Hello, I'm Aidan Foster, and it's my great pleasure to provide you with an introduction to deer in the UK. In recent years I've been working for APHA and with the University of Bristol doing livestock disease surveillance. So those experiences will inevitably impact on what I'm going to say to you today.
I've also been the president and currently past president of the British Deer Veterinary Association, and that too will have a considerable impact on what I'm going to say to you today. I'm currently an honorary senior lecturer at the University of Bristol. I'm going to discuss 6 items, so these are the learning objectives.
I'm always very keen to provide sources of information, so I'll be doing lots of signposting to various sources of information. And we'll talk a bit about different types of deer in the UK and then go on to talk about reindeer, diseases of deer, quite a lot on notifiable disease, and then a fairly important emerging topic. Which is tick-borne diseases.
What is the BDVA? Well, it's, the relatively new name for the Veterinary Deer Society, which was formed in 1981. We're affiliated with the British Veterinary Association.
It's a very small association. And the picture from our website shows a meeting at a Shropshire deer park where we met with colleagues from DEFRA and APHA to explore, discuss the challenges of dealing with park deer when it comes to dealing with TB breakdowns. We have a number of strong, good working relationships with various associations and societies which are listed on the right there.
I'll say a little bit more about each of them as we go through this webinar. Just want to pull out the deer Initiative Partnership, which is an organisation that's administered by the British Deer Society, the BDS, and includes various stakeholders who have an interest in managing and that usually means culling deer. It includes the British Association for Shooting and Conservation, the National Trust, the National Gamekeepers organisation, and similar.
So this. Reflects the fairly substantial community of people who are involved in deer stalking in the UK. Now, It'll be no secret that this webinar is very much our platform to help promote awareness of this new book that we've published with Wiley came out earlier this year.
There are 34 chapters, 37 authors, . This book aims to discuss diseases from a variety of perspectives. It includes specific chapters on reindeer, monk jack, and white-tailed deer, given that the book will hopefully also sell in North America where white-tailed deer are a big issue.
Much of what I'm going to say is in part based on the content of this book, and I commend it to you. If you want to know a little bit more about deer. The new book is very much based in part or derived from the experiences of our colleagues who set up the Veterinary Deer Society, including Tom Alexander and David Buxton, who edited Management and Diseases of Deer, which first came out, I think, in 1989, and the second edition was published in 1994.
Although the book may seem fairly dated, it does actually have a wealth of information that's still valuable today. And it's out of print, but it is available if you become a member of the BDVA. There are other sources of information about deer, the British Deer Deer Farms and Parks Association has a website with a wealth of, material, which I'll touch upon a bit later.
Over the years, in practise has, published a variety of articles that include deer, as the focus. And if you searched here on the BVA Journal's website, you might be surprised how much material comes up. And quite a lot of what I'll be saying is influenced by contact with the BDS that has its website with a wealth of information about the deer that we can find in the UK.
Other books of interest, Reindeer, known as caribou, in various parts of the world are covered in this substantial textbook, by Morton Triland from Norway and Susan Kutz from Canada. This is the most useful book, . On diseases of reindeer, and I commend it to you.
Our colleague John Fletcher, who established probably the first deer farm in Europe in 1974, based in Scotland in Ochtamochty, is the editor of this Springer book, The Management of Enclosed and Domesticated Deer. It includes a wealth of information about deer farming, systems, particularly in New Zealand and North America and other parts of the world. Deer of the World is the most recent book to join our bookshelves.
This describes the various species of deer across the world, and it includes a chapter by Christian Gortazar and colleagues on, the importance of deer potentially with respect to diseases that may affect livestock and humans. And finally, in terms of signposts, we've got the codes of recommendation for the welfare of livestock, specifically for deer. This has been updated, back in 2023 and is based on a fairly old document, but, does provide some useful links to the legislation and is available on the gov.uk website and the link is given there.
So that's the first objective. The next objective is to talk a bit about the composition of deer across the UK. Colleagues have said to me in the past, surely most people don't get come into contact with deer, and yet it's surprising.
There's a, there's a variety of situations in which deer may come across your patch. So, Some of what I'm going to say is based on the data that's available in an Excel spreadsheet, which is available to the public in the enclosed and Captive Deer survey published by the British Deer Society. We know from ONS Data Office for National Statistics, which is based looking at Surveys done by DEFRA that we have something of the order of 40,000 animals in deer farms, and virtually all of the animals in deer farms are red deer.
There are two or three holdings that keep fallow deer, but there sometimes seems to be a misconception that fallow deer are farmed in the UK. They're not really farmed in substantial numbers. The BDS survey lists 75 farm attractions.
These are open to the public. There are probably between 2 to 300 deer farms across the UK. We don't have many reindeer in the UK, probably several 1000.
Park deer, again, we're looking at probably less than 40,000 animals, mainly red deer, seeka, and fallow, plus sometimes a variety of other more exotic species. The BDS survey. Gives details of 113 public parks, like the farms, there's probably several 100 parks that keep deer, many of which will be private.
Zoo collections. There are several 100 zoo collections across the UK of which perhaps around 88 keep a variety of deer species. Taken together, it's important to appreciate that we're looking at a population of enclosed or managed deer of less than 100, 100, 100,000 or so.
And in that regard, they're similar in size to the national goat population. So that's of the order of 100 to 110,000 animals. So very, very small compared to other aspects, other sectors of the livestock industry.
When it comes to wild deer, the numbers are. Not exactly known. There's no doubt that in recent years the numbers have increased.
The estimates of numbers of wild deer in the UK have gone up in part through technology, using drones, the BDS and the Forestry Commission clearly seen a great many more deer than they perhaps initially anticipated from other methods. And then there are studies that have been undertaken through, access to public data. Where software programmes can work out deer density and distribution.
So the British Trust for Ornithology is published on this. Every 4 years or so, the BDS does a survey looking for the 6 main species of deer found in the UK. So the top panel shows, the, the main species that are found in the UK.
So fallow deer found throughout, as are red deer. Roe deer are probably the most abundant. They're probably numbered the greatest amongst all the deer species we have, and they are found across Great Britain, but not in Northern Ireland.
The bottom panel shows water deer, sometimes known as Chinese water deer. They're limited in distribution to eastern England, East Anglia. Munkjack, this is a non-native species like the water deer, and unlike the water deer, they have spread far and wide already, and, they have been translocated deliberately by people into various locations including even Northern Ireland, sadly.
They're very successful. They breed all year round, and there are ongoing concerns about their impact. And then we have various populations of Zika deer which can interbreed with red deer and may be found in deer parks as well.
So a few words about the park deer sector. So what are park deer? Well, they're basically herds of deer that are allowed to behave naturally.
They're managed in order to maintain a breeding cohort, so there's enough males for females in the rut, and the pyramid is is maintained sexes is maintained by culling. So the social structure should imitate what is seen in the wild. But one key difference is that they are Potentially at risk of shortage of food, particularly in, in the winter period, and so they may need supplementary feeding through, through the winter.
For more information about deer in deer parks, I commend Peter Green's chapter in our dear veterinary medicine book. Peter has also published an article in In practise, which describes in detail the somewhat perplexing legislation that surrounds Park deer. DEFRA perceive enclosed deer within a park as being akin to farm deer.
And so for the purposes of TB breakdowns, they have, implemented, new, relatively new legislation to manage TB breakdowns. But the Food Standards Agency and Natural England, see park deer very differently. So the FSA anticipates that deer carcasses from parks are going to go through the meat trade.
System which is the approved game handling establishments, so park deer do not go through abattoirs. Natural England perceived park deer as being wild, and for any intervention. Particularly shooting them, one has to have a licence.
So Natural England are the licencing body for, any engagement with wild deer or park deer. Park Deer are also the focus for another area of debate, confusion. And Argument this is in relation to trying to move deer from park to park where they may be sedated initially to get them into a transport vehicle.
1 may also be called out to deal with deer in an emergency situation where they're trapped or injured. So the first dilemma we have is that POM drugs need to be used, and these need to be under the care of a prescribing veterinary surgeon. Furthermore, in order to deal with captured wild deer, including deer owned deer parks, you need a specified licence from Natural England.
The RCVS consider intramuscular injection. Of an anaesthetic as an act of veterinary surgery and therefore a layperson. Is not meant to be involved in darting, deer, and yet a number of them do.
There's also no established MRLs, maximum residue levels, for any of the drugs in deer, so they have to be tagged, marked in some way. To avoid them going into the food chain. So if deer are managed, wild deer are managed and then released back into the wild, they need to be tagged in some way.
There are special dispensations for people who work for the RSPCA, and the dilemma about the darting of wild and park deer is described in our letter to the vet record from 2021. Unfortunately, there are very few veterinary surgeons who are trained to use dart guns. It's a little bit about farmed deer.
The BDFPA has Fairly small membership reflecting the small size of this livestock sector. They provide a wealth of information including handbooks on the website. They have, events usually held on farms, once or twice a year.
They provide a wealth of leaflets through the deer information, outlook on, on their website, and they also publish booklets that cover important topics like, feeding. So, lots of good things there. Some key things about Farm deer, they have to be retained within very substantial fencing, which is usually at least 2 metres high.
Some farms will have double fencing to try and mitigate the risk of deer escaping. Ironically, this actually helps to mitigate the risk of incursion of animals from outside. In parks historically, it's been well recognised that.
The boundary fences, don't necessarily keep the park deer in, although, although they do tend to stay in, but there is a thing called deer leaps, which is where deer from outside can leap into a park and then not get out again. So biosecurity with fencing is quite critical. It's an expensive.
Commodity, so it makes investment in deer farms, substantial. Deer are very active animals. They fight, they will rub their antlers, so maintenance of the fencing is critical.
You can use electric fencing internally. Deer will learn to use that. Deer don't eat very much during the winter.
They eat a great deal more during the, the spring and summer months when they put on most of their weight. They can be managed on grass of various types of pasture. They will also eat various types of, winter and summer crops.
And the concentrates can be used to supplement their diet if one wants to improve performance. Deer need to be restrained, so one of the other key costs. Is a management system to collect and and then put deer through a crush cradle system that allows one to to weigh them, to administer drugs.
It's worth commenting that farm deer rarely receive antibiotics. They don't tend to get routinely vaccinated unless there's a history of clostridial pustulosis disease where sheep vaccines may be used, but that's not very common. They're inevitably caught up to do TB testing.
But one can use the opportunity to weigh them and apply ear tags. They rarely receive. They also receive elmintics.
And I'll talk a little bit about that a little bit later. Breeding, . They drop their calves usually May June time.
This is red deer hinds. They can breed up to 15 years of age. There's various pros and cons about when to, to wean them.
Whether it's before the rut or after the rut. So now let's turn to the third item which is reindeer. So reindeer are unusual in that the females grow antlers.
They're the only species that do this. They keep, they grow their antlers. In the summer months, initially you get a bony growth that's surrounded by velvet, which is a very highly vascular skin structure, which is the velvet is shed, late summer, and then they're in hard antler right the way through the winter all the way through up to to calving with the females before they cast their antlers.
There are various theories as to why they have antlers for so long. Such as competing for food with males, . And the males, by contrast.
Grow their antlers again during the summer months, but they're only in hard antler until November, December time. So this means that if you go to a garden centre or similar establishment at the in the Christmas period when reindeer are most likely to be seen by the public, you're generally going to be seeing female reindeer or castrated males. Some of which will retain their antlers through the winter period and eventually drop them, so castration can have an impact on how antlers grow.
You will, you should probably never see entire male reindeer. They are potentially quite dangerous animals to deal with. Now one of the unusual features of reindeer and their antlers is that they have this condition called antlerroma, which is a description of a form of antler velvet hyperplasia.
So I'm going to share briefly with you a case example. So this is a male. Who was imported from Norway for breeding purposes and year on year had a large lesion develop on his right antler.
He was castrated in 2018, so this would be several years after he'd been purchased, and he still had a lesion develop. There were other animals in the group who occasionally had lesions, but he was unusual in the sense that he had repeated lesions in the same place year on year. Otherwise he was in good health.
So this lesion that you see in the picture was removed and submitted, very heavy, several kilos in weight. The antler, the, the bony antler is completely normal, and you can hopefully appreciate from the picture on the right that in order to incise the lesion, I've actually had to use a bandsaw. It's actually quite tough.
So I've given the histopathological findings and. We're just finished with the diagnosis, which is that this is a hyperplastic dermatitis. There is some surface infection and we've got marked fibromatous hyperplasia.
So this is a fibrous reaction going on in the antler velvet. Now this is only ever seen in males and since most males are castrates, it's generally only in castrates. This case was unusual that it was an entire male.
It is occasionally seen in in male entire males. It's very, they're very fast growing. They can even involve .
Invading the area around the muzzle, and when they get very large, they can get fly strike or secondary infection. So they may then need to be excised and in some cases the whole antler has to be removed. Studies that we've reported in the vet record given below.
We looked for evidence of viral infection since velvet lesions have been described in other species of deer associated with papilloma and parapox infection. There is absolutely no evidence for papillomavirus infection. Some authors have misunderstood that the papillomatous changes described by histopathologists are not.
Akin to the lesions being due to papillomavirus infection, we're not clear what causes them. There's speculation that the velvet is damaged in some way, traumatised in some way, that this is some kind of hyperplastic response. Furthermore, there's no good quality evidence that administering hormones is going to have any beneficial effect, .
Sex hormones are Often considered by owners to promote casting of the antlers. But in reality, the antlers will be cast in due course, and it's difficult to justify administering these products to reindeer, even though the vast majority of the reindeer will never enter the food chain. Anecdotal cases have been reported in the USA, but it's a particular feature of reindeer kept in, in the UK.
A little bit about the welfare of reindeer. So back in 2013, the Farm Animal Welfare Committee published an opinion on the welfare of farmed and park deer, and in their deliberations, the first recommendation was that the welfare of reindeer should be considered. Because they are particularly likely to be kept by inexperienced owners for commercial purposes, and there's no doubt that many of the owners that keep reindeer have no experience of livestock.
That said, given the number of years that some of them have kept them, there are now some very experienced, very successful owners, who can train the reindeer for public events and are very mindful of their responsibilities, but these are not animals to be taken on lightly. Turning to other aspects of their health and welfare, so this is a surveillance focus article from the Veterinary Record published by myself and Alan White, . So we've both been chair of the APHA Miscellaneous and Exotic Farm Species Group, which covers deer and particularly reindeer, which are a popular submission to the APHA disease surveillance system, which includes APHA labs and various partners including universities.
Samples, carcasses that are submitted are processed and then come up with a diagnostic code called a VIDA code. I should perhaps just comment that, reindeer that are submitted are usually from, commercial smallholdings. There are a small number of larger herds including the long established herd up in the Cairngorms, which is managed by Tilly Smith and family, and a very, Readable, very interesting, very nice source of information about reindeer is Tilly Smith's book Reindeer An Arctic Life.
For more information about the Cairngorm herd, please follow the web link. So if we look at the VIDA coding over a 10 year period for reindeer submitted to APHA, there's no doubt they're very susceptible to parasitic disease, particularly parasitic gastroenteritis. We have seen rumen fluke, but these are not perceived to be a pathogen.
They do get liver fluke. One of the biggest problems with reindeer is malnutrition and acidosis. Acidosis is secondary to changes in feed, particularly introduction of concentrates as a response to trying to manage the fact that during the winter months, the reindeer tend to drop their appetite, drop their body condition, and it can be very difficult to stimulate their appetite.
They're susceptible to a disease called malignant catarrhal fever, which I'll discuss briefly, and then occasionally they'll get clostridial disease and as in all livestock species, they can get colisepticemia. Unfortunately, partly because of the state of autolysis of carcasses. Which is perhaps in part due to the fact that they're very well covered in a thick hairy coat, and we don't make a diagnosis.
It's not reached, and this is because the carcass is too waterized. They do get pneumonia and they can occasionally get yasinia and salmonellosis, which are diseases we also see in other deer species. Turning to feeding, I commend to you the chapter on reindeer in our deer book, with a section by Mary Ruder which describes some of the issues with respect to feeding.
these are also touched upon by the in practise article by Alex McSloy, . Published back in 2014. There's no doubt that new owners, new reindeer owners need to be aware of the challenges of feeding their deer.
MCF. So this is a gamma herpes virus. Unfortunately, it's highly fatal.
It's got a distinctive, lymproroliferative vasculopathy on histopathology and clinically we may see ulceration of mucosal surfaces, in. In terms of susceptibility, we've got deer species, particularly red deer, sorry, reindeer, that are susceptible, Pir David deer, which are kept in some holdings in the UK. We also see MCF in bovids, particularly cattle from time to time and bison.
There are several types of herpes virus implicated. Caprine herpes virus. Has occasionally been shown to infect deer species.
These herpes viruses are naturally carried by sheep and goats, normally to no ill effect, although there are rare cases now described that these viruses causing problems in the, in the what's perceived to be the the reservoir host. So the difficulty with this virus is that infection can be acute. Animals just drop dead, but usually once they get infected and show clinical signs, they will die.
So for reindeer owners this can be particularly tragic. The Mooron Research Institute in Scotland has done a wealth of research on this disease. They've provided access to a PCR, which is the key method by which we diagnose this condition.
Although clinical signs of postmortem histopathology can be very supportive, . Serology antibody testing is not perceived to be very useful for diagnosing this condition. So here are two cases of reindeer with MCF showing a lot of haemorrhage into the thoracic inlet in the top left.
The top right shows mucosal ulceration of the oesophagus, which is a reminder that this might look similar to bluetongue virus infection, which has not been described in reindeer to the best of my knowledge, or BVD pesttivirus infection, which has occasionally been described. The bottom right shows the corneal changes that might be seen. In a reindeer, this animal had been infected for about 10 days.
It was mainly in the left eye rather than the right before it died. And the bottom left picture shows what's supposed to be lung tissue, but it's just a hemorrhagic mess. Some cases of MCF at postmortem will have virtually no overt gross clinical changes because the infection has been so acute.
So there we're looking at histological changes. Another disease that's particular to reindeer is TSEs, transmissible spongiformal encephalopathies, chronic wasting disease is a disease, a condition that's been well described in North America where it's causing havoc for their wild and their enclosed deer, moose, mule deer, white-tailed deer, other species are susceptible, including those that are present in Europe and UK, including. red deer, fallow deer, reindeer, roe, sera, muntjack, .
At the moment there's no clear evidence that in North America in particular that humans are affected by this disease, so There's no clear evidence that animal products or meat are infected. It's continued to spread across large parts of North America killing animals. In its past.
There's never been any evidence of infection with this type of TSE in the UK and it was generally assumed that we didn't have something similar in Europe until in 2016, . A case of a wild deer submitted for routine postmortem examination revealed the first case of CWD in Europe, specifically in Norway. So the Norwegians year on year through the Norwegian Veterinary Institute produce an annual report, which is really a nice way of looking at the the disease situation through monitoring their wild deer.
They've shown that their wild reindeer in one particular part of the country have been affected and they've then gone in and culled all the animals. They've also found atypical forms of CWD in some red deer and in their moose, and the Swedes and the Finns have also found atypical CWD in their moose. Surveillance for TSCs is ongoing in Conventional livestock species and now includes in various parts of Scandinavia and the Baltic states looking for evidence of infection with CWD in wild and some enclosed deer species.
It's perhaps worth pointing out that the CWD that's been detected in the wild reindeer in Norway. Does have differences from the from the form that's seen in North America. So we now go on to talk a little bit about common diseases in Dear, so I'm gonna talk a bit about The following conditions, so Just want to acknowledge that this table was initially put together by Andy Holloman for Veterinary Laboratories Agency at the time.
I've already touched on chronic wasting disease and MCF. We'll talk a bit about Long worm, shortly. So I just want to pick up, Yesenia at this stage.
So euciniosis is a bacteria that can be carried by deer. They can, when stressed, develop clinical signs associated with diarrhoea, weight loss. So it can look very similar to parasitic gastroenteritis.
It is a zoonosis, as is sal analysis, which is occasionally described in deer species. Far and away the most important zoonotic agent in deer species is cryptosporidia. This can be an important cause of morbidity in red deer calves, particularly if, the calving area is .
Unhygienic, so management of the, the carving grounds facilities is, is important. Cryptosporidia, has been an interest of the Mordon Research Institute for a number of years, and they've recently published back in September, the article below on detection of crypto and Giardia in wild deer. So this is part of their ongoing surveillance of wild deer for enteric pathogens, which also includes looking for.
Virotoxic or enterotoxic E. Coli, of which there are various types and perhaps the most well known one is E. Coli 0157.
Sadly, in 2016, in Scotland, there was an outbreak of ETech in humans which was associated with consumption of wild Scottish venison, and this initi led to some ongoing surveillance programmes looking for evidence of infection now. As in other livestock species, 0157 is not a pathogen in deer. It's actually rarely detected, so the prevalence is quite low, but the types that are found in deer do seem to be similar to those that are found in humans, so.
This, these studies help to remind us that it's important when handling not just wild deer but farm deer that one takes due consideration for the risks of zoonotic spread, and if you're handling a deer carcass that it's managed in a very careful way to reduce the risk of contamination of the carcass before it goes into the food chain. Another zoonosis of interest in recent years is an example and also an example of How important the stalker community is in the UK in providing access to blood samples. So Maya Holding and colleagues from the UK, our security agency, published this study.
Back in 2022, which was looking at different deer species in the UK for evidence of sero conversion to COVID. The COVID virus and no evidence was found. Similar studies have been done in Germany, Austria, and Poland with negative results.
Small numbers of deer that have serial converted have been described in Spain and more recently, an interesting study suggested quite high prevalence of exposure to infection of fallow deer which are present in Phoenix Park, Dublin in Ireland. In North America there have been an enormous number of studies looking at COVID to where White-tailed deer in particular, both wild and enclosed, seem to be particularly susceptible in the sense that high levels of serum prevalence are seen. It's important to point out that there's never any evidence of clinical signs in the deer that have been infected.
Studies of wildlife with respect to COVID-2 infection in the UK have been undertaken by the National Wildlife Management centre. This is a website showing their assessment of the risk of UK surveyed populations. Their studies to date have not been formally published, but, suggest that small numbers of deer have been found with evidence of sero conversion.
I'm sure that this will be a topic for consideration for future surveillance. Common diseases are common and perhaps the most important disease for farm deer in particular is lungworm, going back to the wider system of coding, lungworm requires demonstration of lung worm in the bronchial tree or larvae in the faeces through a bayment test, through histopath. There can be other concurrent diseases, and it's not always clear how severe the lungworm infection might be, but it's fair to say that with large lung worm, Dictycolus species.
Including viviparous. That deer will show signs of weight loss and poor growth. They don't usually cough.
Which is a key feature in cattle and unfortunately this can be a significant cause of mortality, particularly in yearlings. So in some situations, some farms will prophylactically treat their animals for long run in anticipation of a potential breakdown. Deer also get protostroglid lung worm, which don't usually cause major problems.
They're seen particularly in wild red and roe deer. They're not thought to be clinically significant, but sometimes lesions can be so extensive that, one would wonder, and you can occasionally see a large lung worm in in wild deer as well, including roe deer. So here's a roe deer with large long worm thanks to Alex Barlow and.
So a very similar presentation to what one might see in in cattle. It's unclear if the . Wild deer species pose a significant risk in terms of endoparasites, including lung worm.
Sometimes wild deer will share a grazing patch with livestock, but at the moment it's unclear that they are a major problem in terms of disease transmission. So here's some pictures from Peter Green which shows the proto-strongli, the small lung worm lesions in in in a roe deer. So we now move on to item objective 5, which is notifiable diseases.
I've already talked a bit about CWD. I'm going to go through the caring for deer website link that I've already given, which lists four diseases specifically for deer, foot and mouth, TB, blue tongue, and epizootic hemorrhagic disease virus. It's only in recent years, thankfully that we've seen FMD back in Europe, and initially in Germany, then Hungary and Slovakia.
It's clear that the Slovak, Slovakians in particular have been managing their wild animals, probably mainly wild boar, but also deer because of the concern that deer. And wild boar harbour, FMD. There's no doubt that British deer species are susceptible to FMD, but it remains to be seen if they would need to be managed if we were unfortunate enough to have an outbreak of FMD in the UK.
And they will show similar, similar, similar clinical signs to those seen in livestock species, cattle and sheep, although they tend to be fairly mild by comparison. With blue tongue and episotic hemorrhagic disease virus, these viruses are very similar in some respects but play out differently. So bluetongue was initially described in deer in North America where it was clear that it was very pathogenic, that white-tailed deer and other deer species would die from infection, .
But in recent years, epizootic disease virus has been more of a concern for North American deer species, which are very susceptible and again will die from infection. By comparison in the UK, bluetongue does not seem to be a major pathogen risk for our indigenous deer species. There are rare reports of blue tongue infection in muntjak, and it's unclear if they pose a disease risk to British livestock at this time.
There's no doubt that British deer can er or convert. There's no doubt that we can find PCR positive cases, but they don't show overt clinical signs. Unfortunately, EHDV has been described in cattle, and one or two deer in, sorry, not in deer in Europe.
The risk of incursion of EHDV is thought to be fairly low at this time. If it did come into the UK, it would pose a significant risk to, our deer species and to reindeer. There's clear evidence that They are susceptible.
For more information about this situation, please consider Kit Heywood's recent article in In practise, and then there's more information about Blue Tongue on the ruminant Health and Welfare website link given below. In terms of TB, one of the key ways in which we suspect TB is through the clinical signs, signs seen at postmortem or antemortem. These are described in some considerable detail in our chapter in the deer veterinary medicine book.
There's also information available on the TB hub. And there's also an article by Tim Crawshaw and colleagues which describes the gross pathology in various species including the deer. So that's, that's the way in suspecting TB.
In recent years we've had the development of serological methods because of the Difficulties in interpreting skin test reactions in deer, and this work's been led by Shelley Rhodes at APHA. So they've investigated a variety of antibody tests which are very useful, particularly if one's able to deploy them. In in collaboration with a prior skin test, unfortunately, farm deer.
As well as park deer will be very difficult, can be very difficult to catch a second time for a blood test. So in some situations, 1 may only get one, sampling, but ideally the, the, the sensitivity of the antibody test will improve markedly if one's able to, give a prior skin test. Another recent development in recent years, which has helped to deal with disease breakdowns, whether it's contiguous testing or, not new, new cases is the PCR method which can take tissue and detect Mycobacteria bovis.
. I think if you're doing a TB investigation, and you've got a postmortem case in front of you, it's prudent, beyond the samples recommended by APHA to submit that one collects small 1 centimetre cubes of diseased tissue, into formalin because histology can be useful ancillary test to, to help suggest, support a diagnosis of mycobacterium infection. What role do deer play in TB? So DEA, regularly report, TB in non-bovine species at this website.
So looking at the most recent data, we have, Variety of columns here and all I'm trying to show is that over the years we've seen an increase in the number of animals that have been tested, particularly with blood tests, and unfortunately we've seen an increase in number of premises that have been put under restriction and given perhaps the relatively small number of premises that I've mentioned earlier on, it's a little bit daunting to think of 4040 or so premises being under restriction. At any one time. So, so TB is a problem for enclosed deer.
There's no doubt about that. So, . And it can lead to the Culling of the whole herd, if the prevalence is high.
So, there is compensation, but it can have a devastating impact on some farms where considerable investment has been made over the years. What about wild deer? Well, the data on wild deer and TB is actually quite limited, .
And so I'm grateful to Jeff Jones from APHA and colleagues who provided access to this data, so. Year on year, we see across different counties, very small numbers of animals have been detected, so these might be carcasses found in high risk areas, . A lot of work has been undertaken over the years on Exmoor, and that's reflected in the numbers.
Reported for Devon and Somerset. The table at the bottom left shows the species that have been described, and so I should point out that red fallow roe, muntjack, and Sika deer have been reported with TB in the UK so far, water deer have not, but they will be susceptible. They just haven't been reported so far.
Sadly, the other species that is susceptible and has been reported in the UK is, is reindeer, . So, It's appreciated that wild deer do get infected with TB. And this is reflected to some extent in a report that was published late last year by the Northern Ireland Office.
I've not said much about the situation in Northern Ireland by talking about the situation in the UK, it has to be acknowledged that there's . Limited component here about Northern Ireland, but it might be interesting to read their report to look at the role of deer in terms of TB, and it's interesting that they describe the situation in County Wicklow, which is where there are Zika deer, badgers, and cattle that are infected with the same type of TB, but they contend that this does not provide conclusive evidence that TB is self-sustaining in the. No, dear.
Nor of the relative contribution of infected deer to local TB epidemiology. And yet, and yet in bold they put at the bottom that deer should be managed to minimise the risk factors known to facilitate. The establishment and perpetuation of deer as a maintenance host, so they do want culling implicated in times.
It has to be emphasised that in general wild deer are not seen. As anything other than a spillover host. This is described to some extent in the article below estimating the risk of cattle exposure to TB.
Posed by wild wild deer relative to badgers. So this is a study done by the National Wildlife Management centre in its current guise, back in 2009. There's also another article that may be of interest, which is by Matt Hartley and colleagues from DEFRA, which was published on the qualitative risk assessment of exotic notifiable diseases in relation to wild deer.
The both these risk assessments have not been formally, replaced, sorry, updated. There is, however, this poster which was published by the Society for Veterinary Epidemiology, conference, I think in 2025 by DEA APHA colleagues which did a literature review looking at the role of wild deer in the epidemiology of cattle TB. So, So it's yet to be seen if this is going to be formally published, so they looked at the deer species in the UK and note 5 of the 6 deer species in Great Britain have been found to have TB.
And it's perhaps worth emphasising their key messages that, the literature reviews highlighted that deer can become a maintenance host if certain conditions are met. However, the transmission risk to livestock and other wildlife species is likely to be localised. So it has to be contended that wild deer probably don't pose a significant risk across the country to livestock with respect to TB.
Now I want to talk a bit about the deer stalker community. So deer stalkers. Usually are trained and have a deer stalker certificate 1, some have a deer stalker certificate 2, and we're looking at tens of thousands of people who've undergone this training.
So this includes, shooting, and how to process a carcass. So the deer management qualification is provided by a variety of organisations including the BDS and the British Association for Shooting and Conservation that I mentioned earlier. The BDS has a website about Lyme disease, and I'm introducing this in part to Now go on to talk a little bit about the importance of Deer in relation to ticks, specifically Iodes rsinus, So it perhaps may not be a surprise to read that.
Deer abundance and tick abundance are related, . So, so deer are described as a reproductive host for the ticks. And in recent years there's been considerable interest and concern about the prevalence increasing of Borreliosis, Lyme disease in humans.
It's To be acknowledged that deer are not a competent host for early infection, that they're generally perceived as a dead end host, it's not quite clear exactly why that is the case. They may act as a dilution host because they divert ticks away from competent hosts and so remove circulating pathogens from the system. I'll come back to this relationship between ticks, tick-borne disease, and deer numbers in due course.
So the deer stalkers have been critical in helping us to understand better the prevalence and distribution of various tick-borne pathogens. So Maya Holding again from UKHSA undertook this study back in 2019, which was a survey of cold deer collecting ticks and blood samples, and the stalker submitted samples. And what they were trying to do was look for evidence of Laupingi virus, but unfortunately this helped to unearth the fact that we do have tick-borne encephalitis virus in our ticks in the UK.
This is a disease that's very well recognised in other parts of the world, particularly in Europe. It's only in recent years that we've, realise that this virus is present, particularly in East Anglia, in Thetford Forest, and then the New Forest, but also elsewhere. So, during this, this summer, the UK HSA have been doing further studies and seeking support from effectively from, from deer stalkers, but others working in in affected areas, particularly here in in the New Forest, .
There have now been several human cases of tick borne. Encephalitis virus infection. This can be quite serious.
There's a risk that it can be overlooked, and so, the detection of the virus has spurred interest in, ticks, their distribution and, and what pathogens they carry. For more information about tick-borne encephalitis and tick bites and Lyme disease, there's the gov.uk websites managed by UKHSA.
So that's the situation in humans to some extent. And then we have yet more data from Maya Holding and colleagues reported in the International Symposium on ticks and tick-borne Diseases where they looked at samples of blood from cold wild deer for evidence of infection with exposure to infection with anaplasma and Babezia, and this has shown that they do carry. These agents, with anaplasma, there are different so-called ecotypes.
So ecotype 1 can be found in all the main wild deer species, while ecotype 2 is only mainly found in almost exclusively found in roe deer, and Babezia species are found in all the British deer. This work complements other studies by APHA on detection of tick-borne pathogens in red deer, mainly, cull deer by Nick Johnson and colleagues in the top left, and then Babezia species detected in deer from cold deer from the southwest of England where tick-borne disease has long been recognised in livestock. And then a slightly older study from Scotland, wild deer in the UK are a reservoir for infection with Babezia.
This is, . More evidence that wild deer can be infected. Generally it's the case that both with anaplasma and with Babezia that the animals, the deer species are not clinically affected.
That said, there are published studies that show that reindeer can be clinically affected, unfortunately, specifically reindeer up on the, in the Cairngorms where, presumably there is an immunity issue there and they may need to be treated. This growing interest in tick-borne diseases in livestock is reflected in the APHA tick-borne disease dashboard, which is well worth a look. So it describes the main types of tick-borne diseases seen in sheep and cattle.
And then just to finish off on this section, just to comment on work by Lucy Gilbert and colleagues at the University of Glasgow. So just to emphasise that deer do transmit Babezia and anaplasma. They're not directly involved in the transmission of Borreliosis, laupingil, or tick-borne encephalitis virus, but they do carry that the ticks, the odes erysinus ticks on these deer do carry these, these agents.
Controlling deer. That may have a dramatic impact on The numbers of ticks and that may have an impact on the spread of vector borne these vector borne diseases, but the the the relationships are complex and they're explored to some extent in this article that's recently been published by Lucy and colleagues. Managing deer is really important because wild deer damage forests.
They're going to have an impact on us. Growing trees for climate change, they damage farm crops. Munkjack and Roe in particular can damage gardens and cemeteries and places like that.
Deer are implicated in traffic accidents, but we also need to control wild deer for their own health because their own health status can be affected if numbers are allowed to grow. Strategies that are bearing down on the wild deer species, so to speak, are, the environment improvement plan, and consultations in England for deer management and there are similar proposals for Scotland. The Deer Aware website describes the situation with respect to DVCs, deer-vehicle collisions.
Which are situations that may lead to the police and others being called out to deal with injured deer. Unfortunately, collisions can lead to substantial damage to vehicles, but more seriously injured humans and occasionally fatal incidents where human Casualties die For more information about wild deer, I would commend to you the RSPCA recently launched a wildlife toolkit which has a specific page for deer and includes a link to Martin Whitehead's article which describes emergency care of injured wild deer. It has to be acknowledged that there are enormous ethical dilemmas around.
Taking wild deer into captivity for veterinary care, some would contend that if one can, one has to attend a wild deer at a roadside or in a. Injured state that it might be best to euthanize them. Rather than commit them to various interventions which will impact on their health and welfare and may prevent them from being released into the wild again, non-native species such as munk jack and ika and water deer shouldn't, shouldn't be allowed back out into the wild.
So it's a difficult area, not to be entered into lightly. So just in summary, deer do get various endoparasitic diseases that we see in livestock. They're particularly susceptible to MCF, so try and avoid excess exposure to sheep and goats if one can.
They are susceptible to a variety of exotic notifiable diseases, which I've discussed a bit here. And at the bottom I've put other diseases such as avian influenza. Given the Spread of AI infection into mammal species including foxes and otters and sea mammals.
It'll be interesting to see if there's any evidence that deer can be infected and what role, if any, they play for back infection into humans. In terms of new and emerging diseases, there's no doubt that tick-borne diseases are important. I've talked briefly about some of those, and I've just put there ticks solve and optic.
These are two major research projects that are ongoing to understand better the role of ticks. Tick-borne diseases, livestock, and the role of deer. And then in terms of zoonoses, they do get VTech E.
Coli. They are a source of crypto and salmonella, and I've just put there for interest ESBLs, which is extended spectrum betalactoase genes, which are a bit like VTech. These are bacteria that are carried in the gut to no ill effect in the deer, but can be a significant pathogen in humans.
Studies have been done in Europe, but nothing in the UK deer on this. So just to finish up, a wealth of colleagues across APHA, the BDVA, . And elsewhere, and I'd also like to acknowledge the help given to me through working with the authors of the dear Veterinary medicine book in putting together this presentation, so.
Thank you very much for Viewing this webinar, I hope you found it useful as an introduction to The world of deer in the UK. Thank you.
