Repository logo
 

Can insecticide-treated netting provide protection for Equids from Culicoides biting midges in the United Kingdom?


Change log

Authors

Baker, Tiffany 
Carpenter, Simon 
Gubbins, Simon 
Newton, Richard 
Lo Iacono, Giovanni 

Abstract

BACKGROUND: Biting midges of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) cause a significant biting nuisance to equines and are responsible for the biological transmission of African horse sickness virus (AHSV). While currently restricted in distribution to sub-Saharan Africa, AHSV has a history of emergence into southern Europe and causes one of the most lethal diseases of horses and other species of Equidae. In the event of an outbreak of AHSV, the use of insecticide treated nets (ITNs) to screen equine accomodation is recommended by competent authorities including the Office International des Épizooties (OIE) in order to reduce vector-host contact. METHODS: Seven commercially avaliable pyrethroid insecticides and three repellent compounds, all of which are licensed for amateur use, were assessed in modified World Health Organization (WHO) cone bioassay trials in the laboratory using a colony line of Culicoides nubeculosus (Meigen), 1830. Two field trials were subsequently conducted to test the efficiency of treated net screens in preventing entry of Culicoides. RESULTS: A formulation of cypermethrin (0.15 % w/w) and pyrethrins (0.2 % w/w) (Tri-Tec 14®, LS Sales (Farnham) Ltd, Bloxham, UK) applied to black polyvinyl-coated polyester insect screen (1.6 mm aperture; 1.6 mm thickness) inflicted 100 % mortality on batches of C. nubeculosus following a three minute exposure in the WHO cone bioassays at 1, 7 and 14 days post-treatment. Tri-Tec 14® outperformed all other treatments tested and was subsequently selected for use in field trials. The first trial demonstrated that treated screens placed around an ultraviolet light-suction trap entirely prevented Culicoides being collected, despite their collection in identical traps with untreated screening or no screening. The second field trial examined entry of Culicoides into stables containing horses and found that while the insecticide treated screens reduced entry substantially, there was still a small risk of exposure to biting. CONCLUSIONS: Screened stables can be utilised as part of an integrated control program in the event of an AHSV outbreak in order to reduce vector-host contact and may also be applicable to protection of horses from Culicoides during transport.

Description

Keywords

African Horse Sickness, African Horse Sickness Virus, Animals, Ceratopogonidae, Disease Outbreaks, Female, Horses, Insecticide-Treated Bednets, Insecticides, Male, Pyrethrins, United Kingdom

Journal Title

Parasit Vectors

Conference Name

Journal ISSN

1756-3305
1756-3305

Volume Title

8

Publisher

Springer Science and Business Media LLC
Sponsorship
European Commission (278976)
The work of LEH and GLI was supported by funding from the Horserace Betting Levy Board (HBLB) (Vet/PRJ/766); TR was supported by funding from the University of Surrey; and JW was supported by the Alborada Trust and by the European Union FP7 project ANTIGONE (contract number 278976). RN is supported through a combined contribution to the Animal Health Trust’s Equine Infectious Disease Service from the HBLB, the Racehorse Owners’ Association (ROA) and the Thoroughbred Breeders’ Association (TBA). The Pirbright Institute receives grant aided support from the Biotechnology and Biological Sciences Research Council of the United Kingdom.