Microplastics increase susceptibility of amphibian larvae to the chytrid fungus Batrachochytrium dendrobatidis

Jaime Bosch,Matthew C Fisher,Naiara López-Rojo,Barbora Thumsová,Alberto Alonso,Luz Boyero,Javier Pérez

doi:10.1038/s41598-021-01973-1

Abstract

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. In tandem, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causing the disease chytridiomycosis is emerging worldwide as a major stressor to amphibians. We here assess whether synergies exist between this infectious disease and MP pollution by mimicking natural contact of a highly susceptible species (midwife toads, Alytes obstetricans) with a Bd-infected reservoir species (fire salamanders, Salamandra salamandra) in the presence and absence of MPs. We found that MP ingestion increases the burden of infection by Bd in a dose-dependent manner. However, MPs accumulated to a greater extent in amphibians that were not exposed to Bd, likely due to Bd-damaged tadpole mouthparts interfering with MP ingestion. Our experimental approach showed compelling interactions between two emergent processes, chytridiomycosis and MP pollution, necessitating further research into potential synergies between these biotic and abiotic threats to amphibians.

Highlights

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern
The emergence of Batrachochytrium dendrobatidis (Bd) and chytridiomycosis worldwide is emblematic of the potential for endemic hotspots of infection to become globalised through anthropogenic processes[33]
This showed that MPs accumulated to a greater extent in tadpoles that were not exposed to Bd

Summary

Introduction

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. When external to the individual, MPs are known to interact with chemical pollutants, which could potentially increase the bioavailability of MPs or the organisms’ vulnerability to them[10,13,14], as well as perhaps serving as physical vectors for the dispersal of pathogens[15,16] Despite their known impacts on biota, there is virtually no information about whether MPs influence the dynamics of infectious diseases in freshwater e cosystems[17]. A relevant system within which to explore potential interactions between infectious disease and MPs are amphibians and the aquatic chytrid fungus Batrachochytrium dendrobatidis (Bd). If interactions between the two do occur, these synergies may alter the epidemiology of chytridiomycosis

Methods

Results

Conclusion