In diverse wildlife communities, exchange of pathogens and symbiotic bacteria among host species influences disease dynamics. The aquatic fungal pathogen Batrachochytrium dendrobatidis has wiped out tropical frog communities, with unresolved declines even in terrestrial-dwelling frogs. Becker et al (2019) studied communities of tropical Brazilian frogs to explore spread of pathogenic and potentially beneficial microbes to the disease-susceptible terrestrial-dwelling pumpkin toadlet Brachycephalus pitanga. Toadlets acquired lethal fungal infections, but rarely acquired protective bacteria, from naturally infected aquatic frogs, with disease causing imbalances in host symbiotic bacteria. Our results suggest that pathogen transmission from mildly infected aquatic frogs may lead to death and disruption of symbiotic bacteria in vulnerable terrestrial species.