Microbiome-pathogen interactions are increasingly recognized as an important element of host immunity. Jervis et al 2021 describes landscape-scale pathogen-microbiome associations across altitudinal gradients in Ecuador about 30 years following amphibian declines (presumably caused by chytridiomycosis epizootics) and collected skin swab-samples which were metabarcoded using both fungal (ITS-2) and bacterial (r16S) amplicons. Stream breeding amphibians were most likely to be infected with Batrachochytrium dendrobatidis and were associated with increased abundance and diversity of non-Batrachochytrium chytrid fungi in the skin and environmental microbiome. The study also found that increased alpha diversity and the relative abundance of fungi are lower in the skin microbiome of adult stream amphibians compared to adult pond-breeding amphibians; and, stream tadpoles exhibited lower proportions of predicted protective microbial taxa than pond tadpoles, suggesting reduced biotic resistance. Thus, host breeding ecology may shape pathogen-microbiome associations at a landscape scale and may influence resilience in the face of emerging infectious diseases.
