Ticks Scotland: Vaccine research for tick-borne louping ill disease shows 'encouraging results'

The bacterial infection can affect many species, including humans, but is principally a problem for sheep and red grouse.

Work on a new vaccine for a tick-borne disease that can affect humans has shown encouraging results, with a prototype expected to enter commercial development soon.

Louping ill is a neurological disease caused by a virus that is transmitted by ticks.

It can affect many species, including humans, but is principally a problem for sheep and red grouse. The disease is a serious animal welfare and economic issue in upland and moorland areas where ticks thrive, with some farmers reporting devastating losses of up to 50 per cent.

A new vaccine for louping ill, which is principally an issue for sheep and red grouse, is showing encouraging results (pic: David Cheskin/PA)

And the prevalence of the disease is expected to increase as a result of the changing climate resulting in warmer and wetter habitats where the parasitic arachnids thrive. Areas where there is a high density of bracken are particularly bad.

Vaccinating sheep would protect against infection and also help to protect grouse as overall numbers of infected ticks would be reduced. A previous commercially available vaccine was withdrawn from sale in 2017 due to manufacturing difficulties.

Since then, hill sheep farmers and grouse estate managers have reported increased numbers of cases, but news of the vaccine has provided some hope this can be reversed.

Dr Beth Wells, of Moredun, a research institute committed to promoting livestock health and welfare, said: “Louping ill is now a very serious issue in many upland areas of the UK. We have had many reports from farmers who have suffered up to 50 per cent losses in replacement hogs, which is completely unsustainable.

"As well as a serious animal welfare issue, louping ill is also a devastating disease for the farmer to deal with, as when it hits a naïve flock that has not been exposed to the virus before. It can cause sudden and high losses.

"We have also had recent reports of cases in cattle, dogs, ponies and humans. We have an effective research vaccine – it is really critical that it becomes available to all who need it as soon as possible.”

The new vaccine was developed with funding from Scottish Government and Scottish estate owners, collated by the Game & Wildlife Conservation Trust, and is based on a new technology that will avoid the manufacturing issues of the previous vaccine.

In experimental trials, the new vaccine triggered a very strong immune response – antibodies against the virus – in the vaccinated sheep and protected them from clinical disease when challenged with the virus, most likely by preventing the virus from spreading to the brain.

The cost of bringing a new vaccine to market is very high, due to the stringent regulatory requirements that are in place to ensure safety and efficacy.

Although louping ill is a significant problem for sheep farmers and grouse moors in specific areas of the UK, the overall market size is relatively small compared to other livestock vaccines. This has deterred veterinary health companies from taking on production of the vaccine.

A spokesperson for Moredun said to get around this obstacle and move towards making the vaccine available as soon as possible, the commercial development would be undertaken by the research institute, working in partnership with several other agencies and companies.