Between 1968 and 2009 there were no sightings of Holdridge's toad in their natural environment. Extensive searches were led to determine if the species was extinct. The searches lasted for seven years before the toad was declared extinct. Multiple causes are believed to have led to the toad's presumed extinction, including chytridiomycosis, climate change, and deforestation. The main threat to Holdridge's toad is thought to be chytridiomycosis, a fungal pathogen, Batrachochytrium dendrobatidis, that causes an infections disease in amphibians. The fungus keratinizes any keratin-containing skin layers in both the tadpoles and adult frogs. High levels of this fungus were detected in the breeding grounds of Holdridge's toad before and after the species appeared to vanish. In 2009, tadpole and adult toads were discovered in two separate ponds that reclassified the species as critically endangered.