Publication Abstract

Development of Proliferative Kidney Disease in rainbow trout, Oncorhynchus mykiss (Walbaum), following short-term exposure to Tetracapsula bryosalmonae infected bryozoans

Development of Proliferative Kidney Disease in rainbow trout, Oncorhynchus mykiss (Walbaum) following short-term exposure to Tetracapsula bryosalmonae infected bryozoans

 

M. Longshaw, R.M. Le Deuff, A. Harris and S.W. Feist

The initial site of infection in the fish host for Tetracapsula bryosalmonae, causative agent of proliferative kidney disease (PKD) is poorly understood. Following the recent recognition that freshwater bryozoans harbour the infective stages to salmonid fish, experiment transmission studies were undertaken to investigate (1) the route of entry of the parasite into the fish host and (2) the minimum exposure time required to induce clinical signs of PKD. In-situ hybridization (ISH) studies were carried out on naive rainbow trout exposed to the naturally infected bryozoan Fredercella sultana for up to 90 min. The sporoplasm of T. bryosalmonae was detected entering the fish via mucous cells in the skin epithlium within the first minute of exposure. In addition, T. bryosalmonae cells were infrequently detected in the skeletal musculature of the exposed experimental fish up to 72 h post-exposure. The route of migration through the fish to the kidney and spleen was not determined. All fish exposed to infected, disrupted bryozoans for 10, 30 and 90 min and manitained for up to 8 weeks developed clinical PKD.

Reference:

M. Longshaw, R.M. Le Deuff, A. Harris and S.W. Feist, 2002. Development of Proliferative Kidney Disease in rainbow trout, Oncorhynchus mykiss (Walbaum) following short-term exposure to Tetracapsula bryosalmonae infected bryozoans. Journal of Fish Disease, 25: 443-449.

M. Longshaw*, R.M. Le Deuff*, A. Harris* and S.W. Feist*

Journal of Fish Diseases, 25: 443-449