Bluetongue: why 2026 is the year farmers need to take BTV-3 seriously
Bluetongue has moved firmly from being a disease that Great Britain’s livestock industry watched from a distance to one that farmers increasingly need to manage as part of everyday herd and flock health.
The current threat is predominantly bluetongue virus serotype 3 (BTV-3). Following its emergence in Great Britain, the virus has demonstrated its ability to spread when conditions favour its Culicoides midge vectors. The 2026 season has again highlighted the challenge, with continuing cases across England and Wales and disease also now affecting Scotland. For farmers, the message is increasingly one of preparedness rather than waiting for disease to arrive at the farm gate.
Bluetongue is a viral disease affecting ruminants, including sheep and cattle. It is transmitted principally by infected biting midges rather than by direct animal-to-animal contact. That makes bluetongue very different from many of the infectious diseases livestock keepers are accustomed to managing. An apparently healthy animal can become infected, and a biting midge can then acquire the virus and transmit it to another animal.
Sheep are generally the species in which the most obvious clinical disease is seen. Signs can include fever, depression, swelling of the head and lips, drooling, nasal discharge, mouth lesions and lameness. Severe disease can result in death. In contrast, cattle often serve as silent carriers of the virus, showing far milder signs such as slight fever or lameness. While they may not always display the dramatic symptoms seen in sheep, cattle act as reservoirs, contributing to the continued circulation of the virus in the environment and are often the preferred host for biting midges.
Why 2026 matters
The continuing appearance of BTV-3 cases during 2026 demonstrates that the virus is not simply an isolated incursion that can be dealt with and forgotten. The epidemiology of bluetongue is closely linked to its vector. Warm conditions encourage midge activity and allow the virus to replicate within the insect. Wind can also assist the movement of infected midges over considerable distances. That therefore means disease risk can change quickly. The result is a disease situation in which the location of a farm alone does not necessarily tell the whole story. A farm that has remained unaffected may still face a significant risk if infected midges move into the area or infected livestock are introduced. For farmers, this makes regular monitoring of government disease updates and local veterinary advice an important part of managing the risk.
The economic damage caused by Bluetongue can be immense, beyond the loss of productivity or animal welfare concerns. Restrictions on animal movement, essential in controlling the disease, can severely disrupt trade, affecting livestock sales, breeding, and farming operations across the board.
Vaccination moves up the agenda
One of the biggest changes in the UK’s approach to BTV-3 has been the development and authorisation of vaccines specifically targeting the serotype. There are currently three BTV-3 vaccines authorised for use in Great Britain: Bluevac-3, BULTAVO 3 and Syvazul BTV 3. They are authorised for use in sheep and cattle, although their individual claims differ. Farmers should not assume that all three products offer exactly the same protection. The choice of vaccine should therefore be made with the farm’s circumstances, vaccine availability and the product information in mind, ideally as part of a discussion with their vet.
For sheep producers, vaccination can be particularly attractive because of the potential severity of BTV-3 disease. A flock affected during a period of high vector activity can face sick animals, deaths, reduced performance and disruption to normal management. The challenge is that vaccination needs to be planned ahead of time. Depending on the product and vaccination programme, animals may need one or more doses before they develop the intended level of immunity. Farmers therefore need to work backwards from periods of anticipated risk rather than treating vaccination as an emergency response once clinical disease is already present. That is particularly relevant to breeding flocks. The timing of vaccination needs to take account of the production system, lambing, housing, movement and exposure risk.
Cattle producers should not assume that because their animals are showing little or no clinical disease, BTV-3 is of little consequence. Infection with BTV-3 in pregnant cattle can cause significant reproductive failure, foetal abnormalities and birth defects. Cattle can develop viraemia while appearing relatively normal. That makes cattle an important component of the transmission cycle. Vaccination may therefore have a role not simply in protecting individual cattle but in reducing viraemia, depending on the vaccine used. For pedigree herds, suckler enterprises and dairy farms, the decision will depend on factors including local risk, animal value, breeding programme, movements and the likely consequences of infection.
Vaccination doesn’t replace biosecurity or testing. Farmers still need to watch animals for clinical signs and report suspected disease. Testing remains an important component of surveillance and livestock movement controls.
Perhaps the biggest change brought by BTV-3 is the need to think about bluetongue as an ongoing livestock-health risk rather than a one-off exotic disease emergency. The combination of susceptible livestock, competent midge vectors and suitable weather means that outbreaks can develop rapidly. Climate and weather patterns will continue to influence the risk, while animal movements and the introduction of infected livestock can add further complexity. Vaccination provides farmers with an important additional layer of protection. But it’s value is greatest when it is part of a wider plan. For many farms, that means incorporating BTV-3 into the annual health-planning conversation alongside diseases such as clostridial disease, enzootic abortion, pneumonia and parasitic disease.
The practical question is no longer simply “Is bluetongue coming?” For many livestock businesses, it is “What level of risk are we prepared to accept, and what can we do now to reduce its impact?”. With three authorised BTV-3 vaccines available in Great Britain, farmers have more options than they did at the beginning of the current outbreak. The challenge now is making informed decisions about vaccination, timing and animal movements before the next wave of transmission arrives.
Bluetongue may be transmitted by a tiny insect, but its consequences can be significant. For livestock keepers, preparation remains the most powerful tool! Veterinary surgeons must remain at the forefront of this effort, leading the charge in surveillance, prevention, and education and we want to do everything we can to support them. Together with farmers, regulators, and researchers, we can ensure that the UK’s livestock remains resilient against the threat of Bluetongue.
Call or email our customer enquiries team to discuss vaccine availability and ordering on 01387 262626/enquiries@covetrus.com.
Hazel Clark
BVMS MRCVS Reg: 7068956