Chytrid Fungal Infection and Frog Welfare
After reading Chad Brouze’s eye-opening post on frog dissection practices I began investigating broader amphibian welfare. This led me to discover Chytridiomycosis (or chytrid fungal infection), a panzootic currently devastating frog and salamander populations worldwide while causing extreme suffering in the process. It’s hard to get a real sense of scale on the threat that this condition poses to amphibians due to the pace of destruction with severe decline being documented in at least 500 species worldwide. Several extinctions as a direct result of the infection having already occurred. Despite the dire outlook and clear urgency, the research on treatment is underfunded but much of the rudimentary trials in the wild hold potential while being relatively cheap and scalable, at least to my eye. Funding this issue would likely to be a cost-effective way to drastically reduce animal suffering and stave off a biodiversity crash. I intend for this post to be a basic whistle-stop tour of the current literature on the topic to try and convince some folks here to throw some money at the problem. But first, further explanation of the disease and its effects are needed.
Chytridiomycosis in frogs is caused by the fungus Batrachochytrium dendrobatidis (often referred to as Bd).[1] It transfers through cutaneous contact and harms through compromising skin osmoregulation. Hosts display symptoms such as frequent skin sloughing, lethargy, loss of certain reflex action, hyperkeratosis, hyperplasia, ulcers and more. After infection death usually comes within two weeks from cardiac arrest. Needless to say, this process is extremely distressing and painful for the victim. The emotional complexity of amphibians is still debated but stress-related tachycardia plus other nociceptive indicators are commonly agreed upon. Therefore we can conclude that the suffering of the afflicted frogs is objectively extreme and occurring on an immense scale. As stated previously, chytridiomycosis is classified as a panzootic. It has impacted amphibian populations globally causing needless deaths that number in the billions since its discovery in 1998, the reason for such a sudden explosion in cases is still obscure.
There have been several proposed treatments to eliminate Bd in a population, or simply control transmission, but they have had varying success in the field. The list of proposed solutions that I am aware of is as follows.
Chemical disinfection—This is performed through manual application of a fungicide to the skin of amphibians or adding trace amounts to their habitats. Use of itraconazole and tebuconazole generally shows a drastic reduction in infection load for a year or two, before returning to an average. Efficacy also differs depending on time of application, varying based on stage of infection and place in the frog’s life-cycle. Use of fungicide also poses some environmental risks plus slightly higher incidence of developmental disorders in amphibians. This is particularly troublesome considering that frog colonies would need repeated treatments to effectively combat the presence of Bd.
Heat treatments—Bd’s tolerance for variation in temperature is comparatively limited. Heating beyond this limit poses little to no risks to frogs while being extremely effective in eradicating zoospores. However, this treatment is shown to only be effective if maintained for several days in lab conditions. Also, depending on the strain of Bd, heat tolerance can vary so there is the potential for the fungi to develop greater resistance.
Salination—Minor increases in a habitat’s salt content has been shown to drastically reduce transmissions. Completely eliminating Bd in a body of water through this method may require higher doses which may pose risk to delicate freshwater ecosystems.
Bacteria cultures—Exposing amphibians to the bacterium Janthinobacterium lividum led to a steep reduction in infection load due to its antifungal properties, however in all field experiments this figure returned to the average in a few months.
While none of these treatments are an absolute solution if refined or applied together I believe they stand a good chance of reducing infection and mortality by a significant amount. I have no qualifications in animal welfare but I can see a future where conservationists create artificial breeding habitats in the field which are equipped with means of applying the above solutions in tandem with monitoring apparatus. I highly encourage anybody with greater expertise to brainstorm in the comments below.
Also, as a little postscript, even if your approach to cause prioritization makes you inclined to not class animal welfare issues as warranting immediate attention I would make the case that this is an exception. The sudden onset of this disease, its virality, as well as its mortality rate raises concern around fungi-based zoonotic disease. You can read more on the topic in this post by emmannaemeka. Conversations around this tend to get a little infohazard-y so discuss with caution.
Sources used:
In situ treatment of juvenile frogs for disease can reverse population declines—Kimberly Cook et al.
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There is also a related fungus, Batrachochytrium salamandrivorans, which causes chytridiomycosis in salamanders but addressing both of these issues at once is beyond the scope of this post. A post or comment on this in particular would be great if anyone wants to chip in!
Cool to see someone writing about this. I have a few miscellaneous thoughts. For context: I’m the strategy director at Wild Animal Initiative and I was recently on the review panel for Morris Animal Foundation’s call for proposals on amphibian and reptile health & welfare.
Wild Animal Initiative has some unpublished, but hopefully forthcoming work from a former staff member on chytrid as a welfare issue.
Chytrid is basically all anyone is talking about in the amphibian space these days. That has made us (WAI) less interested in funding grants on it, because compared to other wild animal welfare issues, it’s less neglected. I can’t disclose non-public details but if you look at Morris’ database of funded studies you can get a sense of how many amphibian proposals connect to chytrid: https://www.morrisanimalfoundation.org/studies?animal_type=466&study_category=All
That said, I still think this issue is wildly neglected given it’s scale. The fact that WAI doesnt’ really have enough resources to work on this is an illustration of how funding constrained the WAW ecosystem is, not that it doesn’t matter.
I suspect that the cost-effective approach to working on this problem is lobbying to get governments to pay for large-scale treatment & mitigation, rather than trying to intervene at the level of providing care, but I haven’t done any cost-effectiveness analyses on this or anything.
For the sake of pointing out why someone might not prioritize this, though, I should note that folks concerned about net-negative lives might think that amphibians are particularly likely to be in that position because of the high numbers of juveniles that don’t survive to adulthood, and those who worry about suffering of insects might worry that high frog populations contribute to high degrees of insect suffering. So the scale of suffering is much higher than the farming issue raised in the other frog post, but perhaps the externalities are more complicated, if your ethics considers those to be an issue.
Thanks for replying! It’s encouraging to hear about these projects in the pipeline, even if attention isn’t as high as it should be generally. You’ve certainly given me plenty of reading by linking the MAF studies. I’d also be very interested in seeing your former staff’s work when public!
As for lobbying states for funding, it is something that crossed my mind but I didn’t comment on it due to my unfamiliarity with the space. My security-adjacent background and cynicism makes me think you’d be more likely to have success if you sought funding on the basis of zoonotic risk. Maybe my time would be well spent looking for a precedent on this topic. An animal welfare issue that attracts the attention of states with the same scope. Would you happen to have any ideas regarding that? That being said, failing interventions at scale, I still think that smaller welfare projects are worthwhile considering the relatively low cost.
Also, I agree that the k-strategist vs r-strategist divide is perhaps the defining issue of this field. I only hope that we survive long enough as a species with the sufficient technological and moral development to address it. But despite that, I’m inclined to say death by gradual fungal infection is a worse fate than a life lived in the wild. Accepting the former as kinder seems as if it would risk slipping into some anti-natalist thinking which I staunchly oppose. I have similar thinking when comparing insect predation to death by chytridiomycosis. If somebody has research I can read to the contrary I would love to read it. I’m still pretty new to this issue and the field at large.
Thank you very much for writing the post. Albeit unsurprising, it’s somewhat disheartening to see this post being much less popular than the frog slaughter one. I have to say excluding tractability, I probably care about this issue than frog slaughter more.
Do you have a sense of the tractability (which includes making enough people care about this) of this issue, and what can be done to increase it?
Although the scale makes this seem like a gargantuan task I think that having a meaningful impact here is relatively easy. This experiment held in lab conditions used 0.0025 parts itraconazole for every liter of water. Another held in the field on tadpoles used tebuconazole at a concentration of 500 µg L^−1. Even without making habitats that concentrate frog populations and slightly reduce the cost, the price seems pretty negligible for basic disinfection. I haven’t found a figure for the salination experiments but the same goes there too. It would be great if someone with a better head on their shoulders than I ran the numbers on this, but I think with below ten volunteers and a small grant you could save 100,000+ frogs annually with good enough information on where they’re breeding and Bd hotspots. For antifungal treatments it seems that you can get away with maintenance and monitoring on a monthly basis or less, so the working hours required are trivial. Seems to me that its really a matter of organization. But with all this being said, I’m still not sure if this is the most effective approach and further research needs to be done to find a proper solution, but in the interest of reducing suffering all of this seems like it could be actioned tomorrow.
As for getting folks to care about the issue, I think the Shrimp Welfare Project is a good model to follow. People who already have sympathies to suffering-focused ethics just need to be given a sense of scale and the ease of treatment to be driven to action. Also, It’s possible that part of Bd’s rise is due to climate change which makes humanity’s culpability in all of this an open question and might inspire a certain type of environmental activist. Plus, nobody likes animal extinction, so a focus on the most endangered species of amphibian that chytrid infection threatens could be a good way to attract attention and funding.
Thank you for writing this post! I worry it’ll get neglected due to difficulty in measuring the scale of suffering. I agree with @Fai that this might be more important the the slaughter issue.
Thank you for writing this post—I like to keep a mental list of ways conservation and wild animal welfare can work together. Somehow I forgot this fit the criteria.