Louping Ill

Louping ill is a pretty potent virus, particularly to young Red Grouse, but it also affects (and therefore is hosted) by a wide range of other animals, including all deer, white (mountain) hares and sheep, to name a few. It is spread by sheep tick and the only known way currently of controlling louping ill, is to limit the number of tick on any Moor. Whilst it is perfectly possible to have high tick numbers and no louping ill, in reality, the two tend to go side by side and with high tick numbers, small pockets of louping ill can quickly spread across the whole of the Moorland Estate. When this occurs, Grouse suffer badly, with up to 85% of infected young Grouse dying.

Until 2017, it was possible to buy a vaccine for sheep against louping ill. Basically, this prevented those sheep which were properly vaccinated, from being a reservoir of blood infected with louping ill, which when ticks attach themselves, they were able to get a blood feed from which was contaminated by the louping ill virus. Over many years, it was found that the most effective way of controlling louping ill (and when it was at a high incidence, reducing its reach), was to have a combination of the right number of “treated” (with acaracides) sheep which were also vaccinated against louping ill, properly raking out over the whole Moorland area. It is these sheep treated with the acaracide (Dysect or Crovect in the main), which killed the tick. Unfortunately, that all came to an end once the louping ill vaccine was no longer available (due to it being a “live” vaccine and therefore having potential health issues to humans manufacturing it). This means that there are now no sheep on the UK’s Moors, which have been injected with the louping ill vaccine and hence all of those sheep on the Moors in the North of England and Scotland are potential reservoirs of blood infected with louping ill. Louping ill does adversely affect the health of sheep, particularly lambs at high rates, but it is its disastrous effect on young Grouse, which is of most concern.

“Grouse suffer badly, with up to 85% of infected young Grouse dying“

Fast forward and the Moredun Institute has been working flat out to try and find an alternative louping ill vaccine. They have done unbelievably sterling work and now have a prototype vaccine, which needs a little further development, before it can be released onto the market for Farmers and shooting Estates to buy and to inoculate our moorland sheep with. However, louping ill is a virus which only affects the moorland parts of England, Wales and Scotland, and sadly, given that the UK’s population of sheep is 70% of the entirety of the sheep flock in the USA, there is not going to be much of a demand for this vaccine anywhere else. As a result, it is not going to be commercially viable, and if we want (as we very definitely do) to have this new louping ill vaccine available for our hill sheep flocks, then we are going to have to financially support it ourselves. I understand that shortly there will be a fundraising initiative to enable this vaccine to get into production. We have seen, due to the lack of moorland sheep fully vaccinated over the last two to three years (and hill sheep tend not to live longer than five years), a significant increase in the spread and quantity of louping ill on Moors where we manage or consult on both in the North of England and Scotland. Going back 15 to 20 years, louping ill was only something which really affected Scottish Grouse Moors, and even there, mostly those in the Highlands. There were one or two areas of moorland in the North of England, particularly the Trough of Bowland, which did have quite high levels of louping ill, but this situation has completely changed over the last five or six years. We now have louping ill quite widespread throughout Moors in the North of England, where it had not been seen before. We also have it similarly spread on Moors in the South of Scotland. This means that whatever else we do to try and ensure that we have a really good Grouse population (when the weather permits!) on our Moors, until and unless we get on top of the louping ill problem, this will in many areas (an increasing number) be one of the major inhibiting factors of the number of Grouse produced. Given that it kills up to 85% of the young Grouse it infects, you can see how devastating widespread louping ill can be. We therefore must back the fundraising efforts and ensure that we have the louping ill vaccine available as soon as possible. 

There is literally no alternative to this. We would recommend interested people read two brief publications produced by the Moredun Institute: “ticks and tick-borne diseases” and “best practice guidelines for LIV control in sheep flocks and on Grouse Moor in the absence of a vaccine”. It is unlikely that any part of the UK’s Moorland areas, will be free of louping ill in a few years’ time, if a new vaccine is not widely available.

Article written by Mark Osborne

Founder and Managing Director of JM Osborne Rural & Sporting