Midges - The Source of Bluetongue and Schmallenberg

ANALYSIS - Midges are responsible for spreading bluetongue, as they are suspected of carrying the newly found Schmallenberg virus, reports Charlotte Johnston, TheCattleSite editor, which makes it hard to prevent disease outbreaks.

15 February 2012

2 minute read

Farmers in the EU will now be allowed to vaccinate livestock against bluetongue.

The EU passed legislation that will allow farmers outside the exclusion zones to use newly developed inactivated vaccines.

In the past this was restricted because of the risk of live vaccines spreading the disease.

It is hoped that the legislation will be passed in time for the 2012 vaccination campaign.

Midges are responsible for spreading bluetongue, as they are suspected of carrying the newly found Schmallenberg virus.

Reports of signs in cattle in the Netherlands and Germany at the end of last year led to scientists at the Friedrich Loeffler Institute in Germany isolating and sequencing viral genetic material from clinically ill cattle and identifying this new virus.

Since then there have been reports of deformities in newborn ruminants (sheep, cattle and goats) in Germany, the Netherlands, Belgium, France and more recently, the UK.

The virus is not contagious from one animal to another, but is transmitted by insects and presents no harm to human health.

On the back of this outbreak, Russia has banned all imports of cattle and beef, including genetic material. European officials have stated that the trade restrictions are unnecessary, but the Russian veterinary authority, Rosselkhoznadzor, has said that it is seriously concerned by the absence of measures to limit animal movements from affected regions.

As of yet the disease it not notifiable, which explains the reasoning that there are no trade restrictions in place. However, industry associations are advising farmers to consider the risks carefully before importing livestock from affected areas.

Because this disease is spread by midges, flies and other insects it is hard to control. Culling infected animals would be ineffective in stopping the disease spread as the virus is in the insect population.

It has taken over two years to develop an effective bluetongue vaccine, and it would take a similar amount of time to develop one for Schmallenberg. Laboratories and vaccine manufacturers in the EU are considering whether it may be possible and effective to develop a vaccine in the future.

The development of a vaccine from inception to market costs a lot of money and vaccine manufacturers must be satisfied that there is enough demand to justify the costs. They are monitoring the situation closely.