Crayfish Plague (Aphanomyces astaci)

Disease carried by North-American crayfish but particularly, signal crayfish. This water mould can wipe out entire populations of white-clawed crayfish within weeks of initial infection. Spreads through water-borne spores which are released from infected crayfish.

Crayfish plague has been reported in Ireland since 2015 and is thought to be attributed to spore release from infected non-indigenous crayfish, contaminated gear, and equipment moving between waterbodies and the release of ornamental crayfish into the wild. Recently, a newly-discovered, close-related species, Aphanomyces fennicus spp., was found to be being amplified on the most-used qPCR assay and giving false-positive results for crayfish plague. At SureScreen Scientifics, we now use the most recent assay alongside internal negative and positive controls to ensure we provide customers with accurate results.

• It is vital biosecurity is taken into account in survey design to reduce the spread of crayfish plague. Thoroughly disinfect all footwear/waders and equipment before entering the sampling site or moving between sites.
• Avoid stepping into the water – this can stir up sediment, throwing up sediment DNA and any inhibitory molecules present. Sediment may clog the filter and prevent sufficient volumes of water being filtered.