Thank you very much. Yes, that, that's, I have to say in my free time since having a small child has probably meant that the, the horses seem to be sort of a, oh, you're in the field, you're OK with that type of job. But no, my .
Paris, I told you, made up quite a a chunk of my PhD and it's something that I'm quite passionate about. So actually this is a really good to be able to be here speaking to you this evening. So I want to, to give you a bit of review of a review of the topic from where we have been to where we are and where we're headed to.
So First of all, a little bit of a focus of where this webinar is going. I think actually a really good starting point is to have a little look back at some history to see where parasite controlling horses relatively sort of started out or, or, or a point where it became quite important because I think actually that history helps us to work out how we've got to where we are today. I think it's also important to put some focus back on to, well, actually, what are the intestinal parasites of veterinary importance, because there are a handful of key ones that are important that we need to monitor and we need to treat effectively, and then there are actually other parasites that we maybe need to consider, monitor, but maybe aren't.
Actually, the, the key treatment priorities. And really thinking about treatment priorities leads us nicely into alimenttic resistance. What is the state of play with alimenttic resistance?
Where are we at? And how are we going to try and manage that moving forward? And then that sort of really nicely brings us into refugia and creating a refusion.
And that's something that's quite practical really. It's something that from a clinicians perspective, being able to get clients to understand the importance of refugia, it's a key tool to help us slow down laytic resistance. I want to talk a little bit about that.
I then want to think about sustainable parasite control, but as, as much sustainable sustainable parasite control, actually barriers to uptake can be a problem. You know, we can, we can all think about what's the ideal method of parasite control, but actually getting clients to to take that method can be more difficult, and that's something that we need to think about a little bit. And then finally, actually some new developments in parasitology and where we're heading to in the future.
So, I think one of the things to, as I say, to start with is to think about the history of parasite control, and I'm only gonna go back here to thinking about sort of the 1950s and early, the early 1960s, where the analmentics that we had available, they were not broad spectrum drugs, and they were either, they either had some analmitic properties that were specifically targeted to some parasites, or they effectively worked on an expulsion. Premise, and parasites became a bit of a focus really and definitely in the 60s and the 70s, there was a, a big push to the idea that worms, especially the, the large strongars and specifically Stronus vulgaris, was heavily associated. With colic, there was an idea that 90% of colic cases were due to strong with Bulgaris.
Now this is in the literature, it's never been scientifically validated, but it, it, I think it actually plays a sort of a key role in how we've got to where we are. And if you look at the little graph that's on the screen from some Gan Lyons's work, it highlights the sort of progression from the 60s. We had the, the first group of broad spectrum antiin, the benzoiddazos, and then in the 70s, the tetrahydraprimmiine, so parentel and such like in the, and then in the 80s and the 90s, the macrocyclingactones appeared.
And I think actually when we start to think about this now, Ivermectin appeared in the early 1980s and then it's partner in the same class, Mockad Eton appeared in the very late 1990s, 1999. It's nearly 20 years since we had any new analytics licenced for treatment of intestinal parasites in the horse. So.
We need to think about, these are the drugs we have available. We have some good efficacy in some and questionable efficacy in others. We have to think about how we can make these drugs work because all these 4 classes are still, all these 3 classes are in these 4 groups that are on the screen, they're still available.
. And we've kind of become reliant on antics, and I think part of it is linked to this broad spectrum approach. I mean, to, to borrow a quote here from Nick Sousa from. Sort of the early 2000s, you know, if in the past, a client had, a question for the vet about, you know, about a certain parasite, a fairly straightforward response, you know, could have been, well, there's a drug for that, because we've had really good broad spectrum.
Analmitics that actually cover this. What we weren't foreseeing was the potential for antalytic resistance, and the failing of those drugs, which has made us think a little bit differently about how we, we go about, treating. And actually one of the kind of the, the big things in the 1960s was the introduction of the Inval dose programme from Drudgeon Lions.
And I think if you spoke to Gene Lyons now, he'd probably have a very different take on, this, but in the 1960s, it seemed like a great idea and we had this problem with . Vulgaris and colic. So if we treat the horses on a regular basis, and we keep removing the adult nematodes, so we only ever have, by the time we get to the end of the pre-painting period, we're treating again anyway.
So we are in a constant cycle of moving those large strongars out of the system. And to be honest, it was an extremely effective system for the large strongile, but by using a broad spectrum anal mint, it didn't necessarily take into account what was happening with other parasites within the horse. And I think, you know, all, all of these things here, this, this kind of history, really frames where we we've started out in this idea that yes, we've got fantastic drugs that we can use to remove parasites, but actually it was a bit of a simplistic approach.
And this has really kind of led to the potential problems that we have with parasite control going forward. And the other interesting thing really with parasitology is for quite a long time, if, if you take sort of 50 years of veterinary medicine, actually parasite control is an area where relatively little has changed until fairly recently. And we need to start thinking about, well, how do we modernise this, how do we move it forward?
How, how do we ensure that we have effective, parasite control measures. And again, one of the problems is thinking about horses as individuals, and this is something that I think clients struggle with because they've been brought up with this calendar-based mechanism of treating all horses at exactly the same time. But actually we forget that horses are individuals, they have an individual immune responses when it comes to parasite control and therefore they won't all have the same parasite burden.
They won't all have a, a, a burden worth treating. And there's a, a brilliant little extract in a, a paper from Martin Nielsen. That identifies, well actually from a clinician's perspective, you go to a yard, you see a horse, from your diagnosis, you decide a course of antibiotics is required.
You wouldn't think, well, OK, this horse needs antibiotics, so I'll give the other horses on the antibiotics as well as a precautionary. And yet historically, that approach may have been taken with parasite control. Well, this horse has worms, so actually let's treat the others as, as a precaution.
And that's just from the, the, the, the, the past, the way that we've treated hor parasites and horses, and that's kind of really been a, a one size fits all approach. And again, I think some of this actually relates back to the fact that especially horse owners have developed this irrational fear of parasites. Now we know that parasites are associated with colic, and we're not arguing that that they're not.
But actually they're only a small part of the problem and careful, clever management can seriously reduce that problem. So we have to be aware of them and we have to manage them, but we can't blow things out of proportion. So we have to think a little bit about how we do this carefully.
Now I think it's quite good to actually refresh a little bit on, on really what are the parasites of veterinary importance. And there really are 4 key parasites that we are concerned about that we want to seriously monitor. So if we start with the parasite we've already mentioned, Stronris Hogaris, the large strongar .
And in the family this Stronulus enters neckinous. Stronsargarus really was the most prevalent and the most pathogenic parasite of the horse until the 1980s, and its life cycle really is part of, of the problem. So you can see on the screen we have a, a little diagram of the life cycle.
The horse excretes eggs in the faeces, and these hatch out in the pasture, and they, moult from larval stage 12, and 3, where they become infective. The horse ingests it in the pasture, it goes off to, seeking the large colon, and then the larvae migrate out into the mesenteric blood vessels. And this is really where the problem occurs and that these larvae they cause damage.
We have thrombus formation, and then you'll get a clot that will break off, and block a blood vessel. And you can see on the little schematic on the screen, we've got this nice little area of infarction, which will lead to a nice potentially fatal colic. And this really was where this idea that Parasites are really associated with colic occurs from.
But in our horse population in the UK today, they are in really low prevalence, and the studies for quite a while now have identified that at least 99% of strongile eggs, in faecal samples tend to come. From, sacstoins. So large strongals are not really so much of a problem these days, and that's simply due to the way that we treated heavily with antalytics.
Now, it's not to say that that is the same worldwide, especially if we use Denmark as an example. Back in the late 90s, in 1999 in Denmark, Antointics became Pom Ve and By putting the onus on the having the client having to speak to their vet about parasite control from an antilytic resistance problem, fantastic move, actually, by working on a much more diagnostic based process and maybe some clients not engaging with that, they have seen an increase in Stronus vulgaris in Denmark, of late, so it's quite interesting. I don't think it's a problem in the UK.
I think we still have enough analmantic usage, even at low usage, that it's keeping the problem at bay, but it, it's quite interesting. So if we move on to probably my favourite parasite of the horse, the sat stonemans. I think the interesting thing about the South stones is we never really thought about them that much when Volgauss was our our key focus.
And actually, you know, these, these parasites are now seen as the most prevalent and the most pathogenic of the horse, and molecular technology is definitely increasing our understanding. But realistically, we still only understand the fairly basic biology of these parasites. We don't know really how important their presence in the hindgut environment is, we don't know, .
If we don't know exactly how long they can stay in hyperbiosis, there are lots and lots of questions. As a little refresher, the life cycle starts very similar to the large strongar, so we have the eggs, it's in the faeces, we've got the little egg image on the screen. They moult from larval stage 1 and 2, become infective at larval stage 3, and ingested.
They don't have a migratory stage in their life cycle, but they do have, an insisted stage. And so you can see in, in the small schematic on the right-hand side of the screen. That they become insiststed and they can either go into an early stage 3 where they become inhibited and go into hyperbiosis, or they can go in at the later stage and then continue to progress to L4 before they pop out back into the gut lumen.
And this is really where one of the, the big problems with sakostos lay in that if we compare saciststoins to parasites of ruminants, those parasites that undergo hyperbiosis are pretty clockwork. They tend to go into hyperbiosis in the late autumn and they re-emerge the next spring. And the problem with the horse is we know that they can be in hyperbiosis for 2 to 3 years.
They could potentially be in hyperbiosis for longer, and while they're sitting insisted in the gut wall, currently we can't detect them. And that really is quite a big problem because with regards to clinical diseases, I'm sure we're all aware, you know, it's, it's the sheer number of cytostoins that could potentially re-emerge in one go en masse where we see larval statistsomiasis. As a clinical disease, it's quite rare.
It's more likely to happen in young horses in the very early spring. And it's a cause for concern, it's something to be aware of, but it's, it's not particularly common. But this, life cycle makes diagnosing burdens quite difficult with regards to the use of faecal egg counts.
There's been some work done that suggests that a faecal egg count that's around 100 eggs per gramme could roughly equate to 100,000 sat sins. Once you get above 500 eggs per gramme, there's no relationship between eggs per gramme and number of insisted larvae. So it's really quite difficult because We're really dealing with the unknown, which then makes it quite difficult.
How do we manage this parasite? And we know there are sort of 50 plus species and that most horses have less than 10 of those that are at a core that they harbour at all times. We don't know much about how much that species, of the, of those 50.
Shift there is in there, and potentially there may be resistance in some species more than in others. But what we do know is the way that we have managed horses with banal and ticks has meant that actually this, that we have resistance, and because there are so many of these parasites continually reproducing, there's a huge genetic pool to be able to, to transfer that gene, relatively easily. So these are really a a parasite to be aware of and hopefully, as as the future progresses, we'll get and some the more molecular technologies improve, we'll get a, a much better handle on these parasites.
But at the moment, actually managing them can be relatively tricky with regards to estimating numbers. But . If there are adults present, we will see the eggs in a faecal egg count.
Moving on to our sort of next parasite for concern, er our tapeworms. And predominantly aphalop prophylata, to some extent acephala magna. And sort of moving on really thinking about the cestodes, we know there is a relationship between tapeworms and colic, and we know from Chris Proudman's work that we, there is a relationship and the relationship has been identified, .
Looking at infection, intensity, of tapeworms using a tapeworm, Eliza against the, odds risk ratio for colic. So we have to be aware of tapeworm burdens, but actually, again, it's about the tapeworm, the life cycle is slightly different. It relies on an intermediate host, a small orbid bite, or with mite even.
So we have to think a little bit from a management perspective. It's, it's maybe slightly more difficult to break the life cycle because that might, may appear in forage, and therefore, there's potential for infection, whereas horses that are grasp of strongiles it's slightly easier to potentially break that particular life cycle. But again, this is a perfect example where.
Collic is what the owner sees and thinks of, so although we do need to manage it because we want to prevent these obstructions, impactions, we definitely want to prevent ruptures and interceptions, but it's really about managing this particular parasite, and thinking about a little bit about its life cycle as well. And the final one that's really of importance, Parascariaccorum, a large roundworm, and this is really of importance for foals. This is 11 case really where, with these particular parasites, as the horse ages, they gain some natural immunity, but definitely for foals, and this is always when you speak to studs, you know, a, a parasite of concern.
And there are a few novel factors really with regards to Pascara in that we can see the, the life cycle schematic. Unlike the other parasites, the first two stages, of the larvae actually still occur inside the eggs. So in this case, the horse ingests the egg from the pasture, and there's a nice little refresher, there's an image of the egg on the screen.
And it's quite different to a strongile egg, and it's really quite robust, and they have ability to survive on pasture, they can survive some pretty extreme weather conditions. They're pretty tufty parasites that are, you know, that we can't necessarily always easily assume that that the weather is going to, to kill these off. Now, the horse, ingests the, the egg, which hatches out into a larvae as they travel off to the small intestine.
Then migrate out to the liver. And then off to the lungs and are then swallowed and going back to the small intestine again. And really the biggest problem with Parascari is the physical size.
You can see in the, the image at the top, the females can be particularly large, the males slightly smaller. And if we think about the, the, the sheer size of the parasite in the small intestine. The the little surgery pictured below, you can see a rather large impaction there, and it's that sheer size of the parasite that actually causes the problem that's gonna cause an impaction colic or worst case a rupture.
And so managing this parasite is important, but we're thinking specifically about these young animals for doing so. Again, we do have some resistance problems, so it's something to to bear in mind. Now with regards to parasites of lower importance, I think it's important to think, OK, we know these parasites are there, they exist, but we actually need to think how important they are and and sort of prioritise how we go about treating them.
So, if we start in on the top left of the screen with our lung worm, we've got a nice little donkey schematic here, and the lung worm. Has a very similar life cycle to all the other parasites we've been talking about. Eggs hatched on the pasture and the faeces and moved to larvae stage 3.
Donkey ingests, goes off to the GI tract, migrates to the lungs where it lays its eggs, which are then coughed up and go back off to the GI tract again. We can actually see the little, larvae next to their lung worm larvae. Actually, Longworm aren't necessarily always the huge problem that people tend to think, and I always think it's quite interesting with owners that are concerned that .
Horses grazing with donkeys will get infected with the lung worm, and actually mature horses in a mature horse, lung worm can't reach sexual maturity, so they're not going to pick up an infection. Very young animals potentially, yes. So.
It's a little bit about prioritising, and again it's about thinking about diagnostics and from previous chats with the donkey sanctuary, you know, often they often highlighted that they didn't have a huge problem with lung women and donkeys, and maybe it's something that's perceived to be more problematic than it really is. Another, parasite that again it is sort of quite focused with regards to a specific lifetime, point of, of, of life is, Strongyloides West Siri, and I think it's quite interesting with Wester that we're focusing on mares just about to fall and, sort of for the early part of foal's life. Realistically, a proportion of this is hygiene associated, and it's perfectly possible to use diagnostics, you know, pre-foling to, identify this specific parasite or for.
Relatively young folks to actually be able to diagnose without having to use preventative treatment. But it, it, it, it's a parasite that's worth being aware of and it's a parasite that studs are often concerned about, but actually, it's one to sort of put on that list of priorities. And then sort of moving down the list of priorities probably and moving down the slide as well, in the bottom left-hand corner, gastrophy of species spots at the bots, I think.
The, the big thing to remember with bots, you know, yeah, they are a management issue. An ectoparasite that, gestates inside the horse. We know that with bots, it can be very location specific as to, to where the horses are based.
We can see the eggs easily on the coat, and we can remove the eggs particularly easily. There is no evidence in the literature of serious gastrointestinal disease associated with bots. So I think we have to rank them as to how important they are and the risk of disease against treatment.
And then, the final parasites are being pinworms, and pinworms have had a little bit of press over the last few years in that where people are seeing pinworms in the horses species. And again, there is no real evidence of pinworms being associated with serious gastrointestinal disease. Maybe a small amount of of GI inflammation in really, really severe cases, but actually it's more likely that the horse is uncomfortable and will rub the dock area.
And this really can be managed well with hygiene, and we have to think if we're treating pinworms, which part of the problem I think with pinworm treatment is the fact that we're right down at the end of the small colon. We're treating a parasite that's that's there, that's actually is laying its eggs on the outside, but again, we can identify diagnostically and then make a call as to how we go about treating for this particular parasite, but it's not a parasite that's going to cause colics, so we have to, to work a little bit out on the, you know, what's the most important priority here. So that's really a little recap of, of these different parasites.
And I want to think now a little bit about sort of parasite control strategies which takes us into resistance and refusia. I want to start with this little clip that I often use with my students. And it's this little idea that this stems from the Victorians when they use tapeworms for weight loss measure and then came up with this little trap here that the patient would swallow the trap, the tapeworm would pop his head into the trap and it would kill the tapeworm.
Obviously, realistically what happened was the patient choked to death. And, and the moral is that all strategies need to be safe and well researched, and I think it's the well thought out aspect that we really need to, to focus on here so that we can minimise risks to health and minimise the the spread of anthoytic resistance. So very pictorial slide here.
I think one thing that people tend to forget, horse owners don't really give enough respect to the idea of pasture management. And if we go back to the 1980s, it's clear in the literature that actually breaking parasite life cycles through pasture management is a simple, straightforward way to break the cycle. It's one of the most effective ways of reducing a parasite burden.
And there have been more recent studies in both horses and donkeys looking at the frequency of this. And, and on small paddocks turnout, if droppings are removed once a week, ideally twice a week, then we can break the, the parasite life cycle definitely of our, our roundworms. So that's something that's really quite important for clients to understand.
Similarly, pasture management is important if they're grazing particularly large pastures, and hopefully horses can display a little bit more natural behaviour in their roughs and lawns in that they shouldn't be continually reinfecting themselves. One of these lovely practises that that horse owners quite like to undertake of, of harrowing faeces on pasture. Needs to be reminded that this is not a particularly good idea because you take nice clean areas and you drag infected larvae across them.
So pasture management actually is a really important step. I think another really important step is to actually think about how horses are kept and managed. Depending on where the horses are, what their role is.
Horses that spend a lot of time in a stable are much less likely to have a notable parasite burden. There was a little bit of work, from McGur and others in 2015 which highlighted that, some that some cystoium larvae could. Actually, survive in a deep littered straw bed, hence that the little deep bitter picture, sort of extreme in the bottom corner of the slide.
But actually, horses generally in a stabled environment will have a low parasite burden. So therefore, thinking about managing their parasite burden and planning diagnostics, that needs to be taken into account. Faecal head counts.
OK, it is, it is a bit of a rough and ready science. It's not particularly new. And it is the cornerstone of, parasitology practises.
And if there are strongile eggs present, then we'll see them, and if there are scar eggs present, we'll definitely see them because the scars are so prolific. So it gives us a, yes, there's a parasite burden, and then the call becomes as to to what. Point do we treat.
I think it's really difficult. I think in the literature, there's probably a bit of hesitancy as to call a figure as to where treatment should sit, and it still sits at less than or greater than 200 eggs per gramme. I think there's some great examples in the literature that actually show us that we don't really know what a high parasite burden is.
A perfect example of this was, a lovely paper from, About 2013, 2014, that looked at faecal egg counts burdens, correlated against race results in standard bred trotters with this idea that horses that had a very low parasite burden would actually have much better performance. And what they found in this particular study was actually the other way around. The horses really high faecal leg counts had, a really good race performance.
But then thinking about this logically, any horses in poor health wouldn't have raced. So it's a skewed population, but I think it just really hammers home the point that we don't really know what a really high, . Parasite burden is, but we know as we start getting over, when we get over 500 eggs per gramme, we don't, there isn't a relationship between eggs and parasite burden, and we are indefinite increasing the risk of colic.
So 200 seems to be a, a sort of a figure that everyone's sitting at. The other thing to think about diagnostic wise is actually a measure for tapeworm. And probably didn't give enough tapeworm life cycle as a recap, but because, the tapeworm progltis, those little sections of tapeworm, the eggs are contained inside there because tapeworms are asexual.
And unless those little progltids, those little sections are really smashed up, then Those eggs won't make it into the faeces. It's not that you don't see tapeworm eggs in faecal egg counts, but at the same time, it's, it's not the most reliable diagnostic. But there are now two methods out there.
And for a long time, we've had the tapewormlizer offered by diagnostic at the University of Liverpool. And and show you all the way, you can send blood samples off and have the tapewormlizer run, and then you can go back to your clients with the result. Slightly more recently is the the ereal, which is another tapewormlizer, but it's something that clients can get involved with by taking a saliva sample and .
Sending this off again for tapeworm Eliza, and both, I mean the the the the Equiel has been validated. And is an effective way of measuring tapeworm, and then really it's down to get the, the client getting the best advice on how to then potentially manage that tapeworm burden, but we do have a, a really useful diagnostic there, which can be used effectively for tapeworm control. I think another thing that's really quite important to remember is, is this, this bit that we've already touched on with regards to the animal's age, and this little graphic that I borrowed from a study from several years ago, identified faecal la counts, .
And looking at mares and yearlings, and we can see here, the majority of the mares that were tested here had no eggs in faecal count or 100 eggs per gramme, so low faecal egg count that we wouldn't be considering treating at this point in time, whereas the majority of the yearlings were sort of 2, 3000 eggs per gramme, plus, and actually when we think about this. It's that adapted immunity, OK, we know that horses don't ever seem to develop a full immunity to cystomens or to to strongos in general, but, as they get older, infections do tend to get lower. And then with all of this information together, it's then thinking about, OK, well, what's the most suitable antimenttic for the job?
And should we should then be efficacy testing this to make sure that actually the drug is doing, what it should be doing. And there are different routes to doing that. There's a sort of a full faecal leg count production route.
But actually, even just post drug dosage, picking a a a select point of 23456, or up to the end of the reappearance period of the drug, and, and placing in a strategic faecal egg count to see if it comes back positive or not, because that will start to tell you as to whether there's an efficacy issue there that needs further investigation. But I do think that what we really need to focus on is that the idea that's been out in the literature for 10+ years that analmitic's a really important part of our sort of armoury I suppose against parasites, but they've almost got to be the, the. The last tool in the box, and especially moxidectin with its efficacy against insisted yhoonemans, we need that for that particular role, so it's thinking cleverly about what we're, what we're treating.
And I think that really comes back to this idea of ranking parasites with regards to importance. So if a horse is a pinworm problem and we use a quest to try and attack the pinworm, then we're over. Exposing all the cystoins within that animal to moxadin.
Do we really want to be doing that? You know, if we're treating horses at the end of the, of the years of December time, for giving an insisted treatment and at the same time we happen to remove any, bots, pinworm, etc. Well, fantastic, that's absolutely fine.
But it's about thinking about the parasites of importance and then sort of working backwards from there. Refusia is I think is something really important that actually if we can kind of get this idea over to clients, it also helps with this idea of why we have to treat horses as individuals. And there's two real concepts of refugia, and the, the main concept is the main image on the screen with these little schematics of horses.
So if we take an example of these 4 horses, live out or live together, they all share the same pasture. And within this group, there are 3 that have faecal e counts that are less than 200 eggs per gramme, and we've got 1 with a faecal egg count that's greater than 200 eggs per gramme. Now in this population of animals, it's likely that there will be some resistant nematodes there.
And in this little schematic, the, the, shaded worms are resistant and the non-shaded worms are drug susceptible. If we treat the horse with the faecal count that's greater than 200 eggs per gramme, then we will remove the majority of those susceptible parasites, and if the drug that we've used is the one that they're resistant to, then those resistant parasites will be left and the horse will put those out onto the pasture. However, it's three grazing companions that will probably also have a mixture of resistance susceptual parasites, will continue to put our eggs of those onto the pasture, and there'll be plenty of susceptual parasites within that population.
The progeny then mix, so you've got resistant and susceptible worm larvae on the pasture. All horses are ingesting all of them. And overall, that population stays drug sensitive for a little bit longer because we've reduced the number of potential resistant worms in the population.
I know it sounds quite complicated, but if we think of it the other way, in that if we treated them in a very traditional manner, and we said, well, this one horse needs treatment, but we'll treat all four of them. We skew that population to be predominantly resistant parasites, and then the environment that they're grazing in is predominantly resistant parasites, which then continue to breed, and we end up with a population of horses that is becoming very difficult to treat their intestinal parasites because the majority of them are resistant because of the way that we've treated them. So by leaving the three horses in this example untreated.
We create a fusion. And this, this refusia is really useful to ensure that we can keep these drugs effective. To take it to a slightly more complex level, you can see in the corner of the screen I've got my nice little systoiner schematic of the, the gut lumina and our insisted sciatotomens.
Technically, if we treat a horse with a drug that is not efficacious on those insisted stages, so parentel. Ivermectin or a single dose of fembbendazole, then those yostoins that are identified by the purple arrow that are sitting in the lumen, they effectively remain in refusia because they have not been . Exposed to the analmentic because it doesn't penetrate the mucosa and therefore they're they're not touched by it, and this is really one of the theories as to why ivermectin has remained efficacious and sciatostoins over such a long period of time.
With heavy usage because the majority of South Estonians and a horse are sitting in a mucosa and insisted, and if they're therefore not exposed to the drug, then we can increase the er er the we increase the refusion. So refusia's really important, can be a bit complicated for horse owners to get their head around, but if we can get this concept over, then actually it's important to keep the population with of parasites that are, are treatable, then refuges are a really good way of doing that. I think thinking a little bit about resistance and reduced efficacy is also important.
We've known for a long time that there is widespread resistance to benzimidazos, and efficacy to this, doesn't appear to return. And some practical examples, the donkey sanctuary for a long time had moved away from benzomidazole and moved back, they'd moved to moxidectin, and they switched back. And for a while they they appeared to have good efficacy, but then the efficacy disappeared.
Similarly, I ran a study back in 2016 and we had, we were looking at the . The overcial effect of fenbendazole, and a lot of the premises that we use in this study hadn't used benzoiddazos for 10+ years to their knowledge, and apart apart from horses that came in to the premises that were unknown, these horses hadn't been exposed to benzimidazole for 10 years, and yet every single premises that were used was benz had benzoidazole resistant cystoins. So there doesn't appear to be any .
Reversion to sensitivity and one of the problems we have with regards to tools is to use the faecal leg count reduction test, you need about 25% of the parasite population to be Resistant to be able to, to, to actually identify this. The likelihood is if you stopped using benzoidazole, you'll probably find that the, the parasites that carry that gene would possibly be a bit smaller in the population, and then when you start to use it again, do they gradually start to increase and increase and increase to a point that we can clearly detect this. So I think, you know, thinking about the fact that resistance is genetic.
We know that we don't get reversion to susceptibility. Parental efficacy is is a bit pocketed in the UK from the different studies that have been conducted, some areas have found really good parental efficacy and some not so good. I think we have to think a little bit about parentel as well, in that actually it was, it was a, an antleman tic that had a sort of 80, 85% efficacy at outset, and actually when we test for reduced efficacy and resistance, we test it against a 90% cutoff, which is probably not overly fair on poor little Patel.
And I think it's probably an aromatic that's really fallen out of fashion, so it definitely has a use but within its limitations of being an adultoidal. I think more concerning is the there have been several studies looking at reduced efficacy in the UK for ivermectin and oxidectin. And if we look back, over the last few years, there have been several studies, a lot from Jackie Matthew's group, up at Morden, with work from Val Ralph, Claire Stratford, Hannah Lester, Thomas Tellos, and I did a study as well looking at egg reappearance times and efficacy of, Irmaxin and oxidectin.
And there are, there, every appearance is really difficult because in the literature there are so many different ways it's interpreted, but there are, there have been cases in all these studies where we've had every appearance from 5 weeks for ivermectin and oxidectin. Now that might be in specific populations of, of higher risk courses. But if we think.
Thinking about antomitics where we should have an appearance period of somewhere between 8 and in excess of 13 or 13 weeks, that's quite short and that's quite concerning because they're really our our analmitics that we need to preserve, that we actually need to be doing a job. So it's really important, I think that we're monitoring and tormented egggri appearance times because egggri appearance times are a really good starting point for reduced for resistance. To date, we're lucky, there are no cases of resistance within cytostoins in the United Kingdom.
That doesn't mean that it's not happening elsewhere. So there is oxidectin resistance in South America. And with regards to ivermectin, we do have resistance within scaris, and that really stems from, heavy use in young stock and it studs as a preventative measure.
And ivermectin's a great drug for that, but if we have to be really careful about how we use it to make sure that it it's sustainable into the future. I think this is actually a really interesting area, the, the idea of of barriers to uptake. Because As an academic, I can sit here and I could tell your clients why they should move to a faecal account programme, and you can tell them why they should move to a faecal leg account problem, but they have to, there's nothing to stop them using Alementtic at the moment, and they have to buy in and they have to get on board.
And that really is quite difficult. And I think quite often clients perceive a cost. They think, oh well, I've got to do it, I've gotta use a diagnostic and then if I then have to go and treat, it's gonna cost me more.
And definitely there are, you know, services practises out there who maybe offer some kind of deal to associated with decla counts followed by treatment. You know, and actually back way back in sort of the early 90s, do you. Duncan and Sandy Love identified this idea that faecal egg counts would have a cost saving effect.
And I did a little bit of work, several years ago looking at the cost saving effect on our yards, and it is more cost effective but getting clients to see that, and, and the setup might not necessarily be as cost effective as their annual andalintic dosing programme, but actually in the long run, there is a saving associated. And there's a a nice study from a couple of years ago which really identified that actually antilytic resistance is not a message that worries clients. You can tell them that antiytic resistance is a problem, but it doesn't worry them enough to change their behaviour.
So it's about finding a way to be able to, to change that behaviour. Equally, there was another, little study from a group at Bristol that nicely identified that clients who get parasite control advice from their vets were more likely to use faecal counts and more likely to use. Efficacy tests in their programmes, but efficacy tests were definitely a smaller proportion, whereas clients who go out, and they get parasite control advice elsewhere, or even, use some maybe, faecal accounting labs to do it, but maybe not as effectively.
So it's definitely, . A benefit to vets, to clients engaging with their vet. It's just how you get them on board.
And I think a really nice point that was actually brought up in Keith Allison's work back in 2011, was that there are horse owners out there who are concerned that the way they're managing parasites isn't the right way or it's not sustainable. But livery yards imply rules that all horses have to follow a specific programme and they all have to be treated at the same time. And therefore there are lots of one horse owners who need to use a livery yard facility and therefore they have to sit with those rules.
With regards to problems, I think it's really quite sad that this October we see the withdrawal of Equitape from the market. Equitape is our, our one, you know, parasite specific. It's a nice little, tapeworms specific rasiontal.
And removing it from the market then makes us think a little bit more about how we go about treating tapeworm. We can use a, a combined, anti tic, maybe a, amoxidectin prosipony at Christmas. Or we could use it combined with Ivermectin, but then, depending on when and the year we're treating, we just think a little bit about How we, how we fit that in and what parasites we're potentially overexposing, again, our South Estonians, if we, if they don't need to be treated.
And we can use a double dose of parentel, but then we're only treating aphal paraphylata and not magna, which may or may not be a problem. It, it's just, it makes things slightly more difficult when it comes to sort of the planning stage. And so finally, a little bit on the future, where are we going?
Because what I've told you so far is not necessarily particularly new, it's just a refresh and a recap. But actually there are things on the horizon. After saying that parasitology is an area of veterinary medicine that hasn't really progressed, there are definitely things that are changing.
So on the screen, there's quite a lot on the screen, there is a system here called poop to proof. And there's a little timeline of how this works and it shows you a little picture on the screen. I was really fortunate last year I was in Kentucky and I visited Martin Nielsen's lab at the Gluck centre.
And one of his PhD students, Jessica Scare, was working on this particular system. And it's an automated faecal egg count system. So it has this little prep bottle and sample collector, and it means that you put the perfect amount of faeces in, fill it up with liquid, it's the perfect amount, you homogenise it, and then you have this little machine that has dye that sits in there, you put the sample and you put the dye in, you press go as the little imaging unit works away and it works with a smartphone or a tablet.
And it then gives you this image here. Now the paper came out at the end of last year and actually poop to proof, it appears to have been available for about, Only a handful of weeks, it is a new concept to the market, but actually this would be a really useful thing for for vets to be able to do faecal counts there and then out on site. It, it's, the concern is that potentially it might be something that maybe some clients might wish to sort of large .
Studs or large yards might want to have in themselves. The problem comes down to being able to interpret it, but I do think from a practitioner's perspective, actually this is quite a useful tool. We know that fecale carrots have their, their limitations, but actually this is a very quick way to be able to, to process samples there and then.
Other types of developments, this has been out a little while now, but it's a nice little paper from Martin Nielsen and others back in 2015 that successfully used ultrasound to be able to identify scarros. So, in groups of folds from 162 to 294 days, . By using 3 locations along the central midline, they could identify scares, especially when there were 10 or more scams present with a a a moderate repeatability, and they could then treat these horses and then they could then re-scan and and re-score.
And so this does, this is, this is a system, you know, actually using a diagnostic that's already you know, readily available out there. To be able to, especially for sub clients that are particularly concerned about a cage, there is a way to be able to do this. So I think that's something that we could probably think about that might be a slightly better version for a garage than a fecalre cats, and it, it's on a practicable practise basis, but there is potential there.
One of the more exciting developments is Zach Stone and Eliza, which Jackie Matthews and her group have been working on for quite a while. There was a paper by Michelin of this in 2016, which identified that they, they'd actually identified the proteins they have in Eliza, but, from their testing they that they. That's going on at the moment, they're looking to validate this again using a, a, a saliva route.
And this will be a huge step forward. Being able to estimate burdens of yotoins, that are sitting in cists in the gut will make a huge difference to the way that we can manage them. So that is something that's on the horizon that will definitely make a big difference.
And then there's sort of the explosion of next generation sequencing, the, the, the omics technologies, and the nema biome hasn't quite made its way to horses yet, but I don't think it would be long. And this is work from John, Gilliard's lab out in Calgary, and he had a PhD student, student Ryan Aframeno, who, worked on identifying the the Nemabi, so it. Uses the same process as the sixing a sequencing, which is, you know, really big and sexy out there at the moment in the research world, and basically he has identified, a section of, of nematode DNA that is then deep apricon sequenced.
And they've used it successfully in cattle nematodes to not only spec shape, but actually to identify antilytic resistance. So at some point in the future this technology will be out there and we will be able to do this type of thing with horses. OK, at the moment it's a research focus, but it will definitely be out there.
And equally there are those of us, myself, a friend Laura Peachy at Cambridge and others that have been working on actually what effect do parasites have in the horse's hung at microbiota? Do they play an important role and again using these 16S approach. Which is to try and identify what their role is, are they affected by treatment and all these different things going forward.
So it, it may have been an area of veterinary medicine that had been relatively slow to develop, but actually it's an area, that has really sort of started to, to come on. So with that in mind, I just like to thank the sponsors for the session this evening and open up the floor to any questions. Thank you very much, Simon.
That was really, really interesting. So, questions popped up, maybe slightly controversial. Should vets be the only, professionals that are prescribing, ants or?
Is, non-vets being able to prescribe and owners just being able to worm as and when the yard manager tells them as opposed to be when they should be doing it or targeting or as you say, doing faecal leg counts. That's a really difficult and interesting question. I think that I, I, I don't know, in some ways, if we moved to, if we moved antimitic to vet prescription only as in Denmark, I think there is a lot of potential with regards to reducing the speed of analytic resistance, but equally, I don't think what they anticipated in Denmark was that actually some clients switched off and they just didn't do anything, so.
There is a, there is that risk. I think if the SQP system can work effectively, then and the and actually all the robust questions are in place, then there should be no reason that analints can't necessarily be purchased from other retailers outside of the vet, but actually in an ideal world, the client and the vet have a good working relationship and the client goes to the vet for advice. Yeah, yeah, which I think is probably possibly where the system is.
It's failing a bit. I think clients are more likely to, well, in my experience, they tend to prefer to, well, they just go with what the yard manager's telling them. Yes, and that's very frustrating and difficult to deal with.
Yeah, so, so there's probably, do you think that there's, you know, because they're like Nottingham, for example, they're doing like a colic awareness campaign to react to colic. Do you think that there's a place that should think similar be done for for worming to try and educate horse owners, to try and kind of kind of encourage them to to do faecal leg counting. Yeah, definitely.
I think, and that was really one of the key things, something that I'm quite interested in as well, that came out of the, the study that identified that telling owners that antiytic resistance is a problem is not switching them on, and it's. It's about knowledge exchange, it's about getting their buy-ins and, you know, telling them doesn't work. You have to kind of give them the problem and then help them to solve it.
And I think you're right, actually, the, the mechanism at Nottingham is a really good one with regards to, to colic, and maybe we need to extend that a little bit and think about that as a mechanism for parasite control and aalytic resistance. Yeah. Brilliant.
OK, well, that's all we have time for. That's an hour. On the dot.
So, thank you very much, Simon. Really, really interesting talk. I think you've covered absolutely everything I didn't really know about Parasitology, so, and really, really interesting as well.
Thank you everybody for attending, and, I hope you all have enjoy the rest of your evening. Bye for now.
