Irish livestock farmers face a heightened risk of bluetongue virus spread following the identification of a second case within a single week, according to the Department of Agriculture, Food and the Marine (DAFM). The latest infection was confirmed in an unvaccinated cow in a Co. Kildare herd, closely following a September case involving a heifer in Co. Wexford that marked the first local infection detected where the animal contracted the disease in 2026, Dr. Avril Hobson, senior superintending veterinary inspector with the National Disease Control Centre, told Agriland.
Infected Midges Blown Across the Irish Sea
Initial investigations by DAFM indicate that the Co. Kildare case stems from a recent infection driven by weather patterns. Dr. Hobson explained that the incident likely involves a fresh incursion of infected midges blown across the Irish Sea, mirroring the transmission pattern observed earlier in the year. Wales and south-west England are currently experiencing a significant number of cases, creating a much higher infection pressure than at the same point last year due to a larger population of infected midges. When wind conditions blow in a north-west direction, the risk of transmission to Irish livestock increases substantially.
Vaccination Rates and Surveillance Strategies
While DAFM noted a very high take-up in vaccination due to strong stakeholder collaboration, officials warn that unimmunized herds remain vulnerable. Dr. Hobson recommends that farmers who have not yet vaccinated their animals should consult their veterinarians or neighbors. According to official timelines, it takes six weeks to protect cattle and three weeks to fully protect sheep, with immunity lasting approximately 12 months. DAFM previously conducted routine surveillance through abattoirs—which successfully detected a BTV-3 case in a Co. Wexford suckler herd in January—though that specific meat factory testing was paused because vaccinated animals triggered antibody false positives, requiring a different blood test to confirm active viral infection.
Pro Tip: Bluetongue virus is spread by biting midges whose activity levels depend on average temperatures. While high-risk periods traditionally run from April to November, rising global temperatures and mild winter weather can extend transmission windows. Farmers are encouraged to submit unusual samples, including stillbirths, early births, weak calves, and deformed calves, to their local regional veterinary laboratory during the autumn calving period.
Impact on Flock Fertility and Breeding
The timing of the virus incursions poses specific threats to breeding stock during the autumn season. Dr. Hobson warned sheep farmers putting out rams that an infection in ewes or rams around this period can cause temporary infertility in rams and lead to detrimental effects on flock fertility. DAFM states that vaccination does not reduce fertility in ewes or cows, positioning the vaccine as an essential insurance policy against significant herd losses. Meanwhile, across the UK, the National Farmers’ Union (NFU) reported 517 total cases of bluetongue this year up to Thursday, urging South East farmers to vaccinate animals as soon as possible and house vulnerable stock during peak dawn and dusk midge activity.
Frequently Asked Questions
What are the clinical signs of bluetongue virus in livestock?
According to DAFM and the NFU, symptoms can include unexplained mortalities, stillbirths, early births, weak or deformed calves, abortions in cows, and temporary infertility in rams or bulls.
How is bluetongue transmitted between animals?
The virus is spread by biting midges of the Culicoides species. Weather conditions, particularly wind speed and direction, can carry infected midges across bodies of water like the Irish Sea.
Does bluetongue affect humans or food safety?
No, the NFU confirms that bluetongue virus does not affect humans or human food safety.
How long does the bluetongue vaccine take to work?
Dr. Hobson states that vaccination takes six weeks to protect cattle and three weeks to fully protect sheep, providing immunity that lasts for approximately 12 months.
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