UK Chytridiomycosis survey (A ZSL/NE partnership)

Chytridiomycosis has apparently been responsible for catastrophic declines in some Australian, North American, Central American, South American and Caribbean species. The situation in Europe is less clear through a lack of data, although some species have seriously declined in upland areas of Spain.

Recently the fungus has been detected in two areas of the UK (coastal Cumbria, and around Canterbury and Tunbridge Wells in Kent), although it is not yet clear whether it is causing population declines here. Both native and introduced amphibians have shown infection and although individuals can be effectively treated with fungicide, this method is likely to be impractical for its control in wild populations.

A nationwide survey in 2008 aims to establish whether the fungus is isolated to the known infected sites or, as is quite feasible, more widely distributed across the country.

NOTE: The chytrid fungus only infects amphibians and poses no risk to humans.

What is Chytridiomycosis?

Chytridiomycosis is a disease that gained attention in late 90s as an explanation for wild and captive population die-offs (Berger et al. 1998,PNAS), and is recognized as a global pathogen of amphibians causing declines and species extinctions.

The disease is caused by a fungus (Batrachochytrium dendrobatidis) that infects the keratinised tissue of amphibians (i.e.the skin of adults and the mouthparts of tadpoles)

Batrachochytrium dendrobatidis has two life stages, an intra-cellular sporangium and a free swimming zoospore.

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How does it kill the amphibian?

The exact mechanism is unknown but currently there are two theories:

• The fungus may release a toxin and so poisons the host.
• Changes to the skin (see diagram below) might interfere with the hosts respiration, ionic balance and water uptake.

Infected skin as seen under a microscope

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So what is being done about it and how can I help?

In collaboration with a number of organisations (Natural England, Herpetological Conservation Trust, Froglife, Amphibian and Reptile Groups-ARG's), the Institute of Zoology is investigating how widespread the chytrid fungus is across the Country. For the majority of the sampling we are using the wealth of experience available amongst voluntary fieldworkers, who will be trained in the appropriate techniques for this study through workshops run by the HCT/ARG's. If you would like to become involved please contact ZSL ( Edward.brede@ioz.ac.uk) in the first instance with your contact details. For additional information on amphibians in the UK contact either of our two NGO collaborators ( Herpetological Conservation Trust , ARG UK )
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So what is involved in the survey and how is it done?

Amphibians are checked for the presence of Batrachochytrium dendrobatidis by swabbing their skin.(Click here swabbing guide bw (0.8 MB) for our guide to swabbing and here for a video and here ARGno4 (147 KB) for our guide to bio-security). This is a quick procedure, with the amphibian being released unharmed straight afterwards at the exact site where it was found. The swab is then sent to the Institute of Zoology where it is screened for the presence of Batrachochytrium dendrobatidis DNA. Gloves are worn throughout the procedure to avoid the spread of disease.

To report unusual amphibian mortality in your garden please see the Froglife disease webpage ( Froglife disease page ) and if necessary complete a frog mortality questionnaire (returning it to the address on the form).

To learn more about the amphibian wildlife in your garden click here ( NE booklet amphibians in your garden ) for the Natural England booklet 'Amphibians in your garden'

In partnership with: