Contagious salmon disease found at four Lerøy salmon farms in Norway

The Norwegian Food Safety Authority, Mattilsynet, has reported the detection of bacterial kidney disease (BKD), a contagious infection, at four Lerøy Midt salmon farming sites in central Norway.

Mattilsynet said BKD is either definitely present or suspected at the four farms, and the authority said it believes there is an increased risk of BKD in all facilities in Norway's salmon-farming region 6 (PO 6). It added that “measures have been put in place” to prevent further infection, including culling all affected fish in cages. 

“BKD is a serious contagious and notifiable disease, which can have major consequences for the health and welfare of both wild and farmed salmon,” the Norwegian Food Safety Authority said in a release.

The authority said it is tracking the infection, and that it is not yet known how the disease – which hasn’t been detected in the region in 15 years – entered the area. Mattilsynet reported it took more than a year between smolt being released into the region and for the detection of the disease at the first of the four facilities.

“This may indicate that the source of infection is not smolt, but another, for example from wild fish in the area,” the authority said.

The Norwegian Food Safety Authority reported that the disease appears to have spread via contact between facilities by wellboats and deworming vessels.

Due to the increased risk of spreading the disease, the authority said BKD tests must be carried out at all facilities in the region. The authority is recommending that all broodstock that die in the nine months before spawning should be examined, all diagnostic health checks in the region should include examinations for BKD, control of smolts and fry should include examinations for BKD, and that the region be “extra careful” when considering biosecurity. 

“This applies in particular to well boats and desalination vessels,” it said. “This is a responsibility that lies both with the shipping company, those responsible on the vessel, and those who use the vessel for transport and treatment.”  

Photo courtesy of Lerøy