Field-based molecular detection of Batrachochytrium dendrobatidis in critically endangered Atelopus toads and aquatic habitats in Ecuador

PLoS One. 2024 Mar 14;19(3):e0299246. doi: 10.1371/journal.pone.0299246. eCollection 2024.

Abstract

Batrachochytrium dendrobatidis (Bd) is a lethal fungal species that parasitizes vertebrates and is associated with the worldwide decline of amphibian populations. The development of sensitive, rapid detection methods, particularly DNA-based techniques, is critical for effective management strategies. This study evaluates the efficacy of DNA extraction and a portable PCR device in a mountable field laboratory setup for detecting Bd near the habitats of three critically endangered Atelopus toad species in Ecuador. We collected skin swabs from Atelopus balios, A. nanay, and A. bomolochos, and environmental DNA (eDNA) samples from streams in Andean and coastal regions of Ecuador. For eDNA, a comparison was made with duplicates of the samples that were processed in the field and in a standard university laboratory. Our findings revealed Bd detection in eDNA and swabs from 6 of 12 water samples and 10 of 12 amphibian swab samples. The eDNA results obtained in the field laboratory were concordant with those obtained under campus laboratory conditions. These findings highlight the potential of field DNA-based monitoring techniques for detecting Bd in amphibian populations and their aquatic habitats, particularly in remote areas. Furthermore, this research aligns with the National Action Plan for the Conservation of Ecuadorian Amphibians and contributes to the global effort to control this invasive and deadly fungus.

MeSH terms

  • Amphibians / microbiology
  • Animals
  • Batrachochytrium / genetics
  • Bufonidae / genetics
  • Chytridiomycota* / genetics
  • DNA
  • DNA, Environmental*
  • Ecosystem
  • Ecuador
  • Humans

Substances

  • DNA
  • DNA, Environmental

Grants and funding

CVdH: “Networks 2019 phase 2 Ecuador biodiversity project”, the VLIR-UOS South Initiative ZEIN 2014Z15. CVdH, JC, JB, HMOA: “DNA-based monitoring for assessing the effect of invasive species on aquatic communities in the Amazon basin of Ecuador”, the VLIR-UOS South Initiative EC 2020 SIN 277B125 “Biomonitoring of aquatic environments in the Amazon using environmental DNA” HMOA: “Conservation of Ecuadorian Amphibians and access to genetic resources-PARG” managed by the Ministry of Environment and Water of Ecuador; Project “On the quest of the golden fleece in Amazonia: The first herpetological DNA - barcoding expedition to unexplored areas on the Napo watershed, Ecuador”, funded by the Secretaría Nacional de Ciencia y Tecnología del Ecuador (Senescyt-ENSAMBLE Grant #PIC-17-BENS-001), The World Academy of Sciences (TWAS Grant #16-095)", Erasmus+ CBHE consortium “Nature-based living-lab for interdisciplinary practical and research semester on sustainable development and environmental protection in the Amazona Rainforest [NB-LAB]” (Grant number: 619346-EPP-12020-1-DE-EPPKA2-CBHE-JP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.