Island Health suspects that the likely source of the norovirus that resulted in shellfish farm closures in Baynes Sound this year was from untreated sewage associated with marine operations during the herring run in March.
That information came from medical officer Dr. Paul Hasselback in a letter responding to a request from the Regional District of Nanaimo for information on recent health concerns regarding the presence of vibrio cholera and norovirus in local seafood products.
An investigation into the norovirus outbreak by the Public Health Agency of Canada, working with provincial public health partners, is ongoing. In an email, the PHAC said the cause of the contamination resulting in the norovirus outbreak has not been identified. The PHAC did not make any connection to marine operations associated with the herring run.
“There are a number of potential risk factors, one of which is the herring fleet in Deep Bay,” said Greg Thomas, executive director of the Herring Conservation and Research Society.
“In pre-season meetings with the herring industry advisors, DFO (Department of Fisheries and Oceans) reviewed the issue of contamination in Baynes Sound and prohibition on sewage discharge nearshore,” said Thomas, adding that the industry will continue to work with government agencies.
In his letter to the RDN, Hasselback said the outbreak was caused by a single genotype that has not been seen in community based illness in British Columbia since 2012, which led to Hasselback to suggest that it was not from a land-based domestic source.
“It appears probably that the event was caused by a single contamination event likely around the time of the herring fishery,” Hasselback explained in his letter. “There is a strong suspicion that the event may be associated with untreated sewerage contamination associated with marine operations.”
The herring run happened last March. Later that month, the presence of vibrio cholera were found in herring eggs samples taken from the area of French Creek and Qualicum Bay, after four people became ill after eating them. The Department of Fisheries and Oceans closed the area for harvesting of herring eggs. Hasselback noted that, while investigations into the presence of vibrio cholera continue, “it is most likely that the organism is naturally occurring in marine waters and unrelated to human sewage.”
RELATED: Norovirus outbreak closes oyster farms off Denman Island, Deep Bay
In April, federal officials closed two shellfish farms due to the outbreak of norovirus. Health authorities have reported about 40 cases of the acute gastrointestinal illness since early March.
Regional District of Nanaimo chair Bill Veenhof at the committee of the whole meeting on May 8, raised concerns about the recent shellfish closures in Baynes Sound due to the norovirus outbreak.
The Electoral Area H director indicated he has nothing against herring fishery but he could not discount the possibility that the source of the virus could be from the dumping of sewage from the herring fleet. Some of the vessels were seen anchored near the shellfish farms.
“The timings of the outbreak compared to the fleet arrival times would suggest a strong linkage,” Veenhof said.
Dumping of raw sewage by vessels is regulated by Transport Canada, said Veenhof, who added that it is an illegal activity. The big problem, Veenhof pointed out, is Transport Canada is unable to fully enforce this law.
Veenhof made a motion that staff look into means of sewage dumping enforcement. The directors endorsed it.
