Good evening and welcome to this evening's platinum webinar entitled Managing Lungworm in practise. I'm delighted that we are joined this evening by our host, speaker Andrew Francis. For those of you who don't know Andrew, Andrew started out in mixed practise in North Cornwall before leaving the beach behind and moving to the beautiful city of Edinburgh to complete his specialist training in small animal veterinary cardiology.
Since being awarded the ECVIM diploma in small animal cardiology, he has worked in pharmaceutical industry and also specialist referral practise where he was head of cardiology Anderson Moor's veterinary Specialists. He now runs his own specialist visiting cardiology company, South Coast Cardiology, and has regular clinics in general practises across south of England, as well as Belfast and Glasgow. Before I hand over to Andrew, I'm sure many of you, have attended one of our webinars before.
But I am joined this evening as well by my colleague Paul. So if you do have any issues, please do, put that into the chat box, which you can access via the bottom of the page, and Paul's on hand to assist with any issues you've got, or certainly if you email office at the webinar vet.com.
Paul will be on there as well to give you any hair support you need. As we're going throughout the presentation, please do have a think of any questions you may have for Andrew, and, pop them in the Q&A box. We will have some time at the end to put those questions to Andrew.
I always say that if you come up with a question that stumps the speaker, we'll, send you a special prize in the post. So, please do, get your thinking hats on and, put some really good questions to Andrew. So as I say, delighted to be joined by Andrew Francis this evening, and, over to you, Andrew.
Thank you very much. Thank you everyone for joining this evening, taking time out of your precious evenings to, join me to delve into the rather difficult and interesting topic of lung worm. So, I just wanted to just cover a couple of things about me, most of which have been covered already.
But mainly in terms of conflicts, potential conflicts of interest, I have previously, had speaking engagements sponsored by Boeing, Engleheim and Bayer, neither of which are sponsoring me in any capacity today. and I also, as a, in a part-time role, work with certain startup companies, and that's that name tabia at the bottom, which is. Veterinary related, but nothing to do with lung worm.
So that's my, I suppose, declared potential conflicts of interest. So, we'll just start now with a quick idea of the plan for this evening. As you'll see, and as you'll see from, the notes as well, it's very angiostrongylus focused, and this reflects the fact that angiostrongylus is the most pathogenic of the lungs when we deal with.
And certainly in my experience, seems to me the most commonly identified. And for that reason, we will spend most of the time talking about Androstrongylus. There are some, useful, cross, ideas between Androstrongylus and the other lung worms.
So we may touch on the other lung worms as we talk about Androstrongylus, but then we will also, look at other lung worms of note that affect dogs, and then just end by touching on feline lung worms as well. In the middle, I have popped a little clinical case in. Because I am a cardiologist, it will be cardiac focused.
the medics tend to see the ones that are more, caused by bleeding problems, and neurologists now tend to see a lot of the neurologically, neurologically affected cases. So the clinical case will focus from my perspective on a dog that presented with cardiovascular signs, but hopefully that'll give you a pause for thought on how things might present to you in practise. So antistrongylushaorum is a metastrongyloid nematode and the definitive host is dogs and related Canidae.
And then if you could, you'll be able to see on your screens, the little arrow, white arrow, is actually pictures of worms falling on seen just within the right ventricle. And then, they're adult and stronglus worms within the pulmonary arteries of a fox on the image on the left hand side. So they're, they're relatively small, certainly smaller than your heartworm, the American, the Diriyaria heartworm, but they are visible to the naked eye as you can see.
Their life cycle, so the L1 is what's released in the faeces, . They are then uptaken by slugs, snails, and sometimes frogs. And there's a, and they have a moulting phase from L1 to L3, and that is a critical part of the life cycle.
So L1s are non-infective, and if there isn't a suitable host, slug or snail in which they develop from L1 to L3, then they cannot become infective. OK, so that's a critical part of the life cycle. The other thing to bear in mind is that the fox.
Is also a definitive host, but acts as a, essentially a reservoir, a wildlife reservoir. So we've also used, fox surveys to track geographical spread of this condition across the UK, and we'll touch on that, in a minute. Now pre-patent period, varies somewhat depending on the, literature point you look at.
But, 1 to 2 months is a good, is a good, ballpark. If you speak to the guys from Bayer, then they're saying 28 days is their minimum prepayment period that they have, have come across. So, as we mentioned before, the intermediate hosts are essential part of the life cycle, and they're essential for the developmental phase from L1 to L3.
Direct ingestion of L3 is possible, and it's thought that free living L3 can exist on wet grass, etc. But most cases, the L3 is ingested by the dog or the fox by actual. Ingestion of the slug or snail itself.
In terms of distribution. Then, there are a number of, reference articles out there which, have looked at survey populations of wildlife reservoirs. The other way we can look at this is there's two, separate databases of clinical cases.
So the one on the left is, the, one that's, collated by Bayer. And the one on the right is the one collated by IEX. And, it just gives you an idea of the fact that this used to be a condition that was very much focused in the south east and southwest of England.
But now we do have geographical spread northwards. I remember the first case that was identified in, Scotland, and that was around about the sort of early to mid 2000s. So not that long ago, but we are now dealing with a situation where this condition is generally widespread throughout the UK.
Although saying that, the incidents in the Southeast, South Wales, and parts of the Midlands, shown by the darker green colours and the darker orange colours still are foci of much higher caseload, than the lighter colours. There's also been a dramatic increase in prevalence in foxes, and this was two separate studies. so 2008, figures in the middle box and 2015 figures on the right hand box.
And as you can see, there's been a significant increase in the prevalence of lung worm in foxes. So there is very clear evidence that this condition is becoming more widespread. Possible causes, I think climate change is quite likely, .
That's probably the main theory as to why things are becoming more widespread. The other thing we have to bear in mind is that if we look back at the the data in affected animals, we are looking and are much more aware of angios stronglus than we were in the past. So that will affect case rate, but that doesn't explain.
The increase in prevalence in foxes. So regardless of whether we're finding more cases cos we're looking for more, we are still seeing an increase in the wildlife reservoir. So then what I wanted to do was look at some of the literature, and see.
Essentially, are there ways that we can help identify this condition? Because it can be tricky to pick up. We can see cases that are anything from severe neurological signs, severe cardiac signs, right down to very subtle bleeding problems, or sometimes completely asymptomatic.
So I just went through a few papers in the literature to try and see if there's things we could pick up to help us narrow down the dogs we should be looking at. So, there was one study, published from a team at the Royal Veterinary College in 2004, and this looked at Andre Stronglus Vassorum, and this is in, real cases rather than lab cases. And the indication was that purebreds could be at greater risk.
So cavi, staffable terriers, and beagles. Now, there's no data as to whether this is just popular breeds in endemic areas, or whether this is a true predisposition, so I don't think we know any more than that. But certainly this is the, that was one of the conclusions of this study that those three breeds might have a.
Greater predisposition than other breeds. The other thing to bear in mind is that the median age of affected dogs in this study was 10 months. So this is often a condition of younger dogs, although saying that there are plenty of cases I've seen of older dogs.
So age doesn't rule it out, but I think the, the group of animals at highest risk tend to be the younger dogs. So if we look now at clinical presentation. This is a rather complicated, graph of the pathogenesis of Angiostrongylus.
And in a nutshell. You've basically got antigenic stimulation by the adult angiostrongylus in the pulmonary artery, and that can cause a number of different clinical signs. OK?
So, the, you can have ocular signs, you can have bleeding problems. You can have pulmonary artery changes. And then chronic inflammation within the lungs.
So that gives you your main, clinical signs of bleeding problems and pulmonary coughing, respiratory changes. And sometimes you will get cardiac changes as well. So these mainly reflect to either direct effects on vascular function within the pulmonary artery.
And or immune mediated androgenic stimulation against the adult worm itself. You then will, if you look at the literature, find these isolated cases of certainly more strange clinical signs, and these can reflect strange things like embolization of the worms themselves, . Embolization of larvae so they can disappear off and .
And Lodge in odd places, and then you can get CNS signs from that perspective, they can sometimes lodge in renal arteries, so a vast array of clinical signs that are possible based on the pathogenesis. But I think the key take home message of panthogenesis pathogenesis is, it's an effect of the immune system on the adult worm itself, and that effect can be quite dog specific. So that reflects why some dogs will have very few clinical signs or no clinical signs.
Some dogs will have quite severe clinical signs, and then it will vary between potentially a mild cough right up to quite severe neurological changes. And then the odd ones to bear in mind is that every so often you get the weird and wonderful ones like, acute renal failure because of embolization of, of larvae to the renal artery and crazy things like that. They're not very common, but they do happen.
So if we try and narrow that down to what is the most common clinical sign that we might expect, so let's look at clinical signs reported by the owner. Then it does tend to be a diverse clinical presentation, as we discussed, as we'd expect from the pathogenesis. And they can be asymptomatic.
But coughing has the biggest occurrence. So you'll see on the graph, on the table at the bottom of this slide that coughing, is in 47% of cases and dyspnea in 42% of cases. Hemorrhagic diaphysis or bleeding problems, only occur in 29% of cases, but.
When they have disorders of coagulation, that's much more likely to be fatal, OK? And when we're looking at what the fatality rate is, then that really depends on the source, and there are relatively few studies on, I think there are any studies on mortality within general practise. There's a study or two on mortality in referral centres, and it's somewhere between 2 and 13% of cases.
The one thing to bear in mind is, intracranial haemorrhage in a young dog, . A an acute onset central neurological signs, it's often worth considering testing for Avasal one first because actually, acute onset CNS signs in young dogs are pretty are pretty uncommon. And a Avase or a diagnostic test, probably an IDEX snap test is a lot cheaper than MRI scan and an MRI scan.
So it's certainly worth considering, . Lung worm in any young dog with acute onset CNS signs, and certainly any dog with bleeding problems, especially a young dog with bleeding problems, it's definitely worth considering lung worm, lung worms should really be ruled out in those cases. So if we now look at cardiovascular abnormalities, er, then the main ones we would tend to expect are right sided heart changes.
Excuse me. Because they tend to reflect the fact that the, the major effect of the lung of the worm itself is pulmonary hypertension, so increased blood pressure within the lungs. That can also cause muffled heart sounds, and that will often reflect a, pericardial effusion caused by a coagulation, a concurrent coagulation defect.
And then in some cases, usually secondary to essentially core pulmonale or because of the pulmonary hypertension, you'll end up with a right-sided congestive heart failure. So, of the cases I tend to see, they tend to have cardiovascular abnormalities. But I think it's worth bearing in mind that cardiovascular abnormalities are certainly not, the most common presentation.
In fact, the most common presentation is likely to be your chronic coughing dog. So I always like to just make sure that everyone is we're on the same page in terms of time. Terminology, and it's easy to bandy around big terms like hemorrhagic dialysis, but just to make sure that everyone's on the same page, I'm just gonna define what I mean by those.
So it's any unusual susceptibility to bleed. Usually due to a hypocoagulability and examples, clinical signs would be petechie, purp ecchymosis, hematogesia, melena, bleeding gums, epistaxis, coughing up blood. So any evidence of spontaneous haemorrhage in a dog, especially a young dog, I think it makes sense to rule out lung worm as a possible cause.
The, the, what the reason why we think, or the, the proposed mechanism for why we think, lung worm infection causes bleeding problems is that we talked about the, antigenic antigenic factors that are released in response to the presence of the worm. These are generalised, they cause excessive intravascular coagulation. And ultimately, that absorbs all the circulating available coagulation, .
factors, and ultimately you end up with a consumptive coagulopathy. So the liver can't cope or keep up with producing, new coagulation factors, and ultimately you end up with consumptive coagulopathy and then ultimately disseminated intravascular coagulation. So in terms of clinical signs, the key one is that respiratory tract disease is probably the most the most common clinical signs that you'll see.
So the major most dogs that you see with this condition are likely to present with respiratory tract signs, coughing and or respiratory distress. You may see evidence of right-sided heart disease, but certainly the absence of right-sided heart disease in no way rules out lung worm. Bleeding tendencies, anemias, anything like that, hematomas, theocranial haemorrhage, anything like that, .
Are less common, so around about 23, 24% of cases, but the problem with these dogs is that their prognosis tends to be a lot worse. The other thing to bear in mind is, a young dog. Certainly the median age in the study that we looked at was 10 months of age.
So I think I would be much more suspicious in a young dog, but at the same time there are plenty of older dogs out there, that will have lung worm. So I think in these situations, you should actively consider, angiostrolus vasorum infection. When I do this talk in, in a room with an audience, I usually ask the question, how anyone in the room has been unlucky enough, to lose a patient, during a routine stay, or routine castration due to uncontrolled bleeding.
There's usually one or two in any, in any, group. And, it usually turns out that that animal were to have, has had angiostrolus. So if you do notice any spontaneous bleeding tendency, however subtle it is, in a young dog around elective surgery time, then it's definitely worth checking to see whether that patient has angiostrongylus or not.
So I'm gonna focus on diagnosis from a point of view of the most rational way of focusing on a dog and how they would present to you, OK? So we talked about the respiratory clinical signs as being most common. And in most cases, therefore, thoracic radiography is often the first logical diagnostic step, particularly if you're not immediately considering lung worm, because the reality is the majority of dogs you still see with coughing, and respiratory signs probably don't have lung worm.
So you're probably not going to do a specific lab diagnostic tests on every coughing dog that you would see in the clinic. So what you're probably gonna find is you're gonna be radiographing a lot of these dogs. So it's worth understanding what you might see.
If you were gonna pick your first logical diagnostic step. So luckily there is a another study, again, quite an early study from 2004, which looks at radiographic findings in 16 dogs infected with Andros strongylus. And the study population was 16 infected dogs.
And 49 control dogs, multiple breeds, again, you'll see the median age here is 11 months, so fits with the study we talked about a little bit earlier. There were 12 dogs with respiratory clinical signs and 4 dogs with bleeding diaphysis. So as you see again, that fits with respiratory being the most common presenting clinical sign.
We looked at the red, they looked at the red graphic findings in these dogs, and 81% of them had a multifocal and or peripheral alveolar pattern. 69% of bronchial thickening, and, there was also interstitial lung pattern. But the key one was a multifocal and all peripheral alveolar lung pattern.
Now I hope you can see, on the screen here, . Now I'm just gonna point out if you can see my Mouse here, marker here, but you'll see that peripherally we're looking for these fluffy alveolar densities. OK.
And they're quite unlike anything like they don't look like heart failure, they don't look like er pneumonia, which would most slightly involve one lobe of of a lung or one part of a lung, but patchy diffuse alveola, interstitial alveolar lung patterns are a relatively uncommon. Radiographic finding to find it. And if you see this, you should immediately think some form of lung worm.
Not necessarily angiostrongylus, but definitely think lung worm. Certainly in my experience, when I've seen this, clinical, seen these radiographs, they usually are angiostrongylus, but as you'll see a bit later, some of the other lung worms can create similar radiographic patterns. This is another example, so you can see a bit more diffuse and a bit more patchy and a bit less clumpy, but very diffuse, very peripheral, interstitial alveolar lung pattern.
And if you see this lung pattern, on a radiograph, and remember you were taking this radio off because the dog was coughing, then you do need to consider other diagnostic tests to confirm the presence of a lung worm. Thoracic radiography cannot confirm, or definitively diagnose if the lung worm is present, but can certainly significantly increase your index of suspicion, as to whether you should be worried about it. Another example, here.
You can see here it's much more, organised here. So you've actually got one long lobe, which is a bit more, consolidated here, but again, patchy and distributed alveolar lung pattern. When you, if you have access to CT scan, then you find that these patchy areas are much more easy to see, as you always find on CT scan, but you see very peripheral, patchy, .
And these are, most likely to be, granulomatous change related to, inflammatory responses to the lung worm itself. So, this is basically a granulomatous disease. It can take a long time to form.
OK, so the fact that you don't, if, if you, if you have a patient that doesn't have it doesn't mean you can rule out long worm. The other thing to bear in mind is that often this pattern does not resolve. So you can treat these animals, you can er cure their lung worm, er their.
They can be clinically normal, but if you repeat the radiographs, they will still look abnormal. So it's just one to bear in mind when you're doing case follow-up is that just because you don't have a normal radiograph does not mean you haven't got adequate clinical cure of these cases. In this study, surprisingly, actually, if you had cardiac chambers, enlargement, you were more likely to have another non-angiostroulus disease.
So therefore, actually, having, right ventricular hypertrophy or bigger pulmonary arteries would actually make it more likely that you didn't have a lung worm. And certainly there is some debate in the literature as to whether pulmonary hypertension is an issue. Certainly in my experience it is.
And more recently, so in 2015, Kieran Borgia at the, when he was at the RVC looked at this from a retrospective point of view. He looked at 96 dogs with Avas or infection and found 14 dogs with moderate to severe pulmonary hypertension. So, you know, not far off 14% of cases.
And the crucial thing was that if they had pulmonary hypertension, they had a significantly shorter survival time and a greater risk of death within 6 months of diagnosis. So I think there definitely is an issue with pulmonary hypertension in dogs with angios strongylos hazorum. I certainly see it in my clinic, but then I am obviously being referred to cases that have been self-selected to have cardiac changes anyway, but.
Kieran's data would suggest that, you know, at least 10% of dogs with with a visor infection, will have quite significant, potentially quite significant pulmonary hypertension. And certainly in the case we'll look at in a minute, the main presenting sign in that case was all related to pulmonary hypertension. So if we look at the bleeding diaphysis patients in that radiographic finding study, 3/4 of the dogs with bleeding problems also had those radiographic changes, even though they didn't have respiratory changes.
One of those, one out of those 4 with bleeding problems had normal radiographs, OK? So the reality is, in that study, the majority of dogs, regardless of their clinical signs had that those radiographic changes. But that actually having normal radiographs does not categorically rule out the presence of angios strongylus, but it, because it's likely to be one of the first diagnotic tests you would do if you weren't clinically, considering lung worms straight away, that's certainly a lung pattern to look out for.
In terms of follow up, then we see, that, after after treatment, all thoracic radiographs remained abnormal. And so that reinforces the fact that we shouldn't expect resolution on radiography in patients with angios strongyloshaal. So, so far, key points from that perspective are, median age of infected dogs is 10 to 11 months.
So this is generally more of a disease of young dogs, but there are plen there will be plenty of dogs, older dogs out there that will have, will get angiostrous as well. The distribution of the alveolar pattern is quite specific for lung worm, not necessarily specific for Androstrongylus, but quite specific for the lung worm. And therefore, it's probably one you should try and commit to your pattern recognition memory bank, because if you are radiographing coughing dogs and you see that that lung pattern, then definitely think lung worm.
Even dogs without respiratory signs may have the radiographic changes. So it certainly seems to be, quite a good indicator, but do remember that the radiographic changes are not diagnostic. So radiography does not provide a definitive diagnosis.
The alveo lung pattern er does not seem to resolve in treated patients, and at the moment, the effect of infection on long term survival is unknown. So what I usually say to my clients is. I cannot say to you that, in 4 or 5 years' time, that your dog will be clinically well and not have any long term chronic lung changes.
But certainly in my experience, I've never come across, cases that have clinically resolved that have then gone on to have problems in the future. But no one has done the studies to show that. So I'm always a little bit more circumspect with owners just so that they, so that I'm not giving them false hope, but I've certainly had no situations where.
I've had cases where, they've had chronic lung function problems at any time in the future after a successful management of their lung worm. So now let's look at er at the shall we say, the more er definitive tests. So the first one to consider is bare and faecal flotation.
The great thing about this test is you can actually ID the LV L1 larvae, . The larvae are not found in the pre pre patent period. And the problem with this test is there's limited sensitivity on a single sample.
So, the, the advice is always to try and pull free samples of faeces, and then that maximises your sensitivity. The other key benefit of about faecal flotation is that you will pick up any lung worm if it's present. And your stronglus tends to be, have the most vigorous L1 larvae, so easiest to pick up, but strictly speaking, you will pick up other lung worms if they're present.
And, with a little bit of expertise can diff differentiate the L1 larvae er within the sample, by looking at them on the microscope. So it's what's known as a multivalent test, it's not just for . For Andiotroylus, and certainly if you suspect other lung worm other than Andiotroylus, then it remains one of the most significant tests we have available.
So in order to improve sensitivity, we need to pull free samples, that decreases your risk of false negatives. And then I think we have to bear in mind is because of the low sensitivity, you can sometimes have other tests that are positive and them and can be negative, OK? .
But the reason why it essentially remains the gold standard test is because it can identify any present lung worms. And remember that the other tests we're gonna talk about are compared to Bearman as the gold standard test. We've covered that one.
So direct faecal smears, these are compared, as I said, against bare and faecal flotation. They're meant to be a way of, of essentially simplifying the process of identifying L1 larvae. So you basically take a small amount of faeces or a drop of tap water on a slide, under the microscope, and you basically look for L1 larvae.
The problem is, is that if you have never done it before, then your sensitivity is very low. If you, get quite experienced and your sensitivity can significantly increase. .
This was looked at in a study by Karen Hammer at the RVC, and their conclusions in their own study was that they should do better faecal flotation as well. So certainly in my experience, I don't think it, it adds a huge deal to the diagnostic pathway, because you're gonna have to do them and faecal flotation in any case, but. It's such a simple test that if you very much like using your in practise microscope, then it's certainly something that's worth trying.
From an, from an and your strong point of view and your detectors probably now the most used test. So again, it's compared to bareman faecal flotation, but because it is so rapid and because it's a bedside test, then, it probably supersedes barein in the vast majority of cases now. The thing to bear in mind is that it will only identify angios strongylus, .
So there has been no cross reactivity identified with other lung worms, which is great if you want to identify lung worm, if you want to identify under your strongylus, but if you're worried about another lung worm, then this test is not for you. the other thing to bear in mind is that the earliest positive test is 9 weeks post infection. But all dogs then test positive after 14 weeks.
And then the other thing to bear in mind is that a negative test, you tend, you should get a negative test within 3 to 7 weeks of treatment. So it probably makes sense to use antigen detector as your follow-up test rather than thoracic radiography, because as we mentioned before, thoracic radiography often remains abnormal. In terms of practical terms of androgen detect, a positive result is very reliable because of that specificity of 100%.
And a negative result in a case highly suspicious for disease should be followed up with an alternative diagnostic test or retested later without delaying treatment, OK, because that reflects the fact that sensitivity is not 100%, so you will sometimes get some false negatives. So a positive test, very reliable, negative test, if you're still highly suspicious, then it's worth retesting. Bronchoscopy, bronchoscopy, is certainly not a test, I do routinely on these cases, but it's often one which you end up, making a diagnosis, because you happen to find them in the fluid.
So you do a standard respiratory workup. It may well be that the radiographs are not classic, so you end up going down the bronchoscopy route and in your BAL fluid, you end up getting, L1 larvae back. So it's certainly not a test that I recommend in every case, but sometimes that's ways we have identified them.
The other benefit is obviously, it is essentially also a multi-ve test because you will pick up other lung worms, larvae in this way as well. When we look at probably the other most common, lung worm at the end, renoso ofulpis, then. That you'll see little nodules, where the larvae sit and you'll see them in the trachea.
So tracheoscopy, actually looking at the trachea itself can be quite useful for some of the other lung worms. So if we're worried about other lung worms and not understrongylus, then bronchoscopy may well end up being, it's often part of the diagnostic process. But certainly I don't think you need to be doing bronchoscopy to identify angiostrongylus in most of your, in most of your patients.
So I think in balance, the key thing is always to be suspicious. So young dogs, so 1011 months of age, . Respiratory signs are the commonest coughing, respiratory distress, be aware of bleeding problems in young dogs.
All bleeding problems in young dogs, spontaneous bleeding problems, should be assessed for lung worm. Be aware of, of advanced CNS system, clinical signs in young dogs. That's certainly worth testing as well.
I think, the key thing is not to be paranoid. There are certainly, you know, not every case is gonna have lung worm. Although the incidences increased significantly, I test a lot of animals, and most of them still come back negative, but I think because it can be difficult to spot, the key is to raise our clinical index of suspicion.
So I think the overall, kind of, take home message from Andy's stronger's point of view is be suspicious. It's also worth remembering that obviously . All ages can be affected, and, Avis or infection should be a differential in any bleeding patient or those with a wide variety of neurological presentations as we just mentioned.
Treatment wise, I don't think there's really much, concern treatment wise at the moment. We have two licenced preparations, for, treatment, and they are shown in green, at the top. The others on the screen are, no longer really recommended.
Some people will add in fembbendazole on top of, either of the combinations in green. The reality is that would be off licence, so, I've certainly managed plenty of cases now without fenbendazole, but plenty of people still do use fembbendazole in addition to the two, products at the top of the screen. In terms of supportive therapy, .
That depends on how clinically affected they are. Certainly if they have bleeding problems, then hospitalisation may well be required. Various supportive therapies, depending on how unwell the animal is.
If the patient has haemorrhage associated with disseminated intravascular coagulation, then the prognosis tends to be poor. And these animals often need quite, invasive supportive therapy, blood products, blood transfusions, and that that may well be required, on top of your, Of your, an intake treatment as well. In terms of efficacy of therapy, then we're looking at resolution of clinical signs, elimination of faecal L1 larvae, .
The thing to bear in mind is that clinical signs may persist, . Chronic progression of respiratory disease may be observed despite effective parasiticide treatment, but certainly in my experience, if they respond well clinically to your treatment with your antalytics and they don't have bleeding problems, then they actually tend to respond, quite well clinically to treatment. there are good preventive options out there, the same two products again.
So certainly prevention is, is very much an option. . One thing I think we need to bear in mind, er, and it's certainly one I come across when I talk to vets, in, in, when I do this meeting face to face, is that we don't actually know the actual compliance rates for monthly dosing.
They're unknown. Depending on who you speak to, they could be as low as 30 to 40%. Bearing in mind that even one missed dose is noticed to significantly increase the risk of a new infection, I think it's very important to bear in mind that just causes a dog is on the clinical history, known to get regular, preventive does not mean that it does, and we need to be mindful that those dogs could still be at risk.
Of angiostrolus infection. I think that's one important point to bear in mind. Very quick look at this clinical case, cos then we are just, running out of time a minute.
So this is a case I saw, about 2 years ago now. So this is a 24 month old, female neutered French bulldog with a 6 month history of exercise intolerance and excitement induced syncope. Physical examination, she had very pale, she had pale but pink mucous membranes.
Her jugular vein evaluation was unremarkable, . Thorascal's auscultation question mark was because she's a French bulldog, and good luck with that in many cases. Heart rate was 120 to 150 with a regular rhythm.
She had no murmur, but she was having incessant pan panting, and abdominal palpation was unremarkable. So a relatively unremarkable physical examination. I've just got some stills of the ultrasound that we did, and what you'll see from here is that in most normal cases, you would not expect the right side of the heart which is here.
To be as big as or bigger than the left side, so I'm immediately worried that the right side of the heart is bigger than it should be. This is here, the pulmonic valve here and then the pulmonary artery is here and here. And here, so a massive pulmonary artery dilation, which is very suggestive of pulmonary hypertension.
This was her thoracic radiograph, you saw this radiograph a little bit earlier in the presentation, so you can see these fluffy, peripheral alveola, . Densities, so when I initially saw this patient, I was very much considering her to have some sort of congenital right sided abnormality. I was certainly not expecting her to have, Lung worm at all, but once I'd done the thoracic radiograph, then there's really nothing else within right-sided cardiac disease that can cause this thoracic radiographic pattern.
So immediately my clinical in of suspicion of angios strongylus was raised, . The rest of her lab tests were largely unremarkable, slightly elevated Matocrit probably reflects her being a French bulldog and not much else, . A coagulation profile was pretty much unremarkable and an angio angio detect test was positive.
So I probably wouldn't have run that unless I'd seen the, the, the thoracic radiograph, so just to give you an idea of how useful that that radiographic pattern can be. Treatment wise, . Then, she did get advocates, she did get famendazole as well.
I suppose the one reason why we might use famendazole is if we're worried about multiple infections with lung worm. Remember with Angiotech, we're only picking up if angiostrongylus is present, so there's always a possibility of lung worms are present. And when I've spoken to the medics, when they give.
For beazole as well, that's often the reason why they're giving it to check for evidence of other infections. Sildenafil, Viagra for the pulmonary hypertension. The advocate, and then prednisolone, short course of prednisolone, for its anti-inflammatory effects.
She was also hospitalised for a couple of days just to make sure that, the, the worry is lung embolization of, of, of, worm fragments. So we usually keep in the hospital for a couple of days just to make sure that she remained well throughout and she certainly had no evidence of bleeding problems or tendencies or any concerns from that perspective. Post-treatment follow-up.
So we followed her, we did recheck her snap test which proved to be negative about eight weeks later, as you'd expect. But we also followed her echocardiographically, and so on the top, screen, top of the screen is the echo presentation, then 1 month later. After treatment, 1 month after treatment, you can see that the right left side is now bigger than, than it was before.
The right side is smaller than it was before. So the heart is remodelling, reverse remodelling, and then at 6 months, you can see the left side is now pretty much back to normal. It's now the dominant chamber again, and the right side is actually barely visible.
So this dog's quite severe cardiac changes normalised, spontaneously. By itself, and all we did was ultimately treat the lung worm and also treat her symptomatically, for the, pulmonary hypertension and the heart remodelled itself back to normal. As far as I know, I think I last heard from this dog about a year ago and she was absolutely fine.
So again, although we don't know what necessarily happens long term, there's every, you know, . Expectation to think that they can actually have a pretty good long-term outcome, a post treatment for a post resolution er of lung worm infection. So just while we're finishing up, we'll just touch on some of the other worms, that we see now in terms of how often we see these, so I probably see angiostrongylus, in a patient maybe once every couple of months.
I might see rednisone and fulpis once every 6 to 12 months, . So, in my experience, a lot less common, er, certainly a lot less, er, pathogenic, so may reflect the fact that we're just not picking them up as frequently because they're left pathogenic. But it's generally gonna be respiratory disease, which can be severe, but Crohn's does not seem to cause bleeding disorders.
The life cycle is similar to avasorum, so there are intermediate hosts slug and intermediate hosts, and the foxes act as a wildlife reservoir. And we do know there's a widespread geographic distribution, so they're out there. We may not be spotting them because in many cases they don't cause significant disease, but they should be kind of in the back of your mind in a dog with chronic respiratory disease.
Diagnosis, so sometimes, these dogs will have a permanent nasal discharge and associated with respiratory clinical signs. So if you see that combination of signs, then definitely it's worth considering renoso ofvolpis. Radiography non-specific findings, can be similar to angios strongylus, but not quite as pronounced in many cases.
Bronchoscopy, I certainly tend to pick up more of these on bronchoscopy. So, then they'll often have an osinophilia, but certainly not in all cases, but in many cases. And then ultimately you'll you'll IV ID the L1 larvae either in BAL fluid or on bareman faecal floatation.
So there is no bedside snap test for kind of allpis. So we are gonna have to go back to the bare and faecal floatation or BAL fluid evaluation to identify these guys. With a bit of practise, they say that you should be able to differentiate the two.
So the little circle on the right shows the little kink in the tail for angiostroylus, and crenosoma orpis does not have a little kink in the tail of the L1 larvae. But many of, many labs with, will not call it. So I think it's harder than people would suggest it is, to identify the two.
In all honesty, it doesn't really matter because, the treatments are the same. So antics used to treat renin andorpis are the same as the ones used to treat. and your strongylus.
The main difference is there is really no licence preventive for quenosome of allus at this stage. So Filaroides, er this er is, has a direct life cycle. So no intermediate host.
This tends to be transmitted from bitches to pups, a disease of young animals, and adult worms inhabit nodules at the base of the trachea. So again, the diagnosis is gonna be I idea of larvae on faecal vermin, tracheoscopy can be useful to, to identify the nodules, and the treatment in this case is fenendazole. So this I.
I think I saw one case when I did my residency and I don't really see any cases now, but it may well just be that, that, that, that, you know, having in young animals, certainly it may be in kennel settings, means they're just probably not coming across my case load. Just before we stop, we'll just, quickly, have a, a quick overview of feline lung worms. It's pretty brief, .
So the main one in cats is lua strongullu substrusus, . Again, it's found within nodules, so in the lung parenchyma and bronchioles. It's a it's an indirect life cycle similar to Calpis and Avesorum.
So it does, use mollusks and, slug and snail hosts, but also, rod and bird parenic hosts. And therefore, cats are most likely to pick it up via predation. There is some debate as to how clinically relevant it is, particularly in the UK.
So most of the data, most of the studies come from Italy and other non-U UK and other countries outside the UK. So, I've certainly come across case reports in the UK, but I'm certainly not aware of, I, I'm certainly not picking this one up, on a regular basis. So I think certainly critically important or not difficult to say at this stage.
They can be asymptomatic, or they can be mild or have mild to severe respiratory disease. There are variable thoracic thoracic radiographic findings. I think the key one is that sternal lymphadenopathy was detected in 43% of cases in one study.
So, in a young cat with sternal lymphadenopathy, then a lure strongullus definitely has to be on the list. To finish diagnosis, again, L1 larvae found in either faeces or BAL. Fluid and a negative test does not rule out disease as we would expect, with the other lung worms as well, because just the fact that you don't pick up lung worm, L1 does not necessarily mean they're not there.
But I think certainly a key one for the lower strongylus is the sternal lymphalonopathesis, certainly one that having in the back of your mind, but we're very unclear, pretty unclear as to how clinically relevant it is, particularly. In the UK. Treatment is fambendazole, some people talk about an anti-inflammatory dose of prednisolone, may be beneficial in alleviating clinical signs during therapy.
There's no licenced product for prevention, and I suppose the other main way to, promote prevention would be to try and prevent hunting where possible. Although I suspect in a cat that very much loves their hunting, that's going to be very difficult, thing to try and achieve. So that is, the end of our, on my presentation on our web, so, .
Thank you for taking the time out of your evenings to join us and I'm open to any questions if there are any. Thank you very much for that, Andrew, and, we do have a number of questions that have come in already, but, we have got a good 10 minutes, so please do, put, have a think about obviously the presentation. If you've got any questions about any of the aspects, put them into the Q&A box and we will work through them.
I could see that you were battling through a bit of a cold then, Andrew, so I appreciate that. Well, no, it's absolutely I'm glad. Get going, that's not a problem.
So the first question relates to really the beginning, and it's asking about in terms of the foxes, the foxes have the same burden of lung lung worm as dogs, or with them being a natural host, if they sort of built up some sort of suppressive ability? And do you know how often foxes, die from long worm. So a couple of parts there really, one about whether they've, built up some suppressive ability to carry the worm because they're a natural host and so, is it common for foxes to die from long worm, lung worm, sorry.
So the data we have on foxes comes from what they. What they call surveys, but basically means it's either from foxes that have been found dead or or when they've done cull, cull studies. So, the short answer is I don't think there's very little data on, on, shall we say, how many foxes have died as a result of lung worm.
So, so certainly what, what the, the survey data is saying is that of these, foxes that are, postmortems we have done, this number of, of foxes have, essentially worms visible in their, in their lung parenchyma. I think the the question about whether they have a natural. Immunity I think is very interesting because I think the reality is that there how can some dogs have horribly severe bleeding problems and other dogs essentially be asymptomatic, is because it very much depends on the response of the animal's immune system to the lung worm itself.
So I think there's variation in . In a pathogenicity within our pet population, as well as probably variation between the fox population and the And the pet dog population. They I'm certainly not aware of any evidence that would suggest that foxes carry this with zero risk.
Our every understanding is that they will get clinical disease like, like dogs would. So that pretty much is what we know from that perspective so far. OK, fantastic, thank you very much.
The following question, . How reliable is the IDEX snap test? They've recently, this, person's recently had a dog that was positive on the test.
Yeah, but on the p.m. Lung worm was found.
So, really, how, you know, from your experience, how reliable is the IEA test. So you said, so they said that that was positive on the test but lung worm was found, or was it negative on the test but lung worm was found? Oh, negative, sorry, yeah, the negative sign there.
So, so the positive, so, so there's one study that looked at compared . The snap test to bare and faecal flotation, OK? So in that study, it took all the dogs with positive bare and faecal flotation.
And then basically tried to identify them using the snap test. OK? And then it took a group of known negatives, so known unrelated and then also compared used the Snap test as well.
So we know that it's, in that one study, its specificity was 100%. That means every dog with a positive result was positive. So a positive test result is a very good, you know, is, you should take a positive as a positive.
What's a little bit more difficult is a negative result. And I didn't, I mentioned it in the slides was that if you have a case that's highly suspicious. And it's a negative result, then that could still have lung worm.
So you should consider retesting. Or use a different diagnostic test. So what I would do in that situation is I would probably treat the patient in any case.
Mhm. So because treatment wise now, it's essentially a spot on on the neck or a tablet. So in terms of antalytic treatment, it's very simple.
So if you have a negative test but you're highly suspicious, it might have the alveolar lung pattern, or it might have bleeding problems or whatever. I would then probably treat it. And then retest a couple of weeks later, because we know if you retest a couple of weeks later, the, the treatment's probably not gonna have turned that positive into a negative.
So it may well be that, that you will then get a positive test, if you test two weeks later. So the, a positive test is. Certainly based on that study, it's gonna be mean the dog has lung worm, but a negative test does not categorically mean the dog is negative.
So if you're highly clinically suspicious of disease, you should retest, but don't delay treatment. So I would probably just treat the dog if you're really worried. Fantastic, thank you.
. Can you have a lung, I don't know if this falls on right. Can you have a positive lung lung worm infection but a negative angio detect result? Yes, so that, yes, I think that's a different, so that's a different way of phrasing the same question.
You can absolutely have a dog with lung worm that tests negative for angio detect. And the reason that is, is probably, it's probably because you're testing that dog. In the pre-patent phase, or, or in that phase before, so we know that it can take up to 7 weeks for it to have a, for all dogs with lung worm to test positive with an angio detect test.
So you may be, you may end up having tested that dog a little bit early. So it's absolutely possible to have a negative test in a dog that has lung worm. It won't happen that often, but it can happen, and that reflects that sensitivity, which was around about 84%.
So if you were to test 100 dogs. Then you might expect 100 consecutive dogs where you were highly suspicious that they had lung worm. Then you would expect 14 of those dogs to, test negative, even though they actually had lung worm.
OK, fantastic. Thank you. Dave here asks, do you think there's a significant difference between FSC of prevention by monthly, Milbamycin, versus monthly, moxidectin?
Which would you use for your own dog if you wish to protect him or her. So, if you, if you read the kind of the marketing blurb, but the difference between the, the two products is, that, the Milbamax is not quite as effective at killing all life stages. And, and so there are some, I suppose there are some technical reasons why.
You might argue that . That, that's spot on, so the printerox or the advocate is a little bit more efficacious. I don't think there's, there's certainly no direct comparative study between the two.
So we're talking a technical rationale argument rather than that two people have, you know, that, that the study has directly compared the two products. Certainly, when I have when I treat cases, I tend to treat them with, the, spot on. I think that certainly in my experience, the spot on seems to be, the owners seem to be happier putting a spot on on.
I think the other thing to bear in mind is once they've had a a definitive case, I want these clients to, pop this spot on on religiously every month. So that's what I tend to do, but there's certainly there is no clinical study which proves. That the spot-ons are categorically more efficacious than Milmax.
No worries. But at the same time, you'd encourage pet owners to do it as part of a regular routine. So I think, I think, I think it's, I think prevention is, it, it prevention is a hard one because absolutely we now have preventive options out there.
I think, so it's a lot of practises now put them in. As you know, because obviously some of these, these spot-ons will do multiple worm, will cover multiple worms, so therefore they're often put in as part of the standard pet healthcare plans in many practises. I think that makes a lot of sense.
I think the key thing, the, the key worry I have with prevent with, with, with preventives is that we then maybe forget. To think about the condition, and I think that, so I, you know, I've asked various suppliers of spot-ons, what they feel the compliance rates are, cos no one knows what the compliance rates are. So if you give 12 per pets to a client for a year, how many actually get on their dog.
The, the, the, the, the numbers have ranged from 3 to 5 for pets a year, so that's pretty much, you know, the owners are already managing every other month. So basically, most dogs who are on preventive treatment for angiostros are probably still at risk of infection because they're just not getting it every month. Yeah.
So I think the main thing with preventives is, by all means consider them, but. That don't rule out the fact that the dog could still get lung worm because the client, the compliance rate is always way less than you think it should be. OK, no problem, fantastic, thank you.
Got time for two more questions. So let's have a look here. Let's see, so we've got, with pulmonary hypertension, I think it is, is there any raise in peripheral blood pressure noticed?
Any age in peripheral blood pressure was that? Yeah, yeah. No, so usually the systems, will, so the right to the left side of the heart will in this respect, function separately, so, .
This, you, you, I certainly don't appreciate significant systemic hypertension in these patients. We are dealing with, you can think of it as the pulmonary hypertension, probably reflects, essentially vascular, dysfunction within the pulmonary tree, pretty isolated, the pulmonary tree, because that's where the main adult lung worms live. .
And unless you get quite severe changes in the systemic circulation, you're very unlikely to see systemic hypertension. So, I mean, I think the caveat would be do we check systemic hypertension in every case of lung MIC? Probably not.
But certainly when I was er Anderson Moors and we would routinely check blood pressure in every patient that came through the door. I certainly didn't appreciate in the cases we saw in that time that these patients ever had. Systemic hypertension, and I, there's certainly not a, a physiological reason why I would expect them to at this stage either.
No problem. We've got two questions here, about hedgehogs. So the first part is, does any part of the life cycle of the angiostrongylus, take part in hedgehogs, and then ducks follows that up with any research evidence on prevalence and treatment of lung worm in hedgehogs.
So, there are some, there are other, there are certainly studies out there looking at potential other . Intermediate hosts. So there was some, some, some, some studies looking into badgers and, I think musterids as well, with some variable, thoughts that they may, you know, are we missing a wildlife reservoir with Anders stronglus?
But certainly it seems to be that the major wildlife reservoir remains the fox. I am not, I'm certainly not, er, I, I don't have any. Personal significant experience on, on, data and hedgehogs, I'm afraid.
Sadly. That's fine, not a problem. But I'd say, it's since it's research is obviously ongoing all the time, isn't it?
But at the moment, you know, sort of foxes is seen as the primary, yeah, carrier. And then just, . We've got one here.
Are there any problems with antigen release during treatment, anaphylactic reactions? Is, have you come across anything along those lines? So it's something, yeah, so it's something that we, hello.
It's something we always worry about, . It's something I always worry about, I would say, and that's because obviously if it does happen, it's catastrophic. But it's actually certainly in my experience, relatively uncommon.
OK, hello. Yeah, so I think you can, so it can, I, I think, so what I, what I usually do to try and mitigate that is certainly if they are. So if they're gonna be hospitalised for their bleeding problems anyway, then in all reality, probably your anaphylactic reaction is gonna be the least of your problems cos the severe bleeding problems do very badly anyway.
But if we take that case we talked about as an example, . Because she had quite severe pulmonary hypertension and quite severe clinical signs, because you have no idea what the worm burden itself actually is, then in order to err on the side of caution, what I usually do. And, and this is what my medical colleagues certainly when I've managed them with, with my internal medicine colleagues would do as well, is that they usually hospitalise them, cage rest them, and what you're trying to do is avoid any, with a worm death, any breakdown of worm and, and embolization and any risk of anaphylaxis in that respect, .
I sometimes would use anti-inflammatory doses of steroids, depending on how clinically well the patient is. But certainly I wouldn't do, I wouldn't, I'm always mindful of it, but I certainly don't do any other, treatments specifically for anaphylaxis, and touch wood. I haven't personally had a case where that's happened as yet.
But it's definitely out there, it's definitely talked about. Again, I can't find a study which says it happens in this percent of cases, but everyone worries about it. No problem, so keep it on the radar, but it's not something that's that relevant.
Right, one last question before we let you go and get some treatment yourself. Obviously, and it's something that's very, very, very prelevant at the moment across all sort of areas. Has there been any resistance shown yet to the drugs used to treat lung worm?
So, this tends to be quite closely guarded information. So I, don't really, I haven't seen anything, specifically at the moment. My, I suppose my kind of pragmatic point of view would probably be at the moment, that probably the biggest risk of, of kind of .
Of treatment problems if they're on on preventive is actually the fact that the compliance rates are probably way lower than we think they are. So, I think that's probably, and I think it's compliance is something we very we we very, it's very, it's relatively poorly understood in human medicine and not very well understood in veterinary medicine. We just always assume as clinicians that we give medications and, Owners give them, but I mean I had a I had a case today of an owner phoning up saying that their dog had got worse, not nothing to do with lung one, but they'd stopped giving the freezamide.
And this is dog and heart failure. So I think, I don't have any data on whether there are resistance issues, but I think certainly from my, my major concern at the moment is compliance rather than resistance. No problem, fantastic.
So I think it obviously always important to stress the importance of the to the clients to continue the course of medication as indicated. Through to the end, even if they think the, animal's getting better to press that through to the end and see the course out, I suppose, is the, yeah, exactly, exactly. Fantastic.
Well, thank you very much. Really was a very informative, presentation. We had a couple of people here saying thank you very much, very informative.
It was a great presentation. And so some great feedback there for you, Andrew. Brilliant, thank you very much, everyone.
I would ask you all before you do leave, you should have had a surveyMonkey feedback form pop up on your browser, so I would appreciate if you could take your time to complete that as all feedback is greatly received. And we look forward to welcoming you on a future webinar. So enjoy the rest of the evening.
Good night.