Significant spread of disease on intensively-managed driven grouse moors

Two new peer-reviewed papers from the GWCT confirm the significant spread of a disease in red grouse on intensively managed driven grouse moors, transmitted through the unregulated use of communal medicated grit trays.

The disease, respiratory cryptosporidiosis (also known as ‘Bulgy Eye’) has been, until recently, almost entirely associated with captive poultry flocks that have been kept at high density, usually for breeding purposes. It was first detected in wild red grouse in 2010 and since then has spread rapidly and has affected high density red grouse on half of the 150 grouse moors in northern England and has also been recorded in Scotland, although the extent of its spread in Scotland appears to be a well-kept secret. Perhaps we’ll learn more through the Scottish Government’s review of grouse moor management practices, particularly as one of the review group’s special advisors is Adam Smith from the GWCT.

We’ve known about the spread of this disease for a couple of years, and learned a great deal from a GWCT-led grouse moor seminar in 2015 where the preliminary research findings were presented (see here). The latest publications confirm the findings, although it’s worth bearing in mind the disease may well have spread further since these studies were conducted (2013-2015).

The first of the new papers was published in November 2017 and confirms that communal medicated grit trays distributed across grouse moors act as a reservoir for disease transmission via the faecal droppings of grouse visiting the trays:

Baines, D., Giles, M. & Richardson, M. (2017). Microscopic and Molecular Tracing of Cryptosporidium Oocysts: Identifying a Possible Reservoir of Infection in Red Grouse. Pathogens 6: 57.

This paper is open access which means we’re allowed to share it in full:

Crypto_Identifying infection reservoirs_red grouse_Baines et al2017

A typical grit tray contaminated with grouse faecal droppings on a Scottish grouse moor, photo by Ruth Tingay

The second paper has recently been accepted by the British Ornithologists Union journal Ibis and details the impact of Bulgy Eye on red grouse populations and highlights the economic loss this may cause to the driven grouse shooting industry:

Baines, D., Allison, H., Duff, J.P., Fuller, H., Newborn, D. and Richardson, M. (2017). Lethal and sub-lethal impacts of respiratory cryptosporidiosis on Red Grouse, a wild gamebird of economic importance. Ibis: accepted online 26 December 2017.

Unfortunately this paper is not open access so we’re only permitted to share the abstract (although we have read the full paper):

The significant spread of this disease is entirely of the grouse-shooting industry’s own making. If they weren’t so keen on cramming as many red grouse as possible on to their driven grouse moors (sometimes up to x 100 the natural density) and then using medicated grit to prevent the natural strongyle worm-induced grouse population crashes every few years (which they have successfully achieved), then Bulgy Eye should never have been a problem.

The question now is, what, if anything, are they going to do about it?

Presumably they’ll do something, if not in the interests of animal welfare or conservation, then certainly in the interest of stifling the economic losses caused by the widespread prevalence of this disease.

In the concluding remarks of the second paper, Baines et al say: “…. a general reduction in grouse densities, brought about through either de-intensified management, increased shooting rates or both may need to be carefully considered“.

May need to be considered? Good grief, you’ve got a disease epidemic on your hands, all of your own making, and you say these proposals may need to be considered?

We’d say the industry needs to do something pretty damn quickly, and the immediate removal of communal medicated grit trays should be right up there as the first obvious step.

34 thoughts on “Significant spread of disease on intensively-managed driven grouse moors”

  1. Given that pro-driven grouse shooting propaganda has often made the point that the grouse are wild and thus “more healthy” than domestic fowl, it’s deliciously ironic that their own intensive overproduction and reckless use of medicated grit has helped to introduce and spread a disease so closely associated with densely packed captive poultry flocks. It does have its comic side since it conjures up the vision of the more neanderthal ‘keepers going out to shoot, trap and poison those pesky trays for reducing grouse stocks!

  2. Hi folks, I know you’ve probably covered this before but – is it legal for non-vets to administer veterinary medicines? Is it legal to introduce veterinary medicines into the environment where non-target species can come into contact with them?

    1. It’s legal – Veterinary Surgeons Act 1963, Schedule 3, Part I

      “Treatment and Operations which may be Given or Carried Out by Unqualified Persons

      1Any minor medical treatment given to an animal by its owner, by another member of the household of which the owner is a member or by a person in the employment of the owner.
      2Any medical treatment or any minor surgery (not involving entry into a body cavity) given, otherwise than for reward, to an animal used in agriculture, as defined in the Agriculture Act 1947, by the owner of the animal or by a person engaged or employed in caring for animals so used.

    2. Sorry. I should have added this – Agriculture Act1947, S109, Interpretation ““livestock” includes any creature kept for the production of food, wool, skins or fur, or for the purpose of its use in the farming of land;”. There is no definition of animal so I presume livestock is the relevant word.

  3. Cryptosporidium baileyi seems to be the main species of parasite involved and has rarely been reported to cause disease in humans. The Pathogens paper, however, reports that one tray of medicated grit also contained oocysts of Cryptosporidium parvum, known to be a regular cause of human disease. Perhaps gamekeepers, especially immunosuppressed ones, should be offered a prophylactic course of Nitazoxanide after a day amongst the grit. The risk to shooters and chefs is likely to be less than that to gamekeepers, especially if they take sensible sanitary precautions.

  4. I assume that this cryptosporidium is not the one that entered the municipal water supply and caused a D & V outbreak, an event which remains in my memory. ISTR that the spores were small enough to pass through the filter system.

      1. Thanks, I’ll take a guess here that the outbreak which affected me and many others may have resulted from farming ‘slurry’ getting into the chalk aquifer via a sinkhole. Possibly it was pumped into a hollow in the corner of a field.

        If this is the same, or similar in effect, I hope it doesn’t get into the reservoirs.

  5. This is very worrying especially the 100,000 or so people served by private water supplies in Scotland. I’ve known of several cases of humans catching cryptosporidium from the private water yet the local environmental health refused to test the water, citing cost. The common denominator of those affected was a private water supply and all lived on shooting estates.
    How many visitors to rural Scotland have been affected by this yet not been aware of the likely source of infection?
    How much is this costing the NHS, days lost at work, children missing school, etc?
    The game shooting ‘industry’ is proving to cost the public an awful lot of money in hidden costs. I have not mentioned the cost to the environment or the wildlife as the readers of RPS are well informed and know the score.

  6. I wonder what the industry will do to solve this troubling (for them) issue?

    The morally correct approach should be to reduce the density of grouse, and in turn the intensity of management practices which turn driven grouse moors into ecological deserts.

    But I guess it’s more likely that they will simply stick lids on the trays to stop the birds defecating on the grit.

    1. It’s a troubling issue for all of us, not just for them. There is concern that Cryptosporidiosis will transmit to Black grouse – indeed they’ve already found the parasite in one tested bird – a species of huge conservation concern.

      Putting lids on the grit trays won’t solve the problem. They’ve found the Crypto parasite in faecal samples collected outside of the grit trays. Forcing birds to congregate, even if there’s a lid on the tray, will aid disease transmission.

      1. The paper you quote acknowledges both the welfare of grouse and conservation risks to other bird species. As this is peer reviewed science, I wonder what action the Animal and Plant Health Agency are going to take? Maybe somebody could ask the official government advisors what they could or should do?

  7. And on and on it goes, the driven grouse shooting industry cocking everything up, its a good job they are the experts and guardians of the countryside or otherwise they would cause some real damage 🤔
    What they need to do is moderate everything they do and accept birds of prey then we might start to see improvement, it won’t happen because they are ignorant brain dead bastards.


    “Respiratory tract cryptosporidiosis has been confirmed for turkeys and other commercially raised birds, including chickens, partridges, peacocks, pheasants, and quail.”

    And, in Australia, Poultryhub notes …

    “There are no satisfactory control measures except isolation and good sanitation. All known anticoccidial drugs are ineffective against Cryptosporidium spp and they are extremely resistant to chemical disinfection. Supportive therapy may reduce mortalities. Steam cleaning is effective in reducing infection as oocysts are inactivated above about 65°C. Treatment and prevention are both based on good hygiene, sanitation and biosecurity practices. All dead infected birds should be incinerated.”

    I wonder what the NFU thinks about this!

  9. The only surprise I have is that this hasn’t happened sooner , disease and falling numbers of grouse might well do for this foul industry . Any animal as unnaturally and intensively farmed as this MUST suffer from disease. Grouse populations fluctuate naturally but estates have been keeping huge unnatural populations on the moors for years ,and to hell with the cost to every one and every thing. Now it looks like good old mother nature is beginning to bite them back .Gives a lie to their crap about creating a natural balance. If I owned a grouse moor I would get out quickly , the net is closing in on your degenerate hobby.

    1. Another DGS own goal. Had this diabolical industry been properly regulated, it would have been brought to book years ago on this and other health-related issues. Are they still claiming that this is healthy organic food? No wonder the official sampling agency reckoned that they couldn’t find any to test – they probably had a good idea what they might find!

  10. I can’t help thinking that there are parallels here with some of the respiratory infections we now see in passerines, particularly Greenfinch. Of course, these are more connected to an innocent attempt to help, but nonetheless it is an example of mankind messing with natural balances, and generally making things worse. Hopefully we will soon be able achieve better education in relation to cleaning garden feeders. However, the grouse industry have to pass an earlier hurdle, that of complete denial.

    1. My thoughts also turned to garden bird feeders. I personally think that encouraging birds to feed in such close proximity puts them at risk of disease and cleaning feeders is not the answer. Far better to equip a garden with many natural food sources so that birds forage in natural ways.

      1. I’m really with you on that one, how much land is being farmed to produce bird feed, rather counter productive I would have thought and why I can’t help having a bit of a sneer whenever I hear that pheasant shooting is good for conservation because some of the grain put out as supplementary feed gets eaten by songbirds – phony conservation at work again. If birds were coming to natural sources of food in a garden such as seed heads left on sunflowers then they’d be more widely dispersed and less at risk from sparrowhawk attack at a bird table, kids would still have the pleasure of seeing birds come into the garden and there’d be more emphasis on garden wildlife generally rather than just birds, echoing natural eco systems more. I certainly wouldn’t criticize anyone for feeding birds in the traditional way, but I think we have to start looking at the bigger picture and it would be good to encourage people to ‘grow their own bird feed’.

      2. This is all very well, if you have the space to do it. My view is that people such as myself, who clean and disinfect feeders and birdtables on a daily basis, do much to lessen the risk of infection to birds from feeders etc. put out by people who do not do so. We also leave seed-heads such as teasels for them to feed onl – best of both worlds.

    1. Dave, May I offer a slightly different spin on your radical idea. What the grouse industry needs is an inexpensive way of culling diseased grouse, so reducing transmission of parasites to healthy birds. In his 1875 book, James Dalziel Dougall explained that “overcrowding creates disease” and that “the whole mischief arose, primarily from over-stocking, and, secondarily from gamekeepers most improperly killing off the falcons”, which he termed “sanitary commissioners” because they killed the most heavily infected birds. Of course, he was writing about the older grouse disease, trichostrongylosis, and doubtless intended “falcons” to include harriers and eagles. But the same principle applies.

  11. You report Baines as saying “…. a general reduction in grouse densities, brought about through either de-intensified management, increased shooting rates or both may need to be carefully considered“. Well, we can all imagine which one of these would be the preferred option! Of course, allowing a natural degree of predation by Hen Harriers could have the same effect, but sustainable and not so severe. Chance would be a fine thing! It all points to one conclusion – grouse shooting has had its day.

    1. …… plus it would be natural and free! What more could you ask for? Leave nature to take care of itself instead of meddling.

  12. “….should this disease cross to other species occupying the same moors”…This statement bears a lot of repitition, after all those attempts to persuade the world that managed grouse moors are wonderful for the environment, as a whole, we are now told by the industry’s own pet scientists that actually, driven grouse shooting is potentially killing other moorland species!….Oh dear…

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