So let us begin. Our first speaker today is Eric Morgan. Eric Morgan qualified in veterinary medicine all way back in the day, in Cambridge in 1997 and following a PhD at Warwick on parasites, joined Bristol vet school in 2003.
He's then enjoyed further, teaching and research in parasite transmission before moving to Queens University, Belfast. In 2017, he's co-authored more than 100 and 50 peer reviewed papers, seeking especially to understand the impact of weather and climate on parasites and how they can be managed. And as a member of various national and international initiatives, he contributes to the development of sustainable parasite control strategies and their translation into practise.
So who better to talk about the effect of climate on parasite distributions in Europe? So, over to you, Eric. Hello and thanks, Ian for the introduction.
So my job today is to take you through the effects of climate change on European parasites and their vectors, and I'm going to do that pretty much from the ground up, pointing out that there are principles that apply across parasites that govern their responses to climate and weather and therefore to climate change. But the outcomes inevitably are very species specific, and you'll be learning a lot more, from the other speakers later about the clinical consequences of those impacts And that variation. I'm also going to stray little into predictive modelling of parasite distributions and parasite infection patterns, and the reason for that is that you will see increasingly, predictions of how climate change will affect these parasites.
And rather than accepting them as prophecy, I hope you will be more literate in interpreting these models and their limitations and therefore be better able to apply them to your clinical practise. So very much a bottom up, series of objectives For this first session, I will final finalise that by discussing how we might apply. Of course, these new insights into clinical practise before those themes are developed further in subsequent webinars today.
So climate change is certainly happening to speak about this topic. A few years ago, we would have been talking about the potential for future climate change. It is clear that climate change is already happening.
It is already having big effects, so these photographs are from an Arctic community, in October, when the sea ice should be fully formed and people should be fishing through the ice. And as you can see, the ice is not formed. So we are all experiencing unusual weather conditions really very frequently now.
No year is typical anymore. We're also starting to understand that the effects of global warming are not simply a small increase in mean temperature. This might be true as a global average, and one degree does not seem very threatening, and two degrees does not seem very threatening.
But of course, if we shift, that mean we will increase the tail of extreme events and we've seen in Europe certainly this year the effects of that. We will not just see a shift in the mean temperature. We will see increased occurrence of extreme events such as heat waves.
We will see intensification of the hydrological cycle, and that is simply because the atmosphere is warmer, the oceans are warmer, the atmosphere can hold more water vapour, and so we see more extreme rainfall events. And in Europe we've seen that in Southern Europe, a very hot, dry summer, very extreme rainfall events in autumn. We've seen it in northern Europe.
So in the UK and Ireland, a very, wet, cool, miserable summer. And these will obviously affect parasites in very different ways. So how can climate and weather so weather is the variation in climate on a short time scale?
And how will this affect parasites? Well, there are some fundamental processes. Most physiological processes accelerate with increasing temperature.
For example, we know that the the Q 10 of respiration of photosynthesis in plants is around two. This means that the rate of these processes doubles with every 10 degree increase in temperature. This leads to a non linear relationship between growth and temperature.
And we can see this. For example, in tree rings, we see rapid growth during summer and in deciduous trees. No growth in winter.
But even in coniferous trees, even evergreens much slower growth in winter. This is a temperature driven process. Homeotherm animals who regulate that regulate their internal temperatures are not so subject to this variation.
But most parasites, when they're outside the host have stages that are experiencing ambient temperature, and so they do follow these rules. There are additional limits on these physiological processes and most physiological processes are driven by enzyme activity and enzyme dynamics, also suffer from upper temperature limits. So as temperature increases, the rate of reaction will increase.
But eventually enzymes, which are proteins with complex folding patterns, will denature, and so they will cease to function. The net effect of these changes is, an increase towards an optimal rate of activity with temperature and then a sudden decrease in function due to enzyme denaturation. How does this pan out in parasites of veterinary importance?
Well, we start with a relatively simple life cycle. So toxic Cara, as I'm sure you're aware, is a zoonotic nematode whose, larvae, when ingested, migrate around the body and can cause ocular and visceral larva migraines. These are the sorts of clinical consequences in humans from toxic car infection and the weight of infection.
And the burden, is thought to be largely underestimated because of presentation of disease that is not diagnosed. It's notable that the egg is not infective. When shed initially, the over have to has to develop into the infective larval stage in order to be infect, and this is strongly temperature dependent.
The response norm is what we call the relationship between temperature and the rate of development of effective larvae, and this can be ex estimated experimentally. If you have an incubator and some eggs, you can put those eggs into the incubator at different temperatures and work out how the temperature relates to development rates From these sorts of experiments. We can estimate, this function, and we can then apply it to predict how changes in temperature will affect infectivity.
And here you see a nice linear relationship between daily development rate and temperature derived from these experiments. The difference is quite remarkable. So across a not unusual temperature range of 15 to 35 we see a decrease in the duration to infectivity from 50 days down to six days, So a very, very strong effect of temperature.
OK, higher temperatures can have negative effects on parasites also, so as temperature increases in many parasites, mortality will also increase. We can see this here for he contorts, even though humus is a parasite of production animals, not companion animals. This is a general rule that you often observe so as temperature increases, the mortality rate of humus will also increase, and this means there's a trade off between development and survival.
So here you see the survival rate, decreasing with increase in temperature also decreasing in very cold conditions, development increasing with temperature to a maximum, it will eventually decline. And there's a zone here where the two are favourable. So you get these tradeoffs and as a result, most parasites actually have a an optimal zone for development success.
And you can see this in the proportion of infected larvae that hatch from humongous eggs at different temperatures. Even though this is a tropically adapted parasite which, shouldn't do too well in Europe, you can see that at high temperatures it doesn't succeed so well. So the optimum is actually a quite reasonable range of temperature.
There are additional limits on transmission imposed in vector bone parasites. So the heart worm Diop imatis, for example, develops within the mosquito, to the infective stage, and the mosquitoes are experiencing ambient temperature. So this is going to be temperature dependent.
And in drahy area, we can do the same sorts of experiments in incubators and work out what those temperature rules are. And the key rules are very simple, so below 14 degrees. There is no development in the mosquito, and above that the parasite must accumulate a certain number of growing degree days.
In this case, 130. The concept of growing degree days is really very useful for establishing the impacts of climate warming on parasite transmission and many, invertebrate populations. The principle is simple.
So for each degree Celsius above 14/1 day, we accumulate one growing degree day. So if we have one day at 15 degrees, we accumulate one growing degree day in that day. If, however, the temperature on a particular day was 24 degrees in that one day we would accumulate 10 growing degree days.
And so, in fluctuating temperatures, we accumulate a certain amount of thermal energy over time that permits that maturation to happen and transmission to occur. However, mosquitoes don't live forever, so if we impose a realistic maximum life, expect expectancy of 30 days on the mosquito. It's a race against time.
The parasite must develop to the L three before that mosquito dies. Otherwise, there is no way it can be injected into a new host. The period for development in the vector is called the Extrinsic Incubation period, and therefore, if this exceeds the life expectancy of the vector transmission is not possible.
We can see how this would affect, outcomes over quite a small temperature range. So at 20 degrees, for example, we are six degrees above the threshold. So each day we accumulate six growing degree days and it takes 22 days to develop to the L three.
If we go down just two degrees, we're still above the threshold. But each day brings only four grown degree days. And so we need more than 30 days for maturation and development, to maturity and transmission is no longer possible.
The reason growing degree days are so useful as opposed to just imposing a threshold, is that it allows us to account for variation in temperature. No day is the same temperature, seasonality in transmission, for example, declining temperatures in autumn, increasing temperatures in spring. And that allows us to have a more realistic projection of effective climate change on transmission probability.
And in the later part of this talk, I'll illustrate how these rules have been applied in that way. For now, though, I just want to emphasise there are There are many processes that affect vector properties. Abundance, for example.
So here we were talking about Dirofilaria in mosquitoes. This is not dependent on moisture because there is hemo lymph. There's moisture within the vector.
But of course, mosquitoes reproduce, and need water so their larvae are found in water. And so vector abundance is gonna be very dependent on water, and that's going to affect transmission. Also, vector capacity, is also affected by temperature.
So, for example, we have some species of mid that are not suitable vectors for bluetongue virus until they reach a certain temperature. And this affects the divi dividing line between the blood and the body fluid. And this will increase the ability of the virus to invade the, mid and to have it act as a vector.
Climate and weather affects vector behaviour also their activity and biting rate, and this will have important impacts on transmission. So, for example, here we have leishmania in sand flies and this paper goes through the different effects of temperature on aspects of vector biology, and we can see that as temperature increases. The yellow markers show that you have a decrease in the extrinsic incubation period.
As we would expect, we get an increase also in the biting rate, and both those things would promote transmission. But we also get an increase in the daily mortality rate of the vector with increasing temperature. So the net effect of all of these processes could be quite complicated to predict, and we'd be different in every vector and every system.
It's not only biting vectors that will be affected by climate and weather, So here we have Angie's strongest theorem. The life cycle involves intermediate hosts that are gastropods so slugs and snails, and they are strongly influenced by weather and climatic conditions in terms of their activity. So regardless of the populations that are present in the soil oil and in the vegetation, the number of gastropods that will be active on the surface will be strongly influenced by the weather conditions.
And that is the proportion of the population that is exposed to dogs. That dogs might ingest is the proportion of the population that will be feeding on the faeces of dogs and foxes, and that increased activity will promote transmission and risk. So here are some results from Transects Just head torch transects of number of slugs that are active in public park grassy areas in the UK, and you can see that when it gets cold towards freezing point, you get much fewer slugs.
Also not shown very dry conditions. Slugs would not be so active. And also heavy rain slugs will not be so active.
Light also influences activity, so following dusk there's an increase in slug activity, and that declines through the night. And then there's a second increase in activity early in the morning, but that is strongly dependent on temperature. So light is not affected by climate change.
Temperature and rainfall are, and so the consequences will lead to changing patterns of activity. And those, as you imagine, might help us to avoid, situations with our pet dogs, where risk of transmission is high because risk of encounter with slugs and ingestion of slugs, including accidental ingestion will be increased. What, therefore will be the net effects of climate change on angios strongs.
Well, we would expect that warmer summers would allow quicker development and more mature infections in slugs. In autumn, the growth and development of Angie Strong's in Slugs follows the growing degree day rule that I mentioned earlier, and there is a trend in Northern Europe towards increasing growing degree days through the summer. So we would expect warmer summers to promote growth in the slugs and infection Warmer autumn.
Then, from what I've shown you would lead to higher gastropod activity, for example, more activity in the morning because the night has been milder and therefore also a greater chance of dogs encountering infection. Wetter summers just as we have seen this summer, in the UK and Ireland would favour gastropod population growth. And then you see a lot of headlines around gardeners struggling with slugs eating their produce.
But those conditions will also fit. Promote inter me host abundance. So we would expect that the year just gone, where we've had a a mild, wet year would promote angio stronger transmission.
However, elsewhere in Europe, where we've had very dry summers, we would expect that to be very difficult for gastropods to reproduce particularly slugs, we should get lower populations. We should get lower activity. We should get lower infection.
However, as winters get milder, the transmission and development in the slugs could shift from summer to winter, and that might offset some of this dryness. The the effect of some of this dryness outcomes will vary locally, and we should take. If we're aware of the basic principles underlying, variation in infection pressure, then we should be able to translate that into advice and also into clinical vigilance.
So, for example, in a particularly war wet year, we might choose to test more for angios strongers when we're presented with complex clinical presentations and we might choose to increase the advice to owners to protect their dogs against Angiostrongylus takes, an example of actors whose lifespan is very long, but their activity is very sporadic. So the life cycle of these risin, for example, it lasts three years, and then each year they will feed on a a host of increasing size, and so they only feed three times. The rest of the time, they will be hiding away in stable, moist conditions where their mortality is reduced.
But when they need a blood meal, they climb up the vegetation and they find a host by questing, and in doing that, they're exposing themselves to conditions that are, dangerous for them. So they only do this when conditions are suitable, and that requires a reasonably high temperature and also humid conditions. What we're seeing with tick biting in several parts of Europe is that previously temperature was largely the driver of tick questing, and we would see in most places in northern Europe a summer peak.
When you get a drier summer, you get a decrease in questing in those dry conditions. But if you have a milder spring and autumn, those are perfect conditions. We move from a single summer peak in questing activity to a much more biphasic pattern where we see peaks in spring and in autumn, and and that seems to be increasing as a pattern.
However, it's worth emphasising here that it's not only effects of weather on tick questing that are gonna be important in tick, in exposure to ticks. So season for sure, there is evidence of a broadening of the tick season. So these are data from a paper that counted ticks on dogs in the UK and found that there was tick attachment in Mo in almost every month of the year, and the proportion the number of ticks that were found on dogs in spring and in autumn was higher than expected.
So here we do see a summer peak, but we see an expansion of the tick questing season into the spring and autumn in Northwest Europe. However, these other factors are also going to be very important. So in a second paper, risk factors and were found to be important included breed type and long coat, and also where this dog, for example, is being tracked using a GPS tag.
And owners were questioned about their walking habits and it was found a very strong risk factor was visits to natural habitat. So habitat that had more woodland longer grass growth, where there was more exercise off the lead were really important. Intuitively, this makes sense.
We really important in determining the risk of a particular dog getting a tick. And my point here is, although that is obvious, it means that small changes in the climate and weather are going to be much less important when the risk factors are dominated by breed type and dog behaviour. So even though there might be an underlying shift in the seasonal patterns of tick questing in this area.
The main thing that determines whether a dog gets bitten is gonna be that dog's behaviour and routine. So climate change is therefore only part of the picture. And this is why predicting climate change effects on parasites is so complex.
We've discussed really the biology, and we tend to focus on biological factors, BEC, because we can test them. And because scientists doing the research of biologists, we focus on parasite development rates, vector biology. But of course, environmental factors are broader than that.
They include, as we've seen canine and human activity and also environment change. So a shift in the way in which we manage our public spaces increased natural, habitat, increased, populations of urban and suburban deer, for example, are gonna be strong drivers of tech risk. And how we manage those environments is gonna be really important.
I'm not suggesting we should, reverse the trend towards rewilding of these public spaces, but we should be aware of the increased challenges they pose and protect our pets in other ways. There are also human factors, of course, and, canine activity is is not spontaneous. The owners are going to determine where the dogs go and how they sample these environments.
And so those human factors are also very important. So to conclude this first part, how might climate change affect parasites? Well increased temperatures generally will accelerate development, and on balance, this will improve conditions for parasite transmission.
However, there are other factors at play, so there are upper limits to temperature effects through increased mortality of parasite and vectors. There are interactions with humidity and also vector behaviour. And there are non climatic factors that could have a dominant effect on risk.
Decreasing the relative importance of climate change in a system. The net effects are are not always obvious, and they're certainly not universal. And this is why we should really consider species individually.
And that's what I'm gonna do in the next section. I'm just checking the chatbox that you can still hear me. It's very lonely speaking to a screen, but so far so good.
So what I'm going to move on to is, how clinically important parasites would be affected in Europe. You'll hear a lot more about this through the rest of today, but I just want to introduce some of the players so that you're familiar with them. And I think when we ask this question, we're asking it in relation to two different panels of parasites.
First, those parasites that we or you listening already have in your area. So here we have toxic Cara universally distributed. We have angios strongness quite widely distributed in Europe.
We have ides resinous ticks, which cause, for example, biosis. And so the climate change will affect those endemic parasite species. But if you're from an area that doesn't have the full range of parasites in Europe, where our major concern is what we might get in future, So in northern Europe we wouldn't be used to seeing dialer ius.
We wouldn't see rius. We wouldn't see, echinococcus multilocularis in some areas of northwestern Europe. So these are what we would call exotic parasites for us and other areas.
They're not exotic parasites, of course, but they are particularly concerning for those areas that don't yet have them. Because we have limited protection, we have limited protection potentially through immunity. So, for example, in the case of babesiosis, it can be much more clinically severe in dogs that have not had early life exposure and transfer of maternal antibodies.
And so when we don't have endemic stability for some of these vector borne diseases, the population is much more susceptible. So this is a concern. We also potentially have limited protection.
So where we don't have heart worm, for example, monthly heartworm prevention is not going to be widely, used. And so that renders the population more vulnerable and, of course, unfamiliarity. So we'll hear more about Angio Strong's theorem later from Manuela.
But it certainly was the experience in the UK that severe clinical cases were missed during the spread of angiostrongylus simply because clinicians were not really aware of what they should be looking for. And they didn't diagnose those cases that now, with a bit more knowledge and being in an endemic area they would easily have picked up on. And I think that's a concern with these exotic parasites arriving in new areas.
What is the level of clinical awareness that will allow clinicians to catch these cases, before they have, really bad clinical outcomes? So if we talk about exotic parasites coming into a new area. Of course, we have to talk about dog movement.
A lot of the regulation of dog movement, would have been really driven by concern over Zoonosis. So Rabies Ayo Coccus Multilocularis some tick borne diseases, particularly rial diseases like bone fever, spotted fevers and then exotic ticks that would carry the zoonosis. So a lot of the regulation would have been considered as human health only.
But of course, there are many parasites. That will potentially spread increasingly with dog movement and climate change. Some of these are zoonosis, but not necessarily part of movement restrictions.
So leash meiosis and some will be mainly concerns around dog health, like Diyar, babesiosis, exotic ticks and Thalia. And this changes the picture. Really?
So no seas will drive the rules, but threats to canine health will be really a matter of private vets. Responsibility in consultation with the owner, just to break down a little bit what I mean by these diseases. So we have canine babesiosis, which is caused by babesia.
But there are different species and subspecies of babesia. Taxonomists argue over what exactly we should call these, but essentially we have babesia canIs, which is transmitted by Dermata ticks. And these ticks are widespread but patchy, whereas bebes canIs vli is transmitted by riyal sanguine.
And that is more of a southern European tick that T will also transmit Alicia canIs and Hepatizon canIs. And these are infections that affect the white blood cells and can lead to quite different clinical consequences. As I'm sure you will discover in terms of the distribution, though, we talk about the RUS line Really, That, south of this line RPI is widely distributed quite common.
And so this is where we have endemic babesiosis and these other, RPI transmitted diseases, whereas further north we occasionally see these diseases. But they will be associated with travel where you have introduction of babesia canIs and you have the incentive populations. Then you can get, establishment, of course, on autonomous cases.
Other parasites, of course, have a more southern distribution as well, but for different reasons. So here we see Daryle Imatis and certainly in Western Europe, you look at that south north divide again is very similar to Rus, but in this case, it's largely driven by the thermal limitations on development in the mosquito host, which I showed you earlier. Diya ripens has ostensibly similar, thermal requirements, but it is more widely distributed.
So this suggests that maybe the rules for development in the mosquito are more relaxed. So in non endemic areas for Dirofilaria, this is, there are many mosquitoes and species that can act as vectors. But we're waiting really for the parasite, to arrive and to be, transmitted in these vectors and that is likely to be limited by climate.
So this is certainly one you would flag as a climate change risk because it's really, climatic, suitability that is keeping it out and nothing more. Leishmania is quite a different situation in that the non endemic areas generally do not have phlebotomus sandfly vectors that are suitable even though there are significant numbers of cases being diagnosed. Sometimes you get non vector transmission.
But essentially, this is a A disease that is already present, in substantial numbers of cases, but is waiting for the sequel vector to spread. Thalia Calida is an eye worm which has AAA fruit fly vector quite unusually and again, the vector suitable vectors are probably found fairly widespread in Europe, although there's some questions over which species can truly act as vectors. So the local situation becomes uncertain, and in that case we should err towards the side of vigilance and be aware that these cases can come in.
And we might expect autonomous cases, locally transmitted cases to pop up in the future, particularly as climate is warming. The kind of coccus is almost a contrast here. The definitive host is the the Fox, the dog.
And in some cases, to some extent, the cat can be infected as definitive hosts. And the intermediate host is, rodents, particularly Vols. When humans get infected as accidental hosts, the cysts can grow.
And here we have an example of alveola echinococcosis. It can be very severe in humans. And so this is a parasite we should be very concerned about spreading through Europe.
This is a case, for example, of a lady who was presented with chronic pain. Following clinical investigation, Alveolar Chinois was confirmed. There was surgical liver resection, but this can be very, very difficult to achieve a cure because the cysts are very invasive through the liver, and it's it's difficult or impossible to successfully resect the lesion.
And so lifelong, anti therapy is necessary. And even with that, we can have negative clinical outcomes. So this is a very, severe and important disease, and it's not universally found throughout Europe.
So again, using the SCP maps, we see that a canco multilocularis in the fox in Europe is really a a central and eastern European parasite. And introduction to areas that are not currently infected is most likely through animal movement. So clearly through movement of dogs that are infected and could shed eggs into new areas, infecting local rodent populations and then spilling over into the fox population and once established in the fox population, it's going to be really, really difficult to eradicate it, as we have found in other countries that have tried to do this.
So our best defence against Alveolar, Aono coos, is to keep it out, not to react following its introduction. In this case, because the intermediate host is warm blooded, then the effects of climate and climate change are much less than in these vector borne diseases, and actually, climate warming is probably not going to be a critical factor for the spread of a kind of caucus through Europe. However, environmental change could be particularly through rewilding and in the UK.
The first case for Koc Coccus multilocularis importation was diagnosed in a beaver that was, imported from Germany in order to, be reintroduced and to RIL conservation areas in the south of England. And so the roots of animal movement are not restricted only to movement of pet dogs. Of course, it's important to be vigilant for these diseases because in this case, the cysts are slow growing.
Diagnosis by medical professionals in people will occur likely long after establishment of the parasite. And so really, vets are in the front line of trying to keep these diseases out. And even though climate change is probably not going to act strongly through establishment risk through thermal suitability for development, environmental change is likely to play a factor.
So in the last two sections, I want to discuss a little bit, how we can make sense of all of this across parasites. And I am going to talk a little bit about climate change. Prediction models, not so much models that predict the extent of climate change, but how we can use those climate change projections to, estimate to our expected consequences for parasites.
So models allow, our knowledge of response norms to be used to predict future scenarios under climate change to integrate other elements of these complex systems. Like, I've described, crucially, to identify key uncertainties. So when we have a model that we think explains likely parasite responses to climate change and we test it and we find that there's some failure or there's some strong dependence on, an element which is not well understood, that points us to go back to the drawing board almost and to to explore the uncertainty in those crucial parameters and areas.
So this is really one of the major uses of models. It's also useful for policymakers when they have choices to make, and they can at least use models to establish, in the absence of solid evidence and solid data, to to guess which course of action is going to be least harmful or most beneficial. So these are some of the main, benefits of modelling, and yet, if you don't know much or think much about models you tend to skip to the bottom one.
And you tend to think these are cast iron, predictions of future patterns that we can take off the shelf and apply to our own practise and not critique, the way in which they have been built and their limitations. And just in this this next five minutes, I want to try to make you a little bit more aware of how such models are built and therefore how they might be limited make you a little more, more literate if you like, so that when you see those projections, you don't simply accept them as face value. Because models are simplified versions of reality, they inevitably have some limitations.
If you make a model more complex, as you can see on on the white board here, you incorporate more and more complex processes. The uncertainty will increase at the same time, so models are always trying to simplify, simplify, simplify. And so if you look at a model, you say this is not realistic.
That's probably intentional because you make it too realistic. You can no longer understand, how its outcomes arose. And you also are, constrained by the amplified uncertainty every time you include a new process or a new parameter, so they are simplified for a reason.
There are probably two types of predictive model one is statistical or empirical, and in this version, we simply look at, for example, a parasite distribution. How it relates to environmental and climatic factors, and we we impose that relationship and extrapolate it. A mechanistic, process based model tries to disentangle the actual drivers of transmission and extrapolate those to future scenarios.
So in the statistical case, we have no assumption in the mechanism. This can be very helpful when we don't understand all of those mechanisms. However, the the the cons or the disadvantage is there is a risk of spurious associations, and these models are not valid beyond the observed conditions.
So, for example, we might observe that, fires are associated with fire engines. And the more, the bigger the fire, the more fire engines you see. And if we didn't know anything about the direction of causation, we might conclude that fire engines cause fires.
So if you don't understand the mechanisms underlying that we can have these spirits associations that are not causative in the context of climate change. It's worth emphasising that this line that you see here, this regression line of outcome based on predictor is only drawn to the extent of the data. We cannot continue that dotted line forever, and you can see in terms of parasite transmission where we have, an increase in development of temperature and then a decline.
We should not continue these lines forever. However, empirical models are very often used beyond the confines of the data, and this is something you should watch out for if you have a model that is fitted based on data and then extrapolated to future climate change scenarios, this is this is not, robust. Mechanistic process based models get over this, limitation in the sense that you can explore that relationship, across the full bound.
So here you have the toxic Cara example. We can continue that upper temperature as high as we like. And we have AAA, robust association, with temperature, however, it they're only as good as, the knowledge of those processes, is so that's a limitation.
So I promise you an example of a mechanistic model. You've seen this slide before. We know simple rules of minimum development threshold and grown degree days for dialer iit transmission, and so we can apply this across Europe using actual climate data.
And this paper did exactly that and found that these red dots are areas in which the average temp temperature, in a summer is adequate for transmission, and you can see that's confined really to Southern Europe. But what the authors did in this paper was also to look at the extremes to look at the warmest year in the last 15 Y 15 because the parasite is very long lived. So it got.
If it got into a dog or a fox within one summer, you would expect it to live for a long time. And so it can survive several years of inadequate conditions for transmission still producing microfilaria. And then you get one year where transmission is possible, and that relaunches the life cycle and infects new hosts.
And that map looks very different. So where summer is adequate for transmission at least one year and 15, we get a you know, a much wider range that is potentially suitable for dialer IOUs establishment. And so the risks of spread can be underestimated when we use average conditions.
The second climate change model I'm gonna show you is concerns Andrea's strongest cantonensis, which is the rat lung worm. So here we have a rat definitive host, shedding eggs that infects gastropods and then when people. So it's a tropical disease of people.
When people accidentally ingest snails that are infected, the worm will migrate, and will prefer the central nervous system and cause eosinophilic meningitis. Other accidental hosts will also suffer from neurological signs. So in this case, dogs that are infected will suffer from Hind Limpar.
If it's a rat that ingests the slug or the snail, then it gets infected as the adult, and it sheds more eggs. So this is a parasite, which is tropical in distribution but has been recently found in Europe. Its development in snails follows a degree day rule, so this means we can predict climatic suitability for transmission.
And when you do that, we find that we predict it's a tropically distributed disease. As as we would expect. We predict that with future climate warming, the range where temperature limited here in the east of the US would expand northwards in the west of the US, where it's limited by dryness.
That doesn't happen. So the expansion only happens where temperatures, the limitation, and we can see that there are some areas of Europe that we believe are currently suitable for transmission. And these include areas like, northeast Spain, where the Paris that has been found circulating animals here are very, important sentinels of disease spread.
So in Spain, the disease was first noticed, on, in Majorca because hedgehogs in rehabilitation centres were presented with neurological disease and, angio cantonensis was found in them, and this has been the case in other parts of the world. So in Australia, as angios strongs cantonensis spread southwards, there was disease in wild birds and domestic dogs, which was noticed. So you should be aware of this parasite, particularly if you're practising in the southern Europe and what should we look out for?
Well, here we have some, pictures and videos from cases in Australia with thanks to Richard Malik, and you can see that you can get mild, proprioceptive deficits, or you can get very severe hind Limpar. So in some areas, where Andrew Stroman's continents has been spread and clinicians are not aware of this. And so when they're asked, have they seen, increase in hind li Preis?
Have they seen some cases that don't have the usual, diagnosis, then then they admit that they have. So it's better to be aware of this before the parasite arrives in Australia. Tawny frogmouth, which eat a lot of slugs and snails, were noticed, as being infected early on here, you can see good, tone and ability, to bite and to move the beak and to move the wings.
But if we go later on, complete hind Limpar. So these birds were falling out of trees. They were afraid of West Nile virus.
But when they did the diagnosis, they eventually discovered that this was due to spread of Andrew stronger cantin. So if your clinicians, whether for dogs or for wildlife, you play a very important role in detecting, the spread of diseases and parasites like this. So this is where we can use models to identify areas where, as clinicians, you should be looking out for strong in these species and strong continents to finish on the models.
I just want to mention that, they can be very useful, but future climate outcomes, climate change outcomes will vary a lot locally. So this is again back to humongous. .
A parasite is small ruminants, but one in which, a lot more climate change modelling has been done for than for many of the companion animal parasites. And we can see that, and current conditions going to future conditions. We expect a shift in climatic suitability for humongous, actually overall, probably downwards.
But this is a fragmented picture, and in some areas we will see an increase. So we have to be aware that it's not again one degree, two degree increase in average conditions leading to gradual northward spread, for example, of tropically adapted parasites. The picture will be much more nuanced.
Locally, we see this also projections for lich mania, where within Germany there are some areas that are suitable for sand flies and others that are not so. It's not just a case of what should we look out for in Germany? What should we look out for in the UK Within those countries or within all countries, we will find a variation in outcomes.
How should we then respond? Well, really. When we talk about the exotic parasite spread, we focus very much on travel consultation.
Where is the client going? How long? If we know where parasites are, we can, tailor that advice accordingly.
We can impose or suggest tests or treatments on reentry, follow up visits, and we should be vigilant for new parasites. This these responses perhaps, are changing. So we are moving from a a period where we've been making rules for movement of animals.
And now the rules are perhaps less constrained, particularly within the EU. But it's more about advising owners, accordingly and making sure that their animals don't get infected when they're away. But also they don't bring these exotic parasites back.
However, as we will hear in the next talk, even though we focus a lot on the travelling pet and pet consultations, it is movement of rehomed dogs, particularly from southern and eastern endemic areas that is now arguably the dominant source of risk for exotic parasite spread in Europe, and therefore it's useful to think about exotic diseases of biological invasions. So what is the relative risk from pet dog movement? Compared with rehoming, we can use models to dig into that, so the chance of establishment is the product of proper pressure.
So the amount of infection coming in and the habitat suitability and we've dealt with habitat suitability is around vector and climate. But the proper pressure is the number of dogs that are coming in and the chance that they're infected, as well as other routes of infection. I mentioned a beaver.
You can also get transfer of ticks within cars. For example, if we look at dogs, though, the chance of infection is crucial. We did a a shorter in the UK.
I'll just share a few key results. So, a large proportion of travel with their dogs. More people from the south of the country travel than those from the North, probably due to logistics.
And so that's where perhaps our vigilance should be highest for exotic parasites. Mo. The most visited countries were, France and other southern European countries, but the duration is relatively short.
And I emphasise that because even though these dogs are going to endemic countries, the chance of infection depends very strong in the duration. And so, for example, for Diyar lich mania, also a dog that is brought up in an endemic area and has lived years there before, being translocated is gonna be much higher risk than a dog that goes for 2 to 5 weeks. On holiday.
Many of these risks are correlated not so much with the choc coccus, but you can see Lys Mania. Diyar are quite strongly correlated in their distribution. The awareness of owners is relatively low, so here we can see most are very aware of Rabies.
But Li mania. Most pet owners in the UK have never heard of it and those who had knew nothing about it. So education is important.
Most are very accepting of, the need for restrictions on movement, and most were, agreeing that the vets were providing the appropriate information. However, despite this recommendation and information, only 65% took specific measures to protect adults from diseases while abroad. In contrast to obtaining the necessary paperwork that would allow them to travel back into the country.
So I leave you really with the thought of what such a survey would look like for rehomed dogs and what the risks would be like in proportion. So I'm coming to the end now, revisiting the learning outcomes. So I was hoping that after this webinar you would be able to do these things and so to conclude really how to climate and weather affect parasites and alter infection patterns.
Well, there are fundamental principles thresholds for thermal requirements, growing degree days, relationship between vector lifespan and development rate. And these apply across parasites as fundamental biological principle. But the outcomes will be species specific, and they'll be influenced by the wider environment.
They'll be influenced by, realisation of of hazard to risk so pet and owner behaviour and exposure of pets, as well as just the thermal and, rainfall effects on development within the vectors and in the environment. In terms of models, I hope I give you a little little taste of the fact that all models are wrong because they're simplifications of reality and they have to deal with uncertainty. However, despite that fact, many are useful in terms of predicting what we expect in the future, and that should drive, appropriate preventive strategies and appropriate vigilance.
And it's important to combine this understanding with knowledge of, those factors including dog movement and owner behaviour, and recommended preventions. And this is what we will hear or you will hear more about through the rest of today. And finally, finally, I want to emphasise that SCP has many useful resources.
And I will refer you, to the ESCAP website to find out more, particularly by our own climate change pet movement travel and, and, actions you can take in the clinics to deal with these shifting threats. That's we finished. Thank you very much for listening.
I'm going to stop share. And I think I have time to take a couple of quick, quick questions. Ian, if there are any Yes, absolutely.
So thanks for that, Eric. That was That was fascinating. There was there was a comment.
That said the the problem with models is maths phobia, and yeah, I think I think we could all all sort of sympathise with that. But, you know, you made that very accessible. So thank you.
We've got a few few questions. Yes. So the first one is, if the Emmaus transmission range is climatic, why is it endemic in Northern Russia?
Which I think we all well, at least assume is perhaps a bit chilly. But perhaps we're wrong. Yeah, well, I, I would, I suppose, take with a pinch of salt the accuracy of those maps, because very often, when you have a large country, you colour it all in and the, the the nuance isn't there.
But it's about if you if you apply growing degree day rules, it's about the total thermal energy. So if you have a short summer that is warm, you potentially have enough thermal energy transmission compared to a long summer. That is much cooler.
So that's the reason the model predicts transmission. Also in those areas there a lot of mosquitoes, a lot of mosquitoes in some of these northern areas, Definitely. Definitely.
I did wonder if it might be very hot for a short period of time, but, I I'm not familiar with northern rush shifts. So, the next one is Should we be restricting the rescue of dogs from Europe, especially where exotic diseases are endemic, particularly leishmaniasis. Any any thoughts on that chestnut?
Well, yeah. I mean, my my personal opinion is it? It should certainly be looked at seriously.
But that's one that you're gonna answer, isn't it, Ian? Well, we'll have a go and perhaps one for the panel discussion later as well, but, yeah, it's the question that's gonna run and run, isn't it, Hank? This one says so common preventative treatments are Oh, So what Common preventative treatments are effective against echinococcus as I travel a lot and have a lot of contact with wild animals.
So, I think it's important to say that I don't think there's any recognised preventatives in people. I don't know if you if you have any comments on that, so no, I mean, I wouldn't wouldn't, say prevention in in people is, something you can do effectively. But but in in dogs, Prosy, of course, will treat It's not a prevention in the sense that if there are worms, present administration of prosy quantel will eliminate those worms.
And I think the main prevention for people is to make sure they're companion animals. Their dogs are not shedding eggs into their environment. And if they're in environments in which, high levels of, contamination with eggs is is possible, such as woodland picnic sites and endemic areas, then then practise hygiene and make sure you don't ingest those eggs.
But I not Manuela was speaking later on re stronger. So we have an expert on a kind of coccus, multilocularis here too, so she'd be better placed, I think to answer that very good. We've got another one here that says, Great scary lecture.
Many thanks. It says, please, may we have, more not Not right now. I don't think.
But it says, question is, where to source? Up to minute info, to pass on to owners. I mean, I don't know if you have, so I mean, the SCA a website is excellent, and I would direct, I don't know for real time data, have you, anywhere that you could send people?
Well, I, I No, I would send them to SCP, And I know SCP is trying to develop more kind of it was updating its offering all the time and is looking at maybe turning some of those maps into more more dashboard elements. So what? This is but I, I think where SCP excels is to provide that kind of independent information in a way that's accessible to veterinary practitioners and also, in some cases to owners.
And and that's really a key resource. Thank you. Should we use prevention all year round or based on seasonal or local outbreaks?
Some practitioners adhere to a seasonal approach. It it makes sense to adhere to a seasonal approach where that seasonal pattern is sufficiently strong. So, for example, going back 10 or 20 years in the UK, we wouldn't have had tick questing activity.
Really? In the winter. So between December and March, whereas in southern areas, particularly that is now common.
So, but that that is influenced by where you go as well. So, you know, if the main drivers of, take risk are going to particular hotspots and engage with those environments, then the fact that you get question in March and April, rather than just April, as in the past is is gonna be of marginal importance. Other parasites like angio strongs por are gonna be much higher risk, really, in late summer and autumn, where the slug populations have had the opportunity to build up high levels of infection.
But by the same token, there's there's no way you can, rule out the possibility of an over inching slug transmitting the infection in spring. So these patterns, particularly in, oceanic areas of Europe, are being blunted. The strong kind of seasonality that we would have expected before is being blunted into a AAA bit more of an all year round pattern.
And we think about climate change having strong effects in summer. But But actually, it's the the milder winters, the prolonging of the spring autumn period that is most notable in those areas. So So I would be wary of saying that, I would agree that prevention should be seasonally applied, But in many cases, that is actually now starting to cover more and more of the year.
Very good. Oh, thank you. I think we're gonna have to leave it there.
We're out of time. But that was wonderful. Thank you, Eric.
