Learn about chytridiomycosis
Chytrid disease is believed to be responsible for one of the most significant losses in biodiversity from disease in recorded history.
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What's the issue?
What's the issue?
Chytridiomycosis (chytrid disease) is an emerging infectious disease caused by the fungi Batrachochytrium dendrobatidis (Bd) or B. salamandrivorans (Bsal), known to affect over 350 species of amphibians. Bd appears to impact frogs most severely and Bsal appears to affect salamanders most severely. Bd alone has caused the decline or complete extinction of over 500 species of frogs and other amphibians.
Bd and Bsal are waterborne fungi whose spores travel through water sources until they find a host and enter through the skin.
As there is no vaccine, it is imperative to protect wild amphibian populations through monitoring and treatment.
Impacts on Ecosystems
Impacts on Ecosystems
Originating in southern Asia, amphibian chytrid diseases now are present on every continent except Antarctica. They are believed to have the biggest impact in South and Central America, Australia and North America, where the highest incidence of the disease is in the western United States.
Amphibians live all over the world and many animals rely on them for food, making them an essential part of many ecosystems’ food webs. Their disappearance can have cascading effects on many other species, including humans.
Impacts on Human Communities
Impacts on Human Communities
Amphibians eat millions of insects each year, including those that can spread disease to humans, such as mosquitos.
Amphibians are considered indicator species. Since their permeable skin allows liquids and gases to pass through, they are sensitive to environmental shifts and are early indicators to scientists when an ecosystem is changing.
What is zoo Atlanta doing to help?
What is zoo Atlanta doing to help?
Since 2004, staff at Zoo Atlanta have been heavily involved in amphibian conservation efforts, especially with regards to the two species of chytrid fungus now known to be primary drivers of amphibian declines. Our field-work, lab-work and conservation breeding efforts focus on the southeastern United States and Central and South America. However, our efforts in developing proactive conservation programs and policies are global in scale.
Zoo staff played pivotal roles during the formation of the IUCN Amphibian Specialist Group, the global Amphibian Survival Alliance, as well as the IUCN Amphibian Ark Program.
Zoo Atlanta played a crucial role in developing the Amphibian Ark (AArk), which was launched here in 2007. Operating under several specialist groups of the International Union for Conservation of Nature (IUCN) in partnership with the World Association of Zoos and Aquariums (WAZA), the mission of AArk is to ensure the survival and diversity of amphibian species, focusing on those that cannot be safe-guarded in their natural environments. The AArk network is an integral part of the Amphibian Conservation Action Plan in which select species that could otherwise go exinct are maintained in human care. Zoo staff regularly teach at AArk workshops globally, serve as the Scientific Advisor since 2007, and provide advice and expertise.
AArk provides species prioritization tools, husbandry training, capacity building, recommendations and guidelines for best practices, communications networks, and seed grants to institutions working with rescue operations, confiscations, long-term breeding programs, and projects to reintroduce amphibians back into the wild when and where it is safe to do so.
Additional amphibian conservation efforts at Zoo Atlanta
Additional amphibian conservation efforts at Zoo Atlanta
Development of husbandry protocols for conservation breeding programs for critically endangered amphibians
Producing instructional materials to standardize sampling for amphibian chytrid fungi
Development of emergency response protocols for amphibian rescues
Development of standardized basic protocols for testing and controlling amphibian diseases in conservation breeding program populations
Serving on the national U.S. Task Force for Batrachochtrium salamandrivorans (Bsal)
Serving as a delegate representing zoos at the IUCN Global Amphibian Summit
Helping organize and facilitating IUCN Amphibian Reintroductions workshop.
Helping organize and facilitating Global Loss of Amphibians session at the U.S. National Conference on Science Policy and the Environment as well as presenting summary materials to the U.S. House of Representatives.
Membership in the National Science Foundation’s Research & Analysis Network for Neotropical Amphibians.
Chytrid fungus research at Zoo Atlanta
Chytrid fungus research at Zoo Atlanta
Field surveys for amphibian chytrid fungi and other amphibian pathogens in hellbenders, gopher frogs and other native Georgia species
Disease and population-status monitoring for imperiled amphibians in Mexico, Guatemala and Ecuador
Modelling spread of epidemics of chytridiomycosis across Latin America
Exploring interactions between amphibian chytrid fungi and wild invertebrates
What can you do to help?
What can you do to help?
Although the disease is not known to affect humans, chytridiomycosis is easily spread by human activity. Cleaning boots, clothes and equipment used outdoors in any potential amphibian habitat can help prevent spread between ecosystems.
If you see an amphibian in the wild, leave it there. Wild amphibians should not be moved between habitats, brought into your home, or used as fishing bait. Do not ever release captive amphibians into natural environments as this can spread disease.
If, after thorough research, you have decided an amphibian is a responsible pet choice for you, only purchase captive-bred animals from reliable and ethical sources. Do not purchase wild-caught amphibians as pets.
If you already have amphibians at home, be sure to quarantine any new amphibians until you can confirm they are disease free. Also make sure to properly disinfect and dispose of anything coming out of an enclosure housing amphibians rather than dumping these items outside.
Support programs and policies which limit and control the movement of animals around the globe – chytrid disease was spread via global trade of amphibians.
Get involved with local environmental clean-up programs for wetlands and other amphibian habitats. Consider creating a wetland habitat, such as a pond, in your backyard.
Try to manage your outdoor space without using pesticides, fertilizers or weed killers, all of which are poisonous to amphibians. If you must use these products, be sure to follow the instructions carefully to avoid overuse. Consider growing native plants that will naturally require less fertilizer as well as less water.
Additional Information
Additional Information
In the United States, chytrid disease has been confirmed in 46 of the 50 states. Currently, the American bullfrog and African clawed frog (a non-native species that has become established in several states) appear to be resistant but may still act as carriers.
In the wild, most outbreaks occur at higher elevations during cooler months.
Susceptibility to chytrid disease is both species and life stage specific. Some species appear to be relatively tolerant across life stages, while other species are more susceptible at different stages of development.
Clinical signs vary but may include abnormal feeding behavior, anorexia, lethargy, excessive shedding of the skin, discoloration of the skin, convulsions, and lack of the righting reflex (a reflex that corrects orientation after the body has been moved out of the normal, upright position). Secondary skin infections can also occur.
The exact cause of chytrid-induced mortality is cardiac arrest, related to the disruption of the water- and electrolyte-balancing functions of the skin function. All aspects of the disease are active areas of research for disease ecologists and conservation biologists.
Animals in human care can be treated with antifungal medications and heat therapy.
Amphibians are the most endangered group of animals on the planet. One-third to one-half of all amphibian species are threatened with extinction, with more than 120 species already extinct.
Recommended resources for additional information
Recommended resources for additional information
References
References
About Us. (n.d.). Amphibian Ark. Retrieved on May 12, 2020 from http://www.amphibianark.org/
Amphibian Ark. (n.d.). Zoo Atlanta. Retrieved on May 12, 2020 from https://zooatlanta.org/project/amphibian-ark/
Chytridiomycosis Disease Fact Sheet [PDF]. (n.d.). Cornell Wildlife Health Lab. Retrieved on May 12, 2020 from https://cwhl.vet.cornell.edu/disease/chytridiomycosis
Daugherty, M. (n.d.). Chytrid Fungus. Center for Invasive Species Research, University of California Riverside. Retrieved on May 12, 2020 from https://cisr.ucr.edu/invasive-species/chytrid-fungus
How You Can Help. (n.d.). Amphibian Ark. Retrieved on May 12, 2020 from http://www.amphibianark.org/support-us/what-can-i-do-to-help/
Mendelson III, J. (2020). Chytrid Research and Conservation Efforts at Zoo Atlanta. [Word Document].
Scheele, B. C., et al. (39 co-authors). 2019. The aftermath of amphibian fungal panzootic reveals unprecedented loss of biodiversity. Science 363:1459–1463. Retrieved 20 May 2020 from Scheele, B. C., et al. (39 co-authors). 2019. The aftermath of amphibian fungal panzootic reveals unprecedented loss of biodiversity. Science 363:1459–1463
Stabile, J. & Mendelson III, J. June 2018. Perspectives in Conservation: Joseph R. Mendelson III. Herpetological Review, 49(2), 271-274. Retrieved from https://www.researchgate.net/publication/327278781_Perspectives_in_Conservation_Joseph_R_Mendelson_III
Why we do it. (n.d.). Amphibian Foundation. Retrieved May 12, 2020 from https://www.amphibianfoundation.org/index.php/pages
Updated May 2020
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