Unknown Neurological Wrasse Disease (UNWD)

[nereefpat]

I'm wondering if there is another species of Scuticociliate, apart from Uronema, that is specifically a parasite for wrasses. Maybe Jay has already suggested that, I forget.

 

[Details]

It seems like we have a real pathology here that needs some methodology to figure out.

Given that the symptoms appear to be neurological (swim dysfunction not related to buoyancy), we should run with neurological/neuromuscular dysfunction and think with all of its causes

Borrowing from diagnostics and expanding our differentials for neurological disease, we have:

1. Vascular: Ischemic/Haemorrhagic events or as mentioned by others air embolism.
2. Infectious: Bacterial/Viral/Protozoal/Parasitic/Other
3. Trauma: From shipping/handling, jumping
4. Autoimmune: Lets not go there
5. Metabolic: Some critical metabolite required for neuronal function missing in diet
6. Toxins: As mentioned earlier, cyanide, organophosphates
7. Neoplastic: Let not go there
8. Congenital: Maybe some of them are born with poor adaptation
8. Degenerative: Some diet/env related decline
9. Endocrine: stress response in a artifical environment

Now lets look at the disease in details
1. Disease progression: Symptoms exacerbation -> Death (not immediate - 9days? 2 weeks or slow progression over years)
2. Mortality: 100%
3. Symptomology: Poor swimming with feeding response

Other characteristics and findings
1. Are all wrasses affected in a tank? -?8%
2. Does it affect all wrasse species? which are not affected? -?some more than others
3. Does it affect wrasses supplied from a certain region? -?unknown
4. Does it affect other species of fish? -?No
5. Historical prevalence? -?New to the hobby last 20 years
6. Not related to prazi
7. Not Uronema, Betanodavirus, ?the other virus tested

----------------------------------------------
Given that it has an acute onset (days to weeks)
- we can rule out: Neoplastic, Degenerative, Congenital, Autoimmune, Endocrine
- we are left with: Vascular, Infectious, Toxins, Trauma, Metabolic

Given that it only affects a subset of wrasses of the same species:
- we can rule out: Metabolic, Toxins
- we are left with: Vascular, Infectious, Trauma

Given that it is a new phenomenon and assuming that techniques for harvesting the fish have not changed much
- we can rule out: Vascular -> barotrauma
- we are left with: Infectious, Trauma

Given that it affects some species of wrasses more than others (assuming that all ornamental wrasses have the same trauma susceptibility) and that it has a 100% mortality rate
- we can rule out: trauma (e.g spinal column damage)
- we are left with: Infectious

Within Infectious we know prazi does not help, copper does not help, uronema negative and betanovirus/other virus negative. We know its not highly contagious among same and other species in the same tank and no other symptoms other than behaviorial, and that it is new

- we can rule out: Schistomite/Echinococcus/Amyloodinium/Cryptocaryon/uromema parasites, the viruses tested, brooklynella protozoans, highly contagious viruses (aquabirnavirus, betanodaviruses, VHSV, IHNV)

- we should still consider: other viruses such as ISAV, bacterial infections and anything that has a close link with fish stress response

-------------
Isolation of viruses is going to be expensive, in this case trial and error with therapeutics should be the go to
1. Try some antibiotics during qt with good gram neg coverage like zosyn
2. Try to lower the wrasse stress response, if someone is brave they can try dosing anticholinergics during qt, diphenhydramine (benadryl) 10mg/L
3. Try to increase the temperature of QT to 28C (82.4F) to inhibit viral replication

Europe PMC

Europe PMC is an archive of life sciences journal literature.

europepmc.org

The stress response in fish - PubMed

The stress response in teleost fish shows many similarities to that of the terrestrial vertebrates. These concern the principal messengers of the brain-sympathetic-chromaffin cell axis (equivalent of the brain-sympathetic-adrenal medulla axis) and the brain-pituitary-interrenal axis (equivalent...

pubmed.ncbi.nlm.nih.gov

The adrenergic stress response in fish: control of catecholamine storage and release - PubMed

In fish, the catecholamine hormones adrenaline and noradrenaline are released into the circulation, from chromaffin cells, during numerous 'stressful' situations. The physiological and biochemical actions of these hormones (the efferent adrenergic response) have been the focus of numerous...

pubmed.ncbi.nlm.nih.gov

Assessment of diphenhydramine toxicity – Is its mode of action conserved between human and zebrafish?

The main aim of the study is to evaluate the effects of the pharmaceutical diphenhydramine (DPH) on embryo-larvae Danio rerio across distinct levels o…

www.sciencedirect.com

 

[abch0as]

Welcome to Reef2Reef!

I also thought about Uronema as a cause, it certainly can invade different tissues in the fish. However, Uronema in other cases is always progressive - the fish get worse and die. In these UNWD cases (at least the typical ones) the fish develop symptoms to a point and then they are more or less stable. You can keep them alive for quite some time if you hand feed them and keep them safe from aggressive fish.

Also, the initial histopath reports did not show Uronema. They also did not show signs of the two most likely viruses.

Here is the trouble now: There are two groups of public aquarium veterinarians working on this issue (or maybe more?). It is sad, but the fact is, they are not communicating their results during their studies. Funding for research is based on the production of scientific works. If a researcher tips their hand by talking about a study in progress, they may get "scooped" and lose out.

Have you seen my article on Uronema here?

Uronema / Red Band Disease - Hemdal

Red Band Syndrome in Marine Fishes: Caused by the Protozoan; Uronema sp. Jay Hemdal Introduction: This moderately common disease of certain species of marine fish is so often misdiagnosed that most aquarists apply incorrect treatment methods...

www.reef2reef.com

Jay

Hi Jay

That's interesting that the initial histopath reports did not show Uronema. If that is the case... I would accept the findings as conclusive.

My observations also support your conclusion... the fish develop symptoms to a point and then they are more or less stable... I am seeing this now and the slow decline seems to be more from starvation than a progression of the disease. I will figure out how to euthanize this fish today as I don't see any possible path to recover and there is no point in allowing the fish to suffer any further. The fish was eating, or attempting to eat through the progression. It would eat now if as you say, I were to hand feed it, but to what end...

I have read your article on Uronema a couple of times. Thank you for that work. I did however miss the fact that there was an attached discussion. I will read through that and perhaps move my conversation on Uronema to that thread.

My thoughts on Uronema here were just a theory. I hadn't seen the possibility of the cause being Uronema explored in this thread, and I think that it more or less fits many of the patterns. However, I accept your conclusions on the point. Unfortunately, that does mean that the question remains unanswered.

Thank you for the update on the research and the indication that "They also did not show signs of the two most likely viruses." You had linked to one possible suspected virus somewhere above. I read that article and agree that it was a close match. I'm not sure whether it's good news or bad that it wasn't found to be present.

I'll track along and if I can contribute I will. On the point of Uronema... I feel like it's transforming into something of a super bug in our closed eco-systems, but I'll table that discussion elsewhere.

Thanks Jay

 

[Jay Hemdal]

Hi Jay

That's interesting that the initial histopath reports did not show Uronema. If that is the case... I would except the findings as conclusive.

My observations also support your conclusion... the fish develop symptoms to a point and then they are more or less stable... I am seeing this now and the slow decline seems to be more from starvation than a progression of the disease. I will figure out how to euthanize this fish today as I don't see any possible path to recover and there is no point in allowing the fish to suffer any further. The fish was eating, or attempting to eat through the progression. It would eat now if as you say, I were to hand feed it, but to what end...

I have read your article on Uronema a couple of times. Thank you for that work. I did however miss the fact that there was an attached discussion. I will read through that and perhaps move my conversation on Uronema to that thread.

My thoughts on Uronema here were just a theory. I hadn't seen the possibility of the cause being Uronema explored in this thread, and I think that it more or less fits many of the patterns. However, I accept your conclusions on the point. Unfortunately, that does mean that the question remains unanswered.

Thank you for the update on the research and the indication that "They also did not show signs of the two most likely viruses." You had linked to one possible suspected virus somewhere above. I read that article and agree that it was a close match. I'm not sure whether it's good news or bad that it wasn't found to be present.

I'll track along and if I can contribute I will. On the point of Uronema... I feel like it's transforming into something of a super bug in our closed eco-systems, but I'll table that discussion elsewhere.

Thanks Jay

That article is about a decade old, and back then, I had some optimism that Uronema could be controlled with chloroquine. It can be, in the aquarium itself, but it doesn't control the virulent inter-cellular form.

Here is my current thoughts about the apparent increase in prevalence of Uronema:

1) Back about 10 years ago, virtually 100% of hobbyist Uronema cases were visually diagnosed as "bacterial", resulting from an injury. Public aquarists and those with microscopes, could see the true pathogen, but it took time to get that information out there. Now, more hobbyists diagnose it correctly.

2) I saw a large (but admittedly subjective) uptick in Uronema since 2020. Is that due to better diagnosis (see above)? Probably in part, but the bigger culprit IMO is the extension of the travel time for imported fish due to shipping changes resulting from Covid. We know that Uronema is most common in newly imported fish. It stands to reason that it is developing due to something in the supply chain. Logic dictates then, that longer supply chains offer more chances for whatever the reason is that some fish get this issue.

I see a similarity there with UNWD - there are still home aquarists out there that deny there is any sort of a trend here, including some advanced disease people. There is also a large base that feels this is all due to strike injuries.

Not counting myself, there are at least three major public aquariums that recognize this as an unknown syndrome.

I think eventually, we'll get to the bottom of this.....but with my retirement, I won't be the one driving it.


Jay

 

[Jay Hemdal]

I'm wondering if there is another species of Scuticociliate, apart from Uronema, that is specifically a parasite for wrasses. Maybe Jay has already suggested that, I forget.

Those would have showed up in the histo as well. When I say "Uronema" I'm really saying "Scuticocilate" because I cannot tell them apart.


Jay

 

[Jay Hemdal]

It seems like we have a real pathology here that needs some methodology to figure out.

Given that the symptoms appear to be neurological (swim dysfunction not related to buoyancy), we should run with neurological/neuromuscular dysfunction and think with all of its causes

Borrowing from diagnostics and expanding our differentials for neurological disease, we have:

1. Vascular: Ischemic/Haemorrhagic events or as mentioned by others air embolism.
2. Infectious: Bacterial/Viral/Protozoal/Parasitic/Other
3. Trauma: From shipping/handling, jumping
4. Autoimmune: Lets not go there
5. Metabolic: Some critical metabolite required for neuronal function missing in diet
6. Toxins: As mentioned earlier, cyanide, organophosphates
7. Neoplastic: Let not go there
8. Congenital: Maybe some of them are born with poor adaptation
8. Degenerative: Some diet/env related decline
9. Endocrine: stress response in a artifical environment

Now lets look at the disease in details
1. Disease progression: Symptoms exacerbation -> Death (not immediate - 9days? 2 weeks or slow progression over years)
2. Mortality: 100%
3. Symptomology: Poor swimming with feeding response

Other characteristics and findings
1. Are all wrasses affected in a tank? -?8%
2. Does it affect all wrasse species? which are not affected? -?some more than others
3. Does it affect wrasses supplied from a certain region? -?unknown
4. Does it affect other species of fish? -?No
5. Historical prevalence? -?New to the hobby last 20 years
6. Not related to prazi
7. Not Uronema, Betanodavirus, ?the other virus tested

----------------------------------------------
Given that it has an acute onset (days to weeks)
- we can rule out: Neoplastic, Degenerative, Congenital, Autoimmune, Endocrine
- we are left with: Vascular, Infectious, Toxins, Trauma, Metabolic

Given that it only affects a subset of wrasses of the same species:
- we can rule out: Metabolic, Toxins
- we are left with: Vascular, Infectious, Trauma

Given that it is a new phenomenon and assuming that techniques for harvesting the fish have not changed much
- we can rule out: Vascular -> barotrauma
- we are left with: Infectious, Trauma

Given that it affects some species of wrasses more than others (assuming that all ornamental wrasses have the same trauma susceptibility) and that it has a 100% mortality rate
- we can rule out: trauma (e.g spinal column damage)
- we are left with: Infectious

Within Infectious we know prazi does not help, copper does not help, uronema negative and betanovirus/other virus negative. We know its not highly contagious among same and other species in the same tank and no other symptoms other than behaviorial, and that it is new

- we can rule out: Schistomite/Echinococcus/Amyloodinium/Cryptocaryon/uromema parasites, the viruses tested, brooklynella protozoans, highly contagious viruses (aquabirnavirus, betanodaviruses, VHSV, IHNV)

- we should still consider: other viruses such as ISAV, bacterial infections and anything that has a close link with fish stress response

-------------
Isolation of viruses is going to be expensive, in this case trial and error with therapeutics should be the go to
1. Try some antibiotics during qt with good gram neg coverage like zosyn
2. Try to lower the wrasse stress response, if someone is brave they can try dosing anticholinergics during qt, diphenhydramine (benadryl) 10mg/L
3. Try to increase the temperature of QT to 28C (82.4F) to inhibit viral replication

Europe PMC

Europe PMC is an archive of life sciences journal literature.

europepmc.org

The stress response in fish - PubMed

The stress response in teleost fish shows many similarities to that of the terrestrial vertebrates. These concern the principal messengers of the brain-sympathetic-chromaffin cell axis (equivalent of the brain-sympathetic-adrenal medulla axis) and the brain-pituitary-interrenal axis (equivalent...

pubmed.ncbi.nlm.nih.gov

The adrenergic stress response in fish: control of catecholamine storage and release - PubMed

In fish, the catecholamine hormones adrenaline and noradrenaline are released into the circulation, from chromaffin cells, during numerous 'stressful' situations. The physiological and biochemical actions of these hormones (the efferent adrenergic response) have been the focus of numerous...

pubmed.ncbi.nlm.nih.gov

Assessment of diphenhydramine toxicity – Is its mode of action conserved between human and zebrafish?

The main aim of the study is to evaluate the effects of the pharmaceutical diphenhydramine (DPH) on embryo-larvae Danio rerio across distinct levels o…

www.sciencedirect.com

Welcome to Reef2Reef!

Some comments:

For your differentials, I think the following are still viable/open:

2. Infectious: Bacterial/Viral/Protozoal/Parasitic/Other
3. Trauma: From shipping/handling, jumping
6. Toxins: As mentioned earlier, cyanide, organophosphates


1. Are all wrasses affected in a tank? -?8% (newly acquired ones only)
2. Does it affect all wrasse species? which are not affected? - (most common in fairy and flashers, but some reports now in Halichoeres)
3. Does it affect wrasses supplied from a certain region? - (we do need to figure this out, like blond naso tangs from Indonesia doing so poorly, there may be a source issue)
4. Does it affect other species of fish? -?No - agreed
5. Historical prevalence? -?New to the hobby last 20 years I think so, but then, these wrasses are much more popular than they used to be in the trade)
6. Not related to prazi Doesn't seem to be.
7. Not Uronema, Betanodavirus, ?the other virus tested correct


Jay

 

[Ev8siveaz]

@Jay Hemdal I have a banana wrasse that I got about 3 weeks ago. He's been doing great up until 2 days ago. I noticed he wasn't out for feeding which was unusual since he was always the first to eat. Then yesterday he came out for morning feeding and was swimming funny. Basically always swimming in circles like the video I have Included. He tries to eat but constantly misses his food and he even runs head first into the rocks, glass, and other fish. He is out and swimming more today but still has these odd behaviors. Do you think that this is UNWD? It was just so random and has me stumped.




Here is what he does when I feed

banana eating

youtube.com

 

[Jay Hemdal]

@Jay Hemdal I have a banana wrasse that I got about 3 weeks ago. He's been doing great up until 2 days ago. I noticed he wasn't out for feeding which was unusual since he was always the first to eat. Then yesterday he came out for morning feeding and was swimming funny. Basically always swimming in circles like the video I have Included. He tries to eat but constantly misses his food and he even runs head first into the rocks, glass, and other fish. He is out and swimming more today but still has these odd behaviors. Do you think that this is UNWD? It was just so random and has me stumped.




Here is what he does when I feed

banana eating

youtube.com

It does look like it. However, it isn't that common in this species (but has been reported). Another thing - do you know the history of this fish? Was it recently wild caught? These are usually shipped at a much smaller size. If this wasn't recently captured, then it is unlikely to b true UNWD.


Jay

 

[Ev8siveaz]

It does look like it. However, it isn't that common in this species (but has been reported). Another thing - do you know the history of this fish? Was it recently wild caught? These are usually shipped at a much smaller size. If this wasn't recently captured, then it is unlikely to b true UNWD.


Jay

@Jay Hemdal We don't really have any good lfs here. The one that we have gets their fish from quality marine and has you take the special order directly from the black out bag when it arrives. That's where this guy came from.

He seems to be swimming much better today. He hasn't spun in those quick circles like before and haven't seen him run into anything. However, he is still missing the food that I put into the tank and hiding a bit in his cave. Not sure if there is anything else I should do to help out but this is definitely sad as he is really actively trying to eat and just having trouble.

Here is a comparison video of how he is swimming today

banana swimming 2

youtube.com

 

[Ev8siveaz]

@Jay Hemdal He is Definitely out a lot more today.

This seems like normal swimming to me.

I also just caught him steal a big piece of frozen shrimp from my starfish and swim around the tank with it. That's normal behavior for him. Not sure if he ate any of it though but he may have.

banana swimming 3

youtube.com

 

[Jay Hemdal]

@Jay Hemdal He is Definitely out a lot more today.

This seems like normal swimming to me.

I also just caught him steal a big piece of frozen shrimp from my starfish and swim around the tank with it. That's normal behavior for him. Not sure if he ate any of it though but he may have.

banana swimming 3

youtube.com

Good to see! Looks much better - that isn’t the true UNWD then, those fish simply don’t recover.
Jay

 

[Ev8siveaz]

Good to see! Looks much better - that isn’t the true UNWD then, those fish simply don’t recover.
Jay

@Jay Hemdal I was thinking the same although he still just swims around food (pe mysis, brine, etc) and misses it. Haven't gotten him to eat on a normal feeding for 3 days now. I want to look at the positives that his swimming is better and he is out more but the non eating factor still has me worried. It's nice to narrow this out of the equation because he does show some improvement. He looks like he really wants to eat but cant. Its looks almost like hes losing his eyesight to me. Do you have any ideas of what could cause him to be missing his food?

 

[Jay Hemdal]

@Jay Hemdal I was thinking the same although he still just swims around food (pe mysis, brine, etc) and misses it. Haven't gotten him to eat on a normal feeding for 3 days now. I want to look at the positives that his swimming is better and he is out more but the non eating factor still has me worried. It's nice to narrow this out of the equation because he does show some improvement. He looks like he really wants to eat but cant. Its looks almost like hes losing his eyesight to me. Do you have any ideas of what could cause him to be missing his food?

It could have a vision problem. However, you said it grabbed some shrimp, so I wasn't going down that path in my mind. One way to try and test for vision issues is to move suddenly outside the tank (don't bump it). If the fish reacts to your movement, it can see.

Jay

 

[Ev8siveaz]

It could have a vision problem. However, you said it grabbed some shrimp, so I wasn't going down that path in my mind. One way to try and test for vision issues is to move suddenly outside the tank (don't bump it). If the fish reacts to your movement, it can see.

Jay

Thanks Jay. I will try that in the morning. I did notice that he has been swimming head first into my lionfish all day. Is it possible he could have gotten stung at some point? I'm not sure what the effects on another fish are from a lionfish sting or how long it could affect them. At first I thought maybe he was being bullied by something but he's out all the time now so the not eating thing is baffling to me. I think you remember that I had dealt with flukes on my big bird wrasse. I ended up getting rid of the big one because he started to get super aggressive and got a smaller one. I also just finished a 4th round of prazi to the tank because I wanted to make sure that flukes weren't a problem anymore. I don't see any symptoms anymore but wanted to mention it to see if you think it's related.

swimming into lion

youtube.com

I caught the end of him with the piece of shrimp in his mouth. It's not the best video but you get the idea that he definitely had it.

banana eating

youtube.com

 

[Jay Hemdal]

Thanks Jay. I will try that in the morning. I did notice that he has been swimming head first into my lionfish all day. Is it possible he could have gotten stung at some point? I'm not sure what the effects on another fish are from a lionfish sting or how long it could affect them. At first I thought maybe he was being bullied by something but he's out all the time now so the not eating thing is baffling to me. I think you remember that I had dealt with flukes on my big bird wrasse. I ended up getting rid of the big one because he started to get super aggressive and got a smaller one. I also just finished a 4th round of prazi to the tank because I wanted to make sure that flukes weren't a problem anymore. I don't see any symptoms anymore but wanted to mention it to see if you think it's related.

swimming into lion

youtube.com

I caught the end of him with the piece of shrimp in his mouth. It's not the best video but you get the idea that he definitely had it.

banana eating

youtube.com

I don't think this is related to flukes, and lionfish stings are acute - they cause injury up front and then the fish gets better. You can also usually see the point of the sting.

One of the common misdiagnosis for the UNWD is the fish "hitting the tank wall". While that isn't the cause of UNWD, perhaps it does happen from time to time, and that happened here? That would account for the fish getting marginally better over time, where with UNWD, the fish continue to get worse.

Jay

 

[Ev8siveaz]

I don't think this is related to flukes, and lionfish stings are acute - they cause injury up front and then the fish gets better. You can also usually see the point of the sting.

One of the common misdiagnosis for the UNWD is the fish "hitting the tank wall". While that isn't the cause of UNWD, perhaps it does happen from time to time, and that happened here? That would account for the fish getting marginally better over time, where with UNWD, the fish continue to get worse.

Jay

He's run into rocks and other fish but not really the glass so much. I did try to move quick next to the tank and he reacted. He did slam head first into the lion so hard this morning that the lion bolted to the other side of the tank. He still will not really eat which is the concern. This has been very strange. He does still look fat so well see if he eventually eats since his swimming has definitely gotten better.

 

[Ev8siveaz]

@Jay Hemdal I really think he is blind. Here are some tests I did to try and spook him by moving my hands quickly in front of the tank. What do you think? Also, what would cause him to just go blind all of a sudden? He was fine before this.

banana can't see

youtube.com

banana can't see 2

youtube.com

 

[Jay Hemdal]

@Jay Hemdal I really think he is blind. Here are some tests I did to try and spook him by moving my hands quickly in front of the tank. What do you think? Also, what would cause him to just go blind all of a sudden? He was fine before this.

banana can't see

youtube.com

banana can't see 2

youtube.com

It isn't reacting to your hand, but it also isn't blindly running into rocks.

I guess I was thinking maybe the wrasse hit a rock or tank wall REALLY hard and developed neurological symptoms from that. An injury like that would tend to improve over time and this wrasse seemed to do that to some extent?

I'm stumped.

FWIW: Here is an article I wrote on fish eye health, but it isn't going to have an answer for you either:

Aquarium Fish: The ‘Eyes’ Have it: A Review of Eye Health in Aquarium Fishes

Aquarists need to inspect their fish closely every day, for signs of impending health problems. It is much easier to resolve a problem when it first starts, than to attempt a drastic emergency treatment when the fish is close to dying.

reefs.com

Jay

 

[Ev8siveaz]

It isn't reacting to your hand, but it also isn't blindly running into rocks.

I guess I was thinking maybe the wrasse hit a rock or tank wall REALLY hard and developed neurological symptoms from that. An injury like that would tend to improve over time and this wrasse seemed to do that to some extent?

I'm stumped.

FWIW: Here is an article I wrote on fish eye health, but it isn't going to have an answer for you either:

Aquarium Fish: The ‘Eyes’ Have it: A Review of Eye Health in Aquarium Fishes

Aquarists need to inspect their fish closely every day, for signs of impending health problems. It is much easier to resolve a problem when it first starts, than to attempt a drastic emergency treatment when the fish is close to dying.

reefs.com

Jay

Thanks Jay. That's a fair diagnosis. He has definitely improved with his swimming but hasn't taken any food in about 5 days now.

Hopefully he starts eating.

 

[nikesb]

Im glad to have found this thread. I purchased a pintail that arrived and it was a bit still in the bag as I was observing it during acclimation. During drip, I noticed it handt moved and thought it might just be acting as a wrasse does. As soon as he went into the tank, the video shows his symptoms. I purchased him from a trusted quarantine vendor so I have no doubt in it being healthy prior to shipping. I first thought a swim bladder/spinal injury but it could potentially be unwd. Thoughts?