Investigation of Rare Frog Deaths Published
Through loss or modification of habitats, infectious disease and climate change, declines and extinction of amphibians are happening all around the world. Unlike other regions of the earth, there are few documented cases of discovering large die-offs of frogs in sub-Saharan Africa. Recently a team of scientists including the Biodiversity Institute's David Blackburn investigated an unusual die-off in Cameroon.
Blackburn, together with colleagues from the United States and Canada, documented the mortality event of the critically endangered Lake-Oku clawed frog (Xenopus longipes). The frog is known to only live near a small crater lake high in the mountains of the west African country. Unlike almost all other vertebrate species, this small frog is biologically unique in having twelve sets of chromosomes (instead of the two sets that people have).
The team sought to document the unexplained die-off event and attempt to determine whether this species has also fallen victim to the chytrid fungus (Batrachochytrium dendrobatidis), which is responsible for many mass mortality events elsewhere in the world.
Using both molecular and anatomical techniques, Blackburn and the team did not find presence of the fungus or the equally deadly ranavirus. Instead, the team’s analysis indicates that the animals may have been exposed to a source of skin irritation that caused large wounds which subsequently became infected.
At present, the causes of these deaths remain unclear, but the observations of the team have led to the development of a conservation action plan in collaboration with the non-government organization, Amphibian Ark.
The findings were published in the African Journal of Herpetology.