Good evening, and welcome to the Webinar vet. My name is Mark Hedberg, and it's my pleasure to welcome Doctor Ian Wright as he presents an update on Dear Feria Emits. Ian is a practising veterinary surgeon and co-owner of the Mountain Veterinary Vet practise in Fleetwood.
He has a master's degree in veterinary parasitology and is chair of the European Scientific Council of Companion Animal Parasites. ESCAP love that name. Ian has over 100 25 published peer reviewed articles and papers and his editorial board member for the companion animal journal.
He continues to carry out research and practise, including work on intestinal nematodes and ticks. We like to once again thank you for coming in here. Right.
Thank you very much, Ian, Over to you. Oh, thank you very much. Thank you for the invites.
And for those of you who are tuning in live after a hard day at the office, I've just returned myself. Haven't seen any heartworm cases, which, you know, is always a little bit disappointing. But there you go.
But yeah. I mean, what a fantastic topic to talk about. I mean, we live in a world now where you know, pet travel has meant that we're coming across in first opinion practise at referral in all in all walks of of veterinary life, exotic pathogens and parasites that, you know, we just wouldn't have seen, like, 15 or 20 years ago.
And in the case of heartworm, you know, it's not endemic in in the UK yet, as far as we know, but we are seeing lots of cases in imported dogs, and cats and the occasional ferret. But it's dogs that I'm gonna be focusing on tonight. So just to remind those of you who perhaps aren't as familiar with the parasite as others thyrolar IIs is the heart worm that we're talking about here.
So there are other heart worms, like Angiostrongylus Forum, which we think of, as lung worm. But these actually a heart worm. But this is the Big 10 centimetre plus impressive, full worms that live in the hearts and in the pulmonary artery of of the pets that it infects.
It's transmitted by mosquitoes, and we're mainly worried about its clinical significance in in those animals that it infects. So in cats, dogs and ferrets, it does have zoonotic potential. So if we're bitten by, mosquitoes, in an endemic country, then potentially people can get infected with heartworm now.
I mean, the ramifications of that aren't really huge. You you might get some benign lung nodules. Probably the greatest ramification that affects people's lives is that unfortunately, it is occasionally misdiagnosed as pulmonary cancer.
And then people, you know, get the revisionist good news later, but still, you know, pretty pretty bad if you are misdiagnosed in that way. But, you know, overall, its zoonotic potential is pretty mild and crucially infected dogs Infected pets pose no direct risk, to their owners or or anyone else. You know, for us to be exposed as people it would have to establish, it would have to establish in, the UK and and remain here.
So, you know, no big worry on the zoonotic front, but we are worried about the clinical effects that it might have in our pets. Now it is a little bit of a misnomer. I mean, there are people who believe that the mosquitoes aren't present in the UK to transmit the parasites, and that's why we don't have it.
But actually, mosquito vectors are present right across Europe, capable of transmitting heartworm. And that is absolutely true in the UK as much as it is anywhere else. And if further concrete proof wasn't required, there's a lovely photo of a cicci mosquito on my bathroom wall.
It is, sadly, no longer with us. But, you know, while it was alive, it would have been capable of transmitting heartworm very, very easily. What's keeping it out is climate.
It isn't currently warm enough, consistently for the heartworm to complete its life cycle in the mosquito. So that is largely at the moment what's keeping us safe. But of course, this is all happening in against a background of climate change is gradually consistently getting warmer across Europe, and as a result, that and a combination of a movement of infected pets means that we're seeing increasing areas of Europe become endemic and particularly Eastern Europe, and we'll have a little look at that in in a moment.
So this is a ESCAP map. Thank you to ESCAP for these lovely, maps that are distributed, even if I say so myself. Not that I did them directly.
But, you know, very nice to see. They essentially show where heartworm has concretely been demonstrated to be endemic. And traditionally, as I say, if we go back a decade, 15 years or so, you know, it would have been very much south of a certain line.
So Southern Europe, Mediterranean Spain have been endemic, for heartworm for a very long time. And that's because, you know, you've got beautiful conditions for mosquito proliferation, and it's nice and warm enough for the for the, heart worm to complete its life cycle. What's happened as pets have been moved around, Europe.
And as that climate has gradually shifted, we've seen that line gradually move northwards. So in the time I've been practising Romania, Bulgaria became, endemic. We've seen it become highly prevalent in Serbia.
And then, you know, we've seen that line steadily move north and eastwards. And that trend, is continuing at the moment just to show you and demonstrate just you know, how important the climate is in preventing sort of wider spread and transmission. It closely related cousin Dirofilaria ripens where the adult worm lives in in nodules in the skin or in and around the eyes.
It doesn't have the same temperature barrier for its transmission, and its endemic countries represented by the stripes hash lines. And we can see that it can already push much further north, than heartworm. But as the years go on, and as the climate gradually warms, that situation is gradually changing.
Now, this is a slightly different map. This is idex, antigen test data. So this is this isn't a prevalence map.
This is just a record between 2016 and 2020 of all the sort of positive cases that were submitted to IDEX as a potential of to, as a percentage of total tests submitted. So we're getting a percentage. But it's not a prevalence.
This isn't necessarily a representative sample. We don't know how many of these pets were sick. We don't know how many of them lived in the country or might have been moved in from abroad, but it does really give a flavour of showing us that heartworm is showing up in countries where it isn't currently endemic.
So we can see that, you know, there are little patches, of sort of yellow light green shading through northern Europe, sort of Central Europe, where it's being identified. But also in the UK. So a big, big patch in Gloucestershire.
I mean, I think we can be fairly confident that heartworms not endemic in Gloucestershire at the moment, certainly not more endemic than Portugal. But we're seeing this because of imported and travelled dogs, and this is gonna be a massive underestimate of the total cases that are being diagnosed. So these are the ones just through idex and just the ones that are being reported through external labs or through snap test readers.
But it just gives us this flavour of move relocated pets, travelling pets, relocated dogs being a real driver and sort of being the spark. If you like the ignition, for new endemic areas to potentially establish if the climate is warm enough. So this is a real burning question, given that we are seeing a lot of positive dogs imported into the UK at the moment, we don't know exactly how many, but I have them flagged to me on a regular basis.
We can see that there are ones being confirmed by IDEX. There have been various case reports and papers showing positive dogs coming into the into the UK. So we have that infection pressure coming in.
And given that that's the case, how likely is it that thyrolar rheumatism might become endemic in the UK over time? Well, this isn't an open question at the moment. I mean, we can say that there isn't any current evidence that it's endemic at the moment.
So there's been no unravel cases yet in the UK. And I think you know, if it was endemic, given that it's a fairly pathogenic parasite, it would it would only be a matter of time before it was identified. We know that the vectors are present, but the temperatures prohibitive, And that means at the moment there's a pretty low risk of it establishing in the UK.
But as temperatures warm, that may change over time. So it's the moulting of the larval stages, in the mosquito that is temperature dependent. We're seeing in the south of England those temperatures reached over more prolonged periods of time, so we're not at a stage at the moment where it could be transmitted year on year.
But I do think we are getting close to the stage where we might say, see, say, single season transmission. We may get untraveled cases over a season without it necessarily becoming endemic at that point for a longer period of time. And if that's gonna happen, it's gonna happen in the south of England, you know, South, East, central, southern England.
It isn't gonna happen where I practise in Fleetwood where, frankly, it's more like the Arctic at the moment. But, you know, I think we can all imagine that there are parts of the UK already that are getting warm enough. We might not be that far away, and this is happening against a background of it's spreading in Eastern Europe.
So we've got the map, that I've just shown you, but also, you know, recent cases have been seen in Latvia in Lithuania. Very brave, brave colleagues of mine at the moment are collecting samples in a war zone essentially, in the sort of battle torn areas of Ukraine looking at stray dogs there and they're finding heartworm there. And there's been a lot of dogs displaced recently from Ukraine because of the fighting because people fleeing the fighting moving to different countries.
It's just those sort of events that could act as big redistributors big spreaders of heartworm positive dogs, and slightly concerningly. There was a paper recently that showed six cases in Estonia and four of those were in untraveled dogs. So if we try and get a flavour, for where that is on our map, I've just done my little blue Peter cross and circle there shows that, you know, I mean, Estonia is pretty far north of the current line, only slightly west of of confirmed, endemic areas.
But I think it does also help to demonstrate that that net is is closing in on those central and northern European areas. It means that we have to be really vigilant and really aware that it may be present in dogs being imported in areas that we might not traditionally think are endemic for heart worm but are becoming endemic over time. So we should absolutely be vigilant for clinical signs in dogs.
So what? What are we looking for? Well, essentially, we're looking for the signs of heart disease.
So one of the first signs that you're gonna see is gradual onset cough. And then we're going to see progressive signs of of congestive heart failure. So just as you would see, you know, chronic congestive heart failure for other reasons, like mitral valve disease, for instance, we're gonna see that that gradual progression of signs with heartworm disease as well those might be picked up, by osculation.
And we might start to see other physical presentations in dogs as the disease progresses. So we might see, loss of appetite, weight loss, and edoema developing in other parts of the body. So ascites pitting edoema.
In addition to this sort of chronic progression, we might also see acute signs happening on top of chronic disease, and that's almost always associated with thromboembolism. So as these heartworms die, they can trigger thromboembolism, and we can get pretty dramatic effects as a result of that, including tragically, sudden death. So you know, it's not a great idea.
I mean, to let these worms die of old age. I mean, they will eventually die of old age. I mean, worms are gonna live for.
Maybe, you know, 57 years, in dogs. But, you know, as they die, this risk from wem is grows. And if you particularly if you've got a large burden, that risk potentially may be quite high.
The other thing that that can happen is as these worms move that move about. If you've got a large number of them, they may decide to get themselves wedged in the tricuspid valve. You might get displacement of the worms from the pulmonary arteries to the right side of the heart, and you get carval syndrome as a result.
We'll talk about this a little bit more later on. But and if we don't intervene at that stage, the patient is going to die. So you know, we have to be aware of that as well as a sudden, complication.
So your dog's showing all the right clinical signs. You know, we absolutely want to be aware of the possibility of heartworm as a differential in dogs with travel history, early diagnosis is gonna make a huge difference. I mean, both in terms of, from wem is risk.
As these worms start to die in an uncontrolled fashion. But also in terms of progressive heart failure. So in general that the later we come to the heart worm party, the worse our chances are gonna be of turning the clinical situation around.
And that at the moment, is our primary concern. So, yes, there is a worry, and that worry is gonna grow of heartworm establishing in the UK. But I wouldn't say that that was a big concern.
Right now, we're trying to get the early diagnosis to get as good a possible as an outcome as we can, for our infected dogs. So we wanna test dogs with relevant clinical signs. And especially ones that have got relevant travel history bearing in mind that, you know, these worms can remain in a subclinical state for years.
Before clinical signs start to develop. So you know, you you travel history might be quite historical. It may have been lost, as as dogs, perhaps have behavioural problems and are rehomed after the end of the UK.
So you might have to dig around for that history a bit. Any index of suspicion, you're better to add heartworm to your differential list. But we also want to be screening all dogs that have a known travel history.
And we want to be doing that ideally on arrival. But it can take, 6 to 9 months before we have, sort of, you know, before infection appears on our diagnostic tests. So, you know, we may want to treat We may want to test on arrival and then 6 to 9 months later, or, you know, if the dog is in good shape and cost is an issue, we could just leave it for 6 to 9 months and then test.
But, you know, we want to be doing ideally, both if not after that time lag. It's also very important to screen before whenever you decide to do it. Before you start routine macrocyclic lactone prevention for other parasites such as lung worm or intestinal round worms.
This is partially cos we want to avoid confusion, over when infection occurred. So if we don't test, before we start treatments, you know we're not going to be certain. You know, when those adult worms developed, we're not going to be sure whether it is an untraveled case or whether it came in from abroad.
We may be worried about drug resistance when you know it may have absolutely nothing to do, with the macrocyclic lactone that we're using for other reasons. But the the biggest reason is the risk of anaphylaxis. So if you have a huge sack of micro filaria and worm larvae in your bloodstream and then you nuclear eradicate them, with your macrocyclic lactone all in one go, that may generate an anaphylactic reaction.
I mean, you know, you may want to do that anyway, in terms of trying to start treating the adult heart worms that are producing the micro filaria. But then you know you can have mitigating measures on standby. It's not gonna come out of the blue at home when your owner's given a macrocyclic lactone for reason that have absolutely nothing to do with heart worm.
So you know much better to know whether you've got a positive dog, how big your micro ferial load is, and then, you know, if necessary, you know you can. Then at the right time, mitigate the risk of anaphylaxis when you start your macrocytic lactose. So we've got the relevant clinical signs or we want to do screening of healthy dogs.
That have travel history, have lived, or spent time in endemic countries. What diagnostic tests are available to us? Well, we we do have a few different options.
I'm gonna run through them now. One of them is we could try and examine the blood in some way for the micro filaria. So looking for the for the little larvae that are wandering around in the bloodstream, there's a number of ways that we could do that.
You know, the simplest way is just to do a direct smear, so always worth doing a direct smear of travel dogs, dogs that have been imported into the UK. Just because not because the sensitivity for most parasites is very high. With blood smears, it can be extremely low, but it will give you a F feeling of the overall, blood picture.
You know, white blood cells, red blood cells, platelets, and you might just get lucky. And if you do get a positive ID, of a parasite on a blood film, you can just tick that one off. It's cheap.
It's cheerful. You know, you might if you're if you're very lucky. Bag a range of parasites that your imported pet might be carrying.
Having said that, sensitivity for heart worm is gonna be staggeringly low. I mean, if you do get one, it's gonna liven up your week. Is it?
You're gonna be incredibly excited, but I, I wouldn't be banking on it. We we generally need some sort of concentration method, to have any reasonable chance of seeing the larvae so you can do that with hematocrit tube. Either you can spin a blood down in a in a Hema hematocrit tube.
Look at the Buffy coat, under the microscope and you'll see micro filaria wriggling around. You won't be able to tell which ones they are, but it's another very easy way of telling whether significant volumes of micro filaria are present. If we want to ID them, though, which is really useful, then, you really you want to do a knots test which again is very straightforward to do.
It's a little bit more involved. You can find, methodologies online. There are sort of, you know, slightly different tweaks, slightly different variations on a theme.
But essentially, what you're doing is, taking, blood that's been prevented from clotting centrifuging it, with form. So the formalin breaks down all these sort of accessory stuff, and your worms form a little plug in the bottom of the tube that you can Then, you know, do a smear, you can stain it up, and then you'll see that the larvae are present. Now, if they are present, you've got two ways, that you could have a crack at identifying them.
You you could have a look morphologically and see if you can identify them. Morphologically There are distinct differences between the sort of subcutaneous worms, like dialer, ripens, dipey, anma and, dire aimetti, which we'd be interested in. Here, you can go slowly, insane, trying to work out if a micro filial head is cone shaped or rounded, you know, trying to measure one when it's in a sort of squiggle like this one at the bottom of the picture.
It is. So it is a refined art, you know, it is it's got a little bit of art in it as well as science. It may be better just to get them speciated by PC R.
And you know, this is possible by sending sending the blood off to the lab. Or, you know, there are some in-house PC R machines that can look for Dirofilaria species. The identification is important.
I mean, it's important to know if you've got thyro. Filaria ripens there, as this is another parasite that is a zoonosis could establish in the UK, and yet fairly straightforward to treat compared to thyrolar ius. But we don't want to be starting any sort of treatment for heartworm unless we're confident that they are heartworm micro area that we're looking at.
Radiographs aren't gonna give us a diagnosis of heart worm on their own. There aren't any changes on a radiograph that are specific for heartworm infection, but they are absolutely crucial in telling us how far that, progressive heart failure has got, very likely to see a diffuse interstitial pattern. That heart is gonna start to enlarge as heart disease progresses.
And we're gonna get enlargement of the pulmonary artery. So you know, we can identify these signs, the more progressed they are overall, the worse the prognosis becomes. And that doesn't mean that we can't try and treat if these changes are advanced.
But we we just have to take it into account. You know, if, if we are considering treatment with ultrasound, though, we can go hunting for the worms. And there if you know one end of an ultrasound from the other, you've got some experience you're used to scanning the heart and the cardiovascular system.
You can you can go hunting for the worms. They're very visible that the walls of the worms show up quite nicely. Which makes it, you know, a very sensitive and very specific test in the right hands.
But you do need need someone who knows their way around the heart. You've got to be able to follow, the caudal pulmonary arteries to their bifurcation, which you know, could be a little bit tricky. And it does become less sensitive if you've got very small numbers of adult worms because they can be quite easy to miss.
But if you've you know, if you've got someone in the practise who who's really handy? Cardiac ultrasonographer. Then you know, this is absolutely an effort that you could pursue The mainstay, though of of screening, especially, is antigen serology.
Now? You know, antigen serology is a wonderful test. You can send it off to an external lab.
You can do patient side testing. There's a whole range of sort of snap tests, lateral flow tests. And some of them, combine other exotic pathogens.
So it makes it quite cheap, relatively affordable to sort of, you know, check for a range of pathogens in one go. However, you're testing for the antigen. It's very specific test, which makes it very useful.
You get a positive. You can be very confident that you've got heartworm infection that you need to treat. And it can be pretty sensitive so highly sensitive as your worm burden increases.
So the antigen that we're looking for is produced primarily, by female worms. It's in uterine secretions. So if you've got female worms, your sensitivity is immediately gonna shoot up.
And if you've got more worms, your sensitivity is going to increase. It takes time for the antigen to be detectable. So we're looking at sort of.
It depends on the study that you look at, but maybe, you know, 6 to 8 months, 6 to 9 months post infection. You would you would expect that antigen to appear. So we want to bear that in mind when we're testing When we're considering the timing of our testing.
In the US and in some other endemic countries, heat treatment of the sample is promoted, and that's because sometimes the antigen can lock up. And that means that then you know it's not as detectable by these tests. Heat treating the sample.
Not not the poor old patient side test itself. But the sample, will increase sensitivity overall, but it has the potential to decrease specificity, so you may start to get false positives. So for that reason, I wouldn't advise doing it in UK practises.
If we get a positive result, we want to be as confident as possible that that test is positive. It can, however, though be combined with micro ferial testing. And that's gonna increase sensitivity overall.
And it's gonna tell you what sort of micro Ferial load. You've got the American Heartworm Society, which is a is a fantastic source of information. For heartworm recommends using this, combination of tests, when we're looking for heart.
So once we've confirmed that our dog is positive, we're reasonably happy. It's positive. You know, we need to then decide whether we're going to treat this patient or not.
Now, you know, over the years, opinion has shifted somewhat. There did used to be the question of Well, you know, if you've got a healthy dog and you've got relatively low worm burdens, should we just let you know these adult heart worms have a happy retirement die of old age? And then everybody's happy.
The the risk of from Wembley is doing. That, though, is significant. So current thinking is that if you've got a healthy dog, you've caught this at a relatively early stage.
Then you should absolutely treat and manage correctly. Prognostic outcomes are pretty good that they've got a lot better as pro protocols have been refined and, you know, caught early enough in a healthy enough patient. You know, heartworm absolutely needn't be a death sentence.
It's a serious infection, but it can be treated and it can be eliminated. But there are other factors that we need to consider that could knock that prognosis back, and make it a lot worse. So one of them is worm burden.
I mean, if we have a very large worm burden that is gonna increase your risk of anaphylaxis and of thromboembolism So it isn't a barrier on its own by any stretch of the imagination. Just because you've got a lot of worms doesn't mean you shouldn't treat you absolutely should treat. But you should be, you know, should warn the owner that there may be greater potential, for complications.
And, you know, we ourselves should be ready to try and manage those if they occur. Coinfections make a huge difference. So a lot of the countries in Europe, that where heartworms endemic, Alicia is also endemic.
Leishmania is also endemic. These are common parasites, co infections relatively common with heartworm. If they're present, they are gonna need treatment as well.
Potentially, and that overall sort of treatment and effects that they're having on the body is gonna affect prognosis as well the S, the state that your heart's in is gonna make a big difference. I mean, even if you've got a low worm burden, I mean, if you're a very advanced heart failure, you're already getting complications from that that is gonna affect your prognos prognostic outcomes, as is other, organ disease comorbidities tumours, anything else that may be affecting the body that isn't parasite related. So as for treating any disease, we want to take the whole clinical picture into account.
And perhaps most crucially of all is the owner's ability to rest the patient. So if you've got dogs, like my friends here, these beard is you just can't keep them. Still, they're running around living the dream that they may not make it to the end O of their heartworm treatment.
So if it isn't gonna be pragmatic practical to rest them, it it's not a complete barrier to treatment. But it is gonna massively increase the risk, of thromboembolism complications so busy slide, you know, But do not be put off. You know, the the thing is that a a lot of people get heartworm positive dogs.
And then well, you know, either that tremendous excitement or perhaps slight moment of panic kicks in. And we still get a lot of a lot of queries at ESCAP, UK and Ireland, about treating heartworm dogs. And and we are more than happy to have them livened up by Monday morning.
But essentially, the way you approach them is the same. So I've tried to put it all on one slide. So, you know, for those of you who are signed up to the webinar there, you can go back in, have a look.
Eden, you can basically just have a look at this slide and follow it through. There are different protocols, different organisations, have slightly different tweaks. They go about it in different ways.
But the the basic theory is still the same. So this is one, I've used for a long time. It's very similar or identical to the American Heartworm Society one.
It it does the trick. So this is the one I would recommend. What you're gonna do is on day one, you're gonna start off with doxycycline, and you're gonna use that for 30 days.
The reason for that is that you're softening up the adult worms. They rely. They have a symbiotic relationship with Wolbachia, a bacteria that lives within the worm.
So you take out the Wolbachia that is already getting that worm on the back foot, and alongside that, you're going to start heartworm preventative. So macrocyclic lactone. And you're gonna use that when you start the treatment and at day 30.
So all of this as a whole is softening up your adult worms for that adult aside treatment. They have options then as to when to start that, adult aside treatment. So we we go for melamine, which you know you can't get in the UK.
You would have to get an import licence and get it in from abroad. Availability is variable, but generally it's something that you can you can get your hands on. But you just have to bear in mind there may be a bit of a time lag, so, you know it's better to order it when you're starting this treatment, on day one, rather than when you're approaching the time when you expect to use it, and it intramuscular de intramuscular injection that can be given at day 30 then two more injections at day 6061.
Or you can wait, and give the first one at day 60. And then, you do it at day 90 Day 91. Now the advantage of waiting is that there is well, I think, let's say, limited evidence, but evidence that you may get better efficacy from waiting longer to give that softening up treatment more time to kick in.
So that's the upside. The downside is, if you've got a patient that's relatively difficult to rest, you're adding another month onto your treatment. So pros and cons, you know you can do it Either way.
What is absolutely essential, as I've just mentioned is exercise needs to be restricted as much as possible, starting from day one and day zero, and then to at least one month after your laal side injection. And this is purely to reduce the risk of thromboembolism. Whatever else you know is discovered about sort of, you know, drug use to reduce thromboembolism.
Up until now, the one single factor that makes the biggest difference is rest and you know people often ask, Well, you know how much rest? And you know what? The more the more the better the more rested the patient is, the better your chances of that patient making it to the end.
Prednisolone, though, has also been found to be very useful in anti-inflammatory doses. I mean, it does have some use in managing sort of bronchial signs. That may be associated with the infection, but it's really to reduce the risk of from wem, Bols and strangely appears to be much better at doing this than aspirin.
So aspirin. No evidence that it helps at all with heartworm infection. There has been at least one study that suggested it may actually make the situation worse.
So don't turn to aspirin. Preds are the way to go a anti-inflammatory, doses. So essentially, that is the plan.
So it is. It is very, very straightforward to implement. And, you know, with, enough rest and with enough planning, you know, and in the right patient, it can and does go very well.
It actually pretty unusual, for me to see treatment. Failure? So you know, you you absolutely shouldn't be put off by the fact that you know, these massive worms are in the heart.
You know, you've got every chance of things going. Well, you know, just the owner's gotta be on board, and that rest is absolutely essential. And then, you know, we're doing, an antigen test.
Timing's not crucial, but round about nine months post Ulta side treatment to see if the infection has gone. And then, you know, assuming the treatment is successful, you know, there's certainly nothing wrong then say testing another sort of 69 months later. I think if all of those tests are negative, then you know things are looking pretty good.
Another thing that's often discussed is what's called the slow kill method. And this is where we don't use an adult aside at all. We just use, doxycycline and macrocyclic lactone to gradually kill the adult worms.
Now, historically, this has been highly controversial because of the risk of it promoting macrocyclic lactone resistance when it's used in in prevention Later on, when this has been used in endemic countries, I mean specifically in in the US, where resistance has developed. It's often been used at suboptimal doses, without a sort of very strict plan in mind. And it totally I see a lot of this coming out of, Eastern Europe as well, which, you know it can be done very well.
But it it's concerning if it's being used a lot in endemic countries, and also if it's not being used in a particularly calculated fashion. So it's got a bit of a bad name that way. I mean, I would say it's absolutely a valid alternative to using adult sides if they're not available or if they're unaffordable.
Sometimes you just can't find them, just can't get them from the continent or the owner just can't can't afford the adult a side part of the treatment. It is a a complete myth. It's a misnomer to say that there are less complications because you're not using an adult side.
The risks are exactly the same as far as we could tell. The only thing, that you've got to just really measure is that micro Faler load before you start, I mean, you will be using a macrocyclic lactone whether you're gonna use an adultery or not. But, you know, it's gonna be this persistent use of macrocyclic lactone that you're using.
You know, you want to be certain that you haven't got a high micros of anaphylaxis occurring. However, with all of those caveats in mind, if you are going to do it, then pretty similar strategy. 30 days of doxycycline alongside a monthly macrocyclic lactone.
I mean, one of the biggest drawbacks, apart from the resistance concerns with this technique is it can take a long time, a long time to clear the parasites. So, you know, sometimes, you know, 69, 12 months. But you always wanna carry on and you're looking, to get two negative antigen tests six and six months apart.
If you're not successful after 12 months, you start the whole cycle again with the doxycycline. On you go. Sometimes you have to surgically extract the worms, and you know, I love worms, but this potentially sounds like my worst nightmare.
Not being the world's most confident surgeon, However, you know there are people that might want to go in there and extract them, via the jugular vein. So you just, you know, pop that jugular vein out. You wander your forceps or your basket instrument down it.
If you've got fluoroscopy, you can track that progress. If not, you do it blind, by measuring, to heart sounds, just wandering in and just seeing, like, a hook. A duck.
How many worms you can get back? I mean, I I would be getting on the big red phone, to someone who actually knows how to do this kind of stuff. But it is important to say that there are circumstances where if you don't do it, your patient is going to die.
And that is is primarily if you've got Carl Syndrome. So, you know, in this situation, you've got adult heart worms that are obstructing blood flow through the triclos PD valve. And that is is gonna kill your patients.
Within a day or two, if you don't get in there quickly and remove those worms so you may not have people who do this on a daily or weekly, basis Is this like, you know, some endemic countries, particularly, popular to to operate and remove sort of bulk of worms. In in some Mediterranean countries. But if you've got a semi competent surgeon your patient's dying.
You might as well have a go, and sort of see what happens. Diagnosis of carval syndrome is is made on the basis that you've got a heart worm positive dog and that the clinical signs back it up. So this is very rapid onset, lethargic dyne patients paleous membranes hemoglobinuria.
So you get your coffee, ground type urine, and a very loud systolic murmur. You got those signs, you know? Well, it's essentially it's either PTS or get in there and surgically save your patient time.
Sometimes as well. You may just try and debulk numbers of worms because you've got so many. And if it's looking like the situation may be bad for thromboembolism to try and treat them medically, and in that situation you've got more of a sort of, cost risk.
You know, a risk benefit analysis that you can make as to whether that's worth doing. But in Carville syndrome, if you're gonna go for treatment, you have very little choice. Macrocyclic lactone resistance is a concern, especially in the US where it's developed, started off in the Mississippi Basin.
It's sort of spread out, into a sort of wider southern United States area. No resistant cases have been recorded in the UK. I mean, not tremendously surprising, because it's not endemic.
But the first case has been seen in Europe, in Italy, and that was in an imported dog. So, you know, we may see it in the UK if dogs are imported from the US. This dog was imported from Mississippi, came into Italy, and and was, tested.
The micro filaria were tested for their susceptibility to macrocyclic lactone, and it was found to be resistant. It's not something that you're gonna be doing routinely in practise. But if your imported pet is from the States and particularly from that part of the States, you just want to be aware you want to be vigilant for the fact that you know you you may have resistant worms there.
So, in summary, how are we looking at controlling heartworm in imported pets? Well, we absolutely want to clinically exam pets that are entering the country. We're looking primarily for signs of cardiopulmonary disease.
Antigen test is a great initial screen for imported dogs. But using the modified knots test alongside is is also, you know, really useful, either as part of the screen or to establish micro ferial load, in in positive pets. Absolutely.
Don't trust imported history with, you know, this this dog is positive or this dog is negative scrawled across the front of it. And if you don't have those original test results, or unless you have absolute trust in the organisation that you're working with and you know which test has been performed, you are just much better just to do it again. It is also very, very important to to control, heartworm for pets that are travelling to endemic countries and to protect them as as individuals.
And you're gonna do that with a monthly macrocyclic lactone. So there's a wide range of them. Spons tablets are available.
In some endemic countries, there's long acting moxidectin injection that will last six months. But travelling from the UK, it's going to be a monthly spot on or tablet. This is the absolute linchpin of you know, for for pets that are travelling abroad, they should all have it.
If there's any suggestion that they may be going to a country that might be endemic and they should carry on for at least one month after they come back, I mean, it is also useful to take practical additional measures. So we want to try and avoid peak, mosquito activity times. And that's gonna depend on local areas.
But in for many mosquito species, it's going to be, Dawn, fruit or dusk. Oh. Sorry.
From from dusk fruit till dawn. And that's also true for some flies. So there's some, you know, communal fly avoidance that you can use there you can use, fly repellents.
Oops. So, you know, there's various products, that are licenced as fly repellents. But for some flies specifically, but in some cases also for mosquitoes.
So you know, that is, that is useful to use in addition, but mosquito avoidance is not a substitute, for using good heartworm preventative treatments while pets are abroad. So, you know, it's very, very important to stress that a little bit like you know, if we we went to a malaria endemic country, we wouldn't be standing out there inviting ourselves to be feasted upon by mosquitoes. You know, just because we have a malaria preventative in place, but we would use a malaria preventative and finally plug, for ESCAP, UK and Ireland.
So ESCAP UK and Ireland is the sort of national association for ESCAP, which is a European wide organisation. We provide lots of parasite advice for a non for profit organisation. And we've done a lot of work.
We have a lot of experts, that that work in countries that are endemic for heartworm and other exotic parasites. But also, have particular interests in, pet movements, epidemiology, of these parasites where they might be moving to and how to manage them. So we have, guidelines.
On the website. We have lots of useful handouts about exotic, parasites and pet importation. But crucially, we will take, advice queries for free, through the website.
So where it says, you know, please contact. If you go to our website, put your query in there, and we will do our very best to answer it. And right at the bottom is my own email address.
I'm I I'm always happy to take a parasite query. You know, like I say, light lightens up my day. Who doesn't love a parasite query.
And for those of you who are interested in parasites would like to know more, about the changing landscape of of parasites and vectors across Europe. Escap is having, a CPD day. With the webinar vet on the 12th of November.
I believe, that a link is gonna appear in the chat box. So you can register there, and that would be absolutely fascinating. I'll be speaking, but there'll be a range of speakers from across Europe, so we have real sort of, you know, pane flavour.
Just looking at how these parasite distributions are changing and how that's gonna affect us. Down on the ground in first opinion practise. So thank you very much.
Thank you for listening, and I'm gonna pass back to Mark, Right. Ian, thank you very, very much. Really enjoyed that.
I've certainly found a few things I I hadn't ever heard before and, well, mainly, just the hook. A duck and heart surgery were 222 senses I'd never thought I'd hear right next to each other. It's like, isn't it?
Yeah. I've got a few questions here, so Yeah. So one of the one of the big ones here, in one of the classic ways of treatment is, prednisolone for, the anti-inflammatory effects.
What do you recommend? If prednisolone is potentially contraindicated, let's say it's an older dog on NONSTEROIDALS. Or maybe it's got some sort of, comorbidity like, say, picking two cushings or diabetes where steroids aren't necessarily a great idea.
Yeah, so So it's all, it it it's all risk benefit, isn't it? And I mean, I think, you know, you've got to weigh that up in the individual patients, so it does depend. You know what the contraindication is?
So I think if you've got, a dog say that is on a non steroidal anti inflammatory for pain, relief it for the time that you're treating the heart worm. It would be well worth looking at alternative forms of pain relief cos the use of the steroids is only going to be temporary. I mean, ah, poor dog.
Hey, if you've got a poor dog that is diabetic and it's got a heartworm or it's got cushions and it's got a heart worm or all three I mean, I, I think you know, you do need to consider overall prognosis. But if your you know, if your patient is stable, you know, say, if it's a stable diabetic, it it really depends on the overall risk of that thromboembolism with the heart worm. It's a question of which is the lesser of two.
So, you know, low numbers of heartworm, clinically healthy dog. You might prioritise your diabetes, particularly if you've had trouble stabilising it. But if that dog you know is is at high risk of from web is you know, you you've really got to take that into account, right?
Thank you very much. Question You mentioned, using modified knots test for testing. And you said there were several versions of of, modified knots tests for the testing.
Is there a particular modification? You yourself favour? I think when I I wanna say there are, you know, several modifications.
They're really slight tweaks. So you know, they're all doing the same job. Essentially, they're all just gonna They're all gonna blow up everything that isn't a heartworm lava.
You, you know, sediment it to the bottom of your tube, and then you're gonna resuspend it and have a look. So the, the nuances of the method absolutely aren't crucial, so I wouldn't want anybody to get hung up on that. If if you can find a method that falls under modified knots test, then you are are good to go.
And I mean, I should have said there there are lots of external labs. That will do modified knots for you. And quite often, if you're sending the blood off as an external package, it will do heartworm, antigen and knots, you know, as as an option.
So it isn't something you have to do in house. I mean, you know, you are You're gonna be handling some form, Malin. But it's also, can be a lot of fun.
You know, you can get your get your larvae suspended, have a look. It's deeply satisfying. Nice.
Lovely, lovely, lovely. Ok, right. One more question here.
So on the one hand, you mentioned macros, macrocyclic lactone resistance cropping up in the southeastern United States. You also, there's also a recommendation for frequent use of them. So how is that another risk benefit thing of, fre frequent?
. Macrocyclic lactone. And yet there is the potential resistance.
Yeah, so So here it it isn't risk benefits, or if it is, it's It's all on the benefits, you know? So the the the the resistance developing is in endemic countries. And you you can't not have dogs on prevention, you know, off prevention.
You know, if they're gonna be at risk of exposure from the parasites, cos the consequences of infection are gonna be quite severe. And even even in, resistant dogs, you know, you can still get efficacy using a preventative. But, you know, you just need to be that much more aware that, you know, your your sort of protection may not be as solid.
So yeah, Unfortunately, it is one of those catch 20 twos where if you're in an endemic country, you you have to protect the dogs and cats that are there. So you you have to use a macrocyclic lactone at least seasonally as a preventative. You know, at the moment, you know, we have the option depending where you are.
Depending. Say, if lung worm is a big problem, you know, you you have the choice essentially in the UK whether to use a macrocyclic lactone as a as a routine real worm. Preventative or not, that the moment that heart worm becomes endemic, then that that is your decision made.
Essentially, and and you have to use it. The the importance is in vigilance. And this is true of, drug resistance.
Or, you know, sort of Antal mic resistance as a whole in in companion animals is that vigilance and surveillance for resistance developing is absolutely crucial. So it can be identified early and then dealt with by sort of, you know, a change in in macrocyclic lactone drug, or, you know, by sort of taking the pets, you know, away from mosquitoes, you can prevent further mosquito exposure and the resistance being propagated. But you can't.
You can't limit the resistance by not treating one of the crucial things in endemic countries. And indeed, wherever you're using Antel Metics is correct. Dosage.
So what's happened? A lot. We, we think in areas where it's become resistant is that people have used suboptimal treatments either as a preventative, sub optimal dose, either as a preventative or as part of the slow kill method to try and kill adult heartworms.
And that has really sort of propagated and promoted resistance. So, you know, correct dosage and surveillance, for resistance is is really, really important. Right?
Well, thank you very, very much. Ian, that's been a really excellent evening. Really.
Thanks so much for really taking on what is often a very intimidating disease and just breaking it down into really sensible bite size chunks. To really make sure that anyone can really tackle this. I hope all your attend all the attendees have had as good a time as I have.
And we hope to see you again soon at the webinar event. Thank you very much. Thank you.
And good night.