Fighting
the frog
fungus
First discovered in the late 1990s, chytrid fungus infections caused the extinction of almost 100 amphibian species. Now there’s a new version of chytrid doing the rounds and it’s already causing worrying amphibian population declines. Here’s what you need to know and what you can do to help.
by Dr Matt Gray
What is it?
Chytrid is a fungus that attacks the skin of amphibians, and it can be lethal. Infectious chytrid zoospores grow in amphibian’s skin and can be transmitted to healthy individuals through physical contact. Zoospores can also swim through water to infect other nearby amphibians.
And there’s not only one type of chytrid. The first is known as Bd, after the fungus’ scientific name. Since it was discovered in the late 1990s, Bd has caused the extinction of nearly 100 amphibian species, most of which were frogs. The other, newer type of chytrid is Bsal. Discovered in 2012, Bsal is already causing worrying population declines for several salamander species across Europe.
Both pathogens are believed to have originated from Asia. But today, Bd occurs on every continent except Antarctica, and Bsal has been detected in both Europe and Asia.
Something needs to be done
Thankfully a dedicated, multi-disciplinary team is working to tackle the chytrid problem on several different fronts. The project began in 2016 when the US Government banned over 200 salamander species due to the impending threat of Bsal invasion. That’s why the Pet Advocacy Network approached our research team at the University of Tennessee seeking ways to negate the threat of chytrid, leading to the development of the Amphibian Healthy Trade project which comprises experts from five American universities, the Pet Advocacy Network and several US pet businesses.
We know pathogens can be transported great distances via animals in trade, and few countries have regulations or programs to mitigate the spread of chytrid via the pet trade. So the goal of our research is to identify husbandry and shipping conditions that reduce the likelihood of chytrid fungi and other pathogens being spread by the trade.
Josh Willard is the owner of Josh’s Frogs and chair of the Pet Advocacy Network Herp Committee. He says ‘The pet trade has an opportunity to help create solutions that will not only promote healthy, sustainable amphibian pets but also protect amphibians in the wild. We’re really excited to be involved in this initiative.’
Our research is supported by:
For more information visit: www.healthyamphibiantrade.org
Adult orange golden dart frog (phyllobates terribilis)
Credit: Josh’s Frogs
The pet trade has an opportunity to help create solutions that will not only promote healthy, sustainable amphibian pets but also protect amphibians in the wild
Josh Willard, Josh’s Frogs
Finding a solution
The chytrid research project involves distributing fact-finding surveys to businesses and pet amphibian owners, as well as offering free pathogen testing kits to businesses with large amphibian collections. The surveys aim to study common amphibian care practices, and find out if there’s the potential to create demand for pathogen-free amphibians.
Businesses that sign up for testing receive a free sampling kit from the Pet Advocacy Network. Sampling involves swabbing an amphibian’s skin and sending it to one of the participating universities in a pre-paid envelope. The business can then download their test results online – usually within one week. If there is a positive result, that business can speak confidentially with the Pet Advocacy Network for advice. The anonymity part of the process is vital, because businesses are far more likely to work with us to address the issue instead of allowing the fungus to go unchecked and unmanaged. And it’s why we have had such an encouraging uptake of the project. So far, over 400 pet amphibian owners and over 100 US businesses have participated.
Testing a dart froglet for chytrid ranavirus
Credit: Josh’s Frogs
What do we know?
Here are some of the project’s findings so far:
US businesses lose approximately $140 million each year in revenues due to amphibian pathogens.
US businesses and consumers overwhelmingly support trade of pathogen-free amphibians.
US consumers are willing to pay up to 75% more for certified pathogen-free amphibians.
US businesses could increase their profit by at least 25% by selling pet amphibians that are certified negative for chytrid and ranavirus.
The majority of businesses in the US that sell pet amphibians support the creation of a Healthy Trade Certification Program.
Making a difference
During 2023, Pet Advocacy Network and more than 20 US businesses and scientists met to discuss essential components of a Healthy Trade Certification Program for pet amphibians. This group identified four essential components:
online training
biosecurity practices
testing
a required response to positive detection of Bd, Bsal or ranavirus
The certification program was launched in 2024 by a newly created non-profit organisation, Healthy Trade Institute (HTI): healthytrade.org.
Participation in the program is voluntary and businesses that become members of the HTI Certification Program are required to follow the procedures for each of the required components. In return, businesses can use HTI’s Certification Seal and set a premium price for the certified-healthy amphibians they sell.
This accreditation reassures buyers that the animals have verified health, and the business they are buying from is following the HTI program of gold-standard biosecurity and testing practices which reduce the likelihood of purchasing amphibians infected with chytrid or ranavirus. This not only safeguards the health of amphibian pets by reducing pathogens in trade, but also reduces the chance of these pathogens being released into the wild, thereby helping prevent negative impacts on native amphibian species. It’s a win-win situation.
Our research and the HTI Certification Program are in their early stages and there’s still a lot more work to do. We urgently need more collaboration with scientists, businesses and government agencies to ensure the project gets the necessary resources and participation levels. We ultimately need to scale the project internationally, particularly within high-trade areas such as the UK and Europe. And, while the program is starting with pet amphibians, we plan to expand it to reptile health in 2025. It’s a big job that requires a lot of resources, but we’re certainly committed to the challenge.
Wild amphibians win too
Chytrid fungi have devastated amphibian populations globally, causing declines in more than 500 species. Ranaviruses can also infect fish and reptiles and have been linked to rapid die-offs involving possibly thousands of individuals in wild- and captive-populations.
By supporting healthy trade, we help fight the impacts of emerging infectious diseases in trade and ensure conservation of biodiversity for generations to come.
Golden mantella frog perched on a pothos leaf
Credit: Josh’s Frogs
Dr Matt Gray is a professor of disease ecology at the University of Tennessee.
He has studied amphibian diseases for over 20 years, and is the founder of the Global Ranavirus Consortium and the Healthy Trade Institute.
What can you do?
If you’re concerned about chytrid and want to help, here’s what you can do.
US-based amphibian businesses are encouraged to participate in the free testing which can be requested at: www.healthyamphibiantrade.org
We also encourage US businesses to become members of the HTI Certification Program. Membership is available on the HTI website
This is currently a US-based program, but discussions are underway to launch it in other countries. Enquiries can be emailed to Dr Matt Gray, director of the HTI: mgray11@utk.edu
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