The first observation that something might be wrong with North American snakes was in 2006. Scientists noticed a severe population crash in timber rattle snakes in New Hampshire, with less than 50% of snakes surviving after the bottle neck event. The cause was determined to be a fungal infection on the snake’s skin. Since this initial outbreak more than 30 species of snakes have been afflicted with the disease.
The fungus is able to attack if the snake’s skin has been damaged. Most snakes have an autoimmune response to the attack, however if the scab falls off and flesh is exposed the fungus can really take off. Another observed issue is when the fungus attacks skin on the snake’s head. This can interfere with the snakes ability to hunt and the can starve to death. The other issue is that it can make a snake stay outside to ‘sun’ longer (when they rest on rocks etc absorbing heat) and can be injured from doing so.
The main snake family that is the most susceptible are rattle snakes. The article claimed this will make it hard for the public to be concerned about this disease, since most people will be happy to see these snakes gone.
What was the most interesting part of this article is that the causal agent has just been identified and its a long known soil dweller, Ophidiomyces ophiodiicola. The researchers that published the articles identifying this fungus looked through museu, collections to see when this started. According to one, they could not find it past 2000, so this was a recent occurrence. They noted that the fungus was resistant to agricultural fungicides, that the weather patterns had been different, and that there were smaller populations of rattle snakes.
The article goes way more in depth than an average BBC story and is worth a read: