Thank you very much. And thank you to, the organisers, the trustees for inviting us to come and present today and also to AWF and the Norman Hayward Fund for funding. This project is a relatively short project, just 12 months, which we completed last year and I was quite glad that Cathy actually highlighted chronic endemic health issues as one of the priorities in her list that she's just presented because I think this project fits very much within that category.

So we do a lot of work on liver fluke in Liverpool. So Liverpool, sorry, live fluke is a highly pathogenic parasite. Liver fluca Liverpool.

So that's OK, so it's it's a highly pathogenic parasite which affects the health, the welfare, and the productivity of sheep and cattle globally. And it's very common in the UK. It's increasing in prevalence.

This graph shows APHA data which shows really since the late 1990s we've seen a big increase in liver flu diagnoses in sheep and cattle. We think that's probably a result of climate change, amongst other reasons, and that's because the parasite is transmitted through a mud snail. Thrives in mild and wet conditions.

You can actually see this is one of our lab colony we call this one Brian people of a certain age that joke appeals to. So you can see the parasites actually emerging from the foot of the from the foot of the snail here, little white dots, so those are the which then go and insist on grass and are consumed by grazing animals. Something else that we're aware of is that resistance to many of the medicines used to control liver fluke is becoming widespread and particularly resistance to the drug trilobendazole.

So liver disease in horses is common and the cause is frequently undiagnosed. I mean, there are obvious causes such as ragwort poisoning, but for many other cases, difficulties in diagnosis results often in suffering in individual courses and in worst case scenario, arguably early euthanasia. So we know that liver flu can infect horses, but it's often neglected as a potential cause of liver flu disease.

So in view of the increasing prevalence of infection that we see, we ask the question can liver fluke account for some of the undiagnosed cases of liver fluke disease in horses? So the aims of the project were to first of all to try and determine the prevalence of infection and we used an abattoir survey for this. We wanted to compare genotypes of flu isolated from horses with those found in sheep and cattle to determine whether flu affecting horses formed a discrete population or formed part of the same population of those in sheep and cattle.

We used a case control study to ascertain whether horses with liver disease are more likely to have been exposed to fluke, and then we wanted to draw up a clinical profile of infected horses to assist with diagnosis, and then we also wanted to come up with some recommendations for treatment and control. So the prevalence study consisted of visits to one of the major horse abattoirs over the 12 months between January and November 2017, and we examined 342 horses. 26% of those horses were tested positive by an antibody detection alizer.

Four of the horses we actually found adult flutes in their livers. So we concluded that the prevalence prevalence of liver fluke in those in the in the standard horse population in the UK was around about 8%. We then wanted to compare the genotypes of fluke in horses, so we used 123 fluke that we'd obtained from a range of horses from our abattoir study from other cases that we had been involved in and also a couple from Ireland.

We genotyped them. And we showed that 96% of the alleles in those flute populations from horses were identical to alleles found in fluke derived from sheep and cattle. We also showed that the flute population was genetically diverse.

There was no evidence of population structure. And so we concluded from that genotyping that the flukecrum horses were from the same population. And as those from sheep and cattle.

So in other words, it's the same parasite which is cycling between sheep, cattle and horses. We then conducted a case control study, so the cases were horses with diagnosed liver disease, and that was either on the basis of clinical signs or blood test results and raised liver enzymes. We used residual blood samples that had been taken for other diagnostic purposes that were submitted by vets, and then we contacted owners and asked them to complete a questionnaire to gather data about their particular animals.

The control population were horses with which were being investigated for other reasons. They all had normal liver enzyme levels and we used serum that had been left over from other diagnostic tests and we extracted clinical and signalment data from hospital records. So the case control study, we had 109 cases, and of those cases, 11% were flu positive by serum antibody.

And of the 160 controls, 2.5% were flu antibody positive. So we calculated the odds ratio and showed that the risk, the likelihood of an animal with liver disease was 6 times greater the risk of being diagnosed with liver fluke compared to the controlled population.

So in other words, horses with liver disease have a significantly higher odds of testing positive for flu compared to the control group of horses. We then wanted to establish a clinical profile for liver fluke infected horses. We had a relatively small number of horses that tested positive for fluke over the time period of the project, so we had 24 horses.

The age range was probably representative of the UK horse population, so between 5 and 30 years of age. The most commonly reported clinical signs were lethargy, dullness, weight loss, and other clinical signs which were reported with things like poor poor performance. And on the blood tests, there were raised liver enzymes, GGT and GLDH, but those were certainly not seen in all horses, and we didn't see evidence of eosinophilia, which is normally associated with parasitic infections, and we didn't see any evidence of anaemia which is often associated with liver fluke disease in sheep and cattle.

But what was significant was that all the infected horses, 64% of those were co-grazed with ruminants and primarily sheep. So overall, in conclusion, we estimated that the prevalence of liver flu infection in the UK horse population was about 8%. So we think, we think this is probably an underestimate.

We think that infection is probably common, particularly in the wetter west of the UK. Horses with liver disease were 6 times more likely to be diagnosed with liver fluke infection. And liver flukes that we found in horses are drawn from the same population as those found in sheep and cattle.

And we also showed that shared grazing with ruminants was an important risk factor for infection. Clinical signs and blood test results were very variable and non-specific, so this makes diagnosis difficult. So we now have a validated serum antibody detection Eliza, which is available to assist with diagnosis.

Which is available. So in conclusion, our advice to owners and vets is that Liverpool Liverpool again, liver fluke is we think is an important cause of liver disease in horses and so our advice would be that horses with liver disease, it is certainly worth testing them for liver fluke to rule in or rule out liver fluke as a cause of that liver disease. Current nematode worm control, so for stomosis, for example, that we give to horse owners is that we advise horse owners to actually rotate grazing with ruminants such as sheep because that assists in reducing contamination of pasture with nematode larvae.

But in the light of our results suggesting that horses are likely to be infected with the same population of liver fluke as that infecting sheep and cattle, we think that that advice should now be given with caution and that you need to consider not only control of nematode infection. But also control of liver fluke and the risk of exposure to liver fluke as well, particularly in areas of the country where liver fluke is highly endemic. And then finally we did some work on treatment options, so there are no licenced treatments for liver fluke infection in horses, so treatment is under the cascade system.

And the drug trilobendazole is probably used as first choice, but we know that resistance to trilobendazole is common, at least in sheep populations, and we're aware of at least 2 cases of infections in horses which have been refractory to treatment with trilobendazole, so alternatives need to be considered. We also produced a leaflet which we sent round to all collaborating practises and indeed other practises that we work with from a diagnostic sense to try and raise the profile of liver fluid disease in horses and raise awareness of the need to consider liver flu as a diagnosis. I just like to thank AWF for funding the project and also particularly Dr.

Alison Howell, who was the postdoc employed on the project, and Harriet Rhodes, who was a 5th year student for Liverpool who for her 5th year elective did some of the work on looking at different treatments for. Thank you OK, so, oh, there's a couple, couple here appearing on the slide just before that, I mean, ideally should all horses grazing with ruminants have a routine blood test even if they're not showing symptoms, and I suppose linked to that, I mean, have you any . Have you any thoughts on a protocol as to whether in fact co-grazed animals should be routinely treated with trilobendazole or should they be done on the basis of a positive Diagnostic.

So I have to say we had a lot of debates with our clinical colleagues over this particular issue, and I think, I think. I think basically it it needs to be considered on a case by case basis. So if if horses are on a dry pasture, Sheep have been moved onto that pasture and there is co grazing or or rotational grazing.

I think if the pasture is relatively dry and liver fluke isn't an issue in that area, then I think there are less concerns. I think where we do have concerns, particularly in areas in the west of the country where liver fluke is very common. Where horses are grazed on rough grazing and often these are sort of horses grazed on rough areas, so Welsh mountain ponies, that sort of thing.

Then actually I think a blood test is no bad thing. I would not treat in the absence of a diagnosis if it's it's a routine screen and if people are concerned, I would first of all a test faecal test or the next question is actually she's linked to that. I mean, based on the sensitivity and specificity of the Eliza, you know, is the faecal useful?

Absolutely. I think that's a good question. So.

Know our serum antibody elizer is only about 1 72% sensitive. It has reasonably good specificity counts, I think, a lot less sensitive. So I think again you have to interpret the results of the diagnostic test with all the other data that you have to hand when considering treatment.

OK, fantastic. Can you please put your hands together again.