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Allan J, Van Winden S. Randomised Control Trial Comparing Cypermethrin-Based Preparations in the Prevention of Infectious Bovine Keratoconjunctivitis in Cattle. Animals (Basel) 2020; 10:ani10020184. [PMID: 31978947 PMCID: PMC7070671 DOI: 10.3390/ani10020184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 11/24/2022] Open
Abstract
Simple Summary Infectious bovine keratoconjunctivitis (IBK) caused by the bacteria Moraxella bovis is commonly seen in the summer months spread by face flies causing a painful eye disease. This trial investigated the difference in number of cases of IBK between two groups of animals that were treated with two different fly control products, one a pour-on and one an impregnated ear tag. The growth rate per day was also investigated between animals with cases and those without and between the treatment groups. The trial enrolled 197 animals. Cases of IBK and growth rate were recorded over the grazing season (April–November 2018). Fifty-four cases of IBK were recorded. There was no difference in number of cases between the two treatment groups and there was no difference in growth rate between animals that had a case and animals that had not. Animals that had white faces, which in this trial were Hereford cattle and also the animals under 12 months old were found to be more likely to get a case. Overall, there was no significant difference between the two fly control preparations in preventing IBK, younger animals and white-faced breeds are significantly more likely to suffer from IBK. Abstract Infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis is commonly seen in the summer months spread by face flies. This trial investigated the difference in incidence of IBK cases from natural exposure between two groups of animals, one treated with Cypermethrin pour-on preparation (PON, n = 98) and one with Cypermethrin impregnated ear tags (TAG, n = 99). Daily Live Weight Gain (DLWG) difference was investigated between animals with cases and those without and between treatment groups. A randomised positive control study, enrolled 197 animals split into two treatment groups. Cases of IBK and DLWG were recorded over the grazing season (April–November 2018). Fifty-four cases of IBK were recorded. There was no association between the two treatment groups (p = 0.362) and case status. Breed and under 12 months old were significant factors for having a case; (OR 2.3, p = 0.014 and OR 3.5, p < 0.001 respectively). There was no difference in DLWG between animals that had a case and animals that had not (p = 0.739) or between the two treatment groups (p = 0.215). Based on our results, there is no significant difference between PON or TAG preparations in the prevention of IBK. Younger animals and white-faced breeds are significantly more likely to suffer with IBK.
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Affiliation(s)
- Jennifer Allan
- The Royal Veterinary College, Regional Veterinary Centre South of England, Stinsford Business Centre, Kingston Maurward College, Dorchester DT2 8PY, UK
- Correspondence:
| | - Steven Van Winden
- Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK;
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White SM, Sanders CJ, Shortall CR, Purse BV. Mechanistic model for predicting the seasonal abundance of Culicoides biting midges and the impacts of insecticide control. Parasit Vectors 2017; 10:162. [PMID: 28347327 PMCID: PMC5369195 DOI: 10.1186/s13071-017-2097-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/20/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Understanding seasonal patterns of abundance of insect vectors is important for optimisation of control strategies of vector-borne diseases. Environmental drivers such as temperature, humidity and photoperiod influence vector abundance, but it is not generally known how these drivers combine to affect seasonal population dynamics. METHODS In this paper, we derive and analyse a novel mechanistic stage-structured simulation model for Culicoides biting midges-the principle vectors of bluetongue and Schmallenberg viruses which cause mortality and morbidity in livestock and impact trade. We model variable life-history traits as functional forms that are dependent on environmental drivers, including air temperature, soil temperature and photoperiod. The model is fitted to Obsoletus group adult suction-trap data sampled daily at five locations throughout the UK for 2008. RESULTS The model predicts population dynamics that closely resemble UK field observations, including the characteristic biannual peaks of adult abundance. Using the model, we then investigate the effects of insecticide control, showing that control strategies focussing on the autumn peak of adult midge abundance have the highest impact in terms of population reduction in the autumn and averaged over the year. Conversely, control during the spring peak of adult abundance leads to adverse increases in adult abundance in the autumn peak. CONCLUSIONS The mechanisms of the biannual peaks of adult abundance, which are important features of midge seasonality in northern Europe and are key determinants of the risk of establishment and spread of midge-borne diseases, have been hypothesised over for many years. Our model suggests that the peaks correspond to two generations per year (bivoltine) are largely determined by pre-adult development. Furthermore, control strategies should focus on reducing the autumn peak since the immature stages are released from density-dependence regulation. We conclude that more extensive modelling of Culicoides biting midge populations in different geographical contexts will help to optimise control strategies and predictions of disease outbreaks.
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Affiliation(s)
- Steven M White
- Centre for Ecology & Hydrology, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK. .,Wolfson Centre for Mathematical Biology, Mathematical Institute, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK.
| | | | | | - Bethan V Purse
- Centre for Ecology & Hydrology, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK
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Abstract
The performance of different bluetongue control measures related to both vaccination and protection from bluetongue virus (BTV) vectors was assessed. By means of a mathematical model, it was concluded that when vaccination is applied on 95% of animals even for 3 years, bluetongue cannot be eradicated and is able to re‐emerge. Only after 5 years of vaccination, the infection may be close to the eradication levels. In the absence of vaccination, the disease can persist for several years, reaching an endemic condition with low level of prevalence of infection. Among the mechanisms for bluetongue persistence, the persistence in the wildlife, the transplacental transmission in the host, the duration of viraemia and the possible vertical transmission in vectors were assessed. The criteria of the current surveillance scheme in place in the EU for demonstration of the virus absence need revision, because it was highlighted that under the current surveillance policy bluetongue circulation might occur undetected. For the safe movement of animals, newborn ruminants from vaccinated mothers with neutralising antibodies can be considered protected against infection, although a protective titre threshold cannot be identified. The presence of colostral antibodies interferes with the vaccine immunisation in the newborn for more than 3 months after birth, whereas the minimum time after vaccination of animal to be considered immune can be up to 48 days. The knowledge about vectors ecology, mechanisms of over‐wintering and criteria for the seasonally vector‐free period was updated. Some Culicoides species are active throughout the year and an absolute vector‐free period may not exist at least in some areas in Europe. To date, there is no evidence that the use of insecticides and repellents reduce the transmission of BTV in the field, although this may reduce host/vector contact. By only using pour‐on insecticides, protection of animals is lower than the one provided by vector‐proof establishments. This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2017.EN-1182/full, http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2017.EN-1171/full
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Crilly JP, Nuttall T, Del Pozo J, Hopker A, Tomlinson M, Sargison N. Hypersensitivity to Culicoides midges causing seasonal dermatitis in sheep. VETERINARY PARASITOLOGY- REGIONAL STUDIES AND REPORTS 2016; 3-4:53-56. [PMID: 31014500 DOI: 10.1016/j.vprsr.2016.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 11/24/2022]
Abstract
Culicoides midges are important as vectors of disease, as an irritant with severe effects on human outdoor activities in certain areas and as the cause of insect bite hypersensitivity in domestic animals (most notably horses). Here we report, for the first time, the confirmation of ovine hypersensitivity to Culicoides midges in Hebridean sheep suffering from seasonal allergic skin disease using intradermal allergen testing. The affected sheep formed 40% of the adults in the small flock, and this indication of a potentially high prevalence of a condition with welfare implications is of concern.
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Affiliation(s)
- James Patrick Crilly
- Farm Animal Practice, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.
| | - Tim Nuttall
- Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Jorge Del Pozo
- Easter Bush Pathology, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Andy Hopker
- Farm Animal Practice, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Martin Tomlinson
- Farm Animal Practice, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
| | - Neil Sargison
- Farm Animal Practice, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK
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Pfannenstiel RS, Mullens BA, Ruder MG, Zurek L, Cohnstaedt LW, Nayduch D. Management of North American Culicoides Biting Midges: Current Knowledge and Research Needs. Vector Borne Zoonotic Dis 2016; 15:374-84. [PMID: 26086558 DOI: 10.1089/vbz.2014.1705] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Culicoides biting midges (Diptera: Ceratopogonidae) are biological vectors of two important viruses impacting North American ruminants--bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). These viruses have been identified for over 60 years in North America, but we still lack an adequate understanding of the basic biology and ecology of the confirmed vector, Culicoides sonorensis, and know even less about other putative Culicoides vector species. The major gaps in our knowledge of the biology of Culicoides midges are broad and include an understanding of the ecology of juveniles, the identity of potential alternate vector species, interactions of midges with both pathogens and vertebrates, and the effectiveness of potential control measures. Due to these broad and numerous fundamental knowledge gaps, vector biologists and livestock producers are left with few options to respond to or understand outbreaks of EHD or BT in North America, or respond to emerging or exotic Culicoides-transmitted pathogens. Here we outline current knowledge of vector ecology and control tactics for North American Culicoides species, and delineate research recommendations aimed to fill knowledge gaps.
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Affiliation(s)
- Robert S Pfannenstiel
- 1 Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service , Manhattan, Kansas
| | - Bradley A Mullens
- 2 Department of Entomology, University of California-Riverside , Riverside, California
| | - Mark G Ruder
- 1 Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service , Manhattan, Kansas
| | - Ludek Zurek
- 3 Department of Entomology, Kansas State University , Manhattan, Kansas
| | - Lee W Cohnstaedt
- 1 Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service , Manhattan, Kansas
| | - Dana Nayduch
- 1 Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service , Manhattan, Kansas
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Reconstruction of the Schmallenberg virus epidemic in Belgium: Complementary use of disease surveillance approaches. Vet Microbiol 2016; 183:50-61. [DOI: 10.1016/j.vetmic.2015.11.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 11/19/2015] [Accepted: 11/27/2015] [Indexed: 01/06/2023]
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Venail R, Lhoir J, Fall M, del Río R, Talavera S, Labuschagne K, Miranda M, Pagès N, Venter G, Rakotoarivony I, Allène X, Scheid B, Gardès L, Gimonneau G, Lancelot R, Garros C, Cêtre-Sossah C, Balenghien T, Carpenter S, Baldet T. How do species, population and active ingredient influence insecticide susceptibility in Culicoides biting midges (Diptera: Ceratopogonidae) of veterinary importance? Parasit Vectors 2015; 8:439. [PMID: 26310789 PMCID: PMC4551713 DOI: 10.1186/s13071-015-1042-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 08/12/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Culicoides biting midges are biological vectors of internationally important arboviruses of livestock and equines. Insecticides are often employed against Culicoides as a part of vector control measures, but systematic assessments of their efficacy have rarely been attempted. The objective of the present study is to determine baseline susceptibility of multiple Culicoides vector species and populations in Europe and Africa to the most commonly used insecticide active ingredients. Six active ingredients are tested: three that are based on synthetic pyrethroids (alpha-cypermethrin, deltamethrin and permethrin) and three on organophosphates (phoxim, diazinon and chlorpyrifos-methyl). METHODS Susceptibility tests were conducted on 29,064 field-collected individuals of Culicoides obsoletus Meigen, Culicoides imicola Kieffer and a laboratory-reared Culicoides nubeculosus Meigen strain using a modified World Health Organization assay. Populations of Culicoides were tested from seven locations in four different countries (France, Spain, Senegal and South Africa) and at least four concentrations of laboratory grade active ingredients were assessed for each population. RESULTS The study revealed that insecticide susceptibility varied at both a species and population level, but that broad conclusions could be drawn regarding the efficacy of active ingredients. Synthetic pyrethroid insecticides were found to inflict greater mortality than organophosphate active ingredients and the colony strain of C. nubeculosus was significantly more susceptible than field populations. Among the synthetic pyrethroids, deltamethrin was found to be the most toxic active ingredient for all species and populations. CONCLUSIONS The data presented represent the first parallel and systematic assessment of Culicoides insecticide susceptibility across several countries. As such, they are an important baseline reference to monitor the susceptibility status of Culicoides to current insecticides and also to assess the toxicity of new active ingredients with practical implications for vector control strategies.
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Affiliation(s)
| | - Jonathan Lhoir
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | - Moussa Fall
- Institut sénégalais de recherches agricoles (ISRA), BP 1386, Dakar, Senegal.
| | - Ricardo del Río
- Laboratory of Zoology, University of the Balearic Islands (UIB), Km 7.5, Palma de Mallorca, Spain.
| | - Sandra Talavera
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
| | - Karien Labuschagne
- Agricultural Research Council - ARC- Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110, Republic of South Africa.
| | - Miguel Miranda
- Laboratory of Zoology, University of the Balearic Islands (UIB), Km 7.5, Palma de Mallorca, Spain.
| | - Nonito Pagès
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
| | - Gert Venter
- Agricultural Research Council - ARC- Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110, Republic of South Africa.
| | | | - Xavier Allène
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | | | - Laëtitia Gardès
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | - Geoffrey Gimonneau
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
- Institut sénégalais de recherches agricoles (ISRA), BP 1386, Dakar, Senegal.
| | - Renaud Lancelot
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | - Claire Garros
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | | | - Thomas Balenghien
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
| | - Simon Carpenter
- The Pirbright Institute, Vector-borne Viral Disease Programme, Woking, GU24 0NF, UK.
| | - Thierry Baldet
- Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.
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Bauer B, Baumann MPO. Laboratory evaluation of efficacy and persistence of a 1% w/w fipronil pour-on formulation (Topline®) against Glossina palpalis gambiensis, Diptera: Glossinidae. Parasitol Res 2015; 114:2919-23. [PMID: 25944739 PMCID: PMC4513204 DOI: 10.1007/s00436-015-4493-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/20/2015] [Indexed: 12/02/2022]
Abstract
One zebu bull of 365 kg live weight was treated along the back line with 36 mL of fipronil as a pour-on formulation. Long-lasting mortalities of Glossina palpalis gambiensis were recorded despite exposure to sunlight and regular rinsing with 50 L of water during the following 5 months. Significantly higher mortalities were still observed even 140, 170 and 190 days after treatment following their triple releases or triple feeding of caged tsetse on the treated bull. Mortalities of 70, 80 and 44 %, respectively, were recorded after 15 days of observation. This contrasted with the mortalities of control flies that were released in the presence of the untreated bull or fed in cages on the animal, amounting to 20 and twice 10 % after 170 and 190 days. The feeding successes of the released or caged flies were higher than 95 % and did not differ between control and experimental groups, indicating no repulsive or irritant effects of fipronil. The findings of this study are discussed, particularly in view of the potential of fipronil as an effective means for tsetse control.
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Affiliation(s)
- B Bauer
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Robert-von-Ostertagstr. 7-13, Berlin, 14163, Germany,
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Robin M, Archer D, McGowan C, Garros C, Gardès L, Baylis M. Repellent effect of topical deltamethrin on blood feeding by Culicoides on horses. Vet Rec 2015; 176:574. [PMID: 25948630 DOI: 10.1136/vr.102800] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2015] [Indexed: 11/04/2022]
Abstract
African horse sickness (AHS) is a vectorborne disease spread by Culicoides biting midges. The UK's Department for Environment, Food and Rural Affairs currently suggests using topical deltamethrin for AHS control; however, no data are available regarding its efficacy in the horse. The aims of this study were to investigate the effect of topical deltamethrin on blood feeding by Culicoides on horses and to investigate which Culicoides species blood fed on horses. Three pairs of horses were placed in partially enclosed cages that allowed samples representing the Culicoides interacting with individual horses to be sampled. Four data collection sessions were completed before one horse from each pair was topically treated with 10 ml of 1 per cent deltamethrin solution and another four sessions were then carried out. Collected Culicoides were identified and each biting midge examined to see if it had blood fed. The most abundant species collected were C. chiopterus, C. dewulfi, C. obsoletus and C. scoticus (44.3 per cent) and either C. pulicaris or C. punctatus (34.7 per cent). These species were also more likely to have blood fed than other species, supporting their potential role as AHS vectors if the virus were to reach the UK. There was no significant effect of treatment on blood feeding by Culicoides. The results do not support the use of topical deltamethrin to prevent blood feeding by Culicoides on individual horses; however, the study does not investigate the effect that the widespread use of topical deltamethrin might have on vector numbers or disease transmission from viraemic individuals during an outbreak of AHS.
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Affiliation(s)
- M Robin
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Chester High Road, Neston, Cheshire CH64 7TE, UK
| | - D Archer
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Chester High Road, Neston, Cheshire CH64 7TE, UK
| | - C McGowan
- Faculty of Health and Life Sciences, Institute of Ageing and Chronic Disease, University of Liverpool, Leahurst, Chester High Road, Neston, Cheshire CH64 7TE, UK
| | - C Garros
- Cirad, UMR15 CMAEE, INRA UMR1309 CMAEE, Montpellier, France
| | - L Gardès
- Cirad, UMR15 CMAEE, INRA UMR1309 CMAEE, Montpellier, France
| | - M Baylis
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Chester High Road, Neston, Cheshire CH64 7TE, UK NIHR Health Protection Research Unit, Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
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González M, Venter GJ, López S, Iturrondobeitia JC, Goldarazena A. Laboratory and field evaluations of chemical and plant-derived potential repellents against Culicoides biting midges in northern Spain. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:421-431. [PMID: 25079042 DOI: 10.1111/mve.12081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/18/2014] [Accepted: 03/27/2014] [Indexed: 06/03/2023]
Abstract
The efficacy of 23 compounds in repelling Culicoides biting midges (Diptera: Ceratopogonidae), particularly Culicoides obsoletus (Meigen) females, was determined by means of a Y-tube olfactometer. The 10 most effective compounds were further evaluated in landing bioassays. The six most promising compounds (including chemical and plant-derived repellents) were evaluated at 10% and 25% concentrations in field assays using Centers for Disease Control (CDC) light traps. At least three compounds showed promising results against Culicoides biting midges with the methodologies used. Whereas olfactometer assays indicated DEET at 1 µg/µL to be the most effective repellent, filter paper landing bioassays showed plant-derived oils to be better. Light traps fitted with polyester mesh impregnated with a mixture of octanoic, decanoic and nonanoic fatty acids at 10% and 25% concentrations collected 2.2 and 3.6 times fewer midges than control traps and were as effective as DEET, which is presently considered the reference standard insect repellent. The best plant-derived product was lemon eucalyptus oil. Although these have been reported as safe potential repellents, the present results indicate DEET and the mixture of organic fatty acids to be superior and longer lasting.
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Affiliation(s)
- M González
- Entomology Laboratory, Basque Institute of Agricultural Research and Development, NEIKER-TECNALIA, Vitoria, Spain
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Venter G, Labuschagne K, Boikanyo S, Morey L, Snyman M. The repellent effect of organic fatty acids on Culicoides midges as determined with suction light traps in South Africa. Vet Parasitol 2011; 181:365-9. [DOI: 10.1016/j.vetpar.2011.04.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 04/13/2011] [Accepted: 04/20/2011] [Indexed: 10/18/2022]
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12
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Venail R, Mathieu B, Setier-Rio ML, Borba C, Alexandre M, Viudes G, Garros C, Allene X, Carpenter S, Baldet T, Balenghien T. Laboratory and field-based tests of deltamethrin insecticides against adult Culicoides biting midges. JOURNAL OF MEDICAL ENTOMOLOGY 2011; 48:351-357. [PMID: 21485373 DOI: 10.1603/me10178] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bluetongue virus (BTV) is an economically important arbovirus of ruminants transmitted by Culicoides biting midges. Vector control using residual spraying or application to livestock is recommended by many authorities to reduce BTV transmission; however, the impact of these measures in terms of both inflicting mortality on Culicoides and subsequently upon BTV transmission is unclear. This study consisted of a standardized World Health Organization laboratory assay to determine the susceptibility of European Culicoides species to deltamethrin and a field trial based upon allowing individuals of a laboratory strain of Culicoides nubeculosus Meigen to feed upon sheep treated with Butox 7.5 pour-on (a deltamethrin-based topical formulation). Susceptibility in the laboratory trial was higher in colony C. nubeculosus (24-h LC90 = 0.00106%), than in field populations of Culicoides obsoletus Meigen (24-h LC90 = 0.00203%) or Culicoides imicola Kieffer (24-h LC90 = 0.00773%). In the field, the pour-on formulation was tested with a total of 816 C. nubeculosus specimens fed upon on the thigh of treated sheep. The study revealed a maximum mortality rate of 49% at 4 d postapplication, and duration of lethal effect was predicted to be as short as 10 d, despite testing being carried out with a highly susceptible strain. The reasons for this low efficacy are discussed with reference both to the potential for lack of spread of the active ingredient on the host and feeding patterns of the major potential vector species on the sheep host. Practical implications for vector control strategies during BTV incursions are also detailed.
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Affiliation(s)
- R Venail
- Entente Interdépartementale pour la Démoustication dulittoral méditerranéen (EID Méditerranée), 165 avenue Paul-Rimbaud, 34184 Montpellier Cedex 4, France.
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Ansari MA, Pope EC, Carpenter S, Scholte EJ, Butt TM. Entomopathogenic fungus as a biological control for an important vector of livestock disease: the Culicoides biting midge. PLoS One 2011; 6:e16108. [PMID: 21264343 PMCID: PMC3018483 DOI: 10.1371/journal.pone.0016108] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 12/08/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The recent outbreak of bluetongue virus in northern Europe has led to an urgent need to identify control measures for the Culicoides (Diptera: Ceratopogonidae) biting midges that transmit it. Following successful use of the entomopathogenic fungus Metarhizium anisopliae against larval stages of biting midge Culicoides nubeculosus Meigen, we investigated the efficacy of this strain and other fungi (Beauveria bassiana, Isaria fumosorosea and Lecanicillium longisporum) as biocontrol agents against adult C. nubeculosus in laboratory and greenhouse studies. METHODOLOGY/FINDINGS Exposure of midges to 'dry' conidia of all fungal isolates caused significant reductions in survival compared to untreated controls. Metarhizium anisopliae strain V275 was the most virulent, causing a significantly decrease in midge survival compared to all other fungal strains tested. The LT(50) value for strain V275 was 1.42 days compared to 2.21-3.22 days for the other isolates. The virulence of this strain was then further evaluated by exposing C. nubeculosus to varying doses (10(8)-10(11) conidia m(-2)) using different substrates (horse manure, damp peat, leaf litter) as a resting site. All exposed adults were found to be infected with the strain V275 four days after exposure. A further study exposed C. nubeculosus adults to 'dry' conidia and 'wet' conidia (conidia suspended in 0.03% aq. Tween 80) of strain V275 applied to damp peat and leaf litter in cages within a greenhouse. 'Dry' conidia were more effective than 'wet' conidia, causing 100% mortality after 5 days. CONCLUSION/SIGNIFICANCE This is the first study to demonstrate that entomopathogenic fungi are potential biocontrol agents against adult Culicoides, through the application of 'dry' conidia on surfaces (e.g., manure, leaf litter, livestock) where the midges tend to rest. Subsequent conidial transmission between males and females may cause an increased level of fungi-induced mortality in midges thus reducing the incidence of disease.
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Papadopoulos E, Rowlinson M, Bartram D, Carpenter S, Mellor P, Wall R. Treatment of horses with cypermethrin against the biting flies Culicoides nubeculosus, Aedes aegypti and Culex quinquefasciatus. Vet Parasitol 2010; 169:165-71. [DOI: 10.1016/j.vetpar.2009.12.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 12/01/2009] [Accepted: 12/16/2009] [Indexed: 11/29/2022]
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