Amphibian chytrid or Bd (Batrachochytrium dendrobatidis) was accidentally introduced to Mallorcan Midwife Toads (Alytes muletensis) before their release into the wild in 1991. Bd was not even known to science before the late 90’s. It’s just another example of how disease can be spread unkowingly through conservation efforts. Luckily, the toads seem to be somewhat resistant to the fungus.

http://www.cnn.com/2008/TECH/science/09/11/frog.extinct.ap/index.html

Maybe there is still hope! The Armoured Mistfrog (Litoria lorica), a critically endangered Hylid from NE Australia has been discovered again. The animal has been thought to be extinct, although it wasn’t listed this way, as it has not been seen since 1991. An animal is usually listed as critically endangered when it is thought that there are less than 50 individuals in the wild. This is an amazing discovery, because this species was thought to have been wiped out by the virulent chytrid fungus.