Spikes in vibrio illness typically occur later in the summer months, in July, August and September. During the summer of 2015, 73 persons became ill with culture-confirmed vibrio after eating raw BC oysters. This is the largest outbreak of vibrio in Canadian history and was 2.5 times the number of cases expected. In response to this apparent outbreak of vibrio, Vancouver Coastal Health Authority banned the sale of raw oysters harvested on Vancouver Island for the first time since 1997. Among possible causes of the high number of 2015 cases was that seasonal sea temperatures during the spring and summer were, on average, 2 degress Celsius above the norm. Graph of sea surface temperatures August 2014 to August 2015.
In response to this outbreak, the industry and their association, BC Shellfish Growers' Association, along with public health partners, regulators and others have engaged in many different activities in an effort to improve control, education, communication and surveillance of vibrio.