The epidemiology of winter ulcer disease in farmed Atlantic salmon in Canada

Primary Investigator: Sophie St-Hilaire Co-Primary Investigator: Novartis (Allison MacKinnon)

Winter ulcer disease caused by Moritella viscosa is the primary reason for antibiotic usage in aquaculture on the east coast of Canada. Anecdotal reports suggest mortality from this disease is increasing and it is unknown whether this is due to treatment resistance, increased virulence, reduction in host immunity, increased exposure, or a combination of these factors.

Identification of risk factors for this disease and management strategies to control the bacterial pathogen are needed to improve the sustainability of the industry. To date, there is no published descriptive epidemiology for M. viscosa in Canada. This basic information is essential for developing hypotheses on control and prevention strategies.

The overall goal of this project is to better understand the epidemiology of M. viscosa on Atlantic salmon fish farms on the East Coast of Canada.

Specific objectives are to:

  1. Describe disease outbreaks with respect to specific environmental and husbandry factors at pen and farm levels;
  2. Assess antibiotic treatment efficacy for this pathogen over the last 5 years; and
  3. Develop a proposal to address potential management strategies for vaccination and treatment applications, based on the epidemiology of the disease.