard et al., 2006). Although the other non-DEET active repellent EBAAP is as well increasingly used (Buechel et al., 2015), no data on surface water concentrations are available; nevertheless, it is reasonable to assume that, similar to DEET and Icaridine, also EBAAP may enter surface waters. ...
Ticks and tick-borne diseases significantly impact animal health, public health, and economic productivity globally, particularly in areas where the wildlife–livestock interface complicates management. This review critically examines the current control strategies, focusing on chemical, biological, physical, and integrated pest management (IPM) approaches. Chemical acaricides, while effective, are increasingly challenged by resistance development and environmental concerns. Biological approaches, including natural predators and entomopathogenic fungi, and physical interventions, such as habitat modification, provide sustainable alternatives but require further optimization. IPM stands out as the most promising long-term solution, integrating multiple approaches to enhance efficacy while reducing environmental risks. Emerging innovations, such as nanotechnology-enhanced acaricides and next-generation vaccines, offer promising avenues for improved tick control. Addressing the complex challenges of tick management requires tailored strategies, interdisciplinary collaboration, and sustained research investment in both veterinary and public health contexts.
Background
N, N-diethyl-m-toluamide (DEET), an active ingredient prevalent in insect repellents, has its effects on human health under ongoing debate and scrutiny.
Objective
This study aimed to investigate the association between exposure to DEET and arthritis outcomes within the broader adult demographic, leveraging data obtained from the National Health and Nutrition Examination Survey (NHANES).
Methods
3-diethyl-carbamoyl benzoic acid (DCBA) was used as a specific indicator of DEET exposure. Drawing on NHANES 2007–2016 data, our study incorporated 7065 adults to examine urinary DCBA impacts on arthritis risks using logistic regression and cubic spline analysis.
Results
Our study included a total of 7065 patients, of which 1860 (26.33%) had arthritis. After adjusting for all covariates, the multivariate logistic regression analysis showed that high DCBA levels (>7.37 ug/L) were associated with an increased likelihood of arthritis (OR: 1.236, 95% CI: 1.037–1.474, p = 0.018). Nevertheless, participants in the highest quartile of DCBA levels (Q4) were associated with a 33.9% decreased risk of rheumatoid arthritis (OR: 0.661; 95% CI: 0.501–0.872; p = 0.003).
Conclusion
It was observed that increased levels of DCBA are positively associated with the prevalence of arthritis in the adult population. Conversely, high concentrations of DCBA showed a reverse correlation with the prevalence of rheumatoid arthritis.
Background
The control and prevention of ticks and tick-borne diseases relies on chemical insecticides and repellents. Plant-derived compounds potentially represent new and safer repellents. Cinnamaldehyde, a component of cinnamon oil, exhibits antibacterial, anti-inflammatory, acaricidal and repellent activity against ticks. Here we studied the molecular mechanism of the repellent effects of cinnamaldehyde on ticks.
Methods
Assessment of cinnamaldehyde as a tick repellent was conducted using a Y-tube olfactometer, transcriptomics and metabolomic analyses. Nymphs were exposed to cinnamaldehyde for 30 min, and the tick acetylcholinesterase (AchE) family was cloned and characterized. The role of AchE in cinnamaldehyde repellency was elucidated through the specific activity of the enzyme, electrophysiology, RNA interference and repellency tests.
Results
A 2% cinnamaldehyde treatment resulted in more than 90% nymph repellency within 6 h. Nymphs were exposed to cinnamaldehyde for 30 min, and subsequent transcriptome and metabolome analyses revealed the involvement of AchE in the response process. The HL-AchE family was cloned and functionally explored. AchE was transcribed in all tick developmental stages and tissues. Following cinnamaldehyde treatment, the transcript and protein levels of AchE were altered, and the specific activity of the enzyme significantly increased. RNAi was used to validate these findings. Following RNAi, electroantennography (EAG) tests demonstrated a significant decrease in response to various repellents as well as a significant decrease in repellency.
Conclusions
AchE mediates cinnamaldehyde-induced tick repellency, and the results provide insights into the mechanism of plant-derived tick repellents.
Background:
N,N-diethyl-m-toluamide (DEET) is a widely used active ingredient in insect repellents, and its effects on human health have been a matter of debate. This study aims to investigate the relationship between DEET exposure and hyperuricemia in the adult population.
Methods:
Our study utilized a cross-sectional design and analyzed data from adult participants of the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016. 3-diethyl-carbamoyl benzoic acid (DCBA) was used as a specific indicator of DEET exposure. DCBA was categorized using quartiles based on its distribution within the study population. Multiple linear regression models were employed to examine the association between DCBA exposure and serum uric acid (SUA) levels in adults. The relationship between DCBA and the prevalence of hyperuricemia in adults was assessed using multiple logistic regression models. Dose-response relationships were analyzed using restricted cubic spline regression.
Results:
A total of 8708 participants were included in the study. The mean age of the participants was 46.49 years, and the total number of male participants was 50.93%. The median levels of DCBA and SUA were 2.07 ng/mL and 5.40 mg/dL, respectively. Hyperuricemia was found in 19.99% of the participants. In multivariate-adjusted linear regression models, it was found that higher SUA levels were associated with the highest quartile of DCBA compared with the lowest quartile of DCBA (β [95% CI]: 0.19 [0.08, 0.30], Ptrend<0.001). After adjusting for confounders, a positive association was found between the prevalence of hyperuricemia and DCBA levels (OR [95% CI] quartile 4 vs. 1: 1.41 [1.14-1.74], Ptrend<0.001). Furthermore, linear associations were observed between DCBA concentrations and SUA levels (P for nonlinearity = 0.479) and the prevalence of hyperuricemia (P for nonlinearity = 0.755).
Conclusion:
Higher DCBA concentrations were found to have a positive association with the prevalence of hyperuricemia in the general adult population.
This work presents permethrin (15%)-based monomers polymerisation in polyamide fabrics using hybrid corona-dielec-tric barrier discharge (DBD) to potentiate insect-parasite repellency functionalities in polyamide fabrics. First of all, the electric characterisation of the discharge was made using the Lissajous figure method for determining the plasma dosage (2841 W min m −2). Before the polymerisation process, the polyamide fabric was activated by DBD discharge, operating at 23 kHz and voltage amplitude of 12.5 kV in atmospheric pressure. After that, the polymerisation process is initiated by injecting permethrin into the system, maintaining the operational parameters used in the activation process. The non-activated and activated polyamide fabrics measured the static and dynamic contact angle, showing a variation from 120° (non-activated) to 34° (immediately after plasma activation). The chemical structure of synthesised permethrin was evaluated by Fourier transformed infrared (FTIR) spectroscopy to confirm the polymerisation (deposition) of permethrin on the fabric surface; it is possible to observe the 648 cm −1 bands that are associated with asymmetric vibration of the C-Cl bonds, but most evident change occurs at 1045 cm −1 , which is associated with cyclopropyl group vibrations. Field emission scanning electron microscopy (FESEM) analysis was used to evaluate the possible degradation of the fabric surface when exposed to plasma activation and the homogeneity of the permethrin coating in the fibres after the polymerisation. The energy dispersive spectrometer (EDS) was used to confirm the polymerisation and the distribution of the permethrin in the fabric.
Background
The purpose of this study was to examine the relationship between N,N-diethyl-m-toluamide (DEET) exposure and obesity-related outcomes in the general adult population using the data from the National Health and Nutrition Examination Survey (NHANES).
Methods
This cross-sectional study examined the data from the NHANES from 2007 to 2016 and totally evaluated 8,770 individuals. DEET's primary oxidative metabolite, 3-(diethylcarbamoyl) benzoic acid (DCBA), is a sensitive and specific indicator of DEET exposure. DCBA was divided into three groups based on the interquartile range. Body mass index (BMI) and waist circumference (WC) were used to define obesity and abdominal obesity, respectively. The association among DCBA and obesity-related outcomes was evaluated using a multivariable linear and logistic regression model.
Results
Overall, median age of participants was 46.0 (IQR 31.0, 59.0) years, with 4295 (49.2%) men, while median BMI and WC were 27.8 (24.0, 32.0) and 29.6 (86.6, 108.1) kg/m², respectively. Approximately 3,251 (35.9%) cases of obesity and 4,778 cases (54.4%) of abdominal obesity were observed. In multivariable-adjusted linear regression models, as the tertiles of DCBA increased, BMI and WC monotonically increased regardless of the adjustments (all p for trend <0.01). By referring the lowest tertile of DCBA, the highest tertile was associated with a higher BMI (β = 0.83, 95% confidence intervals [CI] [0.45, 1.21]; p < 0.001) and WC (β = 1.59, 95% CI [0.59, 2.60]; p = 0.002). The multivariate odds ratios (95% CI) for obesity increased monotonically as 1.18 (0.97–1.44) and 1.36 (1.15–1.61) (p for trend 0.001). Similar associations between DCBA and the prevalence of abdominal obesity were observed across increasing DCBA tertiles compared with the reference tertile (OR = 1.22, 95% CI [1.02, 1.44]; OR = 1.28, 95% CI [1.08–1.54]; p for trend = 0.002).
Conclusions
These findings suggested that higher DCBA concentrations are positively associated with the prevalence of obesity and abdominal obesity in the general adult population.
Tortoises of the genus Testudo are the main hosts of Hyalomma aegyptium ticks. This species serves as a vector of several zoonotic pathogens. Therefore, the present study aimed to investigate the presence of four pathogens associated with H. aegyptium ticks obtained from tortoises from Tunisia. Conventional, multiplex and nested PCRs were used for Aanaplasma phagocytophilum, Ehrlichia canis, Coxiella burnetii and Babesia spp. screening. The molecular analyses revealed the presence of A. phagocytophilum and Babesia spp. None of the ticks, were infected by E. canis or C. burnetii species. Co-infection was detected in four ticks. As a conclusion, this is the first detection of A. phagocytophilum and Babesia spp. in H. aegyptium ticks collected from tortoises, in Tunisia. Thus, considering these results, the spur-thighed tortoise constitute a potential host of H. aegyptium which plays an important role in the transmission of pathogenic agents affecting both human and animals. In term of public health, a strict control and surveillance should be carried to reduce the circulation of such pathogens between different hosts.
Personal protection measures to prevent human tick encounters from resulting in bites are widely recommended as the first line of defense against health impacts associated with ticks. This includes using repellents, wearing untreated or permethrin-treated protective clothing, and conducting tick checks after coming inside, aided by removing outdoor clothing articles and running them in a dryer on high heat (to kill undetected ticks) and taking a shower/bath (to aid in detecting ticks on the skin). These measures have the benefit of incurring no or low cost, but they need to be used consistently to be most effective. In this paper, I review the level of use (acceptability combined with behavior) of the above-mentioned personal protection measures and their effectiveness to prevent tick bites and tick-borne disease. Studies on the level of use of personal protection measures to prevent tick bites have used different recruitment strategies, focused on different types of respondent populations, employed variable phrasings of survey questions relating to a given personal protection measure, and presented results based on variable frequencies of taking action. This complicates the synthesis of the findings, but the studies collectively indicate that members of the public commonly take action to prevent tick bites, most frequently by wearing untreated protective clothing or conducting tick checks (done routinely by 30 to 70% of respondents in most studies of the public), followed by showering/bathing after being outdoors or using repellents on skin/clothing (15 to 40% range), and with permethrin-treated clothing being the least frequently used tick bite prevention method (<5 to 20% range). A suite of experimental studies has shown that applying repellents or permethrin to coveralls or uniform-style clothing can result in decreased numbers of tick bites, but similar studies are lacking for members of the public wearing summer-weight clothing during normal daily activities. Moreover, a set of case-control and cross-sectional studies have explored associations between use of different personal protection measures to prevent tick bites and Lyme disease or other tick-borne infections. The results are mixed for each personal protection measure, with some studies indicating that regular use of the measure is associated with a reduction in tick-borne disease while other studies found no similar protective effect. One possible interpretation is that these personal protection measures can protect against tick-borne infection but the information gathered to date has not been sufficiently detailed to clarify the circumstances under which protection is achieved, especially with regards to frequency of use, parts of the body being protected, and use of combinations of two or more potentially protective measures. In conclusion, personal protection measures to prevent tick bites are used by the public and merit further study to better understand how they need to be used to have the greatest public health impact.
Conventional insect repellent treatments for fibers, fabrics, and garments suffer from limited durability to repeated laundering and, depending on the insecticide, potential irritation, or toxicity. In this work, electrospinning was employed to control the composition of hierarchically structured functional microscale to nanoscale fibers for tunable insect repellent release by physically incorporating picaridin into nylon‐6,6 nanofibers. The size and morphology of nylon fibers were unaffected by picaridin incorporation, even at loading concentrations up to 50 wt%. Picaridin release kinetics were largely dependent on loading concentration and temperature, as picaridin‐nylon intermolecular interactions were minimal affording diffusion based release. Coaxial nanofibers, in which the sheath component has potential to protect additives in the core for more durable fabrics and act as a diffusion barrier for extended release applications, were also developed and demonstrated altered release kinetics compared to monofilament analogues, indicating the capability to further tune release behavior.
N,N-diethyl-meta-toluamide (DEET) is one of the most commonly used insect repellants in the United States, yet the existing literature regarding DEET's potential deleterious impact on humans is mixed and is based mostly on case reports. The primary aim of this study was to address this lack of population-based evidence of the effects of DEET exposure on human health in the United States. Our primary outcome measures were biomarkers related to systemic inflammation (high sensitivity C-reactive protein), immune function (lymphocyte), liver function (aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferace), and kidney function (estimated glomerular filtration rate). We analyzed data from the population-based National Health and Nutrition Examination Survey, 2015-2016, and identified 1,205 patients (age 20+ years) who had DEET metabolite levels recorded at or above detection limits. A Pearson correlation was used to assess the relationship between DEET metabolite, and each biomarker found there was no significant correlation. Thus, there is no evidence that DEET exposure has any impact on the biomarkers identified.
This study was developed to evaluate the repellent activity of N,N-diethyl-3-methylbenzamide (DEET) against Amblyomma cajennense nymphs. Two repellent bioassays were compared and the effective concentration and repellent time were calculated. The fingertip test was accomplished to evaluate in vivo four concentrations of the compound (0.200; 0.100; 0.050 and 0.025 mg.cm-2) and the filter-paper bioassay to evaluate in vitro the two highest concentrations. The compound provided repellence higher than 90% in all concentrations and at least 95% repellency in the highest concentration over 5 hours. The effective concentration against 50% of tested nymphs (EC50) was 0.006 mg.cm-2 and the EC99 was 0.036 mg.cm-2. Those concentrations were lower than the ones obtained against other tick species, denoting the effectiveness of DEET against A. cajennense. The repellency time against 50% of the ticks (RT50) was 4.8 hours and the RT90 was 2.7 hours. Both bioassays were adequate to evaluate A. cajennense repellency and provided similar results; however the in vivo test is more appropriate to estimate the effective concentration and repellency time.Este estudo foi conduzido com o objetivo de avaliar a atividade repelente do N,N-diethyl-3-methylbenzamide (DEET) sobre ninfas de Amblyomma cajennense. Dois bioensaios para a avaliação de repelência foram comparados e cálculos da concentração eficaz e do tempo de repelência foram realizados. Foram empregados o bioensaio da ponta do dedo, para avaliação in vivo de quatro concentações do químico (0,200; 0,100; 0,050 e 0,025 mg.cm-2) e o bioensaio do papel filtro, para a avaliação in vitro das duas concentrações mais altas. O composto conferiu mais de 90% de repelência em todas as concentrações utilizadas e 95% de repelência por mais de cinco horas na maior concentração. A concentração do composto efetiva contra 50% das ninfas testadas (CE50) foi de 0,006 mg.cm-2 e a CE99 foi de 0,036 mg.cm-2. Estas concentrações são mais baixas do que as observadas em outras espécies de carrapatos, denotando a efetividade do princípio contra A. cajennense. O tempo de repelência de 50% dos carrapatos (TR50) foi de 4,8 horas e o TR90 de 2,7 horas. Os dois bioensaios avaliados permitiram a observação de percentuais de repelência igualmente altos e se mostraram adequados para tal avaliação, sendo que o teste in vivo é mais indicado para cálculo da concentração eficaz e da duração da repelência.
Abstract Ticks are arthropods and the most important vectors of major human diseases after mosquitoes. Due to their impact on public health, in vitro and in vivo assays have been developed to identify molecules with repellent activities on ticks. Repellents are useful to reduce tick bite exposure and the potential transmission of pathogens; they can be used topically or in impregnated clothing. Presently, mainly synthetic molecules are commercialized as skin repellents, e.g., N,N-diethyl-meta-toluamide (DEET), IR3535, picaridin or KBR 3023, and para-menthanediol. Permethrin is largely used for fabric impregnation. Intensive research has been conducted to identify new molecules with repellent activity and more recently, plant-derived molecules, as an alternative to synthetic molecules.
Although widely used, the term repellency needs to be employed with care when applied to ticks and other periodic or permanent ectoparasites. Repellency has classically been used to describe the effects of a substance that causes a flying arthropod to make oriented movements away from its source. However, for crawling arthropods such as ticks, the term commonly subsumes a range of effects that include arthropod irritation and consequent avoiding or leaving the host, failing to attach, to bite, or to feed. The objective of the present article is to highlight the need for clarity, to propose consensus descriptions and methods for the evaluation of various effects on ticks caused by chemical substances.
Members of the genus Borrelia are among the most common infectious agents causing tick-borne disease in humans worldwide. Here, we developed a Light Upon
eXtension (LUX) real-time PCR assay that can detect and quantify Borrelia species in ticks that have fed on humans, and we applied the assay to 399 such ticks. Borrelia PCR-positive ticks were identified to species level by sequencing the products of conventional PCR performed using Borrelia group-specific primers. There was a 19% prevalence of Borrelia spp. in the detached ticks, and the number of spirochetes per Borrelia PCR-positive tick ranged from 2.0 × 102 to 4.9 × 105, with a median of 7.8 × 103 spirochetes. Adult ticks had a significantly larger number of spirochetes, with a median of 8.4 × 104 compared to the median of nymphs of 4.4 × 104. Adult ticks also exhibited a higher prevalence of Borrelia (33%) than nymphs (14%). Among the identified species, Borrelia afzelii was found to predominate (61%) and was followed by B. garinii (23%), B. valaisiana (13%), B. burgdorferi sensu stricto (1%), B. lusitaniae (1%), and B. miyamotoi-like (1%). Also, 3% of the ticks were coinfected with multiple strains of B. afzelii. Notably, this is the first report of B. lusitaniae being detected in ticks in Sweden. Our LUX real-time PCR assay proved to be more sensitive than a corresponding TaqMan assay.
In conclusion, the novel LUX real-time PCR method is a rapid and sensitive tool for detection and quantification of Borrelia spp. in ticks.
The efficacies of a 20% 1-methyl-propyl-2- (hydroxyethyl)-1-piperidinecarboxylate (picaridin) spray, 20% 3-(N-acetyl-N-butyl)aminopropionic acid ethyl ester (IR3535) spray, 20% picaridin lotion, 10% IR3535 lotion, and 33% N,N-diethyl-3-methylbenzamide (deet) cream in repelling nymphal lone star ticks, Amblyomma americanum (L.), were determined at 2-h intervals over 12 h using human subjects. A repellent formulation was applied in a 5-cm-wide band encircling a volunteer's lower leg. For each challenge, 70 host-seeking nymphs were released on each volunteer's ankle, and tick locations were recorded 10 min after the ticks were released. Ticks that crawled entirely across the repellent band were considered not repelled. For all formulations and time points, significantly fewer (all P < 0.0001) A. americanum nymphs crossed the treatment bands on the volunteers' ankles than crossed the corresponding area on the untreated control legs. Formulations containing > or = 20% active ingredient were highly effective, with <10% of the ticks crossing through the treatment bands for any challenge during the 12 h. At least 40% of ticks exposed to any formulation for any challenge fell or crawled off the volunteers. There was no difference in effectiveness between the 20% spray and 20% lotion formulations of picaridin. The 10% IR3535 lotion was significantly less effective than the formulations with higher concentrations of repellent. In the formulations tested, deet, picaridin, and IR3535 provided lasting protection against A. americanum.
This study was developed to evaluate the repellent activity of N,N-diethyl-3-methylbenzamide (DEET) against Amblyomma cajennense nymphs. Two repellent bioassays were compared and the effective concentration and repellent time were calculated. The fingertip test was accomplished to evaluate in vivo four concentrations of the compound (0.200; 0.100; 0.050 and 0.025 mg.cm⁻²) and the filter-paper bioassay to evaluate in vitro the two highest concentrations.The compound provided repellence higher than 90% in all concentrations and at least 95% repellency in the highest concentration over 5 hours. The effective concentration against 50% of tested nymphs (EC50) was 0.006 mg.cm⁻² and the EC99 was 0.036 mg.cm⁻². Those concentrations were lower than the ones obtained against other tick species, denoting the effectiveness of DEET against A. cajennense. The repellency time against 50% of the ticks (RT50) was 4.8 hours and the RT90 was 2.7 hours. Both bioassays were adequate to evaluate A. cajennense repellency and provided similar results; however the in vivo test is more appropriate to estimate the effective concentration and repellency time.
Nymphal Ixodes scapularis Say are the principal vectors of Lyme disease spirochetes (Borrelia burgdorferi sensu stricto) in the eastern United States. Physicians frequently face the decision of whether or not to administer prophylactic antibiotics to human tick bite victims in Lyme disease endemic regions, based on the overall probability that such bites will result in infection with B. burgdorferi s.s. We evaluated the transmission dynamics of B. burgdorferi s.s. during the key third day of nymphal I. scapularis feeding, when the risk of transmission rapidly increases. The cumulative probability that 50% of infected ticks transmitted B. burgdorferi s.s. occurred at 68 h of tick attachment and our overall estimate that a human tick bite would result in transmission of B. burgdorferi s.s. was 2.4%.
Here I report the first findings of consistently high, long-duration efficacy of IR3535 (ethyl butyl acetyl aminopropionate) formulations in the United States. I tested novel, controlled-release formulations of IR3535, at 10% in lotion and at 20% in pump spray and aerosol, against mosquitoes in the field and blacklegged ticks in the laboratory. These were also the first studies to be conducted under the authority of the U.S. Environmental Protection Agency's Human Studies Rule of 2006, and the protocols underwent science and ethics reviews by five entities. IR3535 is better known in Europe than in North America, having been marketed in the United States only more recently, and there are comparatively few publications on its efficacy. I began with pretrial studies of dosing behavior to compute formula-specific mean dosing rates for the subsequent efficacy trials. Dosing rates were lower than the 1 ml/600 cm rate commonly used to quantify efficacy. Complete protection times ranged from 7.1 to 10.3 h for mosquitoes and from 9.1 to 12.2 h for blacklegged ticks. Long protection duration resulted in many cases being truncated by darkness or eventual subject withdrawal, which suggests that actual protection times were probably greater.
The repellents N,N-diethyl-3-methylbenzamide (deet) and racemic 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were evaluated using two different laboratory bioassays to determine their relative effectiveness against host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). In a petri dish bioassay, ticks were released within a ring of repellent on a horizontal filter paper disk. In the second bioassay, ticks were allowed to climb a vertical strip of filter paper whose central portion was treated with a repellent. Deet and AI3-37220 were more effective against I. scapularis than A. americanum nymphs. In the petri dish bioassay, none of the concentrations of deet or AI3-37220 tested confined A. americanum within the treated ring. However, in the vertical bioassay, both species exhibited avoidance of the repellents, and I. scapularis was repelled by much lower concentrations than A. americanum. I. scapularis were repelled by lower concentrations in the vertical bioassay than in the petri dish bioassay. Deet was slightly more effective against I. scapularis than AI3-37220 in both bioassays, but AI3-37220 was significantly more effective than deet against A. americanum in the vertical bioassay.
The threat of transmission of Lyme borelliosis and tick-borne encephalitis by ixodid ticks has resulted in an increasing number of tick repellents coming onto the market. To allow proper evaluation of the efficacy of different types of compounds and their formulations, there is a need for standardised methods for testing ticks repellents. Ticks show a marked negative geotactic response following contact with a potential host, i.e., they climb up in order to locate attachment and feeding sites, whereas exposing ticks to repellents induces positive geotaxis, i.e., ticks walk downwards or drop off the treated host or substrate. We describe here complementary tests that employ these geotactic responses to evaluate repellents: one in vitro on a warm glass plate and the other on the lower human leg (shin). The compounds tested were DEET, EBAAP, icaridin, capric acid, lauric acid, geraniol, citriodiol, citronella essential oil and lavender essential oil, all non-proprietary ingredients of widely distributed tick repellent formulations.
Ticks are important vectors of human and animal diseases. One important protective measure against ticks is the use of personal arthropod repellents. Deet and the synthetic pyrethroid permethrin currently serve as the primary personal protective measures against ticks. Concern over the safety of deet and its low repellency against some tick species has led to a search for new user-approved, efficacious tick repellents. In this article, we review the history and efficacy of tick repellents, discovery of new repellents, and areas in need of attention such as assay methodology, repellent formulation, and the lack of information about the physiology of repellency.
The present paper investigates the efficacy of common anti-tick repellents in Europe and in the USA. There were tested Ixodes ricinus, Dermacentor reticulatus, and Rhipcephalus sanguineus when they are placed onto hands and clothes of male and female humans being treated with common tick repellents. It was seen that DEET needed high concentrations to repel ticks, while essential oils are mostly inefficient. On the other hand saltidin=icaridin, p-menthan-diol and IR 3535 showed long-lasting effects, which in the case of combinations of saltidin and Vitex extracts were even increased.
Twenty-nine repellents were tested on human skin for duration of activity as protectants against nymphal lone star ticks (Amblyomma americanum) and against black-legged or deer ticks (Ixodes scapularis Say). Eleven of these repellents, including deet, provided > 2 h of protection against the lone star tick. One repellent, 1-(3-cyclohexenyl-ylcarbonyl) piperidine, was effective > or = 4 h. Four repellents (2 pyridines and 2 piperidines with protection lasting 2.3-3 h) showed acaricidal activity to more than half of the ticks tested after 9-12 min of exposure. Seven repellents that were most effective against A. americanum, including deet, were tested against the black-legged tick. None was effective and no knock-down was observed. These results suggest that the black-legged tick is less sensitive to repellents than the lone star tick.
Regression equations, based on scutal index (body length/scutal width), were developed to determine the duration of attachment for nymphal and adult female lxodes scapularis ticks. Feeding times were calculated for 444 nymphal and 300 female ticks submitted by bite victims between 1985 and 1989 in Westchester County, New York, an area where Lyme disease is highly endemic. Nymphs were attached for a mean of 34.7 hours, with 26.8% removed after 48 hours, the critical time for transmission of Borrelia burgdorferi. Attachment times increased with victim age class (Kruskal-Wallis test, p < 0.05). Mean duration of attachment for female ticks (28.7 hours) was significantly less (Kruskal-Wallis test, p < 0.05) than that for nymphs, with 23.3% attached for more than 48 hours. The 0- to 9-year age class had the highest proportion (37.1%) of females attached for more than 48 hours. Nymphs remain attached to adult tick-bite victims longer than they remain attached to children. However, children have a high risk of acquiring Lyme disease because they receive more nymphal bites and also because they are less likely to have female ticks removed in time to prevent transmission.
Topical repellents can provide effective personal protection from tick-borne diseases by preventing the attachment of ticks. The goal of this study was to assess the effectiveness of a commercially available repellent spray containing both N,N-diethyl-3-methylbenzamide, previously known as N,N-diethyl-m-toluamide (DEET), and ethyl-butylacetylaminopropionate (EBAAP) against tick bites in a population at risk in Switzerland under real-life conditions.
The effectiveness of an insect repellent spray containing both DEET and EBAAP was evaluated in a randomized, double-blind, placebo-controlled field study. The study, requiring simple application of the repellent to exposed skin, was carried out on 276 forestry workers and orienteers under everyday conditions in Switzerland from May to September 1999. We measured total effectiveness of the repellent by the following formula: percentage effectiveness = 100 x (T(P) - T(R))/T(P), where T(P) and T(R) were the average number of ticks per hour spent in wooded areas for the repellent and placebo groups, respectively.
The average number of tick bites per hour of exposure to wooded areas differed significantly between the placebo (n = 138) and repellent (n = 138) groups, 0.17 vs 0.10 (P < .05). Total repellent effectiveness against tick attachment was 41.1% (95% CI, 2.5-79.6). On the arms, an effectiveness of 66% (95% CI, 17.3-114.7) was observed. No significant difference in the average number of unattached ticks could be found.
This study found that an easily applied repellent is moderately effective in reducing the risk of tick bites.
Public health recommendations for Lyme disease prevention generally include daily tick checks and prompt removal of attached ticks as a means of decreasing the risk of acquiring Lyme disease in highly endemic regions. In the current study, we determined whether crushing nymphal ticks during removal with forceps increased the risk of B. burgdorferi transmission, what degree of protection from transmission of B. burgdorferi was provided by removal of nymphal Ixodes scapularis Say at specific intervals, and whether commercial devices marketed for tick removal worked when tested against nymphal I. scapularis. Both removal via gentle pressure (26% transmission) or crushing the tick (30% transmission) caused a significant decrease in transmission as compared with the sham control (70% transmission). The degree of protection provided via tick removal decreased steadily up to 60 h of attachment; between 60 and 66 h, a dramatic falloff in protection occurred to the point where no protection was observed at 66 h. Finally, commercial tick removal devices varied widely in their efficacy for the removal of attached nymphal I. scapudaris.
The bont tick, Amblyomma hebraeum Koch, is the principal vector of Rickettsia africae, the agent of African tick bite fever, in southern Africa. In contrast to most other hard ticks, members of the genus Amblyomma exhibit a characteristic attack host-seeking behavior. The efficacy of topically applied 20% lotions of DEET (diethyl-3-methylbenzamide), the currently considered reference repellent substance, and KBR 3023, a recently developed piperidine compound, was evaluated against laboratory-reared A. hebraeum nymphs on treated fingers. Both substances repelled >85% of nymph attacks at 0 and 1 h postapplication. At 2, 3, and 4 h, the repellent efficacies of DEET were 84%, 68% and 71%, whereas those of KBR 3023 were 56, 55, and 54%. The observed differences between the two test substances were statistically significant only at 2 h postapplication. This first study of topical repellents against A. hebraeum suggests that 20% lotions of DEET and KBR 3023 are effective for 2 and 1 h, respectively, but that the repellent efficacies decrease thereafter.
Tick-borne diseases are on the rise. Lyme borreliosis is prevalent throughout the Northern Hemisphere, and the same Ixodes tick species transmitting the etiologic agents of this disease also serve as vectors of pathogens causing human babesiosis, human granulocytic anaplasmosis, and tick-borne encephalitis. Recently, several novel agents of rickettsial diseases have been described. Despite an explosion of knowledge in the fields of tick biology, genetics, molecular biology, and immunology, transitional research leading to widely applied public health measures to combat tick-borne diseases has not been successful. Except for the vaccine against tick-borne encephalitis virus, and a brief campaign to reduce this disease in the former Soviet Union through widespread application of DDT, success stories in the fight against tick-borne diseases are lacking. Both new approaches to tick and pathogen control and novel ways of translating research findings into practical control measures are needed to prevent tick-borne diseases in the twenty-first century.
The repellent efficacies of the U.S. military repellent 33% N,N-diethyl-3-methylbenzamide (deet), 10% and 20% (1S, 2'S) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (Bayrepel) cream formulations on human volunteers against the lone star tick Amblyomma americanum (L.) were evaluated in a simulated forest floor environment over a 12-h testing period. At 2-h intervals, volunteers, with repellent applied in a 5-cm-wide band around each ankle, stood for 5 min in plastic tubs containing leaf litter and 100 host-seeking A. americanum nymphs. Ticks were allowed to remain on a volunteer's feet and ankles for an additional 5 min after the volunteer exited the tub. All repellent formulations provided high levels of protection for the entire 12 h. No ticks crossed 5-cm-wide bands of 20% SS220 and Bayrepel during any challenge, and thus 100% protection was afforded throughout the test. These formulations showed a long-lasting efficacy hitherto unknown in tick repellents intended for use on human skin.
Product Performance Test Guidelines. OPPTS 810.3700: Insect Repellents to be applied to Human Skin
- U S Epa
U.S. EPA, 2010, July. Product Performance Test Guidelines. OPPTS 810.3700: Insect
Repellents to be applied to Human Skin, EPA 712-C-100-01.