# Chytrid in CR/Panama Pumilio Populations



## austin (Dec 6, 2013)

Might have been discussed already but I could not find it using the search.

My question is what has the general impact of chytrid been on pumilio populations? Same question for ranavirus.


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## Ed (Sep 19, 2004)

austin said:


> Might have been discussed already but I could not find it using the search.
> 
> My question is what has the general impact of chytrid been on pumilio populations? Same question for ranavirus.


Unknown but suspected to not be significant for chytrid as it normally doesn't kill frogs unless the temperature is consistently below 75 F. 

some comments 

Ed


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## austin (Dec 6, 2013)

Thanks Ed, love the simple and straightforward answer! That's good 


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## rmp (Oct 28, 2015)

Dart frogs in general seem not to be affected by the chytrid so much (although recen reports seem to imply otherwise). It isn't uncomon for them to be asymptomatic vectors of the fungus and bring it into captive collections.


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## austin (Dec 6, 2013)

In the wild populations do their toxins provide any increased resistance to the fungus or other maladies?


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## Ravage (Feb 5, 2016)

rmp said:


> Dart frogs in general seem not to be affected by the chytrid so much (although recen reports seem to imply otherwise). It isn't uncomon for them to be asymptomatic vectors of the fungus and bring it into captive collections.


Do you know if life stage has any effect on susceptibility? I think I read that keratin in tissues is the vulnerable point. So only the lips are infected until after emergence from the water.
We have a local post on Facebook (I know, why would anyone look for info on Facebook?) about a possible chytrid infection in one local breeder wiping out his stock. Dart Frogs.This is mentioned mostly in specimens purchased from him that are being reported as dying right after metamorphosis, or just prior to. I don't like hysteria and snap diagnoses: as this might effect everyone here who breeds.
I mean, who needs facts right?
I like facts. Got any?


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## Ed (Sep 19, 2004)

rmp said:


> Dart frogs in general seem not to be affected by the chytrid so much (although recen reports seem to imply otherwise). It isn't uncomon for them to be asymptomatic vectors of the fungus and bring it into captive collections.


Actually this is incorrect, how did you think it was identified as Batrachochytrium *dendrobatidis*? It was first isolated from Dendrobates and they are absolutely sensitive to it. 

The only reason we don't see huge mortality events for species like pumilio is that most of their populations are found in areas where the temperature is frequently above 75 F. The lethality of Bd has been shown to be directly related to temperature, the lower the temperature the more lethal the fungus. At temperatures above 78-80 F mortality approaches zero and frogs that bask or are able to better resist the fungus so any attempt to indicate that dart frogs seem to be less affected by it is a fundamentally false premise. This has been discussed repeatedly on the forum and includes references to the literature to that effect. 

Some comments 

Ed


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## Ed (Sep 19, 2004)

austin said:


> In the wild populations do their toxins provide any increased resistance to the fungus or other maladies?


There is some recent literature that indicates some of the alkaloids can have antimicrobial activity but this varies greatly with the alkaloids (and these vary enormously between geography and time) and as a result the various populations vary greatly in their ability to defend against microbes via skin secretions. 
Not free access but see Mina, Annemarie E., et al. "Variation in alkaloid-based microbial defenses of the dendrobatid poison frog Oophaga pumilio." Chemoecology 25.4 (2015): 169-178.

some comments 

Ed


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## Ed (Sep 19, 2004)

Ravage said:


> Do you know if life stage has any effect on susceptibility?


Tadpoles of several species have shown variations in the ability to survive an infection with Bd leading the idea that fungus also produces a toxic factor in addition to disrupting the ability to osmoregulate. 

See for example 
Blaustein AR, et al. (2005) Interspecific variation in susceptibility of frog tadpoles to the pathogenic fungus Batracbochytrium dendrobatidis. Conserv Biol 19(5):1460–146

In species where the tadpoles are resistant there is often a high mortality in metamorphs, juveniles and adults. 




Ravage said:


> bout a possible chytrid infection in one local breeder wiping out his stock. Dart Frogs.This is mentioned mostly in specimens purchased from him that are being reported as dying right after metamorphosis, or just prior to. I don't like hysteria and snap diagnoses: as this might effect everyone here who breeds.


Did people perform proper quarantine with screening for parasites? Has anyone bothered to get a PCR test done for ranaviruses and chytrid? Has anyone had necropsies performed? 


There are multiple potential causes for this kind of event as for example is everyone who is experiencing mortality keeping the animals below 78 F? 

You would have to be able to rule out nutritional issues as well as other pathogens. 
some comments 

Ed


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## rmp (Oct 28, 2015)

Although what you describe could match some reports from the literature (eg. Marantelli et al. 2004. Distribution of the amphibian chytrid Batrachochytrium dendrobatidis and keratin during tadpole development. Pacific Conservation Biology 10(3) 173 - 179, who found that infection happened early after hatching but only killed the frogs as metamorphs), I agree with Ed. There are many other explanations to this.


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## The Frog Breeder (Sep 28, 2016)

Bocas del Toro, a Province here in my country, has many different islands with different populations (morphs) of O. pumilio. I have not worked with this species directly, but colleagues tell me that some populations have had a decline (i.e. Red frog island). I will check on that more and see. Chytrid is more lethal in higher elevations due to lower temperatures, but some populations are particularly susceptible to the chytrid fungus (i.e. lowland A. limosus, A. varius and A. zeteki) even with higher temperatures. Some dendrobatid species like Andinobates minuta have had entire populations gone, mostly at the specie's higher range, but these species lives on elevations lower than 1000m, even at 200m, 180m. And when chytrid got to the area, boom... GONE, pretty fast. A. minuta used to be a fairly common species, now its rather a rare find (if you find it at all). 

I hope this helps to further the discussion. This is also my first post, I hope I make good friends and help a lot in this forum. I am sure I will LEARN A LOT, many experienced people here.

cheers


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## Encyclia (Aug 23, 2013)

SamFrogs said:


> Bocas del Toro, a Province here in my country, has many different islands with different populations (morphs) of O. pumilio. I have not worked with this species directly, but colleagues tell me that some populations have had a decline (i.e. Red frog island). I will check on that more and see. Chytrid is more lethal in higher elevations due to lower temperatures, but some populations are particularly susceptible to the chytrid fungus (i.e. lowland A. limosus, A. varius and A. zeteki) even with higher temperatures. Some dendrobatid species like Andinobates minuta have had entire populations gone, mostly at the specie's higher range, but these species lives on elevations lower than 1000m, even at 200m, 180m. And when chytrid got to the area, boom... GONE, pretty fast. A. minuta used to be a fairly common species, now its rather a rare find (if you find it at all).
> 
> I hope this helps to further the discussion. This is also my first post, I hope I make good friends and help a lot in this forum. I am sure I will LEARN A LOT, many experienced people here.
> 
> cheers


Thanks for this information, SamFrogs, and welcome to the board! I hit the like button because I like that you shared the information, not because I liked the sad information you shared :-(

Mark


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## Frogsarefun (Nov 25, 2015)

Welcome SamFrogs, great to have on the site !


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## viper69 (Dec 28, 2013)

SamFrogs said:


> Bocas del Toro, a Province here in my country, has many different islands with different populations (morphs) of O. pumilio. I have not worked with this species directly, but colleagues tell me that some populations have had a decline (i.e. Red frog island). I will check on that more and see. Chytrid is more lethal in higher elevations due to lower temperatures, but some populations are particularly susceptible to the chytrid fungus (i.e. lowland A. limosus, A. varius and A. zeteki) even with higher temperatures. Some dendrobatid species like Andinobates minuta have had entire populations gone, mostly at the specie's higher range, but these species lives on elevations lower than 1000m, even at 200m, 180m. And when chytrid got to the area, boom... GONE, pretty fast. A. minuta used to be a fairly common species, now its rather a rare find (if you find it at all).
> 
> I hope this helps to further the discussion. This is also my first post, I hope I make good friends and help a lot in this forum. I am sure I will LEARN A LOT, many experienced people here.
> 
> cheers



Great info, thank you very much.


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