Crayfish disease diagnostics

Towards a Nordic standard

image of Crayfish disease diagnostics

Crayfish utilization is a long-standing Scandinavian tradition, which unfortunately has suffered a major drawback with the introduction of crayfish plague disease about a hundred years ago. In spite of intensive research many problems in management and diagnosis of this disease are not yet solved. To evaluate ongoing research and diagnostic methodology in different countries, representatives of diagnostic laboratories involved in crayfish disease diagnostics were invited to a workshop in Kuopio to discuss the problems with crayfish diseases. The workshop was held at the Kuopio unit of the Finnish Food Safety Authority Evira. Participants from Finland, Sweden, Norway, Estonia and Latvia were present, as well as the OIE expert from the reference laboratory for crayfish plague. In the programme of the first day the state of crayfish stocks, crayfish diseases and diagnostic methods used in each country were presented and discussed. During the second day diagnostic methods were discussed in detail, as well as research projects concerning crayfish diseases. The workshop has been made possible by way of a grant from the Nordic Council of Ministers.



Crayfish disease in Finland

The main disease problem in Finnish crayfish populations is crayfish plague. Other identified specific infections are caused by the parasites Psorospermium haeckeli and Thelohania contejeani. Infection with baculovirus has been recorded in some crayfish populations, without causing clinical signs. During the years 2000-2005 278 batches of noble crayfish and 39 batches of signal crayfish were studied for pathology. Crayfish plague was identified in 66 noble crayfish samples and 12 signal crayfish samples. Psorospermium haeckeli was found in 58 noble crayfish samples, but not all batches were studied in order to find it. This parasite was not recorded in the signal crayfish. Thelohania contejeani was found in 4 cases in noble crayfish. In 32 batches of noble crayfish and 4 batches of signal crayfish miscellaneous pathological conditions were recorded, mostly for unidentified reasons.


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