During the monitoring works for amphibian that is carried out within the framework of the European project "Conservation of river fauna of Community interest in the Natura 2000 network sites of the Ter, Fluvià and Muga river basins" (LIFE Potamo Fauna) an individual of Common Midwife Toad (Alytes obstetricans) was detected died, due to chytridiomycosis, a serious pathology caused by a fungus that causes mass mortalities of amphibians, which could be related to the decline observed in certain species.

When it was found, technician staff of the Project warned the Rural Agents who collected the specimen and analyzed and controlled it, giving positive by chytridiomycosis. It is currently one of the few positives detected in Catalonia known by the Flora and Fauna Service of the Government of Catalonia.

In particular, this animal showed the bottom of the hind legs with pink color, probably due to internal bleeding caused by the bacterium Aeromonas hydrophila. This bacterium is commonly found in soil and water and is considered part of the natural flora of amphibians, but found in high concentrations on the body of the animal and it causes the disease called "red legs", which causes inflammation and bleeding in the affected area.

Currently, many pathologists believe that this bacterium behaves as an opportunistic pathogen because it grows exponentially when it detects an imbalance caused by other biotic agents much more problematic as in this case the fungus Batrachochytrium dendrobatidis, that causes the chytridiomycosis. So when the animal was found with pink-coloured legs technicians felt that it could be also affected by chytridiomycosis and proceeded to the analysis.