Risk Assessment of Chytridiomycosis to European amphibian biodiversity
Total Grant

€ 1,569,444

Consortium partners

School of Public Health, Imperial College London, UK — Coordinator: Matthew C. Fisher

Institute of Zoology, Zooligcal Society of London, UK Experimental Ecology Centre of Moulis,

CNRS, France

Laboratory of Alpine Ecology, CNRS/University of Grenoble/University of Savoie, France

Helmholtz Centre for Environmental Research, Germany

Dept. of Biogeography and Global Change, National Museum of National Sciences, Spain


The RACE team had found that an emerging infectious pathogen, Batrachochytrium dendrobatidis (Bd), poses a widespread threat to amphibians in Europe. The disease chytridiomycosis, caused by Bd, was previously undiagnosed and yet had already caused population declines and extinction in amphibians worldwide. The RACE team aimed at:
1. Assessing the risk that this invasive infectious disease poses to European amphibians; and
2. Implementing the first pan-European attempt to mitigate it.


The RACE team used field-data and next-generation sequencing to identify the disease’s lineages present in Europe and to understand its vectors of introduction and spread, as well as environmental conditions influencing the impact of this disease. A total of 226 sites in 12 countries (www.bd-maps. net) were studied. These findings then fed a risk assessment. RACE also developed mapping tools to build a live-representation of the diseases’ spread and disinfection protocols, which were used to propose and test a European Threat Abatement Plan. The RACE team invested significant efforts in working with policy-makers from local to European level in order to use the outputs of the project and influence the development of appropriate policy at both scales.

Main academic findings

• RACE mapped the Bd distribution in Europe and demonstrated the widespread of the disease.
• The most vulnerable amphibian species and geographical regions were determined, as well as the most likely vectors (mainly three Bd- asymptomatic species) and pathways (global trade of live specimens intended to serve as pets, for biomedical research or consumption) for the disease in Europe.
• Bioticandabioticfactorsleadingtotheemergence of the disease were described and modelled.
• Five different lineages of Bd were identified, three in wild and two in captive specimens, which vary in virulence. This explained the increasing Bd impact in Europe while major declines are observed in the USA, Central America and Australia, and gave clear evidence of the role of global trade in spreading the disease.

The RACE team identified a suite of environmental- and host-dependent variables (in particular ultraviolet radiation and temperature for environmental variables, and Bd genotype and microbial water community composition for biological variables) determining the viability of an infected amphibian population. By manipulating these factors, they could successfully mitigate the disease’s impact on European amphibian populations, and in some cases obtained complete eradication of the pathogen, for example on the island of Mallorca.

Academic results highlight

Part of the project, RACE produced a synthesis on emerging fungal threats*. In particular, the authors documented the increasing occurrence of pathogenic fungi of plants and animals during the last 15 years and the spread of occurrence (see Figure). They also reported that the number of species extinction and/ or extirpation events due to fungal pathogens has broadly increased since 2000 mainly for animals (see red curve in top right panel of the Figure).

* Fisher MC et al. (2012) Emerging fungal threats to animal, plant and ecosystem health. Nature 484: 186- 194

Stakeholder engagement and product relevant to society/policy

• RACE informed a broad number of stakeholders on the threat Bd poses to amphibians, in particular NGOs in nature conservation, local and national policy-makers and the general public (see Figure).
• Training sessions with protected area managers were organised in France, Italy and the UK, leading to the adoption of strategies for standard hygiene protocols of the project to limit the spread of Bd.
• A number of NGOs were either consulted or involved in the project, for example through participation in the UK Amphibian Specialist Group.
• The project organised a multi-stakeholder workshop in Brussels with key European and international policy-makers and NGOs (e.g. several DGs from the European Commission, CITES Animal Committee, Amphibian Survival Alliance) to present project outputs and identify gaps in the international legislation and opportunities in the preparation of the EU Animal Health Law.

RACE produced a set of tools adapted for use by their stakeholders in a proactive manner:
• Maps of Bd distribution (http://www.bd-maps.net/maps/), a citizen alerting system in France, and hygiene protocols were all designed to fulfill the needs of protected area managers;
• Policy recommendations summarized in a RACE policy brief supported by BiodivERsA (http://www.biodi- versa.org/552).

Highlights on society/policy-relevant products

• The European Threat Abatement Plan under development by RACE is an analysis of possible responses to the disease spread embedded in the context of EU and international legislation for wildlife trade, invasive species, and animal health, including a set of concrete recommendations to policy-makers. It is currently being completed with the new chytrid salamander-destroyer, Batrachochytrium salamandrivorans, that is emerging in Belgium and the Netherlands (for a preview see https://www.biodiversa.eu/2022/10/06/wildlife-diseases-on-the-increase/
• Protocols for mitigation and remediation in specific sites were developed and tested. These allowed progress in mitigating the burden of infected populations and in some cases completely cleared the infection.
• Standard hygiene protocols to reduce spread by humans were adopted to limit anthropogenic spread of Bd in French regional and national parks and in la Sierra de Guadarrama National Park (Spain).