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PubMed1994

[Ectoparasites of animals: methods of ecological, biological, genetic and mechanical control].

The use of insecticides is still the basic procedure for controlling most ectoparasites, but various methods are being developed to act in addition to, or in synergy with these products, so as to enhance the efficacy and reduce the adverse effects of insecticides, by contributing to ecologically acceptable strategies. These methods are classified as ecological control (modification of the environment of the parasite), biological control (predation, parasitism, action of pathogens, etc.), genetic control (release of sterile males, hybridisation, genetic manipulations) and mechanical control (insect traps, use of repellents). The application of such methods depends on the biological and ecological characteristics of the ectoparasite, and they may act directly or indirectly, affecting mortality and/or reproduction. The authors review the principal methods applicable to major groups of ectoparasites of veterinary interest. Non-chemical methods are the subject of wide-ranging and promising research, particularly in view of recent developments in biotechnology.

Animals↗
PubMed2001

Caterpillar-induced nocturnal plant volatiles repel conspecific females.

Plants respond to insect herbivory by synthesizing and releasing complex blends of volatile compounds, which provide important host-location cues for insects that are natural enemies of herbivores. The effects of these volatile blends on herbivore behaviour have been investigated to only a limited extent, in part because of the assumption that herbivore-induced volatile emissions occur mainly during the light phase of the photoperiod. Because many moths-whose larvae are some of the most important insect herbivores-are nocturnal, herbivore-induced plant volatiles have not hitherto been considered to be temporally available as host-location cues for ovipositing females. Here we present chemical and behavioural assays showing that tobacco plants (Nicotiana tabacum) release herbivore-induced volatiles during both night and day. Moreover, several volatile compounds are released exclusively at night and are highly repellent to female moths (Heliothis virescens). The demonstration that tobacco plants release temporally different volatile blends and that lepidopteran herbivores use induced plant signals released during the dark phase to choose sites for oviposition adds a new dimension to our understanding of the role of chemical cues in mediating tritrophic interactions.

Animals↗
PubMed2003

Genomics spawns novel approaches to mosquito control.

In spite of advances in medicine and public health, malaria and other mosquito-borne diseases are on the rise worldwide. Although vaccines, genetically modified mosquitoes and safer insecticides are under development, herein we examine a promising new approach to malaria control through better repellents. Current repellents, usually based on DEET, inhibit host finding by impeding insect olfaction, but have significant drawbacks. We discuss how comparative genomics, using data from the Anopheles genome project, allows the rapid identification of members of three protein classes critical to insect olfaction: odorant-binding proteins, G-protein-coupled receptors, and odorant-degrading enzymes. A rational design approach similar to that used by the pharmaceutical industry for drug development can then be applied to the development of products that interfere with mosquito olfaction. Such products have the potential to provide more complete, safer and longer lasting protection than conventional repellents, preventing disease transmission by interrupting the parasite life cycle.

Animals↗
PubMed2000

Repellency and toxicity of oil from Artemisia annua to certain stored-product beetles.

The essential oil of Artemisia annua L. was tested for its toxic repellent and development inhibitory activities against 2 economically important stored product insects: Tribolium castaneum (Herbst) and Callosobruchus maculatus (L.). Adult beetles of T. castaneum were repelled significantly by oil of A. annua at 1% concentration (vol:vol) and above in filter paper arena test. Dose-response relationship of A. annua oil revealed a significant negative correlation between larval survival; pupal survival and adult emergence of T. castaneum (i.e., increase in dose caused decrease in survival and adult emergence). Effective concentration (EC50) to reduce F1 progeny by 50% was calculated to be 2.6 and 4.1 microl/ml solvent against both the insect species, C. maculatus and T. castaneum, respectively. The relationship between bioactivity of oil from A. annua and responses of T. castaneum and C. maculatus is discussed. We found that oil from A. annua was largely responsible for both repellent (behavioral) and toxic (physiological) actions on 2 species of insect tested.

Animals↗
PubMed2006

Toxicity of pyrethroids and repellency of diethyltoluamide in two deltamethrin-resistant colonies of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae).

The aim of the currrent investigation was to evaluate (a) the toxicity of three pyrethroids (deltamethrin, lambda-cyhalothrin, and tetramethrin); (b) the effect of these insecticides on the locomotor activity; and (c) the repellent effect of N,N-diethyl-m-toluamide (DEET) on two deltamethrin-resistant strains of Triatoma infestans from Argentina (El Chorro and La Toma), and one susceptible strain. The resistance ratios (RRs) obtained for the La Toma strain were: > 10,769, 50.7, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The RRs for the El Chorro strain were: > 10,769, 85.8, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The hyperactivity usually caused by the three pyrethroids was in both the deltamethrin-resistant strains compared to the susceptible reference strain. No differences were observed in the repellent effect of DEET between the three groups. These results indicate that the deltamethrin-resistant insects have a cross resistance to lambda-cyhalothrin and tetramethrin, and are also resistant to the first symptom of pyrethroid poisoning (hyperactivity). However, the sensorial process related to DEET repellency does not appear to be altered.

Animals↗
PubMed2005

[Protection against insects].

Successful protection against haematophagous insects and ticks, especially in areas where transmission of diseases occurs, requires a consistent application of a combination of appropriate measures. However, this can never substitute a chemoprophylaxis. Which measures have to be used depends on the circumstances under which they have to work. Indoor, physical means such as mosquito-screens on doors and windows, air-conditioners, and bed nets can be used to keep the insects away. These measures can be supplemented or supported by insecticides used as knock-down sprays, by electrical evaporation or for the treatment of screens and bed nets. In the field, if it is not possible to avoid mosquito-areas during phases of activity, appropriate clothing and repellents must provide the protection. Bright, wide pants and shirts of dense weaving covering as much skin as bearable should be preferred. Repellents are sprays, lotions, milks or creams which are evenly applied to the skin to prevent insects from biting. They contain synthetic or natural active substances of substantially varying effectiveness. The gold standard since about 60 years is diethylbenzamine (DEET). There are a few other active substances with a lower risk of side effects, however, combined with a lower effectiveness mainly on people with a high attractiveness for mosquitoes. Products containing an extract of Eucalyptus citriodora provide the best protection amongst those with natural active substances. Wearing bracelets or necklaces treated with repellents, acoustic devices (buzzers), electrocuters, topical or systemic Vitamin B1 or eating garlic are useless measures to prevent insects from biting.

Animals↗
PubMed1992

Permethrin transfer from treated cloth to the skin surface: potential for exposure in humans.

Permethrin is an agricultural insecticide of great interest to the military because of its repellency toward disease-bearing insects when impregnated into uniforms. However, migration of the substance from clothing to the skin surface is of toxicological importance. To quantitate leaching from treated clothing, studies were performed in which swatches of fabric impregnated with 14C-labeled permethrin were applied to the backs of rabbits for 1 wk. Permethrin migration was quantitated by measuring the fate of the 14C label. Conditions that could affect leaching and/or absorption were also evaluated, that is, varying environments, the presence of sweat, different fabric types, and the effects of prelaundering. Results showed that fabric treated with permethrin at a rate of 0.125 mg/cm2 lost the substance to the skin surface at an average rate of 0.49%/d. At the end of the 7-d exposures in rabbits, about 3.2% of the available permethrin had reached the skin, 2% having been recovered from excreta (absorbed) and 1.2% remaining on the skin surface. Prelaundering the treated fabric had little effect on migration rate, nor did the other variables tested. Exposure dose to humans from wearing permethrin-treated (0.125 mg/cm2) military clothing is predicted to be 6 x 10(-4) mg/kg/d.

Animals↗
PubMed1996

Influence of tapeworm infection on the production of aggregation pheromone and defensive compounds in Tribolium castaneum.

Recent studies suggest that parasites affect host development, reproduction, and behavior through alterations of host hormones and pheromones, or other hormone-triggered biochemical events. We previously reported that Hymenolepis diminuta infection affects surface-seeking and cannibalism behaviors, and reduces male sperm precedence of Tribolium castaneum beetles. This study examined the quantitative effects of H. diminuta on the production of aggregation pheromone and 3 defensive compounds in male T. castaneum beetles, using 2 wild-caught, geographically distinct T. castaneum strains. For the c-Madison strain, infected beetles exhibited a 2- to 22-fold increase in defensive compounds; conversely, no changes were observed in strain c-Africa. Parasite infection did not significantly influence aggregation pheromone secretion in either strain. Because defensive compounds function as repellents or deterrents to other insects, parasite-induced increases in the secretion of defensive compounds may be a physiologic clue for the behavioral changes in infected T. castaneum beetles. Significant among-strain variation in defensive compound production seen in infected beetles suggests that caution is needed before generalizing about changes in volatile production and in host behavior induced by a parasite.

Analysis of Variance↗
PubMedDate not supplied

[The development and introduction of a rational system for the protection of the personnel in a large enterprise against attack by blood-sucking arthropods in western Siberia].

In the middle Ob River Valley (north and moderate taiga), a large number of bloodsucking dipterans (mosquitoes, blackflies, biting midges, horseflies) are recorded during 90-100 days; the activity of Ixodes persulcatus and their attack on humans are notified during 90-115 days. A package of measures that protect petroleum industrial workers from the attacks of bloodsucking insects and ticks includes the use of protective suits, the treatment of premises with insecticides, the use of repellents, and health education. Protective means for workers should be the items included into the list of expenses on safety measures. Work is done on a cost-accounting principle. The introduced system annually shows a high efficiency (95-98%) in protecting large groups of workers in their working places.

Animals↗
PubMed1994

Insect antifeedant activity of clerodane diterpenoids.

Fourteen clerodane-type diterpenoids isolated from plants in the genera Baccharis, Teucrium, and Salvia were assayed for antifeedant activity against Tenebrio molitor larvae in order to establish structure-activity relationships. Among the compounds tested, furanoditerpenes with alpha, beta-unsaturated-gamma-lactone moieties, or C-4-epoxy substitution with C-5-methylacetoxy or C-12-acyloxy functionalities, exhibited maximal antifeedant and repellent activities.

Animals↗
PubMed2000

Effect of some Ghanaian plant components on control of two stored-product insect pests of cereals.

In an attempt to find natural and cheaper methods for the control of stored-product pests of cereals, some traditionally useful Ghanaian plant materials were evaluated. Hexane+isopropyl alcohol extract of leaves of Ocimum viride proved most effective in the control of Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae), followed by that of Chromolaena odorata. O. viride showed strong repellent activity and thus deterred the insects from feeding. It reduced survival of both insect pests to less than 25% after 10 days of treatment at concentrations of 0.1 mg ml(-1) and above. The results show the potential of O. viride and C. odorata in the control of stored-product insects.

Journal Article↗
PubMed2000

Short report: study on the efficacy of a new long-acting formulation of N, N-diethyl-m-toluamide (DEET) for the prevention of tick attachment.

The beneficial effects of N, N-diethyl-m-toluamide (DEET) against biting insects of human and animals appear to last <6 hr after a single application to the skin. To prolong the repellent effects of DEET, recently we developed a new long-acting formulation of DEET called LIPODEET. This preparation was retained in the skin for a longer duration of time with minimal systemic absorption. In this study, we have evaluated the protective effect of three compounds (DEET, LIPODEET, and Morpel 220) against attachment of two species of ticks (Amblyomma americanum and Dermacentor variabilis) to rabbit ears. Results show that LIPODEET and Morpel 220 were highly effective in preventing tick attachment to the skin for a longer duration of time (up to 72 hr) than DEET after a single application. Moreover, LIPODEET was found to be acaricidal to both the species of ticks.

Animals↗
PubMed2006

Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes.

Since ancient times, plant products were used in various aspects. However, their use against pests decreased when chemical products became developed. Recently, concerns increased with respect to public health and environmental security requiring detection of natural products that may be used against insect pests. In this study, 41 plant extracts and 11 oil mixtures were evaluated against the yellow fever mosquito, Aedes aegypti (Linnaeus), the malaria vector, Anopheles stephensi (Liston), and the filariasis and encephalitis vector, Culex quinquefasciatus (Say) (Diptera: Culicidae) using the skin of human volunteers to find out the protection time and repellency. The five most effective oils were those of Litsea (Litsea cubeba), Cajeput (Melaleuca leucadendron), Niaouli (Melaleuca quinquenervia), Violet (Viola odorata), and Catnip (Nepeta cataria), which induced a protection time of 8 h at the maximum and a 100% repellency against all three species. This effect needs, however, a peculiar formulation to fix them on the human skin.

Animals↗
PubMed2004

Efficacy of Piper (Piperaceae) extracts for control of common home and garden insect pests.

Extracts from three species of the plant family Piperaceae, Piper nigrum [L.], Piper guineense [Schum & Thonn, and Piper tuberculatum [Jacq.], were tested for efficacy against insects from five orders. All three species contain isobutyl amides, plant secondary compounds that act as neurotoxins in insects. These materials are considered safe to mammals because Piper spp. were used for centuries for spice and medicinal purposes. When 24-h P. nigrum LC50 values were compared between common insect pests from eastern Canada and the northeastern United States, the most sensitive species in order of increasing lethal concentration were eastern tent caterpillar, Malacosoma americanum (F.) < European pine sawfly larvae, Neodiprion sertifer (Geoffroy) < spindle ermine moth larvae, Yponomeuta cagnagella [Hübner] < viburnum leaf beetle larvae, Pyrrhalta viburni [Paykull] < stripped cucumber beetle adults, Acalymma vittatum (F.) < Colorado potato beetle adults, Leptinotarsa decemlineata (Say) < Japanese beetle adults, Popillia japonica [Newman] < hairy chinch bug, Blissus leucopterus hirtis [Montandon]. The life stage tested was the point at which each species causes the greatest amount of damage to the host plant and the point at which most gardeners would likely choose to treat with a conventional synthetic insecticide. Greenhouse trials revealed that the pepper formulations also had a repellent activity, thus protecting plant leaves from 1) herbivory (lily leaf beetle, Lilioceris lilii [Scopoli], adults and larvae and stripped cucumber beetle adults) and 2) oviposition [European corn borer, Ostrinia nubilalis (Hübner)]. Combinations with other botanical extracts were additive at best in toxicity and repellent trials. Nontarget toxicity to beneficial invertebrates is a possibility because the P. nigrum LC50 for beneficial ladybird beetles was 0.2%. P. nigrum extracts can provide a reasonable level of control against lepidopteran and European pine sawfly larvae and also will work as a short-term repellent and feeding deterrent. It is recommended that the use of Piper extracts be restricted to small-scale spot treatments in residential areas where insect pest outbreaks have occurred.

Animals↗
PubMed2001

Aromatic plants in bird nests as a protection against blood-sucking flying insects?

The nest protection hypothesis suggests that some of the fresh plant material, brought by some bird species to their nests, contain secondary compounds that repel parasites or mask the chemical cues that parasites use to find the host. Corsican blue tits (Parus caeruleus) bring pieces of several species of aromatic plants to the nest at dusk, suggesting a protection against nocturnal agents such as blood-sucking flying insects. The potential repellent or masking effect of these aromatic plant species, alone or in mixture, was experimentally investigated in the mosquito Culex pipiens, using domestic chicks as bird hosts. Aromatic plants had a repellent effect against mosquitoes, although a masking effect could not be ruled out. The plant mixture was the most efficient, although some aromatic plants had a significant effect when used individually. These results are discussed in the context of the nest-protection hypothesis and of the impact of flying blood-sucking insects on bird behaviour and life history traits.

Journal Article↗
PubMed1994

Mucous droplets with multiple membranes in the accessory submandibular glands of long-winged bats.

BACKGROUND: Certain species of bats possess two sets of submandibular glands, namely, principal and accessory. The ultrastructure and histochemistry of the accessory submandibular gland was examined in three species of long-winged bats. METHODS: Specimens of Miniopterus schreibersi and M. magnator were live-trapped in Thailand, and of M. inflatus were live-trapped in Kenya. For electron microscopy, accessory submandibular lands were initially fixed in triple aldehyde-DMSO, postfixed in osmium tetroxide, and embedded in Epon-Maraglas. A portion of the glands collected in Thailand (M. schreibersi and M. magnator) was fixed in buffered formalin and embedded in paraffin. Sections of the latter material were subjected to a battery of histochemical tests for glycoconjugates. RESULTS: Although in all three species the accessory submandibular glands have normal histological structure, the glands in two, M. schreibersi and M. magnator, were distinguished by possessing mucous droplets of unusual morphology. These droplets, whose identity as mucous was confirmed by histochemical tests for glygoconjugates, are delimited by manifold membranes: up to 10 in M. schreibersi and fewer, but still multiple, in M. magnator. In both species, the entire array of surface membranes may fold inward in the fashion of mitochondrial cristae, forming packets of membranes, many of which have the spurious appearance of floating free in the droplet matrix. These multipartite limiting membranes appear to originate simply by Golgi saccules and moderately large, flattened Golgi vesicles repeatedly wrapping themselves around the surface of nascent mucous droplets. During exocytosis, the outermost membrane of each mucous droplet contacts the luminal membrane, this barrier ruptures, then the remainder of the droplet--multiple membranes and matrix--either flow into the lumen or are cast out in toto. In either case, a great deal of membrane phospholipid is added to the saliva. This salivary lipid may permit these bats to consume insects that normally are able to repel predators with chemical defenses that make them unpalatable. The third species that we studied, M. inflatus, has mucous droplets of normal appearance, i.e., they have only one limiting membrane. CONCLUSIONS: The varying structure of mucous secretory products among the species of Miniopterus provides important clues as to the evolution of this genus as well as to the evolution of secretory cells in general.

Animals↗
PubMed2005

New class of linoleic acid metabolites biosynthesized by corn and rice lipoxygenases: suppression of proinflammatory mediator expression via attenuation of MAPK- and Akt-, but not PPARgamma-, dependent pathways in stimulated macrophages.

In response to endogenous and exogenous stimuli, macrophages are activated to produce a cocktail of proinflammatory and anti-apoptotic mediators, thereby participating in the processes of inflammation-associated oncogenesis. Cereals, including corn and rice, have biological potentials to synthesize self-protective chemicals in order to repel the invasion of microorganisms and insects. We examined the suppressive effects of several fatty acids, including a new class of lipoxygenase metabolites of linoleic acid (LA) found in cereals, namely (+/-)-9-hydroxy-trans,cis-10,12-octadecadienoic acid (9-HOA from rice), (+/-)-13-hydroxy-10-oxo-trans-11-octadecenoic acid (13-HOA from corn), and (+/-)-10-oxo-trans-11-octadecen-13-olide (10-ODO from corn), on lipopolysaccharide (LPS)-induced mRNA expression of proinflammatory mediators in RAW264.7 murine macrophages. Each metabolite exhibited a suppressive activity toward nitrite production than LA, octadeca-9Z,11E-dienoic acid (a conjugated LA), and 13S-hydroxyoctadeca-9Z,11E-dienoic acid. LPS-up-regulated mRNA expression of inducible nitric oxide synthase, cyclooxygenase (COX)-2, interleukin-6, and toll-like receptor-2, -4, and -9 was also markedly attenuated without affecting the expression levels of several constitutive genes, including COX-1, as detected by reverse transcription-polymerase chain reactions. In addition, Western blot and luciferase reporter assay results showed that 13-HOA suppressed the phosphorylation of mitogen-activated protein kinases (extracellular signal-regulated kinasel/2, c-Jun N-terminal kinasel/2, p38 mitogen-activated protein kinase), and Akt (Ser473), and also attenuated degradation of inhibitor kappaB, nuclear translocation of nuclear factor kappaB (NFkappaB), and the transcriptional activities of NFkappaB and activator protein-1, both of which have essential roles in the transcription of numerous proinflammatory and oncogenic genes. In contrast, 13-HOA did not serve as a ligand for peroxisome proliferator-activated receptor-gamma. Based on our findings, we propose that 13-HOA, a functionally novel LA-derivative, is a promising agent for anti-inflammatory and chemopreventive strategies with reasonable molecular mechanisms.

Active Transport, Cell Nucleus↗
PubMed1983

[Economic importance of protecting draft horses used in forestry against blood-sucking dipterous insects].

The adverse effect of blood-sucking dipterous insects (gadflies, gnats, black flies, midges) was determined and checked, as exerted on the working performance of draft horses working in forests; the possibilities of protecting horses with repellents were studied at the same time. The trial was conducted under field conditions in the territory of the Broumov Forest Establishment in the Náchod and Trutnov districts. A 10% water emulsion of the repellent, diethyltoluamide, was used; the horses were treated with the emulsion in a 24-hour interval. Over the seventy working days from the 1st of July to the 30th of September, 1981, the performance of the test horse increased by 153 m3 wood in the skidding operation (i. e. by 58.06%), as compared with the control group. Recalculated per horse/day, this improvement is 2.19 m3 wood and the saving of prime costs amounts to 35.50 Czechoslovak crowns. The coefficient of loss per untreated horse was 9180 crowns. The effectiveness of the costs (per each crown of the capital expended) was calculated to be 309.07 crowns. The results were statistically significant.

Animals↗