There are a variety of diseases which affect frogs in the Wet Tropics. Chytrid fungus (or Chytridiomycosis) occurs in upland and lowland stream dwelling frogs in the Wet Tropics. Several species of upland frogs are now presumed to be extinct. It has been listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 and a Recovery Plan for stream dwelling rainforest frogs in the Wet Tropics has been developed.
Frog chytrid fungus was discovered in 1999, but may be responsible for frog population declines in the region dating back to the 1970s. The spores of the fungus grow inside the outer layers of the frogs' skin, resulting in keratin damage that may kill frogs within 10 to 18 days. The exact mechanism by which chytrid fungus kills infected frogs is still unknown.
Spores of the chytrid fungus are transported via water and wet soil. Wet or muddy boots and tyres, and other equipment, may be contributing to the spread of the disease, as may feral and native animals.
The seven frog species listed as endangered under the EPBC Act are:
These declining species are all associated with rainforest streams in upland areas. Some have not been seen for many years and may be extinct, but there has been some good news. Some, like the common mistfrog and the Australian lacelid have disappeared from higher elevations, but can still be found at lower altitudes. The little waterfall frog was previously known from only four upland rainforest sites in the Wet Tropics and had disappeared from all these sites by 1991. In 2008, a healthy population was located in dry forest on the western Carbine Tableland. It is now only known to occur in this one location along a two kilometre stretch of the McLeod River.
Wet Tropics frogs are also susceptible to a wide range of other diseases. For more information about various frog diseases in the Wet Tropics area, see the website for Frog Safe which helps to research frog diseases and care for sick frogs around Cairns..