Hi, I'm Aaron Welsh and this is this podcast Will Kill You. Welcome everyone to the latest bonus episode in our mini series of bonus content that we've been putting out over the past few months. If this is your first time tuning into one of these bonus episodes, I'll give a brief rundown of what I'm doing with them,
so you know what you're getting yourself into. In each of these bonus episodes, I'm following up our last week's regular season episode by interviewing an expert about some aspect of the topic that we covered last week and getting to explore it in much more depth than we did in the regular episode. And also I'm asking these experts about their careers, what they like about them, how to get started, and any advice they may have for people
who are interested. I've had so much fun putting these episodes together so far, and I've learned an incredible amount about fascinating topics, ranging from deadly rabbit viruses to how electricity actually works and beyond. I am super pumped for this week's episode because it combines two things that I didn't expect I would ever get to talk about at
the same time. Koalas and sexually transmitted infection. In last week's episode, Aaron and I covered chlamydia, specifically the different ways that different strains of the bacterium Chlamydia trichomitis can cause disease in humans, diseases such as the classic chlamydia STI,
the eye infection trichoma, and lymphogranuloma venerium. We discussed how these obligately intracellular pathogens complete their life cycle, how they cause, the signs and symptoms they're associated with, the long history of their involvement as human pathogens, and where we stand today in terms of the global prevalence of these diseases.
If you haven't listened to that episode yet, I'm gonna recommend that you pause this, go listen to it, and then come back, because that episode will give you some good background on these bacteria in general. That will probably help in terms of providing more context for this interview today. Okay, so what are we going to be talking about today? Even though we covered quite a bit of ground in our regular season chlamydia episode, more ground than we expected
to cover. In many ways, we only scratch the surface of chlamydia. Because the world of these bacteria is much bigger than just what the human perspective shows. Chlamydia are found in all kinds of animals, from birds to free living ambae, from sheep to salmon, from cats to koalas, and across all continents. They're everywhere, and while some species of chlamydia or chlamydia like organisms don't seem to have a very strong impact on their hosts, others absolutely do.
For instance, Chlamydia pecorum, a species nearly ubiquitous in livestock around the world, has had devastating impacts on koala populations in Australia and maybe you're familiar with this topic from headlines a few years back talking about one direction and
koalas and chlamydia. In any case, these population declines have generated a substantial amount of research into understanding how chlamydia is spreading among koalas and in creating tools that might be able to help us slow or stop transmission, with one of these tools being vaccines. From this research, we have learned an incredible amount about Chlamydia pecorum, and not just as it relates to koalas. While the koala chlamydia relationship might be the one most likely to be splashed
across headlines. Chlamydia pecorum can infect many animals, and several other Chlamydia species can carry great importance for other wildlife, for domestic livestock, or as zonotic pathogens of public health importance, but we don't yet know quite as much about those
host pathogen relationships. So it seems like what we need is a complementary approach conducting more indep studies on koalas, chlamydia and vaccines, while also performing more exploratory research on how Chlamydia picorum and other chlamydia species impact other wildlife
and domestic livestock. In this bonus episode, I am beyond thrilled to talk with two scientists, doctor Martina Yelochnik and doctor Sam Phillips, both at the University of the Sunshine Coast in Australia, whose research aims to do exactly that. These two super cool, clemydiologists have been examining questions of chlamydia in Australia from these different but complementary angles, and I can't wait to hear what they have found. So
let's get to it. We'll take a quick break here and then I'll let them introduce themselves.
Hi. I'm Martina Yolotnik and I am veterinary clomedian veterinary molecular microbiologists from University of the Sunshine Coast here in Queensland, Australia, and I work on veterinary clomedia, livestock, birds, koalas and all the other animals.
Saint Phillips and I also work at the University of the Sunshine Coast at the center of Buying Innovation. I worked with Martina for the last five years and I'm a molecular microbiologist working on the Koala chlamdia vaccine as well as some other human clamia projects as well.
Wonderful Thank you both so much for agreeing to chat with me. I am very excited to talk so much more about Clymythia than I ever thought I ever would, So let's dive in. I was wondering if you could start off by telling me a bit about your educational journeys. Did you always know that you wanted to be a scientist or was that something you discovered later on?
So I always wanted to be a scientist ever since I was in a high school in Australia. I had an interesting journey moving through a diploma in laboratory sciences to fine tune my laboratory techniques, and then an undergraduate and honors degree. My honors degree was actually in looking for vaccine targets in chickens for a disease known as
campbel backta. From there I actually worked in diagnostics, diagnostic pathology and human pathology for seven years and then moved over into research where I was a research assistant for five years working in human papillonavirus vaccine analysis within Australia as well as some Comedia projects which got me interested in chlamydia and collaborating with my eventual PhD supervisor PLA teams and came up to Sanshine Coast to work on the Koala Colonia vaccine from my PhD and since then
I've continued working with Peter on the vaccine and now the lead post doc research fellow running four different vaccentrals.
Well, as you can see, I have a little bit of accent, so I'm actually not originally from Australia. I come from Belgrade, Serbia. Since I was younger, I was influenced by my aunt who was a doctor, so I always wanted to be a medical doctor, and I was just so fascinated when she was talking about disease and microbiology. So as such, I did medical high school in Belgrade and I started medical UNI. But because we moved like family to Australia, so then I had to postpone a
little bit my educational journey. So I wasn't a citizen, and the universities were then a little bit expensive, so I had to wait until I become auzzy, then take a loan and dived in back into the study. So I did undergrads majoring in microbiology. So yep, I always stay true to my micro It was right or die, and that continued with honors and continue it PhD in microbiology, and in honors is where I first heard about this pesky clomedia. So everybody was talking call it clamdia, call
it clamydia. But there was another host, livestock, and I was thinking like, okay, well you don't nobody's talking about livestock. I'll do it. Let's see what happens there and with same so we are actually within the same group. We had the same supervisors, and I I'm kind of like that child that never wants to leave home. So then I stayed with my PhD in clam media and I got my fellowship aget on clamydia, but this time on
a slightly different clamdia. So we started looking at clamydia in birds, some novel cla media that it's you know, doesn't get much attention in Australia. And I'm still here and I think we will see what future holds. But now we are also looking at clamydia and other bugs because clamydia it's never there alone. Interesting.
Wow, what amazing journeys. So I have another question for you before we dive into chamydia talk, and that is advice. Do you have any advice for someone who might be interested in pursuing a career in STIs or wildlife disease or one health anything you wish someone had told you at the beginning of your career.
My journey into where I am now, I've learned a lot along the way, and I made some mistakes and then I moved back into it. And I think, don't be afraid for people wanting to get into research in general, but into SCIS and vaccines, to start off in something which it could open the door to something you've never thought of before. I started out in the HPV vaccine research, which is it's already developed, and I thought, I can't be that much research, we're a ready giving it to people.
But there's so much more you can learn. So don't close your mind off to thinking that if something's already well known.
Don't.
Yeah, there's still lots more that we can learn, and that yeah, sdis they have commonalities between the different species, and so there's different antibiotics treatment between so clamin here and gonera markeroplasmos all basically the same antibiotics, and they share different mechanisms. So I don't think you just pigeonhole down to the one organism. You can always move on.
So my advice to young scientists is collaborate. Collaborate a lot because you need those connections. We need to connect with our vets, with our GPS, with our researchers, researchers who work on a slightly different aspect of the host that you may do. That is the only way that you could get the full picture. And then by collaborating, and I often say talking with ways smarter people than me, I continuously learn a lot and then I pick up
something that I didn't thought of it. So for me, big part of what I do, it's a whole plethora of collaboration from vets, from the producers, because especially in livestock, they're the ones who are feeling the effects of this disease on the farm. So we need to go from the producer to the vet, to the diagnostic laboratory team, to us in research, to all of our colleagues around the world. So I would say, collaborate eorly, and collaborate with good people and with a good team, and the
collaboration cannot be sustained. That's okay too.
Both excellent pieces of advice. All right, Now let's get in to some chlamydia talk, specifically Chlamydia pecorum. Who does this pathogen in fact, and how is it transmitted?
Clomydia pecorum. Although globally it's probably known as the notorious coala pathogen, actually it's not. I often say it's a livestock pathogen more than anything. So in fact, wide range of livestock, including cattle, sheep, goats, as well as wild ruminants such as let's say, reindeer, water buffalos, and recently we also worked on studies when we detect chlamydia pecorum
in birds. How is it transmitted? We think that it's most likely fic laural transmission, but it can also be from direct contact, which same can explain, like when you have to qualifighting, you know they can kind of touch each other and maybe transmit or vent a sheep or catalyts in the close contact, so they can transmit let's say ocular Chlamydia picorm infections, but most likely to feic laural.
And how is it different from Chlamydia trichomedis. I mean, Chlamydia trichomitis is a human specific pathogen, right, but are there any overall big picture differences between those two species?
The differences between the coomas that the core can infect a variety of different hosts. Trichymitis is strictly human pathogen, that doesn't we don't find it anywhere else. We can't even get it really to affect moss, whereas the core will affect Yeah, I'm not tying to mention a variete of different host species and thoughts as far as as disease and infection roots, they're fairly similar. I mean, we know that Trichromais can infect the oculo gasha intestinal eurogenital
quite readily, so that's fairly similar. In the disease presentations are fairly similar. You do get the LGBs, the limphogranuloma venereal strains of chlamydia, which are slightly different to what we see in animals, although that could just be that we're missing a link there with animals, so more research. And the TIGI tropism is really interesting. We've tried many different studies with Pcorum to identify tropisms based on Usually we look at a single gene that out of membrane protein.
The gene responsible for that is of a which we don't find with Chlamydia picorum or other species of chlamydia, but with trichromitis it's fairly stringent. We find that there's specific oculis types and specific eurogenital types. These so you get modeled when you start looking at the gastro intest infections. But yeah, traditionally you can have the ocular strength. Specifically,
they cannot infect the ear general track. That's due to some specific gene mutations that difficult throughout evolution of trachonitists. So yeah, there are there's similarities, but then there's also have some really distinct differences between them.
Two, Where did Chlamydia pecorum come from? What are its natural hosts? And how did it get into Australia.
Erin, that's a five million dollar question. I think we moved from one million I'm going to go now into five million dollar question. So up to you know, a while, we all hypothesized, oh, yes, you know, Chlamydia picora most likely came with the European colonization and with the bringing the livestock, because here and there, you know, using molecular studies, we have these sneepets of information which says, oh, you know you have coal as share in that they're genetically
similar to livestock. Thereby, tantalizingly, we say, oh, yeah, that's the origin. But but I was a believer. I was a believer. But then I converted the wider the event. And of course, you know, beyond gene typing schemes, we started looking at the whole genome sequences again that's still in infancy for pecorum and we are seeing very distinct lineages between koala strains and livestock strains. So then that
opens up, you know, new questions. It's kind of like a Pandora box so you wonder, are we not sampling the intermediate line edge, are we missing a host? Maybe we don't know, you know, especially in Australia, we're kind of like a host centric So it's either quala as a host or it's a livestock, but what about everything in between? So we know from our colleagues from Europe and the US that chlamydia can infect pigs, reindeer, chamois, ibex, birds,
variety of birds. So honestly, erin we do not know. It is very tantalizing to think that we had some that we do have or head some kind of spillovers. But at the moment we really truly don't have solid information to answer that question. So we need to work harder, We need to sample wider, we need to sequence way more than we do now in order to answer such questions. Amazing.
So you know, as we've talked about, one of the species most impacted by Chlamydia pacorum is, of course, the adorable and charismatic koala. When did people first start noticing that koalas were becoming infected with the specteram.
As early as European settlement in Australia, there's reports of indications that the coalas were suffering from chlamydial diseases back then. This is all kind of based on observations of disease presentation back in the wasn't a lot of diagnostic analysis specifically for wildlife back then. It gets a little bit confusing. I'm sure your listeners will know that the chlamydia nonenclature has changed over the years. And it's not that long ago that we only discovered that there was more than
just Chlamydia citizide Colomitia trichromas around. So the quorum has only been around for the last thirty years with identification. So yeah, it's difficult to say how long the chorum has been infecting koalas, but yeah, possibly for at least the last two hundred years.
What does an infection with Chlamydia pecorum look like in koalas and how fetal can it bear?
The top so in ocular disease. Coalas go infection in their conjunct diver and this creates inflammation which normally your conjunk eva is quite smooth, and as it goes over the eyelids, this inflammation causes scarring of the eyelids. You get these nodules and it eventually causes blindness in the colas in their eyes. In the eurogeneral tract, chlamydia can
ascend the urethra and can't go into the bladder. This causes cystitis, which is inflammation of the blood of wall and coilers can carry this for huge amounts of time. They obviously they don't have a local GP that they can go and get some anabiotics for, so they suffer in silence with this disease and it can end up. I've seen coils with golf ball sized necrotic masses in their bladders from slothing off tissue just from these chronic infections.
It can ascend the euroters up to the kidneys, causes lesions in the euroters and then can cause nephritis in the kidneys. Then we also have a reproductive disease as well. So there's been some recent reports showing that male choalas can have inflammation in the testes and can affect fertility emails and in females. We definitely know that there is reproductive tract infections. There are links to the development of reproductive cysts, which can in turn lead to infertility. How
fatal is it kolas coming into wildlife hospitals. It changes over the years depending on breeding, seasonal and not on averages. About fifty percent ofalas die from this disease. It's a horrible disease for them. They come in with these severe euter infections and you can hear them like crying from
the urine. They become incontinent. In severe cases, it stains their fur on their rump so much that they get these extra eurogenital absences from their constant wet staining of they're rump and they can't sit down, and then yeah, it just becomes terrible.
That sounds really horrible. And how is chlamythia transmitted among koalas?
I mean a lot of it is still sexual transmission, but there's also the fecal oil root. We believe that they do get infected when climbing trees. This is a koala above them that say urinates with chlamydia infection. That could be a spill over to ocular sites and things. We know that some joeys do get colminia infections from infected mothers, not necessarily through birthing. There's quite a lot of antibacterial properties within the pouch as well. As obviously marsupial.
But then once they become a joey and they live on the back, they're crawling all over the mother's back and they can get infected that way. Yeah, there's other speculations, but mostly it's through fecal, aural sexual and then you know, mother's a joey.
And if a koala recovers from an infection with chlamythia, can it become reinfected or is there any lasting immunity?
We have some evidence to show that infection doesn't give the coals long lasting community. They can up to maybe a month or so. We see depending on the wildlife, hospital and population densities, you can have up to eighty percent of the koalas that have become infected will eventually come back with new infections. It does differ with the different populations as well.
There are effective antibiotics that exist for chlamydia and Chlamydia pacorum, but they aren't recommended necessarily for use with koalas. Can you talk about why that?
Is?
Coils really interesting species. Their diet is based on eucalyptus leaves, which are highly toxic, so the coals have developed a unique evolutionary trait where they have cytocurrent people fifty gene which detoxifies drugs and chemicals, and coils have huge repeats in this region, up to sixteen repeats in this region, which means they are really good at the toxifying chemicals
and drugs and antibiotics. So a lot of antibiotics that would be useful for chlamydia, they need to be used at such high doses and choalas that it ends up being fatal for the choalas, so the limits the number of antibotics we can use. The first line of defense for at least the last ten to fifteen years was chlorin frenicol that had shady efficacy in treatment, so it does work, but only sixty to seventy percent of cases.
But that was the only antibotic that had been trialed and what we could use, so they were utilizing that. But it also causes gastro intestinal dysbiosis, doesn't work all the time, and when koalas have the gut flora strict, they can't digest so leave and they end up starving to death. So antibotics are a terrible choice anyway, but
they do help in some cases. Recently, there was a trial that showed that we can start using doxy cyclone, which, as you can imagine, there is a lot wider distribution that's used in humans, so access is no problem at all. Chlorophenicol isn't used in humans anymore, so nobody wants to make it anymore, so it's kind of difficult to get hold of as well. Anybody are grateful their use in clearing, but they have a lot of side effects as well, so we like to think the vaccine is your best bet.
What have been some of the population level impacts of Chlamydia percorum on koalas so far? And can you also discuss any of the downstream effects that koala population losses have had on other members of the ecosystem.
Population level impacts of koalas are due to chlamydia, it's not. I can't just say that the population is being affected solely by chlamythia. These animals are affected by deforestation, population encroachion onto their habitat. So as far as direct actally
comparable to committee of thecorum, it's a difficult question. But overall, the koalas, some populations have been completely they're extinct, so we don't have this populations in Queensland that have become extinct local populations and the koala populations in Queensland and Southeast Queensland have decreased. They are been listed as endangered just recently, so they've been decreasing ever since. The list has threatened in twenty eighteen and now they've been further
downgraater to endangered. We're seeing this in New South Wales as well. There's this strong decline. This has been impacted by recent fires as well in twenty twenty, so that's almost sped the decline of these populations. When you get further down into Southern Australia, into Victoria and South Australia, the populations aren't endangered. The disease presentation is a lot less.
There's other factors. So there's a retrovirus Koala retroviral effects coils we believe has an impact on the chlamydia disease. So we do see a shift of disease prevalence increasing in a southerly direction. The ecosystem. That was a really interesting question. I had to go and school myself a little bit on this. So koala's obviously they live in eucalyp forests and not a lot of animals eat eucalyptus leave, so Coala has actually helped to control the growth of
these eucalyptus forests. They allow for light to be able to come through the forest floor to increase the biodiversity on the forest floor, which helps the forest flaw organism, so microorganisms, insects, even small mammals. They also help to control bushfires surprisingly, so as they keep the growth eucalyptus growth under control, it's less likely to have a lot of dry leaves and stuff lying around, so there's less tinder for our bushfires. And the feces also helps with biodiversity.
When it rains, it increases the nutrientsers and the soils and increases all the organisms. So we always write grants. Someone were to save the koalas because there are a huge tourism pool and that's the last species of the Fascala day family, and we should do it for human benefit, But it actually has benefits to the ecosystem, which really
gets downplayed. I think. I mean, we've been working I've been working at Koalas in five years and I have never heard about these I've never heard people talk about this before, So it's I thought it was a hairy question to start with, but it's really interesting looking into a borrow. I'm actually going to go back and read some more about it, and it's quite interesting.
So for koalas, is there any individual or population level variation in resistance or susceptibility to chlamydia infection?
So for chlamitia infection, it's similar to checarma as we see in humans. So probably we estimate about eighty percent of kal as it become effected don't actually develop the disease, so we don't know why that is, though we do think that the Koala retrovirus has an effect on immune responses to chlamydia, which then allows for chronic infections and development of disease. The population level is difficult. The different
populations have different interactions. So in mountainous areas, there's some geographical barriers that stop spread of climyth here into populations that you would assume that interact, whereas in areas where near the coastal areas where there's not huge geographical barriers, the koalas can interact between populations, so they're quite They can be territorial in their population groups and don't have
a lot of exchange between the two populations. So it's a complicated question, but we do know that Yeah, once it gets in there and affects enough koalas, those populations klian and eventually they'll become extinct if we don't get in and do something, especially with the other pressures of increased blush for us, they create forestation, flooding, wild dogs. We had a population that was almost completely wiped up by a single domestic dog.
And also so same actually mentioned Coala retrovirus, which is a huge viral infection. But let's not forget that there is a Quala herpes virus that the research is now starting to emerge to suggest that that virus contributes to decreased immunity or you know, can that now exacerbate chlamydial infection maybe? And plus there are other bacteria also infecting Quala.
That's what I would say, chlamydia. It's never there alone exactly, and you never know whether that's antagonistic, whether that's energistic, mutualistic, We honestly don't know. Is actually so much that we need to look in terms of the co infections.
Yeah, it's such a complicated story, and so what about Chlamydia pecorum. Are there different strains across the landscape that are associated with disease severity or different host species?
So okay, So when we look at genetic diversity of Chlamydia pecorum, so what we see. Let's say, let's look atala quala strains. Sokalastrains are diverse. They are very genetically diverse, but closely related to each other. We have evidence that show that koala strains infecting qualas in the northern parts of Australia like Queensland, New South Wales are genetically distinct than those infecting qualas in Essays South Australia or Weak Victoria.
There there is bit of a necdotal evidence that there is a less disease. However, when we look at the genomes of either of these strains, all genomes contains the same virulence factors. They are highly syntanic, highly conserved. So I would then say that any strain would have a pathogenic potential and any strain of this can cause any level of disease. So now that you looked at colors and we know that they are diverse, we look at livestock. So in livestock actually we see a bit of a
more disease association. So we have this very interesting clonal lineage. So that's my flavor lineage of the month. It's called secreence tip twenty three and it's associated with polyotritis in sheep and cattle, sporadic boine encephalomyelitis in cattle, as well as fetal loss in both sheep and cattle. So these trains are highly clonal, genetically identical, minor differences, and we never see them in callus. So that's a very good thing.
So these guys, the sequence top twenty three, they are specifically contained to livestock at the moment, as best to our knowledge and as best as to our you know, breadth of something. So we do see a bit of our association with a disease severity and whole specie. But within quala we do see differences between strains infecting northern versus southern colus. But honestly, I really don't think that we can say that any equalus change is less or
more severe. In a nutshell, they all cause some level of clinical disease.
Interesting, all right, We're going to take a quick break here, and when we get back, I want to shift our attention to some other committee species of public health or veterinary interest. Welcome back everyone. So far we've mostly chatted about Chlamydia pecorum and in our regular season episode, Chlamydia trachomitus. But these aren't the only two chlamydia species of public health,
veterinary or wildlife importance. What are some other chlamydia species that we should be paying closer attention to and.
Why besides Chlamydia pecorum vetereates called our livestock. I would say that a specie that it's evolved the research and going parpar with you know, Chlamydia pecorum eats your good old Klomdia cita site media cita side. It's an avian pathogen traditionally, and it has zonotic potential quite easily. It can spill to humans and cause disease in humans, respiratory disease which can be mild, which can be very severe, very severe pneumonia. And also Clamydia citasie. I love that specie.
I think it's I'm blown away by citaside and its potential. It actually infects extremely wide range of hosts birds, and there is more than five hundred different species of birds, water birds, pigeons, citazen birds, chickens, poultry, ducks, everything as well as livestock. You can easily find it in livestock. And we recently acquired tiny piece of evidence that Chlamydia citas it can also infect mercupils, so we did find it in kangaroos, and of course zoonotic potential and the
human infections. They're being constantly reported throughout Europe USA as well as in Australia. So in Australia, Cita causa is notifiable disease, so the human hasis they are reportable and notifiable. So that's why Chlamydia cita side it's definitely a specie that we need to be very much aware about. And you know, the hosts that are infected with Sita side, they mix with aquala, they mix with your livestock, they
all mix with us humans. So when we go to the beach, all the lovely citas in the birds they sit with us. You know, they eat our crumps, but there is always danger of spillover. And very recently, not that recently, in past decade, we had a very interesting what we call the Australian Cita side horse story. So we had Chlamydia cita site causing outbreak in thoroughbred horses and causing fetal fault loss. So as such there was
a huge economic impact to the stud owners. But also we also had a novel zonotic transmission where the veterinary practitioners or students, unknowingly that there is a chlamydia the shindled platental material and became infected with Chlamydia cita side and developed pneumonia and or respiratory infection.
With several of these chlamydia species, we've got wildlife, domestic livestock and sometimes humans that can all be involved, which brings to mind of course one health. Can you talk about why it is so important to consider these pathogens from a one health perspective?
Well, for example, I'll go back to the Chlamydia citazie in horses example, because that example, I think really through a Spain or in the very extent, we were all like wow, that's very unique. So to the best of my knowledge, chlamydia in horses is not very common in Europe, nor let's say, in USA, so we really have unique one health story in Australia. So horses wildly interact with our wildlife birds with our wildlife parrots. Parrots are infective
with cita. Side, we believe and we have evidence that spillover from bird to horse was the cause of equine infections. Then we have humans who both interact directly and or indirectly with birds and with horses. So us in research we knew chlamydia Chlamydia cita sized or not in potential all the strains that were clone out belonging to a known virulent lineage, but for example, the GPS, the general practitioners in human medicine that may have not been fully
aware how common is the potential for spillover. So that's why that one health collaboration, it's very important and literally every clamydia should be considered as a one health pathogen rather than yet it is solely contained to human lectrachomitis and or to quala. So it's very important that we broad and that collaboration, that we broad in our communication because especially in Australia, wildlife, domesticated animals and humans, they are very interactive. They are not isolated systems.
Next, I was wondering if we could talk about things like land use change and climate change and how these things are affecting the prevalence and distribution of Chlamydia species is kind of a big question, But what do we know so far?
Yeah, I can comment on especially during droughts, koalas they get their all of their fluids they get from euclipus leaves. During droughts, the trees don't hold as much water and the coals don't get as much fluid, so they have to come down out of their trees and they find water from water holes or from troughs that are from farmers that have used which are encroaching on their on
eucalyptus forests. So there's increase that interaction between your livestock and koalas, which then droughts are pulling the coils down out of the trees and they're moving around between them, so there's a higher risk of spillover for Chlamydius species between koalas, livestock even birds as well. Birds come down and eat the feed that's for the livestock, so then
they're interacting more with koalas. So all of these climate change effects in being drought or even floods and things like that segregated in different populations, they're all affecting the why that the animals are interacting, and then as a one health potential for spillover and transmission of different speceis is increased exponentially. And obviously land use for humans is affecting coals and devastating populations.
The habitat loss I think it's always the biggest problem because if you remove the natural habitat of you, of your wildlife, you know, they become stressed, they go search for food, they encroach the human residential areas. Where As a Stain pointed, there are dogs there were, you know, domestic for example cats in Australia can cause devastation to the natural wildlife. So it is I think it's such
a complex area to have. Idea. What is happening with the land change, land use change as well as climate change.
What do you see as some of our biggest gaps in knowledge regarding other perhaps lesser known chlamydia or maybe just less talked about chlamydia across the landscape. And why is doing exploratory work investigating these host pathogen relationships. Why is that so important?
Well, honestly, I think we really have a lot of knowledge gaps ahead of us. So as I said, like
we are very centric in species and in hosts. And recently we did one of the bigger bird surveillance studies where we looked at the population of wildlife birds for chlamydial species for prevalence and diversity, and that is where we discovered that besides Citasi and Pecorum, we also have this novel emerging avian Chlamydia bortus trains in our cross Then we also saw strains that they are described in
globally overseas in water birds, some novel species. So that is when we're like, okay, well, you know there are more hosts, more species, so who is now the next pillover host? So we have a big surveillance work that we genuinely need to do. And it's also interesting that in Australia in particular, besides sheep and cattle eventually won't goat here and there, we still haven't looked at chicken nor pigs that they are also one of the primary
hosts for chlamydial species. And I think even with our wildlife and Sam would probably say that besides koalas, we still haven't looked at other massupils in more debt. So Kala shares habitat with other smaller massupiels like possum, bandicoot, pottoo, little volla bees. But we still haven't done any proper and in depth surveillance for all these hosts, and it is that is very important because if we not an emerging pathogenic or zonotic special in this host, that is
very important for control of these infections. So we still need to do exploratory and investigative very beyond our everyday research.
It goes back to the other questions. The other answer as well, we're pushing all of these animals into confined environmental spaces where they're having to share population to overlapping between farm animals and qualites. These increased risks are spill over between different speceis. Currently we don't know what species are even there to identify if there is spillover. Some
of these pathogens can have datastating effects. We look at chlamydia borders in our livestock and deci farmed populations of sheep and if we've already identified that there's changes in that species to be able to infect non placental mammals. So we can see Colmoneo abortis avian strains of colmonea aborders.
We still don't know how that happened and what effect it is having on the avian species and they I mean, you get into migratory birds and you can get transmission across different continents, and we just have no way of being und identify if these things are happening and if they're having a significant effects on different areas. We saw with coronavirus, it's so easy for a pandemic to get out of control and then the spread is impossible to
be controlled. And we were looking for these things. Some of these chlamydia species we're not even looking at.
So we we try on the podcast sometimes when we can to end on a hopeful note. We don't always get to do that, so but in this one I would like to try. So let's turn towards vaccines. For decades people have been working on a vaccine for chlamydia, and success finally seems just around the corner with this new chlamydia pecorum vaccine that's currently in trials with Koalas. Can you talk a bit about this vaccine, like what kind of vaccine it is and what have the trials shown us so far?
Yeah, definitely, So as you mentioned. We've been working on the Koala pcorm vaccine for ten I think it's fifteen years now. There's been many different I've got half an hour presentation on this, so I'll try and keep the sure up. So the current vaccine that we use, which has come through a lot of development, is a recomminant protein vaccine. This is using the magi, adam and briane
protein of Chlamity picorum. There's three Chlamity pecorum strines that use in the vaccine and we charge these strines because these are the strines that are wildly spread throughout Australia, so we can use this vaccine in populations right across the country. The specific protein that we use is actually it's not an easy protein to use. There's not a lot of trials in other vaccines as well as human back human trial vaccines using this protein because it's quite
difficult to isolate. It forms hydrophobic regions which makes it difficult to purify. So we've spent quite a lot of time working on being able to get this specific protein to a level that we can use utilizing vaccines. The reason we've done that it is highly menogenic. We believe at least in trachomas. This protein is definitive of different tropism. It's quite an important protein and its surface exposed, so it's it's more likely to attract a stronger immune response
during immanization. The other part to a vaccine when you're using recommon of proteins is an adjuvant. We've trialed several different adjudants and the adgement we use is a three part adjevant which we believe it is really important with our vaccine. So with koalas, we need to have a single dose vaccine. We can't have double dose boosters. Coilers don't come back for appointments when you tell them to,
so we need to have a single dose vaccine. So we've chosen the adjudant that we utilize allows us to have this single dose by forming particles within the vaccine vaccine mix. So it forms these biodegradable particles to allow the vaccine to disseminate across the coala's body, and then as these particles degrade, it exposes the antigens to the koala immune response. You get a systemic response which is a lot much longer lasting. We believe it's at least
two years protection in these koalas. Remember, in koalas only live in the wild between five and eight years and reproductive between the ages of two and five possibly, so we don't need to have a vaccine that lasts eighty you know, the extent of a human last span of eighty years. We only five years. We've tested this after two years. We've got some anecdotal evidence to show that there is protection from infection out to three years, and we're planning on doing a new trial which will go
out for four years. And we believe this is all down to the adjuvant that we've chosen. We get a great immune response due to the antigen, but a systemic response that is long lasting. We believe it's due to the adjuvant that we utilize.
In general, what are some of the biggest challenges in creating an effective and durable vaccine for Chlamydia pericorum as well as other species of chlamydia.
Yeah, in a nutshell, the infection site, so chlamydia is majority of mucosal infection. Newcosal vaccines are notoriously difficult to produce. You look at influenza vaccines and humans, they only last six months maximum. The only mucosal infection vaccine that has proven widely effective, it's the HPV vaccine. Chlamydia can transmit around the body. The range of tissues and presentations of chammilitia has with pcorum, but all with trachomaters and Citicidae borders.
It's so vary, it can affect so many different sites have different fantasific traits that one vaccine to clear all chlamydia infections is highly unlikely. I think there's trials that have shown with trichrometas that the vaccine it works for ocular infections but not figure genital infections, And who knows what it's doing to the gastrom testimal site where you have severe complex immune interactions between bacteria and posts some
mere responses. It's I wouldn't say that there's a vaccine that's going to fix everything around the corner, if at all, that the specific vaccines to fix specific problems is more likely.
I guess we could also say, and we were discussing, actually this, it's sam just the other day. Whether it's called ter it's livestock. So if you create a vaccine that will stop the disease, not necessarily infection, but if it can stop that infection to develop into the full disease. I think that's also one aspect that you could say
that the vaccine is effective. Of course, the ultimate vaccine would be, you know, like your classic vaccine mo modus operandi stops infection that it just you know, blocks the pathogen. But even if we achieve no disease, I think that's also great achievement for veterinary vaccines.
And so besides potentially protecting koala populations and helping koalas to recover, what are some other impacts that this vaccine might have in terms of health or wildlife veterinary health, Like what will this be able to tell us about administering a vaccine in wildlife, which is a little bit more different than administering it to livestock.
Definitely, we're breaking new ground with this. It's as you said, it's never been done before. There's never a fact, as far as I can tell, there's not a vaccine successfully administered in wildlife. So, besides all the complexities and difficulties in actually running vaccine trials, but getting a vaccine to a point where it's available for veterinarians and wildlife cares to be able to utilize is really difficult, and we're trying to induce new policy within the Australian federal governments
to allow for funding of such a vaccine. We can't go we're not looking at a research project, but we're also not looking at a commercially viable vaccine. So this is it's new territory. We can't say that to a company you make this and you'll make so much money, because you won't make any money, And then how do you get to the koalas? And then how do you know which coals have had the vaccine. They don't have a health card or anything to say that they've been vaccinated,
so it's incredibly difficult. We're trying to work our way through it. Our vaccine is getting registered with the APVMA, which is the Australian Veterinarian Therapeutics Administration. It's like the TGA for animals. So we're putting together an application for that to have it registered and be available for people
outside of a research project. But the funding and financing for such a vaccine is still complex and the number of doses we need is small in comparison we need to probably we estimated about two thousand doses a year. When you compare that to say COVID, where we needed two billion doses a year, it's full manufacturers. It's really small and surprisingly it's difficult to be able to produce
small levels of vaccine. It's many different problems which we're trying to work through, and we have solved quite a lot. We've got we've got a manufacturing partner that's willing to come on board and make the vaccine. We've got access to adjuvants, we've got plans to distribute this throughout wildlife hospitals. There is frameworks that have been developed to go out and vaccinate wild populations and use microchips to track which
ones have been vaccinated which ones haven't. And so yeah, we are on our way, well well down the track. There's been two years in the making so far and we're nearly ready to submit our application. So yeah, it's but yeah, this is how you get things, break new territory and get new things done. You have to put people outside of their comfort zones.
Absolutely, it's so exciting, it's it's seems very hopeful. So I've got one last question for you too before I let you go, and that is can you share some of your favorite pieces of chlamydia or koala trivia?
Okay, I'll start so, okay, did you know that chlamydia in fact flamingos no I okay? And recently by our European colleagues, they discovered two new species and belonging to a new genera within family Chlamydiacia. There you go. And did you know where in that another new specie of chlamydia was isolated from crocodiles. What it's termed, Yes, and its name is Chlamydia crocodiley. So it is it is
remarkable that that is exactly what we said. There is a chlo media for every host on every continent, wherever you want it.
You just have to look.
You're just happy to secret. You shall find and you shall find a lot.
I think about saying a stole mine. I was going to say something about the same lines. I can add that there are some theories that chlamydia is responsible for the minochondra in multi seluable organisms. There's some links there. There's also some evolutionary I'll just say that. That's yeah.
Thank you so much, doctor Yulochnik and doctor Phillips for chatting with me today and for answering all of my many, many chlamydia questions. If you would like to learn more about any of the topics we touched on today, check out this episode's post on our website, this podcast will kill You dot com. We're all linked to a few papers.
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