First record of proliferative kidney disease agent Tetracapsuloides bryosalmonae in wild brown trout and European grayling in Finland.

The myxozoan endoparasite Tetracapsuloides bryosalmonae causes temperature-driven proliferative kidney disease (PKD) in salmonid fishes. Despite the economic and ecological importance of PKD, information about the distribution of the parasite is still scarce. Here, we report for the first time the occurrence of T.