‘Alarming’ surge in bluetongue disease among UK sheep

Farmers advised to vaccinate after recent hot weather provides ideal conditions for virus-carrying midges

There has been an alarming surge in the number of sheep affected by an outbreak of bluetongue in the UK, and farmers whose livestock are at risk are being urged to move them out of areas where midges are plentiful.

The viral disease, which does not necessarily kill sheep but makes them ill and can have a long recovery time, presents as high fever and swelling of the lips and tongue. The tongue may go blue and even protrude from the mouth.

More than 590 cases were reported last week, according to the National Sheep Association (NSA).

The virus is transmitted via biting midges (culicoides) and its arrival in the UK is associated with global heating. The World Organisation for Animal Health reported in 2024 that although the virus had historically “been endemic in the tropics and subtropics where temperature and humidity are ideal for biting midge survival … it began to migrate to the Mediterranean basin and southern Europe in the late 1990s” and was first recorded in the UK in 2006.

The National Farmers’ Union vice-president, Robyn Munt, said: “Bluetongue is continuing to spread at an alarming rate and is a significant concern for livestock farmers across the country. The disease is creating additional uncertainty and financial pressures for many businesses, with members doing everything possible to protect their animals.

“To reduce the risk, farmers are moving high-risk or non-vaccinated stock away from wet, low-lying or sheltered areas and keeping vulnerable animals housed during dawn and dusk when midge activity peaks, all of which is added pressure on farmers and forage stocks during this challenging weather period.”

Dominic Elson, who farms sheep in Devon, said he lost one of his flock on Wednesday: “I was saying goodbye to a lovely old ewe that has been on the farm for over 10 years and it’s heartbreaking to see the bluetongue virus take her down.”

He said he had been frustrated by what he regards as the lack of preparedness of the Department for Environment, Food and Rural Affairs (Defra), and the failure of the self-reporting system. Farmers are required to report the disease but he said the phone line appeared to be overwhelmed and it was difficult to get through.

This might mean the numbers were being significantly underestimated, he said, pointing out that although the disease was not always fatal, an outbreak in the Netherlands led to the deaths of more than 4% of the national herd between September and December 2023.

“With the closure of the basic payments system and the reduction in budget available for agri-environment schemes, upland sheep farmers are already teetering on the brink,” Elson said. “This outbreak could push some over the edge.”

The NSA’s chief executive, Phil Stocker, said: “The number of reported cases shot up last week to over 590, from just 115 the previous week. The majority are being seen in the south-west of England – clearly a serious hotspot for this midge-borne virus. As you would expect, calls on stocks of vaccines are increasing and stocks will be reducing but we are assured that vaccine manufacturers are doing what they can to ensure demand can be met.”

He said there seemed to be some confusion over whether to vaccinate, given that full immunity took 28 days. He said: “A level of protection is likely to be reached earlier, particularly if stock were vaccinated last season. Additionally, we have several months of midge activity ahead of us and it is highly advisable that breeding males and females are vaccinated ahead of mating.”

A National Audit Office report last year said the UK may be underprepared for a serious animal disease outbreak. Stocker told Farmer’s Weekly that surveillance had successfully identified infected premises but testing only three animals on affected holdings meant the true scale of infection was unknown.

A spokesperson for Defra said: “We recognise this is an incredibly difficult time for animal keepers who are on the frontline of this disease, and we are monitoring the situation closely. We continue to work closely with industry representatives to ensure that keepers are kept up to date with developments and that issues and concerns are addressed promptly.”

An Animal and Plant Health Agency spokesperson said the virus was circulating in England, particularly the south-west, and parts of Wales . They said the recent hot and humid weather had been favourable for midge populations, which had probably contributed to the increased numbers of cases.

“Livestock keepers should remain vigilant and report any suspicions of disease to APHA,” the spokesperson said. “We encourage all farmers and keepers to discuss vaccination with their vet as this is the most effective way of protecting their animals.”