A REVIEW OF THE CURRENT KNOWLEDGE ON AMPHIBIAN CHYTRIDIOMYCOSES AND THEIR EPIDEMIOLOGY IN EASTERN EUROPE

Abstract

Amphibian chytridiomycoses are emerging fungal diseases caused by Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). They pose a significant threat to amphibians worldwide, driving catastrophic species declines and extinctions with knock-on impacts on the ecosystem and human health. This review examines the expanding distribution of Bd and Bsal, with a focus on Eastern Europe. Advances in diagnostics - including histopathology, PCR, and environmental DNA detection -, including their strengths and limitations, are discussed. This review considers morphological characteristics, pathogen life cycles, mechanisms of pathogenesis, and clinical signs useful for guiding infection and disease detection. Innate and acquired host immune responses in response to Bd and Bsal infection are discussed within the context of host resistance and tolerance. Finally, potential transmission routes are explored, with a focus on the role the pet trade plays in pathogen spread, and current treatment and mitigation approaches for both wild and captive amphibians are summarised. Insights into the epidemiology of Bd and Bsal and environmental factors influencing pathogen spread and resistance can inform proactive conservation and disease management strategies essential for protecting at-risk amphibian populations.