Hello and welcome to this webinar on rabbits, infectious diseases rabbits by myself, Richard Saunders. My name's Richard Saunders, and I'm a vet who's worked with rabbits, both wild and domestic, for many years now. And I'm currently the Rabbit Welfare Association and Fund's veterinary advisor, and I've lectured and written on rabbit medicine surgery, quite a bit.

And today I'm gonna be talking about infectious diseases of, of rabbits. So in terms of what we're going to cover, a broader overview, infectious disease and broadly speaking prevention. Because that's always better than treatment and sometimes it's the only option that some of these diseases are effectively untreatable, diagnosis and treatment where we, where we can.

And then a, a different way of looking at it in terms of what species, what type of actual disease we're looking at treating. I'm going to be talking about eciculae, encephalito and caniculae, reponema, myxomatosis, rabbit viral hemorrhagic disease is, in its various forms, of rabbit viral hemorrhagic disease, and a little bit on pasture. I've, I've really kept that quite light because, firstly, I think it's a slight misnomer and that there are a bunch of other diseases that can cause the snuffles, the sort of upper respiratory tract or sometimes lower respiratory tract diseases of, rabbits.

But also because I think it's, it's sort of covered very well in other, other sources of, of information. And, really, I'm just going to be signposting you to some useful resources on that, having a, a quick discussion about that. I'll also pop in a few differentials, things that can be potentially mistaken for some of these diseases, and, a little bit on the more modern, right up to date, one is about high virulent strains of rabbit, VHD.

So without further ado, we'll start with Eici. I guess the things we're going to kind of cover are testing, Different options in terms of of testing, testing versus treatment, how you can look at a rabbit and say, oh, I think that's got echially or not, as the case may be, and then obviously we'll go on to to treatment and potentially prevention, if you like, by particularly if you're dealing with a breeding situation by looking at the rabbits and and trying to, to remove the potentially infected ones. So we all know the classic can presentation of, of head tilt.

I'd probably say more head tilts are down to otitis media, inner middle ear infections of the of the downmost ear on this particular side, for example. And so sometimes you do have to remember, you do have to kind of look pastechiiculae, even if they test positive, because rabbits can certainly have more than one thing going on at once, and echi, depending on what survey, what study you look at is. Present in anything up to about half the population, so don't necessarily stop a diagnosis, a clinic a a lab diagnosis of ecicula unless it really fits in with the clinical signs, and I would always exclude ear disease as well.

So, and the reason I talk about kind of, screening by clinical sciences and the, the high prevalence, the high incidence of e is, is this paper, and I quite like this, this paper just because of the, the message it sends us really. And this looked at a 5 year period of time, retrospectively, they looked at era from a rabbit breeder who supplied the the lab trait, a single commercial supplier breeder. They tested those rabbits for antibodies to eat, they did screening tests.

They didn't act on those at the time, as I say, this was retrospective. And at the very beginning of that study, pretty much a third of the rabbits that came from that supplier to the lab were were positive. But over over a 5 year period, as as time went by, that number of about a third went down to 2.3%, you know, really, really low numbers.

And that would make sense. That would be obvious if they were culling the seroposit rabbits and they were taking them out of the the group, but they weren't. They were taking out of the group, the ones out of the breeding group, the ones that weren't breeding very well, so the ones that weren't having many in the litter who weren't getting pregnant as effectively and as fast as possible.

The body weights of the animals, whether they had unexplained weight loss, and something as simple as posture where they're sitting upright, standing upright, moving along nicely. And I take this to mean that in any population of rabbits that you see come through the door, those ones that don't look quite right, those ones that just I aren't doing right, are definitely worth testing for chinuae because a significant proportion they're going to have echicula present, and that's going to affect them in all sorts of other ways, whether it be breeding success, which isn't necessarily something we're very interested in, in, in practise, in clinical practise. But it's going to be immune suppressive, it's going to affect them in all sorts of different ways.

If they don't look right, I would suggest that testing prec is is a good idea because it will immune suppress them, it will open them up to other diseases as well as potentially flaring up at times of stress and causing the head tilt, the behind thes and so on. So. If we see something like this, it's pretty obvious what's going on.

This one is a a little bit unfair because it's a little bit too late. In too later stage to be absolutely classic. At this point we've just got this horrible parathalmis.

The whole globe is it's just this horrible sort of ball of puss and inflammation. But if you saw this at the very beginning, you'd have seen the reaction as the e spores, which in this particular case have been localised in the lens in the kit who's in the uterus. They've, he's been infected, she's been infected to infected by an infected mother.

And echini spores have filled that embryo's body, and the immune systems dealt with them except for the ones that are in the lens, which is immunologically privileged, it's sealed off from the outside world, it's sealed off from the rabbit's immune system, and the echinicules spores just merrily replicate and usually in the first few months of life, I, I usually find it in the first year of life and usually unilaterally for some strange reason, that I will suddenly, Come to a tipping point where the, the eye, the lens of the eye fills up with spores as they replicate and replicate and replicate. It'll present as a as a cataract to start with, and then the lens ruptures, and it always seems to rupture anteriorly, or perhaps we just don't see the ones that rupture posteriorly, but it it will turn into this horrible hypopy, this horrible kind of pus-filled anterior chamber. It will open itself up to a secondary bacterial infection by stretching, by making more diffuse by making more open the capillaries of the ciliary body and such like, the blood supply there, and we'll get bacteria in and we'll have this, as I say, horrible pa ophthalmitis.

At this stage, a bit difficult to tell. It could have been a penetrating foreign body, but that's more of a guinea pig thing and coming from bursting from within is more of a, a rabbit thing with echiula. So those weirdly, until that rupture happens, quite possibly don't show a positive for a euchi on blood tests because the rest of the body hasn't hasn't responded to them.

Once this happens, then yes, potentially the the rest of the rabbit and its immune system will will respond. So this, if you do test these, 99.9% of them are, are positive for echiiculate, and you've got a ready-made sampling opportunity in that the aqueous humour of that eye is is a good source of genetic material for echinaulae.

So that's pretty clear cut. The ones on the other hand, who have a head tilt, who have hindliparesis, there's all sorts of other things that could be going on with those those rabbits. So.

We can test and the typical tests to do are a blood test looking at IGG and IGM and we'll come on to those in a second, or we can do a PCR test based on, Fluids and sources of potential genetic material from the rabbit. So I already mentioned aqueous, that's unlikely to be your, your classic in vivo test. So again, it's probably going to be something like urine or or faeces, and we'll come on to that in a second.

So here's a lovely, lovely big lateral suffus vein there held just as we raise the vein above the the stifle. That brings up the vein quite nicely and, I tend to just spirit these because I find that skin over there with some clippers, that very, very fine rabbit skin can get caught by the clippers over the hock, and I find that if you spirit it in just the right place, you can see the the vein come up nicely. So we can take a blood sample, there we go, and get a decent volume out of the lateral svennus.

If I want a really big sample I'd go for the jocula, if I want literally a drop of blood for a glucose, I'd go for the marginal vein. If I want enough for biochemistry, haematology, or in this case serology, I'll go for the lateral subveus. But you've got to remember that depending on your lab and your scale of charges, this, the fee for this could easily be approaching 100 pounds or so, whereas the the fee for treating them is going to be potentially considerably lower.

So it's very, very common that people don't test and they jump straight to treatment and, yeah, I can understand the practicalities of that, but it is, it does mean that we, if we're not careful, treat rabbits. Who haven't got echiicula or for whom echiicula isn't the problem, and we run the risk of delaying the diagnosis. So ideally test rather than treat, but, you know, we live in the real world and treating is a lot, lot cheaper.

Other test methods we can use, well histopathology is the gold standard and we potentially should be looking at the kidneys, and you can see this classic pitted appearance, and this is how rabbits were identified as being positive uicula in in the meat trade. The kidneys were identified as having this this poked appearance as a result of granulomatous, focal granulomas all over the the kidney damaging it gradually, with each replicating surge of replicating spores. Obviously CAS histopathology at postmortem is again definitive, but not something we're gonna do in in life.

And just going back to that, yes, we could look at in vivo. Renal biopsy, fine needle aspirates, ultrasound guided, fine needlelaspirate, but again, look at the the nature of it. It's, it's sort of diffuse in that these lesions are dotted all over, but they aren't uniformly homogeneously affecting the kidney pacuma.

So you could be unlucky and take one or be even more unlucky if you took multiple samples and still found that you had a false negative. So the main tests we're gonna do are serology, which I touched on before. And here we're looking at IGG and IGM.

And traditionally, it was just an IGM test. I don't think any labs are really sort of offering that, particularly in isolation anymore. Most offer IGM IGG together.

And basically, I wonder if I can draw this, let's see if I can draw this. Very simply put, if this is our, our, Scales, there we go. Of our graph, the IGM.

That serro conversion takes place quite quickly and we see a peak within about a week and then that falls down to an immeasurable low level after about a month. So as I say, it peaks at a week. Let's make that the kind of 7 day point there.

So that's all well and good if the rabbit's been infected in the last week, we should see a peak at a week with IGM. But we also then have IGG in the picture, and I'm just going to find a different colour for that. And IGM does lags behind really and takes a while to come up and you can't really make a scale of my wonderful graph here.

Oops. But what we're looking at is a peak, measurable high peak at about the month line. So this is one week.

And this is one month, broadly speaking, and the beauty of this is that if you've got a, Peak of IGM sorry, yeah, IGM but not IGG. Then you've got an early infection, and to be honest, in such a case, you probably haven't got You probably haven't got clinical sciences at that point. So if you're seeing a let me just correct that, that's yeah, that's one week and that's 1 month.

And that's IGM just to be confusing, and that's IGG Right, back to the laser pointer. Right, so in the first week, you've got a positive on IGM but you won't have er conversion with IGG yet, and as the as time goes by, we'll see that IGM decrease and decline and IGM start to rise. And the, the beauty of this is that because there's a time lag between infection and the settling out of the spores in the tissues that we're particularly interested in, the brain and the the kidney.

If you've only got an IGM peak, then it's too early for infection to take place. So if you've got clinical signs and you test the rabbit and you get IGM positive and IgG negative, then the signs are not due to the to reconnect and you need to look elsewhere for your your cause of the problem. If you've got just IgG then, as I said, you know, that's that's about a month onwards down that fits quite nicely with with with the infection with the Echi.

And I would say up until quite recently that if you see both, you've got some sort of glitch, you've got something going on, wrong because that doesn't fit. But what I'm increasingly seeing is a positive for both, and what I think must be going on there. Is that we're seeing a rabbit who's, because this IGG can go on for months if not years, we're seeing a rabbit with relatively, historic infection, who then has those little spores replicating, and sending out, spores into the urine, which are then reinfecting the rabbit, and we're getting a fresh immune response a week later to that.

With the IGM rise. So basically, you know, if you've got both up, you've got an active flare up of infection, and that I would say, counter, countermands the, the previous thing I was saying about IGG only, not indicating, sorry, IGM only not indicating an infection. If, if IGM only is up, it's not the cause of the problem.

If IGG. Is up by itself or with IGM it most likely is. OK, so that needs a little bit of interpretation, and I can see why the temptation to look at PCR testing is it's a great, it's a, a simple yes or no.

The problem is that whilst you can really trust a positive, a positive means that the genetic material of the organism is there. And it's, if it's being excreted by the animal, it's not just there, but it's active and proliferating. So you can be fairly certain it's, it's effectively significant.

But what do you do if it's a negative? Well, if it's a negative, if you get a negative result back on your test, it could be that the rabbit's negative, obviously. It could be that the rabbit is simply not shedding at that particular time, and it's really difficult to to determine which of those things is going on.

Coupled with that, I've done a a study where which is unpublished, it's my diploma thesis, but we looked at doing a PCR on urine and faeces from the same rabbits at the same time. And we got PCR positive results from the faecal test, but not the urine tests in some cases. And that just doesn't make sense because it's a renal disease.

If anything, it's more likely to be passed out in the urine and give positive results. So looking back on the methodology, the conclusion we came to was that if you see your classic rabbit urine sample here. It's a syringe full of of whole urine, if you like, and the bottom half or or even more of that.

When it's been allowed to settle out, it's this fabulous sandy gritty material, this calcium oxalate or most likely, sorry, calcium carbonate, gritty sandy material, which causes problems in rabbits if untreated, that's a whole different conversation. But it's where the spores tend to live. So if we let that settle out and we ignore that and then we sample the supernatant the clear to pretty much, clear liquid sample that off the top, that probably isn't going to come up with a positive because all the spores are in the the gritty stuff which is too thick to come up through perhaps a a syringe and needle which you're using to sample it.

So the moral of the story here is if you want to maximise your chance of getting a positive result, should the rabbit be positive, you want to take, ideally, I think, faeces and urine ideally over a period of time because that maximises the chance of getting a true positive. We've got intermittent shedding over maybe 3 or 4 days and probably putting a whole lot in a pooled sample container and submitting it for for PCR. But if you're taking just urine, making sure you get the whole urine sample and you're not just getting the the super latent from the top.

So we have to have genetic material in there to get a positive, and if we don't, we got the false negative. And if you look at faeces, there are all sorts of other complicating factors, due to inhibition by, organic material, potentially false positives, as a result of organic materials. So, I think personally that serology is a better, test, but with the caveats and nuances that I talked about before.

And I just put these in for pretty pictures and this kind of does explain, help to explain what's going on. We've got the trichomes trichrome staining here which shows up the spores very nicely, but those spores do live in the gritty calcium carbonate material, so probably you're avoiding observation either microscopically or on PCR. You'd think that CSF taps would be a, a really good source of, material, of testing material, but they're not, they give a non-specific appearance of inflammatory changes, inflammatory markers in the, in the brain.

They're not pathomonic for deiculate. And you can look at other, other more sort of general, parameters, and I suspect if we look at things like C-reactive protein, and we look at a lot of other inflammatory markers, we'll get even more information, but at the moment I would say really just, you, you would expect in many cases to get a reversed albumin globulin ratio to to see quite a high globulin or globulins in comparison to to albumin. And if we look at those gamma er if we look at those globulins in in more detail, doing serum protein electrophoresis or serum electrophy serum plasma electrophoresis, then we're going to see spikes in the gamma components, the gamma globulins in particular.

And always have in the back of your mind, you know, could this be something else? It's, it's, even if you get eclinally positive results, if it isn't quite fitting, think a little bit beyond that and wonder whether we've got either the echi being a red herring, or we've got something else going on there. And this is a youngish rabbit who was presented for for neutering, and she'd almost died under anaesthesia when the referring practise had induced her, she'd you know, gone into respiratory.

Arrest and such like and you can see why this, this poor rabbit's got a a a a sort of folding old pathological compression type fracture probably being stood on or squeezed when she was a youngster and the tho the thoracic vertebrae have set in this kind of position, so I think historic trauma that the rabbit was living with surprisingly well, but as soon as she was under anaesthesia, she, She wasn't able to, to use, utilise even that small amount of, of lung capacity fully, and she was struggling. So this, if this had been low down, we could well have had neurological problems and so you know, think about spinal damage, think about spinal fractures, think about other causes for for paresis, as well as the ears, which I, I mentioned being the the most common one. This rabbit was ataxic, wobbly, and so on.

This was showing non-specific neurological signs, which again, you could easily put down to eat. And on X-ray, she had clinical lead poisoning, one of only about 2 cases of, well, 2 cases of heavy metal poisoning in total I've seen in rabbits, and this was due to a lead airgun pellet or a lead fishing weight, I can't remember which. She lived in the bottom of a shed.

These tins of weights and pallets and such like were put up on the shelf, but they'd obviously got knocked off and fallen in their hundreds onto the floor, and she'd just hoovered one up along with some food material. And this was leaching into the body and the the lead doing so was was causing neurological abnormalities. So if we've decided that these rabbits are, are positive, what do we do about treating them?

Well, a lot of different drug classes have been investigated for use against the clinically. It is a human disease. There is a zoonotic possibility, particularly with or only really, I think with severely immune suppressed people.

So there's been a little bit of work done, especially in humans to look at what treats it. And although some of these things have shown some degree of promise, it's the the bentoiddazos that really have been the only ones that have kind of stood out as a, as a treatment option. Interesting to see some of these drugs here that are antifungals because this, this organism isn't really a a protozoal organism, it's a, it's closest to being a a a unice cellular fungal organism, and it involves chitin in its exoskeletal.

Spore covering, which forms a kind of spike, physical spike that drives through the cell wall and inoculates genetic material into the next little cell, and that's how it spreads from cell to cell, whether it be in the, the brain, or whether it be in the the kidney or whatever. So antifungals have been used to try and combat that chitin, spur production. In the UK really fenbenzo is the treatment of choice.

There are a couple of other benzoiddazos that tend to get used around the world, but it's, also has the advantage that it's pretty much the only one that's got published data behind it. But although that published data is interesting, there are a couple of caveats I wanted to point out as we as we go. And it's been utilised as a prophylaxis in inverted commas.

Hopefully you'll we'll get to show you why prophylaxis is a, is a bit of an inappropriate term in these cases. It's relatively safe, it's widely used in puppies and kittens and so on. It has caused bone marrow suppression in a range of species, particularly, I think, to say birds, but there have been a couple of mammalian species, where it's been demonstrated.

So I'm always a bit cautious about using. For long periods of time, at relatively high doses and you know, sort of giving it to rabbits that we're not really sure even are positive, which is why again we should go ideally back to testing rather than just jumping in the treatment. The paper that I'm referencing was by Suterreel in 2001, and it was a two-part paper.

The first part used 20 milligrammes per kilogramme per ounce, for 28 days. It was actually slightly more complicated than this. It was either put into the food at that level or it's given 10 mg per gig twice a day.

But in practise, we're using 20 mg per gig per ounce, once a day for 28 days, although there have been. Questions for for animals that aren't responding to treatment that we up the dose to 50 megs per gig or up the duration of treatment to 28 days or in sometimes both, and that starts to get closer and closer to levels that I worry about causing bone marrow suppression and intestinal villa damage and villi damage and renal damage and so on. And this was shown in a 28 day course to eliminate active infection from the test subjects who then were histopathologically clear of of infection after a month or so of treatment.

The second part, that that's fairly, I think, undramatic and uncontroversial. It's the second part that I think is is a little bit problematic. And this looked at taking specific pathogen-free rabbits, rabbits who absolutely did not have ula.

Giving them a 9 day treatment with enmbenzo, at 20 mg per gig, and 7 days into that study, they deliberately inoculated these rabbits with a dose of chilli spores and continued for 2 days afterwards with feenzo. But we don't know in practise, this is great if you know exactly when they're going to be infected, but we don't know in practise when this rabbit's going to be infected. You could maybe say, well, if two rabbits are coming together to, to mate, which is pretty much the only one-off, time limited interaction rabbits are likely to have, it certainly doesn't really apply to bringing them together and and bonding them and so on.

It would be useful around that, especially since, as part of the bonding process, they tend to urinate all the all over each other. . And that these rabbits didn't go on then if they were treated to develop infections.

So prophylaxis, I think, is a little bit inaccurate, but it's been taken to mean, yes, we should treat these rabbits for 9 days every 3 months, and I think that follows the slightly old fashioned worming advice of every 3 months or 4 times a year, and I don't think it does rabbits a lot of good. Having said that, There are places with large populations of rabbits, typically rescues and shelters, who do tend to to use 9 day courses perhaps every 3 months or so. And I think what they're doing perhaps is damping down infection, if you like, or maybe if you've got this, if you can't have an all in, all out policy and infected rabbits are just trickling through the gates, through the doors every so often, maybe it's just keeping the, the level low.

But that's a recipe potentially for resistance, so I don't think it's a good idea, and I think we should test and treat. Also remember that this isn't a disease that's that's hanging around in the reservoir that is the wider wild rabbit population, so it's not like we're worried about reinfection from from them. Reinfection is only going to come from other domestic rabbits.

So hopefully that all makes sense and if you have questions, if you send them through to the organisers, I can, I can reply. But otherwise, without further ado, we'll crack on with some other infectious diseases. Treponema, I'm including as much as anything as a differential diagnosis for myxomatosis because I promise you there is nothing better than an owner coming in worried about the rabbit having myxomatosis and, You look at the rabbit, you, you, you disagree, you, you treat them for treponema, they get better and you know, the, the rabbit, 3 days later after the first treatment is, is showing, you know, the lesions are already disappearing and showing signs of recovery.

So I think well worth including, although it's not that common, well worth including as a differential. So worth screening new arrivals if you're bringing a new rabbit in to bond with a partner or whatever. Testing them, you can, there are various tests you can do, dark field microscopy, silver stains, and so on.

There is a serological test, but it's a little bit, flaky in terms of false positives and false negatives. But it does have a fairly classic clinical appearance, which I think the only thing you could mistake it for is early myxomatosis, hence the, the worry. So really, really, really important to treat this rabbit and all in contact, if you don't, it just shares itself back around.

And to treat them systemically, I have had some places where only the eyes, eyelids are affected and they've treated them with penicillin or tetracycline baseded eye drops to to kind of make the the appearance of the disease go away and then it just spreads further and further throughout our breeding colony and so on. So classic nasal iltram lesions which do look as they blister and ulcerate, they do look a little bit like or very much like early myxomatosis. It can also affect the eyelids again like lynxomatosis, it can affect the genitals again likelyxomatosis, so important differential.

And this is a another case. As we get on to treatment, just wanted to, to say that the classic treatment of a penicillin of pretty much any type, because, the traponema syphilis organism is so susceptible to penicillins, so people like to use things like penicillin G, fin B, and so on, but you can use more modern, penicillin based treatments, any beta lactones tend to work. But remember that they're so exquisitely sensitive that you don't need to treat them every day.

You treat them sort of with pulse treatment once a week, and that A isn't particularly good in terms of developing resistance to, to penicillins from other infections, from bacterial infections. And also there is some confusion, sometimes people use that treatment regime for abscesses and suchlike, whereas you really need daily high levels of penicillin based antibiotics and other antibiotics can also be used, things like azithromycin and doxycycline, but for relatively long courses up to, yeah, typically about 3 weeks. So this isn't, this is not traponema, it's not myxomatosis.

It is a dactyocystitis where we've got pus coming out into the eye, and as such it's non-infectious. This on the other hand, whilst not bacterial and affecting the ear canal and usually around the base of the ear, is infectious but isn't a bacteria, and this is Ceroptes cannucule the, the rabbit ear my courtesy of my colleague James. So again, I've, I've kept these, these elements in these lines in because the, the principle is the same.

It's a case of examining new arrivals, biosecurity, testing, treating, quarantine, making sure this doesn't spread because it is very, very infectious. And this is another one which at first I thought was reponema but turned out to be ring one, turned out to be dermatophytosis and again follows the same kind of pattern, easily spread. Lesions on the face are very often mirrored by lesions on the genital area because rabbits eat yotrophs and spread the the organs, whether it's bacterial or viral, backwards and forwards.

And the one, sorry, and this is dermatohysis on the dermatophytosis on the foot, we've got nail bed, flakiness and inflammation and so on, so that's perhaps the, the one area, it does differ from some of these others and it affects other parts of the body apart from the face and genitals. And this is again not infectious, it's an electrocuted rabbit, this is a rabbit who's chewed on the hay, er sorry, spicy hay, wires and frazzled his whiskers. So that's not something that can be, spread from rabbit to rabbit unless they give each other ideas.

So as we go on to the viral diseases, the the the key part of today, we're very, very much, I should stress this throughout myself, any rabbit vets are all gonna be, you know, saying we should vaccinate rabbits more. We're not really doing very well, if you look at the poor report, we're not doing very well in terms of, how many rabbits in the population are vaccinated, and I'll come to that in in a moment. They must be vaccinated.

We have a disease fulfilled wild reservoir population of rabbits out there with myxomatosis, with viral hemorrhagic disease, probably just two, because one's pretty much burnt itself out. And you know, even in urban areas they potentially come into direct contact with owned rabbits, but even if they don't come into direct contact and they sneeze on them or they rub up against them or fleas jump from one to the other, we're worried about biting flying insects like midges and mosquitoes spreading eczematosis, so. Rabbits are at about 50% of the population being vaccinated, cats 65%, dogs about 85%, and yet there are higher risks.

So a real plea to, you know, to really push vaccination especially at this kind of time of year where we're worried about nsomatosis particularly. And we have a good vaccine, we have the Novacc RHD plus vaccine, which is a genetically engineered vaccine which can be given technically from 5 weeks, but with some thoughts and caveats attached to that. If you let re-vaccination go over 12 months, I, I don't believe this is a vaccine that lasts any any significant degree over the 12 month period, so I wouldn't really let them, let them do that.

I would be quite tight with reminders and get them in as soon as possible. And it is possible if you're bringing rabbits into a pair or group or a collection to separate them and hold them separate for anything up to about 10 days, 14 days to allow for the expression of infection so you don't bring it into your collection. Vaccination at 5 weeks, I, I mentioned, but that's the absolute earliest you can do it and to be honest, at that point, there's probably so much interference with MDA, maternity derived immunity, I don't know why I've called it that, that we really need to re-vaccinate following, you know, the kind of 78 week mark or so on, and there's a bit of a delay before the onset of immunity, so.

Vaccination in the face of infection is a good idea, but it doesn't guarantee safety, and I would still try and keep these these populations biosecure as much as possible. The clinical signs are really well known. Everyone's seen rabbits with this blephy edoema of the eyelids, but also the nose, the base of the ears, the skin, the penny of the ears, and the, the gentles.

A note of, you know, sad caution in that as the ears tend to be quite edematous, it makes placement with an i cannula or injection intravenously from an eagle to be a little bit more tricky with these rabbits. Mucocutaneous junction lesions, wherever they may be, face or genitals, and again, you know, have a look underneath and the screw. It can be swollen up, the vulval skin, the propecial skin or mucosa can be all swollen up, and so on.

There is, a much, much less serious cutaneous form, whilst classic, full blown, if you like, mixomatosis has pretty much a 100% mortality rate. Cutaneous myxomatosis, unless it's accompanied by respiratory complications, tends to be eminently survivable. And the worst that tends to happen is that you tend to get these, these kind of big holes in the rabbit's face.

So this lesion is about the size of 10p piece. It goes black, it goes necrotic, and it takes about, in my experience, about 3 weeks before this falls off, and you've either got healing skin underneath and it can just continue to heal by granulation, or you end up with a full thing this hole right down to the bone or all the way through an ear or an eyelid. And those might require closing if they're interfering with, say, eyelid motility over the eye and clearing the moving the TFL across the eye.

So these sort of things, these null looking lesions can interfere with breathing, and this rabbit had, as I said, a nice clean, this hasn't been, this is before debriding or anything, this was a nice clean wound that lent itself very nicely to to closure. Prevention Well, vaccination is the absolute key, but if we keep biting insides out, biting insects out, that's great. But in the summer months, probably the last thing we want is fine material fly screens that will further decrease ventilation.

So you can use insecticides, be careful with them certainly don't use fipronil and be cautious about any other insecticidal or ulthracidal product. And trying to stop a buildup of mosquitoes and midges in the area by putting vegetable oil on the surface of a pond or using biological control measures to control mosquito larvae. Moving on to RHDs, or the first form of RHD identified was RHD1 in the 80s.

And this killed pretty much every rabbit came into contact with that was under about 8 to 12 weeks. So every rabbit, sorry, over 8 to 12 weeks. So every rabbit over about 10 weeks dropped dead, just leaving that surviving, you know, next generation.

And bleeding was very, very quick, very complete, out of the nose, the the mouth, the penis, the preppi, the, vagina, the anus, etc. And so it was too efficient, too good a a viral killer basically, and killed it so, so quickly that RHD2 was a lot more successful and pretty much all the PCR results that we get back in the UK at least these days are RHD2. So again, you've got the other component of the Nova vaccine does that very nicely, it's on top of RHD1 and RHD 2 very nicely.

RHD2, as I mentioned, isn't so fatal, it only kills about half the rabbits. It's, it's, infects, but of all ages, it doesn't spare the, the youngsters. And it can take a lot longer to, to kill them.

That's, that's why it's more successful, it can spread itself around more. But because it can look vague and it can take a while, these rabbits may well come into vet surgeries with some mysterious other problem going on. I've seen them present as as GI stasis cases, for example, so you have to kind of be a bit suspicious of any of these rabbits coming in that they might harbour the HD2.

And then most recently, in the past year or so, we've had reported, well, the past 2 or 3 years on the continent, we've had reported high virulent strains of RHD2, and these have been reported in a number of different countries across continental Europe, but not so far as we know in this country, but it's difficult to test for them because PCRs don't distinguish between, Different strains of RHD2, they just tell you whether it's RHD1 or RHD2, that's, that's it. You need full genetic profile, genetic probes to to deduce whether it's a high virulence strain. And the definition of a high virulence strain basically is RHD2 on PCR with the, the kind of mortality rates that you'd expect from RHD1 killing pretty much all the rabbits in a collection.

So there's a lot more information on the welfare site which I've I've just kind of summarised there. But in, in broad summary, it's definitely present, these high virulence strains are definitely present in continental Europe, on mainland Europe. No evidence it's in the UK yet, but RHD1 got here eventually, after a bit of, you know, time wandering around on fomides.

RHD2 made it here after less time, again, moving via fomides. There's no reason to not expect RHD 2 virulent strains to do the same, so I think we need to prevent disease rather than wait for it. Unfortunately, there's no demonstrated efficacy by the no vaccines against these strains, but there is demonstrated efficacy and it's in the private licence, the summary of product characteristics for YAC against those high virulent strains.

So personally I would be using both vaccines, you giving one and then boosting it with the other effectively. How's it's bred? Well, I mentioned, very, very, persistent in the environment, hangs onto the fomites could be passed through predator guts.

So the classic is scavenging bird of prey, something like a kite or a buzzard, eats a dead rabbit that's been infected and then brings up a pellet, brings up a a casting of the indigestible material later. And that is absolutely cooing with RHD virus as a result, or simply coming out in their their faeces. It can obviously be spread from rabbit to rabbit via normal bodily secretions and everything as well, but the main worry is that if you're going out and you're walking the dog and you're you're walking through areas that rabbits have been in the wild, you're going to come back with it on your feet, that the organism and the the bacteria the virus is, is very, very resistant in the environment.

And this is why I don't really like these warnings to say, right, vaccinate your rabbits in this area because of these deaths, because I, I think it, it, it sort of encourages people to only worry about it when they hear about it in an area, whereas I, I think we need to worry about it before it hits an area it's, it's out there, it will affect all these rabbits. it could affect all these rabbits, at some point, don't just wait for it. And we can do a lot in terms of biosecurity, you know, cleaning is the first step, you know, cleaning those feet they've been walking around where rabbits live, using foot tips, changing clothes after handling rabbits that are infected in the practise and so on.

And with the newer strains being taking at least a few days to kill rabbits, quarantine and biosecurity is, is more practical, these days. This is a bit of a scary number, this is one of those things that scares people and needs a bit of explanation. Yes, the organism does survive well, particularly at low temperatures, so at 4 °C, it survives about 8 months, but.

That was done under strict laboratory conditions with the organism in a supernatant broth of rabbit liver or something similarly, you know, supportive organic material in the dark, free of vibration, free of UV light, free of any other sort of complicating factors, but, To flip the, flip it again, that is almost exactly the same surroundings as you will see if you dig a hole and bury a dead rabbit who died of mix of RHD. So we need to be very, very careful about disposal of rabbits who've died from this disease, ideally double backing them, taking to them to the vet for cremation rather than burial in a garden. This is me after I get lots of, you know, sort of worrying emails about RHD.

I just want, to, to not hear all the bad news, for a change. So I'll very quickly follow up with a tiny bit on pastorella not respiratory tract disease, just really to say it's not all pastorella. We get a lot of false negatives, pustuol is present in pretty much any rabbit unless it's specific pathogen free, unless it's been born to sterile caesarean section, but you're going to get a lot of false negatives because to to get deep enough into the sinuses to to get a positive, you really need to anaesthetize the rabbit, use local anaesthetic around the the outside or fairway down the the nasal cavity, passing a ideally shielded swab.

As deep as it needs to, to make the rabbit sort of cough and sneeze and there should be blood on the swab when you retract it. And that's not something you can do too easily. You can also find it but miss other causes and think that something is is past or other, when in fact, perhaps it's a an anaerobic organism, which sounds counterintuitive because you expect the respiratory tract not to be an anaerobic site, but it, it certainly can be.

And so it's quite possible that that anaerobes's present, but we're seeing the pastorella on the swab and getting excited about that. And also we used to think that borderail was very much a a a benign normal bacterial or semi-bacterial element of the population. And they killed guinea pigs if you introduce them to rabbits.

Well, it certainly can kill the guinea pigs, but it certainly can cause respiratory tracts, clinical signs in rabbits as well, so don't dismiss it. If it's all that you find, and the rabbit's got clinical signs associated with it, then treat it. And I won't go into massive detail through time and other pressures, but I just want to say that you, you can scope even some of the smaller rabbits, you can do nasal flushes to to to look for organisms and also to do cytology to decide whether those organisms are associated with actual clinical lesions in the rabbits.

This is rabbit unilateral nasal discharge which required advanced imaging to, to really see inside the the the sinus, the problem being with X-rays, with plan or even contrast radiography, that the two sides being superimposed makes it very, very difficult to assess the presence of purulent material, which in this case was pretty much occupying the whole nasal cavity and sinuses. Treatment isn't just going to be antibiotics, although effective antibiotics based on culture and sense to be really important, but might involve non-steroidals, may involve nebulization with fluids, just to kind of free up that prudent material, but also perhaps nebulizing antibiotics in there to hit it from both ends, and remember back to peakingchie and being an immune suppressant organism, we may have immune suppressants. Infections or immune suppressant environmental conditions like poor husbandry, generally, so think about the whole rabbit, think about the whole environment, think about the whole group.

And finally, I just wanted to finish on this, this is not infectious. But this rabbit has, slightly distended eyes. I, I globes, I think you'll all agree, and on X-ray, I'm sure you can fill in what's going on here.

We have a, a space occupying lesion in the front of the chest. It's difficult in X-rays of rabbits because the triceps gets in the way and also the thymus, occupies still going into adult life. But sometimes that thymus gets a bit too big, and sometimes we get, effects on the back flow of blood to the heart and we see an increase in blood pressure behind the eye.

And, as I said, we can X-ray, we can ultrasound, we can CT we can do all of those things. But a nice quick, simple test is, and be careful with this and do, do it whilst you watch the rabbit very carefully and stop when you, and if you need to. But if you gen.

Elevate the hindquarters if you do a kind of wheelbarrow test, this is what we saw in this case, so very little doubt as to what was going on. So not infectious, but I just thought it was a fun one, and I'm grateful to my colleague Roina for providing the the images for this. So I'll stop there and if there are any questions, please send them through to the organisers and they can pass them on to me for for answers.

Thank you very much.