Frog Chytrid fungus
Scientists think the decline and disappearance of some frogs species in Australia and overseas may be partly due to a disease caused by a Chytrid fungus.
The fungus attacks the parts of a frog's skin that have keratin in them. Since frogs use their skin in respiration, this makes it difficult for the frog to breathe. The fungus also damages the nervous system, affecting the frog's behaviour.
A sick frog may:
- have discoloured skin
- be sloughing, or peeling, on the outside layers of its skin - this can vary from obvious peeling of skin (particularly on the feet), to a roughness of the frog's skin that you can barely see
- sit out in the open, not protecting itself by hiding
- be sluggish, and have no appetite
- have its legs spread slightly away from itself, rather than keeping them tucked close to its body. In more extreme cases, the frog's body will be rigid, and its back legs will trail behind it.
fungus is probably transferred by direct contact between frogs and tadpoles, or through exposure to infected water. The disease may not kill frogs immediately, and they can swim or hop to other areas before they die, spreading fungal spores to new ponds and streams. This means it is very important not to move frogs from one area to another.
Wet or muddy boots and tyres, fishing, camping, gardening or frog-survey equipment may also be contributing to the spread of the disease.
Help stop the spread of Chytrid fungus
Please take the following precautions if you intend visiting frog habitats in the wild, including nature ponds in parks or gardens:
- Only touch frogs when absolutely necessary. Remember to use disposable gloves, sample bags and sterile equipment.
- Clean and dry all equipment and wet or muddy footwear before and between visiting frog sites. This may include cleaning the tyres of your vehicle before visiting known high-risk sites where threatened frog species may live.
- Never move a frog from one area to another.
- Carry cleaning utensils and a disinfectant for use between sites.
You'll find more details, particularly for frog researchers, managers and keepers, in the NPWS Hygiene Protocol for the Control of Disease in Frogs (PDF - 1.6MB).
What to do if you find a sick frog
Some of the symptoms of Chytrid fungal infections are described above. If you think you've found a sick frog, or if you see a frog which has died recently from no obvious cause (ie. not killed by a car), please:
1. Place the frog into a container without directly touching it.
2. If the frog is still alive, make sure the container is escape-proof and has a few small air holes and a small amount of water. Ring the Frogwatch Helpline on 0419 249 728 for an opinion on whether the frog is sick or whether it is likely to survive transportation. If the frog is dead, put the container into a plastic bag and into your freezer as soon as possible.
3. Consult the Frog Hygiene Protocol (PDF- 1.6MB) or visit the James Cook University Amphibian Diseases Website for instructions on how to send frozen or live frogs by courier to a laboratory and how to be reimbursed by OEH for your expenses.
(PDF- 1.6MB) or visit the for instructions on how to send frozen or live frogs by courier to a laboratory and how to be reimbursed by OEH for your expenses.
Infection of frogs by amphibian chytrid causing the disease chytridiomycosis - key threatening process listing
The NSW Scientific Committee has declared amphibian chytrid infection to be a 'key threatening process' in NSW. See its reasons for making this declaration.
Keratin in a frog's skin: how Chytrid fungus spreads
Find out what keratin is, and where it's found in a frog. See how Chytrid fungus attacks these parts of the frog's body.
Page last updated: 15 April 2011