Investigating Vectors Of Bluetongue

NORTHERN IRELAND, UK - Scientists at the Agri-Food and Biosciences Institute (AFBI) have initiated a DARD-funded surveillance programme to determine the geographical and seasonal distribution of biting midges (Culicoides spp.) that may potentially be involved in transmission of bluetongue virus should it reach the island of Ireland.
calendar icon 15 July 2010
clock icon 2 minute read

Since October 2007, the AFBI scientists have installed 19 light traps at 14 locations across Northern Ireland to gather information on the geographical and seasonal distribution of adult biting midges.

This network complements a similar study in the Republic of Ireland which involves 34 farm sites and provides a comprehensive database that will be used to develop mathematical models for analyses of Culicoides population dynamics and behaviour.

A number of Culicoides species from two complexes, C. obsoletus and C. pulicaris, have been recorded in large numbers during the surveillance programme. Among these are species that have potential to transmit bluetongue virus. Adult midge activity in Northern Ireland typically occurs from April to December, but with considerable regional and weekly variation which requires further analysis.

During December, adult midge activity declines, and a vector-free period is declared when fewer than five reproductive females are observed in traps. Resumption of adult activity typically occurs the following April.

The data collected from the AFBI monitoring programme are vital for the development of risk analyses, not only for the introduction of bluetongue but for other exotic vector-borne diseases such as African horse sickness.

In 2008, AFBI identified bluetongue virus in a batch of cattle that had been imported from continental Europe. The occurrence of this incident during the winter vector-free period facilitated DARD in preventing spread of the virus from the affected animals. As it has been estimated that a bite from a single infected midge is sufficient to infect a susceptible animal, importation of even one infected animal during the period of midge vector activity, could result in an outbreak of bluetongue that could be difficult to control.

Importation of livestock from a bluetongue affected area continues to represent a major risk of introduction of bluetongue to Northern Ireland, and the AFBI data on midge vectors indicate the potential for even one infected animal to cause significant economic damage to the agri-food industry.

TheCattleSite News Desk

© 2000 - 2024 - Global Ag Media. All Rights Reserved | No part of this site may be reproduced without permission.