A 2019 "Science" review assessed that chytridiomycosis was a factor in the decline of at least 501 amphibian species during the past 50 years, of which 90 species were confirmed or presumed to have gone extinct in the wild and another 124 had declined in numbers by more than 90%. The review characterized the overall toll as the "greatest recorded loss of biodiversity attributable to a disease". However, a follow-up study in "Science" found the 2019 study by Scheele et al. to be lacking in the necessary evidence to make these claims and found the conclusions could not be reproduced with the original study's data and methods. It remains unclear how many and which species have been impacted by chytridiomycosis, but there are good data for a limited number of species such as the mountain yellow-legged frog in the Sierra Nevada mountains.