Good Mor morning, good afternoon or good night. Depending on where you guys are seeing this. My name is Estelle Soto.
I am a Professor of Aquatic Animal Health at the University of California Davis in the School of Veterinary Medicine. And I'm pretty excited to share with you guys, you know, a little bit of stenosis associated with ornamental fish. Of course, we want to stay away from these type of infections, you know, but as veterinarians, you know, and particularly as veterinarians working with either ornamental or re research animals, you know, or production animals, you know, we need to be aware of what type of diseases might affect us, you know.
If exposed to them, I want to start by sharing this light, you know, I just acknowledging that a lot of this material has been shared to me by a great amount of great colleagues as well as materials, you know, from books online or publish peer review publications and it is intended only for educational purposes. So, one of the first questions that I get when people ask me what I do and I tell them that I'm a fish veterinarian, you know, they get surprised, you know, because they think, you know, in a veterinary sector, although it is really wide, they still think, you know, particularly on a small animal medicine and in large animal medicine. So they think dogs, cats and then they think about ruminants, you know, and horses.
But, they have to remember as well, you know, that there are some of us, you know, that like exotic animals, you know, and even with with fish specimens, you know, this actually could be a pretty wide sector that needs, it requires more veterinarians to get involved with it. So, what type of clients, you know, do we get, we can be veterinarians for aquariums and zoos. We can serve aquaculture farms or their associates.
So, basically pharmaceutical companies or feeding type companies or seeding stocks, you know, all of them required a veterinarian and they required someone that is fully knowledgeable on health issues, you know, of the fish, different research facilities will employ fish, veterinarians. As a point, you know, to make here, zebra fish, you know, has become one of the most common lab animals, you know, pretty much worldwide in the UC system. So University of California wide system, actually, zebra fish is the most widely used laboratory animals.
So of course, knowledgeable of you know, knowledgeable folks, you know, on diseases, you know, on the health of a zebra fish are extremely important for the success of those type of programs. You can also be employed by different government, you know, type programs, you know, it could be at the state or provincial levels. So for example, the California Department of Fish and Wildlife, you know, employs at least five different veterinarians to help, you know, with their different hatchery and conservation type programs at the national or international level.
You know, there is also associations that will employ veterinarians. So the Food and drug administration, you know, for example, in the United States will employ also veterinarians, USDA US fish and wildlife services, you know, and of course, you know, we have F and other, again, international type associations will also hire veterinarians, you know, that have a full focus on aquatic animals. And of course, you know, you have your pet owners or hobbies, you know, that have increased, you know, tremendously and particularly after the, the pandemia, there has been an increase on ownership, you know, of ornamental fish where as a veterinarian, you can provide, you know, field services, you know, for example, in here, there's a photo of Dr Britton Stevens, you know, myself, you know, basically providing services, you know, for a coy on site and in here in the bottom you know, for example, you know, treating in traditional giving traditional B oyin, you know, basically trying to treat, you know, this neoplasm in a goldfish.
So you can provide services, you know, to the population level or you can provide services at the individual level. And specifically in this point, you know, it's important that as a veterinarian that wants to get, you know, in the field, you understand, you know, the type of industry that you might be serving. So the ornamental trade is not a small one actually worldwide, you know, it can produce anything between 15 to $30 billion.
It is really dominated by fresh water fish. And within those, you know, there are four different orders that really dominate the cynodontis, the perms, the carris and the smes, the two main species, you know, that you find in this sector are the copy and the neon tetra. And most of them, we have to understand that originate in third world countries, you know, so a lot of countries, you know, within Southeast Asia and in South America are where most of these species, you know, are either culture or are collected, you know, from the wild.
So at the level of these countries, you know, at the level of these markets, you know, it becomes extremely important because they actually signify a very important economic sector for for the local folks. OK. So it's important and this paper in here, you know, details a little bit more in depth about what is it, you know, how it means, you know, what it means, you know, to these regions.
And we have become better and better on culturing some of these species, you know, and now about 90% of the freshwater specimens, you know that you can get in the ornamental trade are cultured still in marine specimens. You know, we're way, way, way, way, way far behind. And most of those are actually collected, you know, from the wild just to put a little bit more perspective, you know, on this market, if we focus on the US pet market, you know, in total, and this is including the different animals.
You know, we're talking about 100 and $37 billion market for 2022 where you can see veterinary services, you know, where it falls of approximately around $40 billion. But what more people, what most people means is that fresh water specimens is actually the third more common pet animal, you know, that that are present at least in the US, you know, so just behind dogs and cats, freshwater fish are really the most common animal in the households, you know, of of us folks. And if you put it in perspective of individual animals own freshwater fish dominate, you know, because when someone has one fish, it is likely that they will have 10 to 20 of them.
So not only think about this, you know, to that individual animal that you might be serving, you know, if you get cold, you know, for example, one of these beautiful Koi ponds, but also think about, you know, this industry as a whole because again, it can become, you know, more of a population, medicine type approach, you know, that you have to follow in a lot of these cases. So with all of that, we're gonna do a little bit of a mixing here. I forgot to mention a little bit about my background, you know, but my background, I'm a, I'm a, a trained veterinarian microbiologist.
So both my masters and my phd were focused on infectious diseases of of aquatic animals, you know, however, one important point, you know, is that when you start investigating, you know, some of these infectious agents, you know, you start falling into a love hate relationship with them, you know, you get surprised about, you know, how interesting they are, you know, as an organism, you know, that can infect, you know, that can persist in the environment, you know, that can cause so much damage into different holds. And of course, you know, as a veterinarian, you know, you have to focus, you know, a lot of efforts, you know, into preventing these type of infections, you know, to develop, you know, diseases and particularly for a subset of them as the ones that we are going to talk about. We wanna make sure that they, lower the risk, you know, and not only to the clients, you know, but also to the veterinarians, you know, as you will see a lot of the organisms that we are going to be talking about today, can have a higher risk, you know, of infection in veterinarians.
You know, because we're the ones that will be dealing the most of the time, you know, with you know, with diseased animals. So we're gonna talk about different agents, you know, the diseases that they can cause in fish, but also the type of infections that we might see it in in humans, you know, so that risk, you know, of. So no, that they might have, I'm gonna talk about some of the clinical signs, the gross changes, you know, in the histo pathological features of some of these diseases.
We're gonna outline or discuss briefly some of the diagnostic methods, you know, for them particularly in in fish. And again, you know, discuss, you know, that so potential that they have, of course, you know, a lot of this, you know, is changing by the day as more molecular tools become a more genomes become available, we get AAA more in depth understanding on the persistence of these organisms in different environments. But also with the advent of whole genomes, you know, we're now understanding a lot more the diversity that a lot of these organisms have.
And this really has complicated matters, you know, because if you go into, you know, books from 5, 10 years ago, it is very likely that a lot of the organisms that they are referring now are basically in a different species. So we're gonna talk, you know, a little bit about these emerging, you know, type organisms, you know, are they really emerging, you know, or we're just basically becoming better microbiologists and diagnosticians, you that are recognizing what we were just basically clumping before recognizing them now as different species. So I found this quote, you know, to be really important when we start diving into microbiology, particularly of fish, you know.
So in wine, there is wisdom in beer, there is freedom and in water, there is bacteria. So we got to recognize, you know, that these environments, you know, where we t are reached in different micro micro organisms and maintaining this microbiome, a healthy microbiome is not only important, you know, for the lab life support system, but also for the fish itself. OK.
So it's very important that we recognize, you know, that just the detection or detection of the DNA or even detection of the micro organism, you know, in the water or even within some of the mucosal membranes of the fish does not signify that those fish are infected or that there is a disease occurring. Ok. So it's very, very important, you know, to that because you will find a lot, a lot of papers nowadays that refer particularly with Edn A&E environmental RN A detection.
Those are great, you know, those are great tools, but we have to recognize, you know, what they are doing and use them in the correct way. Again, the detection of nucleic material does not signify that an animal is sick. OK.
So we're gonna talk about different organisms. You know, I'm a simple type person. So I like to simplify things, you know, particularly when I'm giving a lecture for them.
So we're gonna talk about organisms that I recognize, I recognize as the classical sonore agents. You know, that people refer to when they talk about aquatic animals. And we're gonna talk also about some emerging organisms that again, even we are now recognizing them as pathogens of fish or that we're just basically becoming better at detecting them.
So are they really just basically new agents, you know, infecting fish or we're just recognizing them now, by the advent of some, you know, better microbiological methods or molecular methods that still a line, a whole line of research that I will not get into. So, within the classical organisms, we're going to discuss mycobacteriosis Streptococcus as well as Amon AIS or vibriosis and within the emerging ones, we're going to talk about EIP and Eduard Clos. Ok.
So, probably the most famous one and, and extremely important organisms, you know, a group of diseases, you know, to talk are mycobacteriosis. You know, this is a gigantic genus. It has even been proposed, you know, by different authors, you know, that most of the species, you know, that we describe in these should be split even in five other different genera, but this hasn't occurred yet.
So, we're gonna still group them within the genus. Mycobacterium. So mycobacterium are aerobic facultative intracellular non sport forming rods.
And again, I'm giving you here important characteristics, you know, that you should remember that probably the most important in terms of treatment, you know, is this facultative intracellular type, characteristic, you know, a lifestyle that mycobacterium have that becomes, you know, a headache for veterinarians, you know, to try to treat them because again, we have to kill not only that extracellular life stage, you know, but also that intracellular one. Ok. So in here, we have the classic histological finding of mycobacterium.
I hope all of you can recognize, you know, you in different places, you know, might be referred as a tubercle or a granuloma where we have in here, an example of caseous necrosis, you know, you can have vaulted macrophages, you know, and then encapsulation by this Nero tissue and then, you know, you have again, an infiltrate, mainly a granulomatosis infiltrate, you know, where you can recognize, you know, a large number of lymphocytes, you know, and again, you know, other mononuclear cells, you know, like macrophages. What's happening here is a way of the organism to try to, again encapsulate what I cannot kill. I'm gonna try to encapsulate, but it's staining with hematoxylin eeoh and e regular stain.
If you're a pathologist, you probably recognize, you know, a large number of microorganisms, you know, within these vaulted macrophages. I am not a pathologist but I do know that these organisms, you know, I have special features, for example, in their cell wall, these long complex mycotic acids that make mycobacterium, one of the f organism that stain positive, for example, with acid fast stain that these specific acid path stains, you know, target against these large complex mycotic acids that then allow us to be able to recognize, you know, the bacterium a lot easier. Ok.
So if we use acid fast stains, you know, like the cyl Nelsen, for example, then we recognize, you know, we easily can see this bacterium within these vacuoles, you know of the macrophage is completely packed again and this is this intracellular lifestyle but also the presence, you know, persistence of this my bacterium within the Grand Loma makes treatment of mycobacteriosis, particularly challenging. And this inflammatory reaction, you know, not only occurs in fish but also is a similar reaction as we will see in in humans and other mammals. Ok.
So as I mentioned to you before, there is over 200 different species, you know, within that genera. And the mycobacterium genus has been proposed, you know that they should be placed in a different genera. For example, Gupta al proposed this, but this really hasn't gone too much traction.
However, I like, you know, this table or this figure, you know, because you can actually see in here the vision of what is typically referred to as the rapid growers and as low growers, microbacterium and some of them, again, it's again, very, very large genus and within them, you know, we have representatives, you know, of organisms that have been recognized, you know, to cause disease in fish. However, the most common ones, you know, are within these microbacterium konni abscesses as well as in the tuberculosis glad, you know, which basically is represented for sure by mycobacterium Marino, shorty, pseudo shorty and ulcer, but particularly M koni and and now m salmon in some places, you know, in some fish host are becoming more and more common. And these are referred, you know, so that known to colloid mycobacterium are typically referred as the atypical mycobacterium and they cause atypical mycobacteriosis.
So again, they do not cause tuberculosis. Still, they do present, you know, a sonic risk. Ok.
So they can be associated with disease in a wide range of host. We're gonna talk again and focus mainly on fish. But I have to put, you know, here that some of these same species of mycobacterium can be found in amphibians and reptiles.
And in all of these 3 kg term group of animals, they cause chronic wasting conditions. So again, it is not one of those agents that you see acute mortalities, you know, occurring within a week or two weeks, you know, and here you see low moderate mortalities through a long period of time. Ok.
In here, for example, you have, you know, examples of two different amphibians in one with a non healing. You know, and poor body conditions. What is very wrong, you know, from this photo, you should be recognizing that again from the topic that we're and handling these animals should be wearing gloves.
Ok. So these mycobacterium, you know, not only infect a wide range of different fish species, you know, but again, remember that they can infect, you know, and cause disease in not only other pothers but also mammals, you know, for example, that can live, you know, within this environment in all of these holes. You know, the disease is considered non treatable one established, you know, and of course, you know, this means that as with all of them, prevention basically is the key.
Ok, establishing good quarantine programs, you know, to prevent you know, these infectious organisms to come into our stock is absolutely key. But again, the the biggest thing that I want to discuss, you know, in here is that these organisms, you know, have astronaut potential. So, so it has been recognized, you know, for decades, you know, that mycobacterium can persist again, you know, in different aquatic environments.
And this type of stenosis, you know, has been called, you know, in different places, you know, with different names like the swimming pool, granuloma or the fish handlers disease. Ok. So different activities, you know, where people come in close contact, you know, with the aquatic environment, you know, makes them at risk.
So if they own aquariums, you know, if they do water related activities like swimming, fishing, boating, etcetera, they can actually become at higher risk of developing microbacteria. One important point, you know, in here is that unfortunately, in the ornamental trade in aquariums, you know, et cetera, there is an extremely high prevalence of mycobacterium. Again, not only in infecting host, you know, you know, the infected hosting, of course, you know, will be the source, you know, most of the times, you know, at least initially, but this mycobacterium are also champions in environmental persistence.
You know, most of them can form biofilms and they're pretty hardy. So they can actually form biofilms in the life support system. So in the filters, the tubing, et cetera.
But also they can contaminate, you know, a lot of the, you know, plastic plants, you know, of the substrate, you know, that we might be using in a different aquarium. Ok. So it has been well established, you know, that there is occupational hazards, you know, from pet shop workers, you know, fishermen and fisher women.
And of course, you know, veterinarians, you know, that are usually called upon into action, you know, to try to save, you know, the lives, you know, of different fish, different presentations, you know, have been reported, you know, again, for most of the agents that we're going to talk about today, I'm mainly going to focus on basically at risk, you know, from contact, you know, not, not really from consumption, you know, contaminated material but veterinarians, you know, that have, you know, any type of abrasion, any type of ulcer, any type of cut, you know, in their hands and they might come in contact, you know, with infected fish, you know, or infected environments, you know, I can develop again all of these different presentations, you know, from cutaneous, you know, presentations, cellulitis, you know, to more serious ones, you know, again, you know, these eye infections, you know, but even in immunosuppressed host, you know, there have been reports of septicemia and of course deaths associated with these organisms, there's some practices, you know, that I would for sure advise you guys, you know, to stay away from, the use of fish for pedicure and some of you might have done this already. But there is, of course, you know, there is a nice study presented in here back, you know, almost 12 years now. Where they did, you know, a study looking at the presence of different sonic agents, you know, within fish, you know, used for pedicure.
And they found that of course, you know, mycobacterium, you know, was highly prevalent, you know, in some of these fish. So there could be reverse stenosis, you know, but very likely your classic stenosis, you know, it will be what, what will be occurring. And again, you know, people that might have culture operations, you know, in the foot, that's an excellent source of the bacteria.
And they can get infected and of course, it's gonna be a persistent infection in fish. What we see as I mentioned to you before, there is a wide range of different species, you know, that can be infected. These are some of the most common ornamental fish, you know, a goldfish, goldfish, there's a wide variety of them short bodied, long bodied, you know, fish, et cetera and different presentations.
You know, in this case, you know, you can note that a negative buoyancy. So the fish is having a very hard time maintaining, you know, position, you know, in the water, a lot of effort, look at that of peril. So basically, the movement of the perla, this is how we actually evaluate, you know, our respiratory and this fish is having a very, very hard time.
Ok. In this case, you know, we had collected a guilt clip, you know, and run analysis again with goldfish, you have to put my bacteriosis really on top of your different shows, you know, most of the times. And we see in the necropsy like the amount of ascites, you know, within this animal.
That's part of why you can see s distended. But in other cases, you know, what you typically see is skin lesions, you know, these skin lesions could be ulcerative, you know, they could be more you know, they can look like a new plasm sometimes but collecting a biopsy of this, either submitting it for PC R or microbiology or histology where you can do the acid fast stains, you know, are very, very fast and easy ways to make the diagnosis additionally, within these lesions, you know, again, you know, you can get a scalpel blade, you know, and you can take imprints and again, you know, you can go ahead and stain them with acid fast stains very, very easy diagnosis. But most of the gross findings, you know, come once you start opening the fish performing a full necropsy.
And you realize, you know that most of the secondary lymphoid tissue in fish, they do not have lymph nodes like mammals do. And the secondary lymphoid tissues, you know, become the post interior kidney and the anterior and the, the spleen, sorry, the posterior kidney and the spleen. The anterior kidney is the primary lymphoid organ.
But anyhow, in these secondary lymphoid organs is where antigen presentation will occur. And again, you know, there's a lot of foy activity presentation, et cetera, you know, within these tissues. There's a lot of blood circulating within the tissues.
So typically, those are excellent organs, you know, to collect samples for and submit for microbiology. But you can see a very, very severe cases in here, you can see these white nodules, you know, within pretty much, you know, the entire camic cavity, pretty much every organ it is affected. These are these granulomas, histologically, those granulomas that we were seeing it before and we were discussing before, how you can appreciate them grossly.
Ok. So again, the main target tissue typically, those are secondary lymphoid tissue in the posterior kidney and the spleen. It's not only present as I mentioned to you in the ornamental trade or in aquariums, we see it also in a conservation medicine and conservation programs in California.
For example, we have a keystone species, you know, within the Chinook salmon, for example, and we also have the delta smelt, you know, that is recognized as an endangered species. And in both cases, you know, we have seen very, very aggressive, you know, infections by mycobacterium in this case, mainly mycobacterium salmon and mycobacterium koni. And we published, you know, this case presentations a couple of years ago.
So I'm just leaving that reference in there if you're more interested, you know, to look at this very, very interesting within that presentation in the Chinook salmon is this type of ulcerative lesions, you know, that were really the focus of infection of the mycobacterium salmon and koni. So, although, you know, there was presence of the bacteria and also in internal organs was very interesting that these type of to pa, you know, that we were seeing, you know, within the Chinook sound. All right.
Let's switch gears, you know, we're gonna keep ourselves, you know, within the gram positive organisms and talk a little bit about a streptococcal disease, you know, in and streptococcus and lactococcus, you know, are two different diseases, you know that we need to, to address. Ok. So P streptococcus, you know, I'm I'm gonna be a little bit more of a, a lumper and not a splitter when I talk about this one, you know, but streptococcus, you know, I'm gonna refer to them as disease caused by different species within the order lactobacillus and within them, you know, in fish, you know, we have species that are more represented in these caves.
You know, streptococcus, enea, streptococcus, agalactiae and streptococcus. This galacia lactococcus, Garvey and Lactococcus PTU. Some of these species, you know, are known or recognized as emerging or re emerging in the Americas in a wide range of animals.
Again from production animals, you know, to ornamental fish, you know, to even, wild animals, you know, a couple, it had to be already, almost a little bit over a decade ago. We dealt, you know, with a big outbreak of Streptococcus AIA in reef fish, you know, out in the, the Caribbean in the beautiful island of Saint Kitts, you know, where I used to live. And at this, of course, it will become, you know, a big issue, a one health type issue because, you're dealing not only with a so big agent, you know, but also the livelihood of a lot of the local folks, you know, that depend on the fisheries and in the tourism, but anyhow, Pisces Cryptococcosis, you know, again, you know, can be found in a wide range of warm water, cold water, marine and freshwater fish, in all of them, you know, they can cause high mortalities.
These organisms, you know, have to be recognized, you know, with a global distribution, a very diverse host and and habitats. And again, you know, these opportunistically stenosis, you know, type characteristic, there are a wide range, you know, even within the different species, you know, they're very, very, they have characteristics that make them, you know, pretty unique. One of such, you know, is a different type of stereotypes that they can present, you know, that of course, complicate matters, you know, when you're trying to develop prophylactic type programs like vaccines.
OK. And with, for example, streptococcus in one of the issues have been this capacity of the streptococcus to mute, you know, their capsular operon. So these genes that are responsible to encode the capsule of the organism that is main target of some of the vaccines basically is capable of mutate, you know, every so often making this a headache, you know, for vaccine companies because you might develop an excellent vaccine against serotype A.
But eventually, if the stereotype changes into stereotype B, then that vaccine, you know, is pretty much useless. OK. The diagnosis, you know, it is not too complicated, you know, these organisms are not as fastidious or slow growers as mycobacterium.
The clinical signs are non specific, you know. So what you can appreciate is exo Thalia camic distension. A lot of camic adhesions, you know, within the tissues.
But if you are able to inoculate them in media like trippy case, soy agar supplemented with blood, we typically use 5% sheep blood. Most of them grow fairly fine, you know, within, you know, 2 to 4 days, you know, at around 25 to 28 °C, depending on the environment, you know, where the fish is, maintain that temperature might look, we, so if you're dealing with a cold water fish, you might want to, you know, incubate that media a little bit into the colder side, you know, so like 15 to 20 °C and this is very important as veterinarians to recognize, you know, because one of the first advices, you know, that I will give, you know, folks that are getting into this business, this line of business is to identify a microbiology lab, you know, that works with fish because the type of media and then the type of environment, you know, to culture these organisms is absolutely key in the success successful diagnosis. All right.
So we got gram positive COCA these are catalase and oxidase negative. They can produce different patterns of hermosa and even morphologies. But typically, they have been associated with climate change, you know, in different environments and particular with warmer weathers.
So some of the streptococcus, you know, that we have recognized, you know, can, can change, you know, in a fluctuating environment, you know, within temperatures. Typically, it is at the higher range of the temperature for the fish species, you know, that we start seeing these outbreaks, of course, other factors, you know, that might stress the fish, you know, like elevated nitrates, you know, high stocking densities, movement, handling of the animals, all of those, you know, can increase, you know, the chances of an outbreak of streptococcus. However, again, you know, that temperature is something that we really need to recognize.
Pyne lacto Cocos is sister, let's say like that, you know, of Pisces Streptococcus. It is caused by different species within the genus Lactococcus. Historically, it has been attributed, you know, to Lactococcus, Garvie.
So again, a lot of the literature, you will find lactococcus garb here and there. However, in the past, you know, 10 years or so, we have recognized, you know, there's other species, you know, within the genus Lactococcus that might be even more important ecological agent than El Garvie. These are also gram positive kai, they can form chains.
They're not as long as some of the streptococci but they grow as well in the different media. Some of them, you know, may cause some hemolysis. A lot of them do not cause hemolysis also have global distribution.
But again, particular has been emerging, you know, in different countries, you know, and, and again, it can infect, you know, a wide range of different fish species is in those stressed fish, you know, towards that higher temperature range, you know, for the fish where we can start seeing more important outbreaks. And again, it is a recognized, you know, sona agent, you know, that again, similar as what we will discuss, you know, for streptococcus is important for us to recognize. So pissy lactococcus is, you know, part particularly in the Americas have been found, you know, to be really, really important agent causing outbreaks in culture.
Rainbow trout, ok. In the rainbow trout, it causes a hyper acute hemorrhagic septicemia. So in here we start seeing mortalities similar as what we see with streptococcus.
In, for example, some sicklids in some, you know, marine species, you know, and in the ornamental trade, you know, we see it, you know, with rainbow trout, you know, so we see high mortalities, you know, within 4 to 7 days characterized, you know, with an exo talia darkening of the skin. And of course, you know, internal and external hemorrhages, one interesting feature in here was that, with this bug, you know, we have seen a lot of antimicrobial resistance rising particularly towards oxytetracycline, which oxytetracycline is one of the most common drugs, you know, used in in fish medicine, but also similar as with the streptococcus as we describe vaccine escapes. So, in the Americas, you know, we saw the first reports of lacto Cocos back in 2007.
So again, even then it hasn't been, you know, 20 years you know, since the first, diagnosis in Brazil in Pintado as well as in tilapia. But then within that past decade, you know, we really saw an increase in the reports, you know, in culture rainbow trout in North America, particularly in, Mexico in Washington, later on in California. And from there pretty much in, in, in a different states, you know, including, Arizona and even in Canada where they saw a rise in temperature above 15 °C.
So that really becomes, again, you know, an important characteristic, you know, for this disease in salmon that higher than 15 °C temperature in tilapia. And in Pinta, in Brazil, mainly seeing it, you know, with temperatures above 27 °C. And since 2015, there has been a rise in the reports in different species of fish, you know, again, native species, you know, as well as those introduced, you know, for aquaculture, like the tilapia has been an increase, you know, so an important impact, you know, for food fish as well.
So there has been wide range of published presentations, you know, all the sona potential. Again, people handling fish, you know, and particularly fresh fish have become at risk, you know. So different presentations from c colitis, you know, to septic arthritis, lymphangitis, you know, and then increasing in severity into an endocarditis, meningitis, sepsis, you know, and of course, you know, mortalities have been reported, you know, with these organisms in this study, with an outbreak of streptococcus Inia in Taiwan.
They did epidemiological analysis, you know, to investigate risk factors, you know, associated with people that were infected, you know, with this outbreak, you know, they found Asian ethnicity as a risk factor, of course, you know, Asian, you know, like to handle or process, you know, a really fresh fish. So in those live markets, you know, becomes, you know, increasingly risky because they can, there is higher risk, you know, for example of puncture, you know, from a spines, you know. So those cellulite is et cetera from inoculation of those contaminated spines, you know, have become a risk old age, you know.
So median age, you know, during the outbreak of 71. And again, you know, in here you start thinking about potential immunosuppression, you know, associated with age and underlying medical conditions. Again, things like diabetes Melius, you know, or cirrhosis of the liver also, again, you know, becoming risk factors, you know, for streptococcus.
So again, immunosuppression in all cases, you know, becomes more of a risk, you know, of the severity of these presentations in humans. But there has been a wide range of different outbreaks, you know, reported, you know, pretty much worldwide, you know, in California, there were some, you know, you know, Ontario, there were others, you know, in in Asia, of course, and the same is true for Lactococcus, you know. So within Lactococcus, you know, again, as we recognize more and more of the presence of these different species, you know, now we are actually finding that a lot of the cases that were likely called lactococcus garb are, in fact, Lactococcus TUI.
And this is one of the agents that we investigate the most in my laboratory. And we have found that for example, Lato Cocos Pei is really the number one theology of lacrosse, at least in the Americas. OK.
We're gonna start switching gears now into a group of gram negative organisms, you know, and here we're going to discuss, you know, the Mo Amona and video and why do I group them, you know, I group them because these organisms are considered a classic opportunist opportunistic, you know, type a, you know, particularly in fish medicine. OK. They are ubiquitous in the aquatic environment.
Not in the same environment, you know, because aroa actually is more persistent in fresh water and brackish water, whereas, vs, you know, are more halophilic, you know, they like salt. So they're mainly present, you know, in brackish water and salt water, but they are champions of persistence, you know, they are champions of developing antimicrobial resistance, you know, and again, this makes them and they also grow very fast. Ok.
They grow very fast and they grow in a wide range of different temperatures. So these give them characteristics, you know, of environmental persistence, you know, that again make them an excellent opportunistic pathogen. As soon as they see any type of immune suppression, you know, in different host, they can take advantage cause disease.
And again, because they can persist, you know, in a wide range of different environments, you know, again, any sort of puncture, any type of cut, you know, can become risk, you know, they can become again a port of entry towards a new host. Ok. So motile amona septicemia.
Why do I talk about motility in here? Because you know, there are non motile amona that are important fish pathogens. For example, Amona Salonica, we're not talking about that one.
We're talking about particularly three different species, you know, that are known to be important agents, you know, of of diseases, you know, in for kilo terms, because again, these organisms also can infect a wide range of amphibians as well as reptiles. So, aroa, hydrophil, Soria and Cavia are the three most commonly reported mobile aroa, you know that cause, you know, infections, these are both side from oxidase positive and they are insensitive to the vibrio static agent. 01 29.
Why I say this? Because this is an excellent and easy test, you know, to distinguish, you know, to the vibrio, OK. They are short gram negative motile villi.
They grow well at 37. And this is one of the reasons why these organs, you know, when infecting a mammal, they can actually replicate very fast and they can cause important diseases in and including mortalities. Ok.
So it is important that we recognize, you know that this type of infection, you know, can occur very fast, is more of an acute type infection. IVS. In the other hand, again, we have other agents like vibrio, Guar, Lione and Guar vibrio or Dali viri unicos vibrio Cerra.
So again, a wide range of different vibrio species, you know, also associated they're very, very heterogeneous species which help make it pretty complicated, you know, to develop a successful vaccines. But again, one important characteristic is that they are halophilic. So they like salt.
So if you want to grow these organisms, you have to supplement with some salt. You know, most of the media, some of them can grow in media without salt, but for sure, grow better with addition of salt and they are susceptible to these videos, static agents. So again, you know, if you get samples, you know from this gram negative cyto Comox is positive, you know, rods, you know, are growing in media from an outbreak in brackish water.
You need to distinguish between aero and video. You can utilize, you know, these agents, you know, and V will be susceptible whereas aroa will be resistant. But in either case, you know, these organisms are mainly associated or mainly characterized, you know, as an opportunistic agent.
The type of lesions that they cause, you know, in the fish are non-specific. So again, we have a very clear extalia and here you again, see bilateral exo in this fish and then a pretty impressive in Oslo distension in these cases, you know, it's very hard, you know, to treat these animals. However, with the use of the right antimicrobial.
So, antimicrobial testing is absolutely key for them. Some of the other animals, you know, within the stock, you know, can be treated. Ok, very important to test, you know, for antimicrobial susceptibility because v videos and amona are again, champions of persistence and they have developed, you know, a wide range of tools, you know, to exchange genetic materials, making them a headache, you know, for microbiologists, you know, because again, they can gain different plasmids, different resistant cassettes, you know, different genes that can make them resistant to a wide range of antimicrobials and in aquaculture and in fish medicine, there's no that many antimicrobials that we can use, particularly within the country that you might be living.
There will be very different laws, you know, to even neighbor countries, you know, so you gotta be careful with what you start using to treat. And that again, you know, legislation and rules, you know, governing antimicrobial therapy, regardless of this judicious use, you know, of the antimicrobials is absolutely mandated, you know, for all of us veterinarians, you know, so we need to recognize, you know, how to better treat these animals. So, again, non-specific clinical signs, you know, but these can occur, you know, fairly rapid, you know.
So in here we're talking more of a para acute to acute type presentations any humans, you know, again, it is not that it is uncommon to see really probably like, you know, between mycobacterium, you know, and again, these aroa and B infections, you know, are probably the most common ones that we see, particularly for us, you know, that work a lot, you know, with with fish. There are a couple of examples, you know, I gave you here, you know, some of the references, you know, that you might be interested in looking a little bit more in depth. But you can see that vibrio is p you know, type diseases, you know, again, from aquatic animals is not really uncommon at all.
Different presentations, of course, you know, from consuming contaminated materials. So like shellfish, you know, for example, or fish to also basically infections, you know, from handling infected animals. So in this report, for example, this necrotic fasciitis caused by bics, you know, from a contaminated eel.
So eel gets infected, you know, with bics. And again, you know, this, farmer basically gets, unfortunately, infected from the eel. Ok, peloid is another organism we're switching back, you know, to grammar positives.
You might recognize, you know, Ella, you know, we don't use that term, you know, in here because Ella is a disease caused by another agent, streptococcus, you know, in mammals. So the term peloid, you know, would be the one that we were talking, you know, four diseases called by members of the genus tri. And you probably remember icy tricks, you know, from infections, particularly in the swine and poultry industry more often, you know, in the swine but not.
But clos, you know, are a group of organisms that actually persist, you know, are very efficacious, you know, persisting in aquatic environment. So these are gram positive long splendor rods, they're a little bit more fastidious, you know, than the other ones that we have discussed, you know, so far. But particularly the type strain or the type species tris, you know, Rosia is recognized as a pretty important pathogen of domesticated swine in which, you know, they can cause, you know, a very, very important, economical losses, you know, in production animals.
But Ricci threes, you know, rusia and other novel AIP are now recognized in other marine mammals, you know, as well as in fish and they can cause important mortalities in them as well. So for those of you that like conservation medicine and marine mammal medicine, this is one for example that if you were going to be working at a rescue center or in an aquarium, you really need to be aware of, you know, because it can cause, you know, very important, you know, disease, you know, in not only dolphins, you know, but even whales, you know, there have been reports, you know, of course, of wild animals, you know, that basically get beach, you know, and one of the reasons, you know, or the reason, you know, for, again, you know, the mortality is the infection by cella in fish. There has been reports, you know, of a clo TRX ria for a while particularly because again, you know, fishing are typically fed, you know, to marine mammals that are kept in captivity and in different aquariums in different, you know, conservation centers, et cetera.
They will have to test, you know, the fish, you know, basically to investigate the premise or not of this agent because they know it's an important pathogen of the marine mammals. But there has been occasions, you know, this was the first report as far as I know back in 2015 where there were outbreaks were reported in fish due to the bacteria. So again, not really being part of the normal flora but actually mortalities associated with the bac bacteria itself.
We started seeing more and more cases, you know, about 10 years ago in captive fish, you know, in the US barbs, you know, as I mentioned to you is one of the most common species, you know, of ornamental fish. And we started seeing reports, you know, of mortality particularly after breeding, harvest or shipping. So again, handling, which are all stressful events, you know, in the fish, as you can see here in the photo on the right, you know, this is a normal long fin tiger barb.
But what you see in the left, you know, is a fish, you know, that very obvious, you know, lesion, you know, in in the mouth. So the presence of these ulcerative stomatitis, you know, basically was the main finding, you know, when we were performing analysis of this fish, particularly in temperatures, you know, from 24 to 30 °C. So again, nothing crazy within the range, you know, for this species.
And here a different view of the lesions, you know, within the mouth histologically, what we were finding, you know, is a presence of large amounts, you know, of these gram positive bacterium. Ok. So again, you know, we are just highlighting this area in here, hope you can recognize, you know, this is the mouth of the fish in here.
You have, you know, the eye of the, you know, here the gills, you know, here the brain OK. This is the lesion that we're highlighting in here and all that you see in here are large numbers of basically gram positive bacteria sometimes even seem like, you know, they were forming in vivo biofilms. So we dial in a lot more into the genome characterization of these species.
You know, we published a couple of papers, you know, in here that you can read a little bit more in detail, but from different outbreaks, you know, in different regions, you know, we were able to isolate, you know, a species, you know, that end up being a new species within the genus Icy three which we named icy three species cardi. So basically the killer of fish, so very, very different, you know, to that one of tri you know, which could be considered more of a normal flora type, you know, of a different mucosal tissues, you know, within the fish species, cardio, you know, should be considered a primary pathogen, you know of some of these ornamental fish. And with the description of this novel eyas.
Not not long after the description, you know, of the agent, you know, coy fish we started finding now in the literature, basically the presence you know, or characterization the diagnosis, you know of these same species is ac three species cardio, you know, also causing infection in humans. Ok. So how common it is, you know, how much of an impact, you know, it has as a sona agent.
I don't know what I can tell you is that there has been already reports of these same species also causing disease in other host, you know, including birds. Ok. So not only captive birds, you know, but also in in wild birds.
So something you know, that we need to recognize, you know, and of course, you know, be in the local why also, you know, as you practice, you know, preventative medicine, you know, we tested, you know, some of the vaccines, you know, for example, that are available against Cipro three rusia and they were, of course, you know, ineffective, you know, against Cipro three species carum. Of course, you know, there's different complete species, you know, but sometimes, you know, there could be some proactivity. All right.
Now we're gonna start discussing Edward Csis, you know, and I think, you know, this is gonna be the last one. Edward celas, the members of the genus Edward celas are not new to fish medicine. OK.
These are gram negatives that from oxidase negative rods belonging to the family have NC A. Historically, there has been the recognition of two different Eduard Clas important for fish. Eduard Sa Iuri and Eduard Sila Tard.
However, about 10 years ago, there was research basically describing again, you know, with the advent of a whole G analysis, you know that a lot of what people were calling a typical Edward Satara were in fact other species of bacteria. So a lot of the organisms that folks were calling Edward Cla Tard are now divided, you know, into two recently described species. Edu cla Pisa and Eduard cla anguilla room.
So really, we have four different species within the genus that can cause important disease in fish. Ok. So even here in this video, we have Nile tilapia infected you with, in this case, Eduard Ciela and will arum.
What we can see in the video is erratic swimming. So you see that cork throwing, you know, a swimming pattern, we see lethargy. So we have fish, you know, that are not moving at all and we have a fish, you know, that are really not maintaining position in the water.
So basically, they are into the side. So these also as clinicians are giving us guidance as to which tissues, you know, we should be sampling. So I hope that you can recognize, you know, that these very abnormal behavior makes you suspect, you know, for the central nervous system.
So particularly checking out the brain will be very important in these cases. So, enteric septicemia of catfish or EFC has been recognized, you know, for over two or three decades, you know, since the 19 eighties, four decades, now as an important pathogen of channel catfish, particularly culture channel catfish in the Southeastern US, which is again, you know, the most common, you know, culture species, you know, food fish that we have in the US where we can recognize, you know, different patterns. You know, there are different clinical signs, you know, including hemorrhages, you know, within the Brum of the fish, you know, a camic distension characterized by ascites.
These lesions, you know, in the liver, liver making it, you know, one of the target organs, you know, where you can see again, you know, these congested areas, you know, in areas of necrosis, you know, within the liver, but also in more sub acute to chronic cases, you know, what we see is referred to as hole in the head after the description, you know, and recognition of Edward Cai Tao for years, you know, in catfish, you know, we started recognizing that it can actually be present in other species, you know, as well. So we start seeing Edward Cla Tao in now different species of fish including tilapia and particularly important all. So for those folks, you know, working in Southeast Asia now becoming really one of the most important pathogens, you know, or emerging pathogens of culture tilapia in Southeast Asia, very important, very different than your classic silla Iori in catfish.
But at the same time, you know, as we were describing this in tilapia. Doctor John Hawk, you know, out of LSU as well, started seeing like, you know, new emerging strains of a dor like tour in zebrafish. So again, we now have, you know, a species of bacteria that for A or B reason seem to be jumping hosts and in a different type of evolutionary pattern, you know, where a clade, you know, a basically seem to be particularly focusing on tilapia, some in zebra fish and some in catfish.
So it's not the same organism that was infected catfish. The one that we found in tilapia or zebra fish, there is some sort of evolutionary divergence, you know, where they started affecting the different hosts. And since then, we have now recognized, you know, that edu select all is one of the most important pathogens of silver fish, cela aguilar, as I mentioned to you before, also appearing more and more important in cichlids.
Not only in in, in a tilapia and their culture for human consumption, you know, but also in cli you know, that are maintained in the ornamental trade in Costa Rica. We develop different multiple essays, you know, to distinguish between these important agents, but started recognizing also the presence of Eduard Ciela Pisa. So adding up yet another member of the genus Edward Ciela that can call a head infect, you know, a fish.
In this case, you know, we have photos in catfish as well as in salmon. So again, a wide range of environment and a wide range of host, you know, that can get infected with this Eduarda Pisa and even within the species Pisa, we have now six different plates, you know, that have some sort of post reference, you know, so this become a threat, you know, because Edward celas are also known, you know, to develop antimicrobial resistance, you know, and particularly because the fact, you know, that they can infect a wide range of host, you know, make them really, really, really important because they also can infect humans. So all of these different sources, you know, from food fish, you know, to research animals, you know, to ornamentals end up, you know, with a risk, you know, for those folks, you know, that work in these different industries where Edward Ciela particular Edward Ciela tara have been recognized, you know, to cause a number of different presentation, you know, from this chronic osteomyelitis, you know, to bacteremia, et cetera and particularly a lot of these patients, you know, that have been associated with Eduard Ciela, t infections, you know, were for some reason or not, you know, associated with aquatic environments.
And of course, fish, this story, I thought it was interesting, you know, just because again, you know, you have to start dealing a little bit with the epidemiology that we see in humans, in this case, you know, from a single hospital where they analyze, you know, over 9000 blood cultures, only 38 you know, were Edward Ciela. So very low. No, no, that's common.
But underlying cancer. So again, another type of risk factor, again, immunosuppressive towards the host, you know, opens the door for some of these Eduard cl A, you know, to cause, you know, the disease. Importantly, there was about 25% mortality in 90 days when this infection in, in fact, you know, took place.
So again, i it's not a common, you know, type of infection in immunosuppressed host, you know, it can impact, you know, cause very high mortalities. Ok. So some practical recommendations, you know, that hope that you can take back, you know, into practice if you're already practicing fish medicine or that you can incorporate, you know, of course, you know, as you dive into this new world, where appropriate P pe you saw in a lot of the photos, you know, again, folks not wearing gloves, extremely important, you know, if you are going to be handling infected animals or infected environments, you know, very unlikely unfortunate that veterinarians are gonna be cold, you know, to work with healthy stocks of fish, we're typically cold when there is an issue.
So this, this becomes extremely important, wear gloves, you know, not only to take, you know, working with the fish, you know, but also with the different, environmental, you know, a different plants, you know, or the filters, you know, etcetera. You, you really need to wear, gloves all the time. Particularly important.
You know, if you have a braided skin cuts or scrapes, you know, any type of lesion in, the hand or the foot, fish really like to splash everywhere, particularly as you catch them and anesthetize them. So in those cases, you know, where, where eye protection, you know, so some goggles, you know, glasses, you know, protective glasses, you know, are, are important as well as dedicated protective clothing, you know, when handling the animals because you're gonna get wet. Ok?
Needless to say, do not eat or drink while handling the animals or the housing areas. But this is also important for you to educate, you know, your clients, you know, your clients might not be aware at all of all of these agents, you know, that are in some cases fairly common to, to be with. So, a little bit of education might come a long way.
And of course, you know, if you have these infected wounds, you know, if you have these lesions that typically are associated with swelling, redness, pain and draining fluids, seek physician physician attention, you know, because the earlier that you can treat them, of course, you know, the more successful, particularly for agents like mycobacterium where they can cause, you know, this prolonged, you know, type disease, mycobacteriosis. It, it is a difficult one to treat. Usually in mammals, you know, you will be having to treat, you know, for months to years.
Ok. And keeping animal areas clean and disinfected, practicing good quarantine programs, you know, for the animals, of course, that will reduce, you know, the risk, you know, of these soos to even occur in humans. So I leave you with these four different papers, I think, you know, are fairly useful.
And I hope you know that I was clear but if I wasn't, I'm 100% happy to receive questions. My email is Soto Martinez at UC davis.edu.
And of course, I appreciate, you know, the organizers of this meeting and all of you for your attention. Thank you.
