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  • Writer's pictureCésar L. Barrio-Amorós CRWild




Although there is a clear trend towards adopting biosecurity protocols when handling amphibians, there are still many people who are unaware of them or choose to ignore them for various reasons. But what do these protocols indicate, and why is it important to understand and follow them?

First of all, it is necessary to understand several factors. Firstly, how an amphibian works. We know that amphibians (class AMPHIBIA) are the only vertebrates whose skin is not protected by any external layer (such as scales, feathers, or fur), but is completely naked and usually moist (except toads). So, how do they protect themselves from external pathogens? Many of them have elaborate protections against bacteria, viruses, and fungi in the form of natural antibiotics on their skin, which, due to millions of years of adaptation to their biomes, work well and are actually being studied as possible antibiotic compounds for humans. However, amphibians do not possess this natural protection against all pathogens, and even less so nowadays, when those pathogens travel at incalculable speeds (obviously aided by humans). If a frog has evolved protection against pathogenic fungi it coexists with for millions of years, what happens if humans (accidentally and unintentionally) transfer and introduce a fungus from another area into the frog's habitat? Well, it can become pathogenic, and the frog will die, as it is not adapted and has not had time to develop protection through its skin.


But why would humans want to do that, bringing new pathogenic fungi to where they did not exist? It's not that we want to, it's that we don't realize it. Fungi, as well as other invisible pathogens (bacteria and viruses), are in the environment, and generally, all organisms that coexist with them are adapted and therefore do not die. The same case happened in the conquest of America. It wasn't 200 Spanish soldiers who wiped out entire empires, but the viruses and bacteria they carried, to which they were adapted, but not the native inhabitants. In the same way, the infamous chytrid fungus was unintentionally introduced in multiple places around the world by people who never wanted to harm those animals.

In the 1980s and 1990s, researchers began to gather pieces of the puzzle, assembling the mystery and starting to determine that in many areas of the planet, amphibians that were once common had disappeared or were rapidly disappearing. Even one researcher predicted how a wave (tsunami effect) of this pathogenic fungus, which was only described in 1999, would wipe out almost entire populations of amphibians in Costa Rica and Panama. Currently, the fungus is distributed worldwide. After devastating extinctions of multiple species (many of them in the Neotropics = Latin America), it seems that this fungus is no longer so catastrophic, or rather, survivors of many species that greatly reduced their numbers have been able to adapt and in some cases are recovering. But the numbers are shocking. For example, in our research on Atelopus varius in Costa Rica (Barrio-Amorós et al. 2021), we have seen that out of 166 known populations before the disaster, only 8 currently survive, and perhaps only one is completely out of the danger of extinction.


But the problem is not only this zoonosis (=pandemic), but currently, many more people are in the field, in nature, going further, and can spread many diseases that can affect amphibians or other organisms, without knowing it. Nobody knows what a human carries with them, but you can be sure that millions of bacteria, fungi, and viruses inhabit our skin, which are not harmful to us, but can be harmful to other beings that are not adapted.

Therefore, we have to be cautious, we already know that pandemics happen, whether at the human or animal level. And with a foolish oversight, we can unintentionally carry pathogens to other places. If we like frogs and touch one, and then another, remember that they have no type of protective skin, what we can do is transfer a pathogen from a sick one to a healthy one. Or we can simply transmit a new virus that doesn't affect us as humans at all, but jumps to a new host, e.g. a salamander, and it reproduces with another and at the same time transmits the infection.

In short, to avoid going on for too long, the summary is: if we love amphibians, we should be the first to try to protect them. We should not touch them, grab them, or play with them. Think about how many infections someone can carry by handling one frog after another, a toad, a salamander, or among them. Only people conducting research with permits from their respective countries should be allowed to handle them. But in such a case, anyone who needs to touch an amphibian for any reason (rescue it from a place where it shouldn't be, save it from a domestic animal, etc.) should do so with latex or talcum-free nitrile gloves, or with a clean plastic bag. Never directly with bare hands.


In cases such as showing an amphibian for a documentary, especially if it is for educational purposes, it is imperative and the only way to demonstrate professionalism is to do it with nitrile gloves. Any other method should not be acceptable.


Of course, this creates another problem. If we use gloves or plastic bags for each frog, and each one is for single use, we will be contributing significantly to the generation of more waste. On the other hand, there are multiple ways to handle waste. Personally, I put used gloves in plastic bottles of water or soda until they can no longer fit one more, and I save them for reuse or donate them to someone who builds with this recycled material. There are countries where these rubber products are recycled.

Another important protocol to follow, especially if you are going to enter an area where an endangered species lives or could potentially live, is to disinfect boots, tools, and clothing that will be brought in.

Table 1 reproduces the biosecurity protocols for amphibians approved by the Chilean Herpetology Network, applicable to any country. However, some products may not be easy to find in your region, so in general, for plastic, rubber, or metal items, 4% chlorine or virkon is valid.

Table 1. Suitable strategies for the elimination of Batrachochytrium dendrobatidis and Ranavirus in field studies. Taken from Lobos et al. (2011).


Aguirre, A. & M. Lampo. 2006. Protocolo de bioseguridad y cuarentena para prevenir la transmisión de enfermedades en anfibios.  En: Angulo, A., J.V. Rueda-Almonacid, J.V. Rodríguez-Mahecha, E. La Marca: Técnicas de Inventario y Monitoreo para los Anfibios de la Región Tropical Andina. Conservation International.

Barrio-Amorós.  C.L., G. Chaves & R. Puschendorf. 2021. Current Status and Natural History of the Critically Endangered Variable Harlequin Toad (Atelopus varius) in Costa Rica. Reptiles & Amphibians 28: 1-15.

Lobos, G.A., M. Vidal, M.A. Labra, C. Correa, F. Rabanal, H. Díaz-Páez, A. Alzamora y C. Soto. 2011. Protocolo para el control de enfermedades infecciosas en Anfibios durante estudios de campo. Red chilena de herpetología.


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