- Ds RNA Orbivirus, 25 serotypes, causes vasculitis and often severe disease (OIE List A)
- Viraemia typically 3-5 days, but can persist for 30-60 days (sheep) or up to 100 days (cattle) which may enable overwintering and recrudescence.
- Transmission reliant on vector midge (Culicoides spp) or injection. No spread via meat, minor spread via germplasm.
- Outbreaks of two serotypes in Northern Europe, both involving novel species of Culicoides, have occurred much further north than previously, with the potential for future outbreaks
- There may be wildlife hosts
The disease is the result of primary vascular damage. There are no zoonotic implications. Disease can be from inapparent through to mild or severe. There is variability in species and breed susceptibility. Experience in Holland generally was of low morbidity and mortality, although in sheep deaths could reach 12%, and case fatality up to 50%.
- Ongoing voluntary vaccination policy in England and Wales; voluntary from 2010 in Scotland: see BVA web pages www.bva.co.uk/atoz/bluetongue.aspx, www.bva.co.uk/public/documents/nfu_bluetongue_poster.pdf
- Post-import surveillance (UK Protection Zone is currently confluent with mainland Europe)
- Report cases: if you suspect bluetongue, it must be reported to your local Animal Health Office
- Increased intensity winter surveillance 2009
- Post-mortem monitoring of young ruminants (VLA and SAC)
- The advice from BCVA, in line with BVA , Defra and industry, is to continue to promote vaccination against BTV8 as widely as possible to minimise the numbers of susceptible animals present
See the following web pages for more details: