Vancouver Island, Canada.- There have been cases of shellfish-related illness on the south section of Vancouver Island in individuals who have self-harvested in closed areas in June. Island Health is reminding self-harvesters to be aware of shellfish closures during the harvest season. The best way to protect yourself and others is not to harvest shellfish from closed areas.
Toxic forms of algae often increase in ocean water in the summer with warming water temperatures. Concentrations of toxins can accumulate in filter-feeding shellfish. Shellfish that can be affected include: clams, oysters, whole scallops, mussels, cockles, geoducks, whelks, periwinkles, or the innards of crab (toxin can be in flesh if the crab is boiled before innards are removed).
Shellfish that have accumulated toxins will not appear to be ill or contaminated. Cooking does not render the shellfish safe from toxins though will reduce disease from bacteria and viruses. When contaminated shellfish are consumed, illness can result. Toxins, such as saxitoxin, can cause human illness including Paralytic Shellfish Poisoning (PSP). Saxitoxin and PSP are a frequent cause for shellfish closures.
There is no safe place to harvest shellfish without checking shellfish closures first. Environmental testing in June has shown very high environmental levels of toxins in the harvesting area where human illness occurred. The absence of an algae bloom is not an indicator of shellfish safety.
Symptoms of shellfish poisoning can occur within minutes and/or up to 24 hours after eating contaminated shellfish. In mild cases, symptoms may include tingling, vomiting, diarrhea, abdominal cramps, headache, dizziness, muscle weakness, disorientation, memory loss, loss of coordination, or difficulty swallowing. These symptoms disappear within several days. In serious cases, seizures, unstable blood pressure, paralysis, difficulty breathing, coma or death may occur.
At the first sign of symptoms, contact your Poison Control Centre at 1-800-567-8911 for first aid advice and seek medical attention immediately.
Shellfish harvested for sale are monitored and tested by the CFIA; shellfish from an approved source are considered safe for consumption in moderate amounts. Island Health, BCCDC and FNHA work with agencies to improve monitoring in areas not used for commercial harvesting and which may have greater use by self-harvesters.
• Closure information can be found at:
http://maps.bccdc.org/shellfish/
http://www.pac.dfo-mpo.gc.ca/fmgp/contamination/biotox/index-eng.html
• Information on marine toxins can be found at: http://www.healthlinkbc.ca/healthtopics/content.asp?hwid=ug2961
• More information for self-harvesters can be found at:
http://www.bccdc.ca/health-info/food-your-health/fish-shellfish/shellfish-harvesting-control
Source: VIHA
