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Crayfish plague

Crayfish plague is caused by the oomycete Aphanomyces astaci. In Norway, the disease is notifiable and listed as a list 3 disease (national disease). Crayfish plague is lethal for all freshwater crayfish that are not of North-American origin including the native european noble crayfish (Astacus astacus).

Aphanomyces astaci is originally a natural, harmless parasite living on the exosceleton of North-American freshwater crayfish including signal crayfish (Pacifastacus leniusculus). These have evolved natural defence mechanisms against the parasite and are usually symptomfree and cronic carriers of the disease. European freshwater crayfish are lacking a similar defence system and will die if infected by A. astaci.

Facts about crayfish plague