In June, our laboratory confirmed three outbreaks of crayfish plague from dead crayfish in the Oleska and Nedvědička river and in the Chlebský brook. Crayfish plague is a disease caused by the oomycete crayfish rot (Aphanomyces astaci). It mainly affects European crayfish of the genus Astacus, for which the disease is almost always fatal. In the Czech Republic, river and stone crayfish populations are negatively affected by the disease. The disease is spread by non-native North American crayfish species, most commonly by contact between crayfish, transfer of zoospores with water or on wet objects.
To confirm crayfish plague, it is ideal to collect individuals just before death or very soon after, before the crayfish body begins to decompose. The diagnosis of crayfish plague is made from the cuticle of the crayfish using a highly specific PCR method, which determines the presence of Aphanomyces astaci in the sample. The State Veterinary Institute in Prague is the only one in the Czech Republic to routinely diagnose crayfish plague.
