Batrachochytrium dendrobatidis



Conservation status

Not Assessed


Invasive species - risk of High Impact

Irish status


Introduction pathways - 1

Transport Contaminant

Introduction pathways subclass - 1

Parasites on animals

Invasive score


NAPRA Ireland risk assessed


Species Biology


A fungus it is an external parasite of amphibians. Clinical signs in Australian frogs with chytridiomycosis were lethargy, loss of appetite, skin discolouration, presence of excessive sloughed skin, and sitting unprotected during the day with hind legs held loosely to the body (Berger et al., 1999). Positive identification of the fungus requires specialist skills.


Low host specificity it infects at least 14 families and over 100 species of amphibians (Cunningham et al., 2005). Potential to decimate Irish amphibian populations.


Flagellated (tailed) zoospores of Batrachochytrium are waterborne, can live for over 24 hours and are infective to frogs and tadpoles (Berger et al., 1999).

Pathway and vector description

Likely to be introduced with amphibian species, such as Alytes obstetricans, Xenopus laevis or Rana catesbeiana.

Mechanism of impact


Habitat description

Ectoparasite on amphibians.

Species group


Native region



World distribution(GBIF)

Native distribution

Not established conclusively established where the species is native to. Only described in 1998  there are three theories surrounding its origin and effects (in increasing order of likelihood) 1) Unlikely - Widespread globally and the regions affected and the amphibian deaths and declines attributed to it have only recently been discovered, i.e. unrecorded; 2) Possible - Widespread globally and endemic and has recently become pathogenic, i.e. something has changed in the disease or the environment to make the disease more effective or the amphibians more susceptible to the disease, or 3) Possible - Only recently been introduced into new areas, with a likely source South Africa, or less likely Japan (Berger et al., 1999; Cunningham et al., 2005, Daszak et al., 1999).

Temporal change

Records submitted to Data Centre in 2019

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How can you help

Report any sightings of dead or diseased frogs to the National Biodiversity Data Centre. Do not allow non-native amphibian species to be introduced into the wild.

Further information

Invasive Species Specialist Group (ISSG) of the SSC- Species Survival Commission of the IUCN -International Union for Conservation Nature 100 Worst Invaders globally. Delivering Alien Invasive Species In Europe (DAISIE) project list this species as one of its 100 worst invaders.



Daszak, P., Berger, L., Cunningham, A. A., Hyatt, A. D., Green, D. E., & Speare, R. (1999). Emerging infectious diseases and amphibian population declines. Emerging infectious diseases, 5(6), 735. Fisher, M. C., & Garner, T. W. (2007). The relationship between the emergence of Batrachochytrium dendrobatidis, the international trade in amphibians and introduced amphibian species. Fungal Biology Reviews, 21(1), 2-9. Berger, L., Speare, R., & Hyatt, A. (1999). Chytrid fungi and amphibian declines: overview, implications and future directions. Declines and disappearances of Australian frogs. Environment Australia, Canberra, 1999, 23-33. Cunningham, A. A., Garner, T. W. J., Aguilar-Sanchez, V., Banks, B., Foster, J., Sainsbury, A. W., Perkins, M., Walker, S.F., Hyatt, A.D., & Fisher, M. C. (2005). Emergence of amphibian chytridiomycosis in Britain. Veterinary Record, 157(13), 386.

Global Invasive Species Database

BD-Maps - A project for mapping the global spread of the species

CABI Datasheet