Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Insect Repellents”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed2004

Olfaction: mosquito receptor for human-sweat odorant.

Female Anopheles mosquitoes, the world's most important vector of Plasmodium falciparum malaria, locate their human hosts primarily through olfactory cues, but the molecular mechanisms that underlie this recognition are a mystery. Here we show that the Anopheles gambiae protein AgOr1, a female-specific member of a family of putative odorant receptors, responds to a component of human sweat. Compounds designed to activate or block receptors of this type could function as attractants for trapping mosquitoes or as insect repellents in helping to control Anopheles and other insect pests.

Animals↗
PubMed2004

Comparative efficacy of IR3535 and deet as repellents against adult Aedes aegypti and Culex quinquefasciatus.

Arm-in-cage laboratory evaluations of 2 proprietary formulations of the mosquito repellents IR3535 and N,N-diethyl-3-methylbenzamide (deet; aqueous cream, hydroalcoholic spray) were made with 10 and 20% concentrations of each repellent. Also, 4 commercially available products containing IR3535 (Expedition insect repellent 20.07% active ingredient [AI], Bug Guard Plus with SPF30 sunscreen 7.5% AI, Bug Guard Plus with SPF15 sunscreen 7.5% AI, and Bug Guard Plus 7.5% AI) were tested. All comparisons were made on an equal formulation or concentration basis. Eight volunteers tested all formulations or products 3 times against laboratory-reared, Aedes aegypti and Culex quinquefasciatus mosquitoes (6-10 days old). Products were applied to a forearm at the rate of 0.002 g/cm2. The other forearm was not treated and served as a control. Elapsed time to 1st and 2nd consecutive bite was recorded. Mean protection time (i.e., time to 1st bite) with proprietary formulations of IR3535 were comparable to those of deet, with 20% concentrations providing greater protection against Ae. aegypti (3 h) and Cx. quinquefasciatus (6 h). Mean protection time for commercial products containing IR3535 ranged from nearly 90 to 170 min for Ae. aegypti and 3.5 to 6.5 h for Cx. quinquefasciatus. Mean time to the 2nd bite was similar to time to 1st bite for each mosquito species, product, and formulation.

Aedes↗
PubMed1987

Chiggers.

Chigger infestations are caused by mite larvae that feed on the host's epidermal cells. The combination of digestive enzymes secreted by the mite and the immune response of the host produces the typical "chigger bite." Intense pruritus is the usual response, but more severe reactions and chigger-borne disease may also occur. Treatment is primarily symptomatic and consists of antipruritics, antihistamines and steroids. Chigger infestation may be minimized by the use of proper clothing and insect repellents.

Diagnosis, Differential↗
PubMed2002

Malaria outbreak control in an African village by community application of 'deet' mosquito repellent to ankles and feet.

The malaria vector Anopheles arabiensis Patton (Diptera: Culicidae) shows a marked predilection (> 80%) for biting the ankles and feet of human subjects, as revealed by our previous observations at Malahlapanga in the Kruger National Park, South Africa. Topical application of insect repellent, 15% deet (N,N-diethyl-3-methylbenzamide), to feet and ankles reduced the overall biting rate of An. arabiensis by 69%. A focal malaria epidemic in Albertsnek village (25 degrees 33'S, 31 degrees 59' E) near the Mozambique border, following flooding during February 2000, provided an opportunity to apply these findings of operational research for outbreak containment. Twice-nightly topical application of deet to ankles and feet of Albertsnek inhabitants was followed by rapid restoration of preepidemic malaria incidence levels after one incubation period. This encouraging outcome should be attempted in other outbreak-prone settings where infective mosquito bites are sporadic and malaria has unstable endemicity.

Animals↗
PubMed1998

Effect of skin abrasions on the efficacy of the repellent deet against Aedes aegypti.

Abrasion of repellent-treated human skin affected the efficacy of a sustained-release insect repellent containing N,N-diethyl-3-methylbenzamide (deet) against bites of Aedes aegypti. Skin treated with repellent when abraded up to 30 times showed significantly lower protection than unabraded skin against mosquito bites for 10 h. The mean value of the kinetic coefficient of friction during skin abrasion by clothing (battle dress uniform fabric) for repellent-treated skin (0.159 +/- 0.003) was significantly higher than untreated skin (0.122 +/- 0.005). Repellent-treated skin appeared stickier than the untreated skin. An increase in the number of skin abrasions by clothing resulted in a reduced duration of protection against mosquito bites.

Aedes↗
PubMed1971

Diethylamide of thujic acid: a potent repellent of Aedes aegypti.

A series of novel, representatively substituted amides of thujic acid were prepared and screened for insect repellent and attractant potential. In repel-lency tests the N,N-diethylamide was the most potent compound, surpassing the activity of the standard repellents dimethyl phthalate and fencholic acid. In contrast, the N-monoethylamide displayed attractant activity.

Aedes↗
PubMed2005

Biological assay methods for mosquito repellents.

Three biological assay procedures for repellents are currently documented in the literature: 1) ASTM E951-94, Laboratory testing of non-commercial repellent formulations on the skin. 2) ASTM E939-94, Field testing topical applications of compounds as repellents for medically important and pest arthropods. 1. Mosquitoes. 3) WHO/CTD/WHOPES/IC/96.1, Report of WHOPES informal consultation on the evaluation and testing of insecticides. One public draft set of repellent-testing guidelines is available on the internet: 4) USEPA OPPTS 810.3700, Product performance test guidelines. Insect repellents for human skin and outdoor premises. In practice, the outcome of a repellent bioassay using any of these procedures is affected by the absorption, penetration, and chemical modification of repellent on skin and by evaporation, abrasion, and perspiration. Other abiotic factors that influence mosquito responses to repellent stimuli are light, temperature, humidity, repellent dose, exposure time, and test-cage shape and size. Biotic variables in repellent bioassays are larval nutrition, carbohydrate availability for adult mosquitoes, age and parity of females, and differences in the innate attraction/ repellency of test subjects. Geographic location and seasonal and diel activity cycles in mosquitoes determine when and where repellents can be tested in the field. Critical knowledge of these sources of variation can be converted to improved precision and accuracy in repellent bioassays and the resulting information used to efficiently select new repellent compounds for toxicological evaluation and field testing.

Animals↗
PubMed2001

Repellent effects on Anopheles arabiensis biting humans in Kruger Park, South Africa.

Distribution of biting sites on the human body by the malaria vector Anopheles arabiensis Patton (Diptera: Culicidae) was investigated near a source of mosquitoes in the Kruger National Park, South Africa. Eight adult male volunteers (2 teams x 2 pairs of subjects) conducted human bait collections while seated on camp chairs in the open-air, wearing only short trousers (no shirt, socks or shoes). Mosquito collections during 18.30-22.30 hours on five consecutive nights in April 1998 yielded a total of 679 An. arabiensis females biting subjects with or without their ankles and feet treated with deet insect repellent (15% diethyl-3-methylbenzamide, Tabard lotion). On subjects whose feet and ankles were smeared with repellent, 160 An. arabiensis females were captured biting in 60 manhours: 88.1% on the legs, 1.4% on the arms and 1.2% on other parts of the body, but none on the repellent-treated feet or ankles. On subjects without repellent treatment, 519 An. arabiensis were caught biting in 60 man-hours: 81.1% on feet and ankles, 16.4% on legs, 1.4% on arms and 1.2% on the rest of the body. For individual subjects, the reduction of An. arabiensis bites ranged from 36.4 to 78.2% (mean protection 69.2%). Results of this study confirm previous findings that, in this part of South Africa - inhabited only by wildlife - when people sit outside during the evening An. arabiensis prefers to bite their lower limbs: 97.5% below the knees. Overall, the number of bites by the malaria vector An. arabiensis was reduced more than three-fold (from 26 to 8/person/evening), simply by treating ankles and feet with a consumer brand of deet repellent. Whether or not this provides a satisfactory degree of protection against malaria risk would depend on the malaria sporozoite rate in the malaria vector population.

Adult↗
PubMed1983

[Antihistaminic effect of a hydrogel with the components diphenhydramine, N,N-diethyl-m-toluamide and phthalic acid dimethyl ester].

The combination of the antihistamine diphenhydramine as well as the repellents N,N-diethyl-m-toluamide and dimethylphthalate as the active constituents of an insect repellent (Pellit) guarantees a remarkable antihistaminic effect. Surprisingly the repellent N,N-diethyl-m-toluamide proved itself to be an antihistamine. The UV-erythema model was used on the dorsal skin of male volunteers.

Adult↗
PubMed1993

Arena tests with piperonal, a new louse repellent.

Piperonal, once used to kill lice in Australian hospitals, was acclaimed as an effective pediculicide (Corlette, 1925) by the standards of the day. It is unusual in also exhibiting a repellent action against lice, a property only recently realised. A new, easy to use, low-fragrance, pump action spray, which incorporates 2% piperonal, was tested in the laboratory using clothing lice in an arena test and was found to exhibit consistently high repellency after half an hour, dropping only slightly after 24 hours. A well known multi-purpose insect repellent, diethyltoluamide (DEET), was then tested against piperonal. A 2% solution of piperonal was found to be almost twice as effective as a 50% solution of DEET. In arena tests using lice with the tip segments of both antennae removed, no behavioural differences or statistically significant differences from a random distribution could be found between untreated and Rappell-treated areas. This strongly suggests that sense organ(s) on the tip of the antenna are necessary for detection of the repellent. Although there can be no strict correlation between results in the laboratory and potential efficacy in the field, materials such as insecticides found to be effective in the laboratory have been found to be equally effective in the field. Furthermore, what with the threat of resistance to head lice insecticides, ineffectual treatment and the lack of contact tracing, a repellent would be of obvious use in the control of head lice.

Animals↗
PubMed2005

A new in vitro bioassay system for discovery of novel human-use mosquito repellents.

A Klun & Debboun (K&D) test module, previously developed and used for quantitative measurement of the efficacy of mosquito repellents on human volunteers, was adapted for in vitro evaluation of repellents by coupling the module with a membrane-blood reservoir. Performance of Deet, Bayrepel, and SS-220 insect repellents in the new in vitro system was compared with their performance on humans against mosquitoes using our standard in vivo system. For each compound, in vitro dose-response assays were conducted with compounds applied to cloth positioned over blood reservoirs covered with Baudruche membrane against Aedes aegypti. The repellents were also tested in vitro against Anopheles stephensi and Ae. aegypti at a fixed dose of 24 nmol compound/cm2 cloth over the Baudruche and Edicol collagen membranes. Concurrently, the repellents were tested at the fixed dose using the K&D module on human volunteers. The observed proportions of both mosquito species deterred from biting in the fixed doses in the in vitro assays were similar to those obtained using humans, being clearly able to distinguish controls from repellents, and differing only in the ranking of the effectiveness of some of the repellents. Dose-response relationships of the in vitro and in vivo systems were also very similar, although not directly comparable because the data were not collected concurrently. This new in vitro assay system can be used in high throughput screening of compounds to identify new repellents having potential for use as topical mosquito repellents on humans.

Aedes↗
PubMed2000

[Epidemics of cutaneous leishmaniasis in military personnel working in French Guiana].

Cutaneous leishmaniasis transmitted by phlebotomine sandflies is endemic in the rain forests of French Guyana. The 3rd Régiment Etranger d'Infanterie, based in Kourou carries out numerous operations in the Amazonian areas. In 1998 two outbreaks of cutaneous leishmaniasis occurred: one during an exercise at the training center in the equatorial forest of Regina (10 patients) and the other during a mission in Saint Elie (21 patients). Clinical findings were variable and diagnosis was confirmed by skin smear tests. Patients were treated by two intramuscular injections of pentmidine isethionate (Pentacarinate). Recurrence was observed in two patients who were retreated using the same agent. Persistent lesions were treated by intralesional injection of meglumine antimoniate (Glucantime). Both outbreaks were characterized by high attack rates (91 p. 100 and 84 p. 100) and were facilitated by non-observance of standard procedures because of training or operational requirements at the beginning of the leishmaniasis season. Strict planning of activities, wearing protective clothing, deployment of insecticide treated bed nets, and of candles rather than electrical lamps for lighting are key preventive measures. Greater emphasis is needed on the use of insect repellents.

Antiprotozoal Agents↗
PubMed2006

Field evaluation of deet, Repel Care, and three plant based essential oil repellents against mosquitoes, black flies (Diptera: Simuliidae) and land leeches (Arhynchobdellida: Haemadipsidae) in Thailand.

Diethyl methyl benzamide, or deet, a commercial plant-based repellent (Repel Care), and essential ils from 3 species of plants (finger root rhizomes, guava leaves, and turmeric rhizomes), steam distillated and formulated as insect repellents, were evaluated in the field on human volunteers against hematophagous mosquitoes, black flies, and land leeches in Thailand. Field trials were conducted against wild mosquitoes in Bang Bua Thong District, Nonthaburi Province, and in the Thap Lan National Park Headquarters, Nadee District, Pranchinburi Province; anthroophilic black flies (Diptera: Simuliidae) at the Forestry Fire Control Station in Doi Inthanon National Park, Chomthong district, Chiang Mai Province; and land leeches (Arhynchobdellida: Haemadipsidae) in the Khao Yai National Park, Pak Chong District, Nakhon Ratchasima Province. The 3 experimental plant-based essential oil formulations as well as Repel Care and deet provided complete protection from mosquito landing and biting for up to 9 h (duration of the experiment). Similar results were obtained with the 5 products against black flies, providing 100% protection for 9 h but 96-82% protection after 10 and 11 h posttreatment. The 5 repellent products also provided 100% protection against land leeches for at least 8 h. Thi is the 1st report of repellency of plant-based repellents against black flies and land leeches in Thailand. The identification and availability of inexpensive sources of plant-based oils, i.e., finger root rhizomes, guava leaves, and turmeric rhizomes providing long-lasting repellency against blood-sucking organisms are promising leads into commercial production of relatively safe and effective repellents.

Aedes↗
PubMed1985

Chiral-phase capillary gas chromatography and mosquito repellent activity of some oxazolidine derivatives of (+)- and (-)-citronellol.

Fourteen stereoisomeric mixtures of six oxazolidine heterocycles and one amino alcohol were obtained from commercial samples of (+)-, (-), or (+/-)-citronellol and evaluated in a cloth test system as mosquito repellents. A technical sample of 3-acetyl-2-(2',6'-dimethyl-5'-heptenyl)oxazolidine, evaluated initially as a mixture of two pairs of enantiomers, was an effective repellent against two of the three species of mosquitoes. To study repellency-stereochemistry relationships, 1 was isolated as fractions G-1, G-2, I-1, and I-2, corresponding to representative samples of the four possible stereoisomers. The enantiomeric composition of 1, but not of the other derivatives, could be determined by chiral-phase capillary gas chromatography with Chirasil-Val. Two chiral phases showed that experimental samples of 1, and hence the commercial samples of 2, were composed of not more than 90% of one enantiomer. Differences in repellency of isomerically enriched samples were generally small. Fraction G, a mixture of diastereoisomers readily prepared from (+)-2, was considerably more effective than standard insect repellents in bioassays with three mosquito species.

Acyclic Monoterpenes↗
PubMed1999

Predicting mosquito repellent potency of N,N-diethyl-m-toluamide (DEET) analogs from molecular electronic properties.

Specific molecular electronic properties of 30 N,N-diethyl-m-toluamide (DEET) analogs demonstrate functional dependence with their reported duration of protection against mosquito bites, thus providing predictors of insect repellent efficacy. No single electronic property is sufficient to predict repellent efficacy as measured by protection time, rather a set of specific electronic properties is required. Thus, the values of the van der Waals surface electrostatic potential by the amide nitrogen and oxygen atoms, the atomic charge at the amide nitrogen atom, and the dipole moment must all be in optimal ranges for potent repellency. The electronic properties were calculated using the AM semi-empirical quantum chemical method using commercial software. These easily calculable predictors of repellent efficacy should be useful in predicting the relative efficacy of newly designed compounds, thus guiding the selection of new repellents for testing.

Animals↗
PubMed2006

Evaluation of synthetic repellents on mosquito nets in experimental huts against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes.

Owing to the development of pyrethroid resistance in Anopheles gambiae, there is a need to develop chemical alternatives for use on mosquito nets. Synthetic insect repellents are widely used for personal protection as skin or clothing applications. The efficacy of repellent-treated nets (RTN) was evaluated in experimental huts in Côte d'Ivoire against pyrethroid-resistant populations of An. gambiae and Culex quinquefasciatus. The repellents tested were DEET (N,N-diethyl-3-methylbenzamide) at 7.9 g/m2 and two formulations of ethyl butylacetylaminopropionate (IR3535) at 7.6 g/m2 and 7.3 g/m2. Over 45 nights there was a 74-82% reduction in the number of An. gambiae entering the huts containing RTNs but no significant reduction in entry of C. quinquefasciatus. There was a 63-64% reduction in the proportion of An. gambiae blood feeding but no reduction in the proportion of C. quinquefasciatus blood feeding in huts with RTNs. An unexpected result was the 69-76% mortality of An. gambiae and 51-61% mortality of C. quinquefasciatus in huts containing RTNs. Treated filter paper bioassays in WHO test kits confirmed that confined contact with DEET induces mortality. The DEET-based product provided better and longer protection; tunnel test bioassays confirmed that residual activity lasted for up to 6 weeks. Application of repellents to nets warrants further investigation and development.

Animals↗
PubMed2005

Personal protection measures against fire ant attacks.

BACKGROUND: Fire ant stings lead to significant morbidity and mortality each year. Virtually no information exists in the scientific literature about the effectiveness of personal protection measures against these ants. OBJECTIVES: To quantify the level of protection from ant stings by socks and cotton tights and to evaluate the efficacy of repellents and other chemicals in preventing stings. METHODS: Commercially obtained infant socks were fitted on a plastic doll's foot, which was touched to fire ant mounds in a series of controlled experiments. Socks and cotton tights were stretched over a human finger and placed in a fire ant mound to test the ability of ants to sting through fabric. Assays were developed to screen chemical substances for their ability to stop or prevent fire ant stings. RESULTS: Socks of any type reduced the number of fire ants that reached the skin and delayed the time required for ants to reach the skin above the sock level. Fire ants were unable to sting through all socks tested. Ants successfully stung both paper towels and human skin, regardless of chemical substance or repellent applied to them. CONCLUSIONS: Socks provide some degree of protection from fire ant stings; therefore, children living in fire ant-infested areas should wear them. Fire ants appear unable to sting through many commercially available socks. Cotton tights may be useful in protecting the lower extremities of children. Fire ants are not deterred from stinging by a wide variety of insect repellents and chemical substances.

Animals↗
PubMed2002

Effectiveness of a repellent containing DEET and EBAAP for preventing tick bites.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: This study found that an easily applied repellent is moderately effective in reducing the risk of tick bites.

Administration, Cutaneous↗