Characteristics of British Columbia isolates of Piscirickettsia salmonis relevant for understanding pathogen transmission and infectivity
The bacterium Piscirickettsia salmonis is the causative agent of salmonid rickettsial septicaemia, a disease in marine farmed salmon with significant outbreaks in Europe, Chile and Canada. In British Columbia, P. salmonis has been detected in wild Pink and Chinook salmon and in farmed Atlantic salmon, but the disease has not been reported in wild salmon. Infections were originally detected at farm sites in southwestern Vancouver Island, but since 2015, the range has expanded northward to include the Sunshine Coast, Discovery Islands, Broughton Archipelago and northwestern Vancouver Island. Between 2002 and 2016, 36 fish health events (FHE*) associated with P. salmonis were reported at Atlantic Salmon farms in BC. Concern regarding pathogen transfer from farmed fish to wild Sockeye Salmon in the Discovery Islands necessitates a risk assessment analysis for P. salmonis. FHTT-2018-P-01 will conduct a series of laboratory experiments on factors influencing survival of P. salmonis in the marine environment, susceptibility of Sockeye Salmon to P. salmonis, the minimum infectious dose for Atlantic, Pink and Sockeye Salmon, progression of disease and host response to infection, and the bacterial shedding rate from infected salmon. FHTT-2018-P-01 will address the many knowledge gaps needed in the pending risk assessment and inform both Aquaculture Management and aquaculture industry of the nature of this disease.
*FHE is defined as “a suspected or active disease occurrence within an aquaculture facility that requires the involvement of a veterinarian and any measure that is intended to reduce or mitigate impact and risk that is associated with that occurrence or event.”
Program for Aquaculture Regulatory Research (PARR)
Simon R.M. Jones
Research scientist, Pacific Biological Station, 3190 Hammond Bay Rd, Nanaimo, BC, V9T 6N7
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