Bluetongue virus – what is the latest situation?

Wednesday, 7 February 2024

Defra has announced that we are in a seasonally vector low period when midge activity is much lower, leading to some changes to disease control measures for the strain of bluetongue virus (BTV) currently being found in northern Europe and the UK.

However, with lambing and spring calving well underway, it is important to look out for signs of BTV and other viruses such as Schmallenberg and bovine viral diarrhoea (BVD), which can cause abortions and birth defects.

BTV-3 is the new strain of bluetongue currently being found in northern Europe and the UK and is mainly transmitted via biting midge, affecting cattle, goats, sheep, deer and camelids such as llamas.

“The current weather conditions and time of year mean that Culicoides – the type of midge able to spread viruses such as BTV-3 – are highly unlikely to transmit the virus to livestock”, explains Dr Marion England, Institute Fellow in Vector Ecology at The Pirbright Institute.

“Under these conditions, midges previously infected with BTV-3 are currently highly unlikely to transmit the virus.

“The most active period for midges is during the warmer months in spring, summer and autumn, and midges can become newly infected with bluetongue virus and spread disease when the weather is above 12°C for a sustained period.

“Midges infected in late autumn 2023 are now not likely to be a risk for spreading disease because they usually die off during winter, and are not actively biting when temperatures are below 4°C”, adds Dr England.

Because of the reduced risk of transmission between midges and animals, Defra has taken the decision not to cull infected animals where test results indicate older infection and the presence of BTV-3 antibodies.

Infected animals may still be restricted at their current locations and other disease mitigation measures taken as appropriate.

The reduced risk from midges means that some restrictions on movements of live animals from the temporary control zones (TCZ) can now be eased if they meet certain conditions, including testing negative in a pre-movement test; a licence is required.

Some restrictions on movements of animals into and within the TCZ have also been eased.

For the latest update on BTV-3 and restrictions please visit the Ruminant Health and Welfare bluetongue hub that contains the most up to date information and signposts all of Defra and APHA’s latest updates:

Surveillance of susceptible animals and epidemiological assessments within the TCZ will continue and Defra will keep the situation under review.

The advice from Ruminant Health and Welfare remains three-fold: farmers need to be aware, take action to report any signs, and remain vigilant.

Farmers can call the dedicated bluetongue hotline (024 7771 0386) to get advice or ask questions linked to the current situation.

In the UK, bluetongue, including BTV-3, is a notifiable disease, so anyone suspecting the disease must take action and report it to the Animal and Plant Health Agency (APHA).

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