# chytrid cross contamination



## Rain_Frog (Apr 27, 2004)

I will shortly be aquiring some highly marbled Xenopus laevis soon. I know as a fact they can carry chytrids that can be harmful to other frogs. However, I do not know the extent how dangerous it is, or if the frogs have to be SICK to know if the frogs carry the chytrids.

What are the signs of chytrids? I have not heard much of Dart frogs in nature being killed by chytrids, mostly Atelopus. But obviously, I should err on the caution of cleanliness as my 100 gallon is next to the dart and mantella tanks.

Sorry, i do not know much about this disease in general.


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## Ed (Sep 19, 2004)

Xenopus when infected are asymptomatic and healthy looking frogs can carry chytrid. Bullfrogs have been relatively recently been shown to be able to carry chytrid for significant periods of time without showing any demonstrable symptoms but are infectious to other frogs or the enviroment. 

I would strongly suggest contacting a vet and discuss prophylactic treatmening the Xenopus. Skin scrapings do not always catch infected frogs, but there is a accurate PCR test. 

Ed


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## dmatychuk (Apr 20, 2005)

DONT RISK IT. Read this.

http://www.jwildlifedis.org/cgi/reprint/37/1/1


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## Ed (Sep 19, 2004)

People need to be aware that it is likely that all collections are at risk of chytrid infection given that 
1) people collect organic materials from the wild and place into their cages and chytrid is found in many areas in the USA
2) chytrid has been isolated from both importer/wholesaler's stock 
3) Zoos have isolated chytrid from thier collections
4) collections are not usually adequately quarantined or screened for most pathogens. 

Until testing becomes widespread and the addition of uncontrolled materials stops, I suspect all amphibians to be at risk of carrying chytrid. 

Ed


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## dmatychuk (Apr 20, 2005)

Ed,
What would be your recommendation of any kind of preventative treatment?


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## Ed (Sep 19, 2004)

The best treatment involves a buffered itraconazole bath daily for 5 days which so far has always eliminated it from infected frogs. You will need to see a vet to get itraconazole. 
But if the substrate in the encliosure is contaminated (chytrid lives just fine in substrates and so far remains infective) then this a moot point. 

Ed


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## dmatychuk (Apr 20, 2005)

Is this hard or stressful on the frog at all or passive? I am wonder if I should just make this part of my routine....your opinion?


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## Catfur (Oct 5, 2004)

If you are using leaf litter from the wild, is there any way you can disinfect it, to remove chytrid?


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## Ed (Sep 19, 2004)

A lot of Zoos now routinely treat some species of amphibians upon recipt while in quarantine. This has worked well with what are percieved to be sensitive species such as Atelopus zeteki. I think the amount of stress that is incurred in a (hopefully) onetime treatment regimen is less than the risk chytid can pose to collections (given that a lot of species such as pumilio are from the wild (even if they are farmed) and pass through importers/exporters. While these frogs may not show symptoms in the wild because the temps at which they are found are not as conducive to the fungus, the stress from the trip and cooler conditions we keep the frogs could then allow a infection that is lethal.
The reason you use a buffered bath is because otherwise it is irritating to the skin. In a buffered bath, this problem is eliminated. 

But as I mentioned above, the risk of infection from other sources should also be kept in mind. 

Ed


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## Ed (Sep 19, 2004)

with respect to the leaf litter, dry it throughly and/or expose it to temps that are about 120 F. 

Ed


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## dmatychuk (Apr 20, 2005)

Ed,
As always thanks


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## Rain_Frog (Apr 27, 2004)

Goodness.

Now I'm not so sure if the moss I've been collecting from some time out in my backyard is safe anymore...


I could contact Xenopus express about this and what he suggests. Burley Lilley might be able to detect this for me.

What is prophylactic treatment? I don't want to harm my frogs in anyway!


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## Ed (Sep 19, 2004)

I do not know if chytrid has been documented in Kansas as of yet but it has been found in a number of species that are found in Kansas (so it would not surprise me) such as R. catesbeiana, the various leopard frogs, and the tiger salamander complex. 

The prophylactic treatment is what I listed above. 

Ed


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## Rain_Frog (Apr 27, 2004)

i took some logs from outside and put it in my giant xenopus tank. Are there any treatments to destroy pathogens in the water, but NOT destroy the bacteria that cycled my aquarium?


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## Ed (Sep 19, 2004)

Typically pieces of wood and bark cannot be disinfected via chemical treatments as organisms can live deep in the wood in cracks and crevices or under bark that prevents the wood from being disinfected. Additionally, wood will absorb the disinfectant and release it slowly over a period of time, potentially resulting in toxic levels. The only way to disinfect the wood of chytrid would be to get all of the wood above 120 F for 4 hours or to dry it until there was no moisture left in the wood. 

I think you could remove the frogs and heat the tank above 120 F for 4 hours and potentially remove any chytrid but it might be better to get the frogs tested via a PCR test (see http://www.open.ac.uk/daptf/declines/decl2.htm ) as the frogs would need to be treated if there is chytrid and disinfecting the enclosure will not help if the frogs are positive. 

Ed


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## dmatychuk (Apr 20, 2005)

> The best treatment involves a buffered itraconazole bath daily for 5 days which so far has always eliminated it from infected frogs. You will need to see a vet to get itraconazole.


Ed, 
I have spoken to my vet and i can't get this in a water soluble mix. Apparently he says it is oil based. He called 2 of his medication suppliers for me asking for it as a water soluble. How do I give them a bath in it if it is a oil based medication? Thanks in advance!

I was thinking of just bringing it to a boil and then pouring on their backs, what do you think?.........just kidding  :lol:


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## melissa68 (Feb 16, 2004)

Dave - great link. 




dmatychuk said:


> DONT RISK IT. Read this.
> 
> http://www.jwildlifedis.org/cgi/reprint/37/1/1


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## dmatychuk (Apr 20, 2005)

I think it was Rob Melancon sent me that link a while back helping with any issue I was concerned over........man I love this board and the members that make it great.


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## Ed (Sep 19, 2004)

Hi David,

Take this to your vet 
http://www.open.ac.uk/daptf/froglog/FROGLOG-46-1.html

With respect to the miscibility, at work, when I make up the solution it makes a cloudy solution which leads me to think that it is the water insoluable stuff. 

Ed


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## Guest (Sep 23, 2005)

Hello we have also a discussion in the Geraman Frog-board (http://www.dendrobatenforum.de) about Chytrid.

Maybe I can post you some results hope my English will be good enough:

1. Most Frogkeepers Vets and biologists are common that nearly 100% of the terrarias are infected with Chytrid.
2. We make a difference between Chytrid-infection and Chytrid-desease.

So we know (or belive to know) that nearly 100% of the frogs in captivity is infected with Chytrid and we know in some cases the desase breaks our and in some not - so what could be the Reasons for an outbreak?

1. sub-optimal keeping
- Keeping one species together with one or more other species will set the immunsystem under preassure - so its easy for the chytrid-desease to break out.
- Stress while the transport 
- Terrarias with a huge popolation on other bakterias and fungis
- bad food - breeded insects include more fad then wild caught and the captive breed insects missing Omega-3-fat-Acids (dont know the exact english word for it hope i am right)
- other infections which are not known or not treated if they have benn known (like parasits and so on)
- missing or bad air-exchange in Terrarias
- missung UV-Light and Infrared-Light (but we are not sure about the last if it will take an effect)

2. other reasons
- changing fro a dry-period to a rain-period in easy words in the dry-period the fungi sleeps and if the rain-period starts the fungi will find better conditions.


So what can frogkeepers do?
1. New frogs need to be seperated form the others for the first time.
2. Diagnostics if the frog is infected with parasites in this time
3. Improving the Captivity-Keeping
4. transporting with less stress as possible
5. Improving the Food - someone in swizerland is working on a new breeding-substrate for fruitflys.

What makes less sense?
1. prohylaktic treatment (we are scared that the fungi could become resistent against itraknonazole)
2. Panic
3. PCR-Methods its relatively new and dosent work well yet. Its still experimental.


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## Rain_Frog (Apr 27, 2004)

Sir, do you have a source for all of this (or somebody that can translate that page for us here)?

But, are we talking about the "new" species of chytrid (the one responsible in the experimental paper shown by Ed Kolowski), or all of them present?

What about temperature as well? I've heard that it comes out more when temps are consistently below 27 degrees Celsius.


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## Ed (Sep 19, 2004)

At this time there is only one type of chytrid that infects amphibians. There are other chytrid but they are harmless to vertebrates. 

snip "1. Most Frogkeepers Vets and biologists are common that nearly 100% of the terrarias are infected with Chytrid. 
2. We make a difference between Chytrid-infection and Chytrid-desease."


I'm not sure why there should be a distinction give the rate of infectivity and the risk of mortality in the amphibians. At this time, I do not think that the evidence supports a 100% infection of terraria (at least in the USA) but the risk is there. 

snip "So we know (or belive to know) that nearly 100% of the frogs in captivity is infected with Chytrid and we know in some cases the desase breaks our and in some not - so what could be the Reasons for an outbreak?"

1) in wild populations, there appears to be a lag between infection and mass mortality of the frogs. In some populations this appears to be as long as three years. This could be one of the reasons why massive deaths have not been seen in captive populations. 

2) temperature, the fungus shows a higher lethality at cooler temperatures which is why most of the deaths in Central and South America have occured at higher alttitudes. There also appear to be spikes in the temperate zones during the spring, fall and winter months as opposed to the summer months. This does not mean that the frogs are not infected, they remain infected but there are peaks in these periods. 

snip "1. sub-optimal keeping 
- Keeping one species together with one or more other species will set the immunsystem under preassure - so its easy for the chytrid-desease to break out. 
- Stress while the transport " endsnip 

Stress can be a problem but if the stress is consistant then the animals typically will adapt to the stressor and the effects vanish as long as the stress remains pretty constant (otherwise the frogs would never adapt to captivity). (for a good review as well as a good bibliography see Health and Welfare of Captive Reptiles by Warwick). 

snip "- Terrarias with a huge popolation on other bakterias and fungis" endsnip

Populations in the soils of bacteria and fungi are normallly huge so unless the enclosure is a sterile one this is an inevitable occurance. 
I maybe misunderstanding this due to the translation issues. 

snip "- bad food - breeded insects include more fad then wild caught and the captive breed insects missing Omega-3-fat-Acids (dont know the exact english word for it hope i am right)"

Do you have any analysis that prove this? Cultured insects do contain levels of saturated fats but I am unaware of any studies that prove the levels of unsaturated fatty acids like omega-3s in wild insects. As far as I can tell there has been very little analyis done on the fat content of wild collected invertebrates that have not been consumed by humans. For example termites contain high levels of cholesterol (see 2002, Nutritional evaluation of terrestrial invertebrates as traditional food in Amazonia, Biotropica 34(2): 273-280). 
. 
snio "- other infections which are not known or not treated if they have benn known (like parasits and so on) " 
- missing or bad air-exchange in Terrarias " endsnip 

As this would increase stress levels, this is a reasonable supposition.

-snip "missung UV-Light and Infrared-Light (but we are not sure about the last if it will take an effect)" endsnip

I am not sure why you would except UV lighting from this. 

snip "2. other reasons changing fro a dry-period to a rain-period in easy words in the dry-period the fungi sleeps and if the rain-period starts the fungi will find better conditions. "

While moisture in the soil will allow for colonization of the substrate and it has been theorized that increased rain levels increase the spread via waterways, the cooler temperatures that come with the rains are more likely to be the problem. The fungus can also be spread via frog to frog contact so hoping that the fungus is dormant is not accurate. 

snip "So what can frogkeepers do? 
1. New frogs need to be seperated form the others for the first time. 
2. Diagnostics if the frog is infected with parasites in this time"

Until diagnosed as clear of the pathogen. 


snip "5. Improving the Food - someone in swizerland is working on a new breeding-substrate for fruitflys. "

There are a lot of different recipes on media for more nutritious fruit flies but the effectiveness of the changes need to be analyzed and this typically is expensive and takes a lot of flies (often a pound (0.5 kg)) to get the analysis done correctly. 

snip "What makes less sense? 
1. prohylaktic treatment (we are scared that the fungi could become resistent against itraknonazole)" end snip

This is a correct idea but as long as the correct regimen is followed this is a relatively low risk at this time. The risk increases if people are not following the correct procedures and do not complete the treatments. Also if they begin to use products for treatments that are not as effective then the risk becomes higher (as microbes typically do not develop resistance to only one drug at a time). 


snip "3. PCR-Methods its relatively new and dosent work well yet. Its still experimental "

Hmm, this contraindicates what I know of the test as we use it at work. Do you have any supporting data? True, as of 2004, it was not that accurate it testing for the specific chytrid in water washes but it works well on tissue samples preserved in 70% ethanol. 
The other confounding factor is that there appears to be more than one fungus in Northern South America (anecdotal reports) that on analysis is not Batrachochytrium dendrobatidis and causing mass mortality of frogs. It is possible that if you are seeing different results in Europe due to the PCR test, that it is due to a novel pathogen. It is possible that one or more of these has been introduced to Europe via imported frogs (smuggled or otherwise). 

Some comments

Ed


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## Rain_Frog (Apr 27, 2004)

ed, is it possible to test water itself for chytrids? Pisces Molecular says they cannot test water, but know of a place that will?


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## Ed (Sep 19, 2004)

In the last publication I saw, the test was not that accurate for water that the frogs were rinsed in or kept in but I do not want to rule out any advances that may have changed that....
I would suggest checking with the company Pisces recommends and see what the rate of success is versus false positives and negatives. 


Ed


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