White-nose syndrome is a fungal disease that affects bats, primarily in North America. It is caused by the fungus Pseudogymnoascus destructans, which grows on the skin of hibernating bats, leading to severe skin lesions. This condition disrupts their hibernation, causing them to wake more frequently and deplete their fat reserves, ultimately resulting in high mortality rates. Since its discovery in 2006, White-nose syndrome has spread rapidly, impacting several bat species, including the little brown bat and the northern long-eared bat. Conservation efforts are ongoing to understand the disease better and protect affected bat populations.