Mustapha Debboun

Insect Repellents : Principles, Methods, and Uses

Preface, M. Debboun, S. Frances, and D. Strickman Principles History of Insect Repellents, S.J. Moore and M. Debboun Terminology of Insect Repellents, G.B. White Vertebrate Chemical Defense: Secreted and Topically Acquired Deterrents of Arthropods, P.J. Weldon and J.F. Carroll Human Emanations and Related Natural Compounds that Inhibit Mosquito Host-Finding Ability, U.R. Bernier, D.L. Kline, and K.H. Posey Methods Standard Methods for Testing Mosquito Repellents, D.R. Barnard, U.R. Bernier, R.-d. Xue, and M. Debboun Biometrics and Behavior in Mosquito Repellent Assays, D.R. Barnard and R.-d. Xue Animal Models in Research and Development of Insect Repellents for Human Use, L.C. Rutledge and R.K. Gupta Techniques for Evaluating Insect Repellents, J.M. Govere and D.N. Durrheim Use of an Olfactometer for Determining Attractants and Repellents, J.F. Butler Discovery and Design of New Arthropod/Insect Repellents by Computer-Aided Molecular Modeling, R.K. Gupta and A.K. Bhattacharjee Molecular-Based Chemical Prospecting of Mosquito Attractants and Repellents, W.S. Leal Products and Active Ingredients Evaluation of Topical Insect Repellents and Factors that Affect Their Performance, S.P. Carroll Repellents Used in Fabric: The Experience of the U.S. Military, W.C. McCain and G.J. Leach Plant-Based Insect Repellents, S.J. Moore, A. Lenglet, and N. Hill Considerations on the Use of Botanically-Derived Repellent Products, E.J. Gerberg and R.J. Novak Efficacy and Safety of Repellents Containing Deet, S.P. Frances Lipodeet: An Improved Formulation for a Safe, Long-Lasting Repellent, B. Salafsky, T. Shibuya, Y.-X. He, J. Ha, and K. Ramaswamy Picaridin, S.P. Frances DEPA: Efficacy, Safety and Use of N,N-Diethyl Phenylacetamide, a Multi-Insect Repellent, S. Prakash, R. Vijayaraghavan, and K. Sekhar PMD (p-Menthane-3,8-Diol) and Quwenling, D. Strickman IR3535(R) (Ethyl Butylacetylaminopropionate), G. Puccetti Older Synthetic Active Ingredients and Current Additives, D. Strickman Area Repellent Products, D. Strickman Uses User Acceptability: Public Perceptions of Insect Repellents, S.P. Frances and M. Debboun Commercially Available Insect Repellents and Criteria for Their Use, R.-D. Xue, A. Ali, and J.F. Day Global Regulatory Perspectives on Insect Repellent Development and Registration, K.J. Sweeney Epilogue Prospects for the Future, D. Strickman, S.P. Frances, and M. Debboun Appendices Index

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

ABSTRACT 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.

Expert Review of the Evidence Base for Arthropod Bite Avoidance

Bite avoidance measures are commonly recommended to international travelers to help reduce the risk of various arthropod‐borne diseases. A key strategy is the use of repellents applied topically to skin or clothing which are considered in the first part of this review. Also advised are a variety of methods that employ the use of insecticides and physical barriers such as mosquito nets or oil preparations applied to the skin. In the following document, the authors considered some of the most widely used bite avoidance methods and identified the strength and quality of evidence that determined efficacy. The overall purpose of the review is to provide the available evidence, in a graded format, upon which to base recommendations for the selection of appropriate repellents and other methods of bite avoidance in those traveling overseas. The authors were asked to consider the effectiveness of the most commonly used active ingredients (AIs) in repellent formulations and methods of bite avoidance. The evidence base considered protection against nuisance biting insects, reduction in the incidence of arthropod‐borne diseases, and safety profile. Effectiveness of the repellent related to spectrum of activity against various mosquito species and other arthropods was examined as well as longevity of applied dose. Where possible, efficacy was compared to deet as being the accepted gold standard. All sections employed MEDLINE via PubMed in literature searches augmented by others depending on the subject area investigated. Details of the review process can be found at http://www.istm.org; click on “ISTM Committees” and then “Publications.” ### Major Findings N , N ‐diethyl‐3‐methylbenzamide (deet), (2‐(2‐hydroxyethyl)‐piperidinecarboxylic acid 1‐methyl ester (icaridin), p ‐methane 3, 8‐diol (PMD), and ethyl butylacetylaminopropionate (IR3535)‐based repellents all provide protection against biting arthropods, but volatile oils and other natural products are less reliable. On the strength of available evidence, the first‐line choice for those visiting areas where …

Insecticide Resistance in Bedbugs in Thailand and Laboratory Evaluation of Insecticides for the Control of Cimex hemipterus and Cimex lectularius (Hemiptera: Cimicidae)

ABSTRACT Bedbugs are found in many countries around the world, and in some regions they are resistant to numerous insecticides. This study surveyed bedbugs in Thailand and determined their resistance to insecticides. The surveys were carried out in six provinces that attract large numbers of foreign tourists: Bangkok, Chonburi, Chiang Mai, Ubon Ratchathani, Phuket, and Krabi. Bedbugs were collected from hotels and colonized in the laboratory to evaluate their resistance to insecticides. Cimex hemipterus (F.) was found in some hotels in Bangkok, Chonburi, Phuket, and Krabi, whereas Cimex lectularius L. was found only in hotels in Chiang Mai. No bedbugs were found in Ubon Ratchathani. The colonized bedbugs showed resistance to groups of insecticides, including organochlorines (dichlorodiphenyl trichloroethane, dieldrin), carbamates (bendiocarb, propoxur), organophosphates (malathion, fenitrothion), and pyrethroids (cyfluthrin, deltamethrin, permethrin, &lgr;-cyhalothrin, etofenprox) in tests using World Health Organization insecticide-impregnated papers. The new insecticides imidacloprid (neonicotinoid group), chlorfenapyr (pyrrole group), and fipronil (phenylpyrazole group) were effective against the bedbugs; however, organophosphate (diazinon), carbamates (fenobucarb, propoxur), and pyrethroids (bifenthrin, cypermethrin, esfenvalerate, etofenprox) were ineffective. Aerosols containing various pyrethroid insecticides with two to four different active ingredients were effective against the bedbugs. The results obtained from this study suggested that both species of bedbugs in Thailand have developed marked resistance to various groups of insecticides, especially those in the pyrethroid group, which are the most common insecticides used for pest control. Therefore, an integrated pest management should be implemented for managing bedbugs in Thailand.

Benzoquinones from millipedes deter mosquitoes and elicit self-anointing in capuchin monkeys ( Cebus spp.)

Neotropical monkeys of the genus Cebus anoint themselves by rubbing arthropods and plants against their pelage. A recent study has shown that free-ranging wedge-capped capuchin monkeys (C. olivaceus) in Venezuela self-anoint with a benzoquinone-secreting millipede, an activity by which they are hypothesized to appropriate chemical deterrents of mosquitoes. To evaluate the plausibility of this hypothesis, female yellow fever mosquitoes (Aedes aegypti) were presented with two millipede secretory compounds, 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone, on nylon-reinforced silicone membranes placed over wells filled with human blood, a highly preferred food. Mosquitoes exhibited fewer landings, fed less frequently, and flew more frequently (a possible indication of repellency) in the presence of membranes treated with benzoquinones than with controls. These compounds also elicit self-anointing in captive male and female tufted (C. apella) and white-faced (C. capucinus) capuchin monkeys.

Field Evaluation of Repellent Formulations Against Daytime and Nighttime Biting Mosquitoes in a Tropical Rainforest in Northern Australia

Abstract Field trials to compare repellent formulations containing either picaridin or deet against rainforest mosquitoes in northern Queensland, Australia, were conducted. Three repellents were compared at night: 9.3% picaridin and 19.2% picaridin (Autan Repel and Autan Repel Army 20, respectively, Bayer, Sydney, Australia) and 35% deet in a gel (Australian Defense Force [ADF]). During the day, the following three repellents were compared: 19.2% picaridin, 20% deet in a controlled release formulation (Sawyer Controlled Release Deet), and 33% deet in a polymer formulation (U.S. Army Extended Duration Topical Insect and Arthropod Repellent [EDTIAR]). The predominant mosquito species collected was Verrallina lineata (Taylor), with smaller numbers of Ochlerotatus kochi (Donitz), Anopheles farauti s.s. Laveran, Ochlerotatus notoscriptus (Skuse), and Coquilletidia xanthogaster (Edwards). In nighttime tests, 19.2% picaridin provided >94.7% protection for at least 9 h, and ADF deet provided >95% protection for 7 h. The 9.3% picaridin formulation provided >95% protection for only 2 h, and provided 60% protection at 9 h. In daytime tests, Sawyer 20% deet provided >95% protection for 6 h, and both 19.2% picaridin and U.S. Army EDTIAR provided >95% protection for 8 h. In both nighttime and daytime tests 19.2% picaridin provided similar or better protection than deet formulations.

Repellent and deterrent effects of SS220, Picaridin, and Deet suppress human blood feeding by Aedes aegypti, Anopheles stephensi, and Phlebotomus papatasi.

Abstract A series of behavioral tests with Aedes aegypti (L.), Anopheles stephensi Liston, mosquitoes, and the sand fly Phlebotomus papatasi Scopoli in the presence of Deet, SS220, and Picaridin topically applied to the skin of human volunteers showed that the insects were deterred from feeding on and repelled from surfaces emanating the compounds. When offered a 12- or 24-cm2 area of skin, one-half treated with compound and one-half untreated, the insects fed almost exclusively on untreated skin. The sand flies and mosquitoes did not at any time physically contact chemically treated surfaces. When treated and untreated skin areas were covered with cloth, insects contacted, landed, and bit only through cloth covering untreated skin. These observations provided evidence that the compounds deterred feeding and repelled insects from treated surfaces primarily as a result of olfactory sensing. When cloth, one-half untreated and one-half treated with chemical, was placed over untreated skin, insects only touched and specifically bit through the untreated cloth. This showed that the activity of the chemicals does not involve a chemical × skin interaction. In the presence of any of the three chemicals, no matter how they were presented to the insects, overall population biting activity was reduced by about one-half relative to controls. This reduction showed a true repellent effect for the compounds. Results clearly showed that Deet, SS220, and Picaridin exert repellent and deterrent effects upon the behavior of mosquitoes and sand flies. Heretofore, the combined behavioral effects of these compounds upon mosquito and sand fly behavior were unknown. Moreover, protection afforded by Deet, SS220, and Picaridin against the feeding of these three disease vectors on humans is mechanistically a consequence of the two chemical effects.

Synthesis and Repellent Efficacy of a New Chiral Piperidine Analog: Comparison with Deet and Bayrepel Activity in Human-Volunteer Laboratory Assays Against Aedes aegypti and Anopheles stephensi

Abstract Optically active (1S, 2′S)-2-methylpiperidinyl-3-cyclohexen-1-carboxamide (SS220) is a new synthetic arthropod repellent. A three-step synthesis based on a chiral Diels-Alder reaction and diastereomeric resolution of 2-methylpiperidine was developed to prepare the compound. Quantitative laboratory assays using human volunteers compared the effectiveness of SS220 with the commonly used repellents Deet and Bayrepel against Aedes aegypti (Linnaeus) and Anopheles stephensi Liston mosquitoes. In two experiments using Aedes aegypti, one using a single identical dose and one with varying doses used to develop a dose–response curve, SS220 was as effective as Deet and both compounds were more effective than Bayrepel. The three compounds were equally effective against An. stephensi. Based on the ease of its synthetic preparation and its repellent efficacy, we surmise that SS220 is a candidate to serve as a new and effective alternate repellent for protection against arthropod disease vectors.

Isolongifolenone: A Novel Sesquiterpene Repellent of Ticks and Mosquitoes

ABSTRACT A naturally occurring sesquiterpene, isolongifolenone, derivatives of which have been used extensively as ingredients in the cosmetics industry, was discovered to effectively repel blood-feeding arthropods that are important disease vectors. We show that (—)-isolongifolenone deters the biting of the mosquitoes, Aedes aegypti (L.) and Anopheles stephensi Liston, more effectively than the widely used synthetic chemical repellent, N,N-diethyl-3-methyl benzamide (DEET), in laboratory bioassays. The compound also repelled blacklegged ticks, Ixodes scapularis Say, and lone star ticks, Amblyomma americanum (L.), as effectively as DEET. Isolongifolenone is easily synthesized from inexpensive turpentine oil feedstock. We are therefore confident that the compound has significant potential as an inexpensive and safe repellent for protection of large human populations against blood-feeding arthropods.

Comparative Resistance of Anopheles albimanus and Aedes aegypti to N,N-Diethyl-3-methylbenzamide (Deet) and 2-Methylpiperidinyl-3-cyclohexen-1-carboxamide (AI3-37220) in Laboratory Human-Volunteer Repellent Assays

Abstract The insect repellents N,N-diethyl-3-methylbenzamide (Deet) and the racemate and 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were tested against Anopheles albimanus Wiedemann and Aedes aegypti (L.) in laboratory human-volunteer assays. Estimated skin doses of Deet or racemic AI3–37220 required to reduce biting by 95% in Ae. aegypti were 2.3 and 3.5 × 10–2 μmol/cm2 skin, respectively, whereas estimated doses for 95% bite reduction of An. albimanus in an ≈40-yr-old laboratory colony established from El Salvador were 5 times higher at 12 × 10–2 μmol Deet/cm2 skin and >20 × 10–2 μmol/cm2 skin for AI3-37220. In tests with the 1S,2′S stereoisomer of AI3-37220, a newly established colony of An. albimanus from Belize bit less aggressively than El Salvador An. albimanus. However, the Belize-derived mosquitoes were as resistant as the old El Salvador colony to repellent effects of 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide. Earlier workers surmised that usual skin doses of Deet would offer only limited protection against An. albimanus in the field. Our findings support this speculation, but they also indicate that doses of Deet higher than those needed for protection against Ae. aegypti might offer reasonable protection against An. albimanus. Results indicate that neither racemate nor 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide offer as much protection as Deet against An. Albimanus, despite being highly effective against Ae. aegypti.