Treatment of horses with cypermethrin against the biting flies Culicoides nubeculosus, Aedes aegypti and Culex quinquefasciatus

Laboratory of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, University Campus, Thessaloniki, Greece.
Veterinary Parasitology (Impact Factor: 2.46). 04/2010; 169(1-2):165-71. DOI: 10.1016/j.vetpar.2009.12.023
Source: PubMed


An in vitro assay was used to assess the efficacy of the proprietary pyrethroid insecticide cypermethrin applied to horses (Deosect spray, 5.0%, w/v Fort Dodge Animal Health) against the biting midge Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae) and the mosquitoes Aedes aegypti Linneaus and Culex quinquefasciatus Say (Diptera: Culicidae). Hair was collected from the back, belly and legs of the horses immediately prior to treatment and 7, 14, 21, 28 and 35 days after treatment, and also from untreated controls. In laboratory assays groups of 10 adult female C. nubeculosus, Ae. aegypti or C. quinquefasciatus were exposed to 0.5g of hair for 3min. In all cases, little or no mortality was observed in insects kept in contact with the pre-treatment samples or the untreated controls. With post-treatment samples for C. nubeculosus, mortality was close to 80% 7 days after treatment and then declined gradually; mean mortality was still at around 50% for hair collected 35 days after treatment. In general, Ae. aegypti and C. quinquefasciatus appeared to be less susceptible to cypermethrin than C. nubeculosus and the attenuation of the toxic effect declined more quickly with time after treatment. There were differences in the toxicity of hair from different body regions, with hair from the back consistently inducing the highest mortality and hair from the legs the lowest; this effect was more pronounced for C. nubeculosus than Ae. aegypti or C. quinquefasciatus. The results demonstrate the potential for topical insecticide treatment to offer protection to horses against biting flies; but highlight the major differences that exist in susceptibility between different insect species.

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Available from: Simon Carpenter, Jun 15, 2015
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    • "It has been observed that temperature can have a large effect on insecticide susceptibility (WHO, 1998) and also affect the efficacy of the compound. Previous works on susceptibility of biting midges to different insecticides were done on tropical and sub-tropical species, and assays were carried out at room temperature (Mehlhorn et al., 2008; Schmahl et al., 2008; Schmahl et al., 2009a; Schmahl et al., 2009b; Papadopoulos et al., 2010; Venial et al., 2011). The major aim of this study was to determine the effects of deltamethrin on mortality, feeding behaviour and oviposition in the UK Culicoides species and at UK environmental temperatures. "

    Full-text · Article · Jun 2015
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    • "The objectives of this study were to determine if alphacypermethrin-treated high density polyethylene (HDPE) mesh applied to light traps will reduce the entry of Culicoides midges, particularly C. imicola, into the traps. Following on the promising results of Papadopoulos et al. (2010) with cypermethrin and the northern European C. nubeculosus, the in vitro insecticidal efficacy of alphacypermethrin-treated HDPE mesh against field populations of C. imicola was investigated. These results may support potential of alphacypermethrin-treated HDPE nets for protecting livestock against Culicoides midges, and be applicable to containerised transport systems of horses. "
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    ABSTRACT: The efficacy of untreated and alphacypermethrin-treated high density polyethylene (HDPE) mesh against Culicoides biting midges (Diptera: Ceratopogonidae) was determined using Onderstepoort downdraught black light traps and a contact bioassay. Three traps were operated overnight in four replicates of a 3 × 3 randomised Latin square design near horses under South African field conditions. Both the untreated and alphacypermethrin-treated HDPE mesh significantly (P < 0.05) reduced the numbers of Culicoides midges, predominantly Culicoides (Avaritia) imicola Kieffer, collected in the light traps by 4.2 and 7.2 times respectively. A repellent effect of the alphacypermethrin-treated mesh was not confirmed because the number of midges collected in the light traps with untreated and alphacypermethrin-treated HDPE mesh were not significantly different (P = 0.656). Bioassay of the insecticidal contact efficacy indicated median C. imicola mortality of 100% from 30 and 10 min following exposure to the alphacypermethrin-treated HDPE mesh for 1 or 3 min, respectively. In the bioassay, mortality was significantly higher (P = 0.016) at 5 min post exposure in the midges exposed to the alphacypermethrin-treated mesh for 3 min (74.8%) compared to the 1 min exposure group (59.5%). The HDPE mesh could be used to reduce exposure of housed animals to Culicoides midges, specifically C. imicola, and viruses transmitted by these midges. Mesh treated with alphacypermethrin had the additional benefit of a rapid insecticidal effect on C. imicola.
    Full-text · Article · Jun 2014 · Veterinary Parasitology
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    • "The susceptibility of Culicoides species to insecticides is poorly documented. Only a few publications describe the responses of some Culicoides species to organochlorines, 2 R. Del Río et al. organophosphates, carbamates and pyrethroids (Hill & Roberts, 1947; Kline & Roberts, 1981; Floore, 1985; Mehlhorn et al., 2008a, 2008b; Schmahl et al., 2009a, 2009b; Papadopoulos et al., 2010). "
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    ABSTRACT: ABSTRACT Culicoides Latreille (Diptera: Ceratopogonidae) are vectors of several arboviruses, including bluetongue virus (BTV) and African horse sickness virus (AHSV), which cause diseases in, respectively, sheep and cattle, and horses, and have economic repercussions mainly as a result of trade restrictions. Insecticides can be used to reduce vector populations and hence the spread of disease. Despite the economic importance of these diseases, relatively few studies have evaluated the efficacy of commercially available insecticides and the effectiveness of treated nets against Culicoides species. The aim of the present study was to evaluate the insecticidal effect of commercially available polyethylene nets (ZeroVector®) treated with deltamethrin (4.4 g/kg ± 15%) on Culicoides species. Laboratory and field trials were conducted in Culicoides populations collected in Majorca in the Balearic Islands, Spain. The present study shows that deltamethrin-treated nets provoke high and rapid mortality (90–100%) in Culicoides midges under laboratory conditions and increase mortality by 13% when deployed in the field.
    Full-text · Article · May 2014 · Medical and Veterinary Entomology
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