Dead pygmy rattlesnake with the parasite Raillietiella orientalis emerging from the mouth. Credit: Corinna Mishin Snakes around the world are increasingly facing the threat of extinction, with disease emerging as a major concern alongside habitat loss. One of the most serious illnesses affecting snakes is ophidiomycosis, commonly called snake fungal disease, which is caused by the fungus Ophidiomyces ophidiicola ( Oo ). Since researchers first identified the disease about 20 years ago, it has