Infectious pancreatic necrosis virus: experimental infection of goldsinny wrasse, Ctenolabrus rupestris L. (Labridae)

The use of wrasse as cleaner fish in farming of Atlantic salmon, Salmo sala r L., is now widespread in Scotland, Ireland and Norway, but little is know n about the susceptibility of these fish to the common pathogens of cage-cu ltured salmon. The susceptibility of goldsinny wrasse, Ctenolabrus rupestri s L., to infectious pancreatic necrosis virus (IPNV) was investigated. Capt ive-bred C. rupestris were infected with IPNV-Sp (Shetland strain) using a bath challenge method. Two infection doses were used, low (4.1 x 10(5) pfu mL(-1)) and high (2.4 x 10(6) pfu mL(-1)), with two replicates for each exp eriment. Bathing times were 1 h for the low dose and 5 h for the high dose. A maximum prevalence of infection (30%) was seen 2 weeks post-infection in replicate 1 of the low dose experiment and was accompanied by low tissue t itres. The tissue titres dropped to an undetectable level by 4 weeks post-i nfection. In the high dose experiment, a high prevalence of infection was s een along with moderate titres in tissues as well as a marked pathological response. Both prevalence and intensity declined rapidly and the fish recov ered. In the high dose experiment, faecal titres followed the same pattern as those in the tissues. The implications for the use of wrasse in the farm ing of Atlantic salmon are discussed.