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PubMed1998

Field efficacy of a new repellent, KBR 3023, against Aedes albopictus (SKUSE) and Culex quinquefasciatus (SAY) in a tropical environment.

Two new repellent formulations, KBR 3023 10% and 20% from Bayer AG, Germany, were evaluated together with DEET 10% and 20% as standard repellent formulations. Evaluation was based on two separate field studies: a daytime study (0900-1700 hr) in a forested orchard on Penang Island and a nighttime study (2100-0100 hr) in a squatter residential area on the adjacent mainland of peninsular Malaysia. Both studies were carried out by exposing humans with bare arms and legs to mosquitoes landing/biting for an eight hour period. Right arms and legs of the human baits were treated with different repellent formulations (KBR 3023 10%, 20% and DEET 10%, 20%) and the left limbs were left untreated to act as controls. The daytime study indicated that all four formulations were equally effective (P < 0.05) as repellents against the predominant Aedes albopictus with greater than 88.5% reduction in landing/biting in the first four hours and not less than 65.0% in the next four hours of the assessment period. In the night study, all four formulations were also found to be equally effective (P < 0.05) in repelling Culex quinquefasciatus, the predominant species. All four formulations provided complete protection against Cx. quinquefasciatus in the first two hours of exposure. The percentage reduction values were maintained above 90.0% for the next six hours of the assessment period. In conclusion, both the KBR 3023 and DEET formulations were found to be equally effective (P < 0.05) in providing a long-lasting reduction in human-mosquito contact in both the day and night field studies.

Aedes↗
PubMed1995

Repellent and acaricidal properties of Ocimum suave against Rhipicephalus appendiculatus ticks.

An oil extracted from the leaves of a tropical shrub Ocimum suave was found to repel as well as kill all stages of the tick Rhipicephalus appendiculatus. In an in vitro bioassay for the larvae, the LC50 of the oil in liquid paraffin was 0.024%. A 10% solution was found to kill all immatures and more than 70% of adults feeding on rabbits. Rabbits were protected for 5 days against attaching larvae using a 10% solution. Preliminary experiments undertaken with cattle kept in the field suggest that the oil may have potential in tick control, and a role in integrated tick management.

Animals↗
PubMed1994

Field trial of esbiothrin-impregnated rope in Ramgarh village, Dadri PHC, District Ghaziabad (U.P.).

A village-scale field trial was carried out to assess the operational feasibility and efficacy of smouldering 250 ppm esbiothrin-impregnated rope in repelling mosquitoes and its impact on transmission of malaria. Entomological monitoring revealed that smoke from smouldering rope resulted in 67.2-97.9% reduction of An. culicifacies densities in human and mixed dwellings. The reduction was obviously due to diversion of An. culicifacies population to cattlesheds where ropes were not burnt. The impact was more pronounced when indoor mosquito landing rate on human bait was compared with that of experimental and control areas. This was also reflected in reduced anthropophilic index and curtailment of malaria transmission in experimental area.

Allethrins↗
PubMed2005

Evidence for an isobutylamide associated with host-plant resistance to western flower thrips, Frankliniella occidentalis, in chrysanthemum.

Bioassay-directed fractionation of extracts of chrysanthemum leaves using a choice test permitted isolation of a fraction that exhibited repellent activity against the western flower thrips (WFT). Analysis of this fraction from cultivars exhibiting varying degrees of host-plant resistance to WFT by high performance liquid chromatography revealed a distinctive peak, the height of which correlated with the degree of resistance of those cultivars to WFT. The peak was attributed to a novel unsaturated isobutylamide, N-isobutyl-(E, E, E, Z)-2,4,10,1 2-tetradecatetraen-8-ynamide.

Alkynes↗
PubMed2006

Characterization of dog repellent factor from cuticular secretion of female yellow dog tick, Haemaphysalis leachi.

During its natural life cycle, the yellow dog tick, Haemaphysalis leachi, has three hosts, and it has to spend enough time on each of them to complete a blood meal. When irritated, the females of this tick species produce a cuticular secretion that contains a dog-repelling allomone. This improves the tick's chances of survival by deterring the dog from biting the tick off its body. Employing response-guided isolation techniques in conjunction with gas chromatography-mass spectrometry, the defensive allomone of H. leachi was found to consist of the six homologous aliphatic aldehydes from hexanal to undecanal. A mixture of synthetic versions of these six aldehydes in quantities corresponding to those secreted by one tick elicited strong aversion reactions in the majority of dogs of various breeds.

Animals↗
PubMed1999

Behavioural mode of action of deet: inhibition of lactic acid attraction.

Using the mosquito Aedes aegypti in a novel olfactometer that measures movement towards and away from a stimulus, we could not confirm that 'deet' is a repellent of mosquitoes. In the absence of a host, deet was an attractant and in the presence of a host, it was an inhibitor of attraction. This inhibition occurred in the gaseous phase and was therefore not the result of the physical properties of deet. We determined that L-lactic acid, a component of human sweat that is an attractant to mosquitoes, is the target of this inhibition, implying that lactic acid may be a bottleneck in the behavioural cascade preceding blood-sucking.

Aedes↗
PubMed2004

Repellency and toxicity of mint oil granules to red imported fire ants (Hymenoptera: Formicidae).

Repellency and toxicity of 2% mint oil granules were evaluated against worker red imported fire ants. Solenopsis invicta Buren, in a series of laboratory and field experiments. In continuous exposure experiments, LT50 values ranged from 1.2 h with 164.8 mg/cm2 of 2% mint oil granules to 15.3 h with 1.65 mg/cm2 of granules. LT50 values declined exponentially with increasing rate of mint oil granules. Limited exposure to 164.8 mg/cm2 mint oil granules resulted in > 50% knock down (KD) after 30 min; however, there was no KD at 15 min. Twenty-four hour mortality increased linearly with increasing exposure time. Mean repellency of worker red imported fire ants ranged from 49.2 +/- 5.4% for 0 mg/cm2 (untreated control) of mint oil granules at 30 min to 100% for 147.8 mg/cm2 of mint oil granules at 3 h. Repellency increased with increasing milligrams per square centimeter of mint oil granules and exposure time. In field tests, 100% of mounds opened and treated with mint oil granules were abandoned 5 d after treatment and ants had relocated or formed satellite mounds by 2 d after treatment. Unopened mounds treated topically with mint oil granules were not abandoned, but ants formed satellite mounds 2 d after treatment. Mint oil granules could provide another tool for red imported fire ant integrated pest management, particularly in situations in which conventional insecticides would be inappropriate.

Animals↗
PubMedDate not supplied

[Experimental evaluation in mice of vitamin B complex repellent activity against Culex quinquefasciatus].

One untested but widely held opinion in Brazil is that oral use of vitamin B complex is useful as a mosquito repellent. We exposed Balb-C mice to a large number of Culex quinquefasciatus females, after giving vitamin B complex to mice (drops by mouth). There was no difference between mice attractiveness to mosquitoes in the vitamin B group compared to normal, but very few of the females bite mice in both groups, so the experiment was inconclusive. We suggest further experiments in this subject, using other models were the animals are more attractive to mosquitoes.

Animals↗
PubMed2006

Morbidity assessment in sand flea disease (tungiasis).

Tungiasis, caused by the sand flea Tunga penetrans, is a health problem in many impoverished communities in Latin America, the Caribbean, and sub-Saharan Africa. Sand flea disease is associated with a broad spectrum of clinical and histological pathology. The factors determining the disease burden in endemic communities are not well understood, and severity of clinical pathology has never been assessed quantitatively. Thus, two severity scores were developed: one for acute disease and one for chronic sequels. These scores were evaluated in a cohort of 70 severely infested patients living in a shantytown in Fortaleza, a capital city in Northeast Brazil. Patients were examined during a period of 25 days and followed-up after a twice daily application of a plant-based repellent to prevent reinfestation. The severity score for acute disease symptoms significantly correlated with the infestation rate and the number of embedded fleas. It turned zero when reinfestation was prevented. The score for chronic disease also significantly correlated with the infestation rate. Tungiasis is associated with considerable acute and chronic morbidity. The degree of acute morbidity is directly related to the number of embedded sand fleas. When transmission is interrupted, the chronic morbidity reflects the infestation rates individuals have experienced in the past.

Adolescent↗
PubMed1994

Studies on the inheritance of repellent tolerances in Aedes aegypti.

Two laboratory strains and 6 inbred strains of Aedes aegypti were tested against deet, ethyl hexanediol, dimethyl phthalate, and Indalone. Reciprocal crosses and backcrosses of 2 inbred strains were tested against deet only. Results obtained were compatible with a quantitative genetic model in which the effects of the factors involved were multiplicative. Certain inbred strains differed significantly from cognate laboratory and/or inbred strains in tolerance to one or more test materials. Heritability in the broad sense (H2) was estimated at 0.05 for deet, 0.22 for ethyl hexanediol, 0.48 for dimethyl phthalate, and 0.51 for Indalone. Partial dominance was observed in the inheritance of tolerance to deet.

Aedes↗
PubMed1995

Performance of abamectin bait formulations against German cockroaches (Dictyoptera: Blattellidae).

Commercial and experimental formulations of abamectin-based baits were evaluated in laboratory and field studies against the German cockroach, Blattella germanica (L.). In continuous exposure tests with adult males, toxicity and presumably bait consumption varied with the design of the bioassay. LT50s ranged from approximately 0.9 to > 41 d for an aerosol gel formulation for males deprived of water for 72 h before the test and for undeprived males tested with alternative food and water, respectively. Dry formulations had lower LT50s than water containing formulations for nondeprived males. There was no difference in bait toxicity between males deprived of food or water, but in arena tests, moist formulations were preferred by mixed-stage populations of cockroaches. Powder formulations were more repellent (approximately 14.9%) than moist formulations (approximately 6.4%) in Ebeling choice boxes assays, but all abamectin formulations had positive performance indices. A powder formulation reduced cockroach trap catch in infested apartments more rapidly when applied to 50, rather than 12 sites, even when the same amount of bait was applied per apartment. When applied at approximately 50 sites as a series of thin smears, an aerosol formulation provided nearly an 80% reduction in trap catch. Other abamectin formulations provided substantial, but smaller reductions in trap catch. Abamectin-based baits can reduce German cockroach populations when properly applied.

Animals↗
PubMed1998

[The principal arthropod vectors of disease. What are the risks of travellers' to be bitten? To be infected?].

Many blood-sucking arthropods are potential vectors of disease. To become a vector, the arthropod must be susceptible to the infective agent and must survive the incubation period so as to transmit the pathogens to a host. While some arthropod associated diseases affect only man (e.g. malaria) most of these diseases are (anthropo-) zoonoses with man often an accidental host. The risk of contamination depends on the one hand on the biting behaviour of the vector, its biology and distribution, and on the other hand on the sites visited by the traveller, the length of his stay, his activities, the conditions of sleeping accommodation. The risk of contracting malaria is very high in tropical Africa, in the forest area of South America and South East Asia, in Papua New Guinea. Malaria can be prevented if measures (e.g. pyrethroid impregnated bed nets, repellents) are taken to avoid bites of Anopheline mosquitoes between sunset and sunrise, but appropriate chemoprophylaxis must not be neglected. Lethal cases of yellow fever among unvaccinated travellers still occur despite a strict international regulation on vaccination requirements. Dengue is a major health problem in intertropical areas. As no vaccine is available, personal protection measures are recommended against daytime-biting mosquitoes, including the use of protective clothing, repellents. Other arthropod borne diseases among travellers are less common but the risks increase during adventure trips (e.g. zoonotic leishmaniasis, tick-borne relapsing fever) and humanitarian actions (e.g. risk of louse-borne typhus during visits of overcrowded prisons). Tick-borne diseases receive nowadays more attention. These diseases are not only restricted to some occupations (farmers, veterinarians) but also ramblers and campers are at risk. Attached ticks should be removed rapidly and carefully, since several hours of attachment are needed for transmission of spirochetes of LYME disease.

Animals↗
PubMed2005

Testing vitamin B as a home remedy against mosquitoes.

Vitamin B is often recommended in the popular media as a systemic repellent against mosquitoes. This information is especially prevalent on the Web. The results of a small number of published studies suggested that vitamin B complex supplements are not effective as repellents, but these studies were limited by the use of very few human subjects and only 1 species of mosquito, Aedes aegypti. We extended this work with the use of larger samples of human subjects and with Anopheles stephensi as the test organism. We tested whether ingestion of vitamin B supplements under various regimens affected the attractiveness of volatile skin components transferred to glass vials. Although there was substantial and consistent individual variation in attractiveness, we found no effect of vitamin B supplementation.

Adolescent↗
PubMed2006

Larvicidal and repellent potential of Albizzia amara Boivin and Ocimum basilicum Linn against dengue vector, Aedes aegypti (Insecta:Diptera:Culicidae).

Investigations were made to test the larval toxicity and smoke repellent potential of Albizzia amara and Ocimum basilicum at different concentration (2%, 4%, 6%, 8% and 10%) against the different instar (I, II, III and IV) larvae and pupae of Aedes aegypti. The LC50 values of A. amara and O. basilicum for I instar larvae was 5.412 and 3.734, II instar 6.480 and 4.154, III instar 7.106 and 4.664, IV instar 7.515 and 5.124, respectively. The LC50 and LC90 values of pupae were 6.792%, 5.449% and 16.925%, 15.474%. The smoke toxicity of A. amara was more effective against A. aegypti than the O. basilicum.

Aedes↗
PubMed2003

Field trials on the repellent activity of four plant products against mainly Mansonia population in western Ethiopia.

The repellent activity of essential oils of lemon eucalyptus (Eucalyptus maculata citrodion), rue (Ruta chalepensis), oleoresin of pyrethrum (Chrysanthemum cinerariaefolium) and neem (Azadiracta indica) have been field tested as 40%, 50% and 75% solutions in coconut oil against populations of mosquitoes consisting mainly of Mansonia in Gambella, western Ethiopia. A latin square design was used to randomize the test subjects for possible individual differences for mosquito attraction. Repellency was evaluated as the percentage protection. Deet was included in the study for comparison. All the plant products manifested repellency. At 50% concentration at which the highest repellency was recorded the protection was 91.6%, 87.0%, 96.0%, 97.9% for rue, neem, pyrethrum and deet, respectively. The essential oil of lemon eucalyptus was not tried at this concentration. At a 40% concentration deet, lemon eucalyptus and pyrethrum were significantly (p < 0.05) more effective than rue and neem. At a 50% concentration, deet and pyrethrum were significantly better (p < 0.05) than rue and neem. At a 75% concentration concentration, deet and lemon eucalypus performed significantly better (p < 0.05) than pyrethrum and neem. The difference between pyrethrum and neem was also significant (p < 0.01).

Animals↗
PubMed1992

Esbiothrin-impregnated ropes as mosquito repellent.

Esbiothrin [(+/-)-3-allyl-2-methyl-4-oxocylopent-2-enyl-(+)-trans- chrysanthemate] is an improved isomeric composition of allethrin series and consists essentially of esters of chrysanthemic acid and allethrolone. Jute rope was impregnated with esbiothrin and the smoke from smouldering ropes was evaluated as mosquito repellent in human dwellings and cattlesheds with open doors and windows at different dosages. Esbiothrin-impregranted (500 ppm) ropes prevented the entry of more than 95% An. culicifacles and other anophelines, 90.9-88.8% Culex quinquefasciatus and 96-95.1% total mosquitoes in open rooms of houses and cattlesheds respectively. The impact of ropes was more pronounced on the biting rate of mosquitoes. Indoors and outdoors human baits seated at a distance of about 3 m from smouldering esbiothrin ropes experienced no bite at all from An. culicifacies. An iron mesh around the rope prevents fire hazards.

Allethrins↗
PubMed1996

Laboratory tests of arthropod repellents against Leptotrombidium deliense--noninfected and infected with Rickettsia tsutsugamushi--and noninfected L. fletcheri (Acari: Trombiculidae).

Laboratory tests were conducted to compare the response of noninfected Leptotrombidium deliense Sambon and Leptotrombidium fletcheri (Womersley & Heaslip) and L. deliense naturally infected with Rickettsia tsutsugamushi, the etiologic agent of scrub typhus, to 8 chemical repellents and toxicants. Low concentrations of permethrin, dimethylphthalate, diethyl methylbenzamide, benzyl benzoate, di-n-propyl 2,5-pyridine-dicarboxylate, 1-(3-Cyclohexen-1-yl-carbonyl)-2-methylpiperidine (AI3-37220), 2-hydroxymethyl-cyclohexyl acetic acid lactone, and a high concentration of dibutylphthalate (DBP) were toxic for noninfected larvae of both species tested. The median effective knockdown time for all chemicals, except 1% AI3-37220 and 5% permethrin, were longer against infected L. deliense than uninfected larvae of the same species. However, the results indicate that low concentrations of all chemicals, except DBP, should be effective against 2 important vectors of scrub typhus.

Animals↗
PubMed1994

Personal protection from mosquitoes (Diptera: Culicidae) by burning neem oil in kerosene.

The repellent action of neem oil (extracted from the seeds of Azadirachta indica A. Juss) was evaluated on mosquitoes at two villages near Delhi, India. Kerosene lamps containing neem oil were burned in the living rooms, and mosquitoes resting walls or attracted to human bait were collected inside rooms from 1800 to 0600 h. Neem oil (0.01-1%) mixed in kerosene reduced biting of human volunteers and catches of mosquitoes resting on walls in the rooms. Protection was more pronounced against Anopheles than against Culex. A 1% neem oil-kerosene mixture may provide economical personal protection from mosquito bites.

Animals↗