The chytrid fungus (Batrachochytrium dendrobatidis), or Bd for short, is considered one of the causes of the worldwide decline in amphibian populations. In recent years, researchers have identified different genetic strains of the fungus that causes chytridiomycosis in various parts of the world. This has already led to the decline of at least 500 species of anuran amphibians, including toads and frogs.