Subsequent to further information received this morning from the Ministry of Primary Industries and Northland DHB, the Auckland Regional Public Health Service confirms a lift of the shellfish public health warning in all areas of the Auckland region.
Recent monitoring results for the Kaipara Harbour now show that PSP (paralytic shellfish poisoning) levels have fallen to non detectable levels, meaning that shellfish collection and consumption is again safe for the public in all of the Auckland Region, including the Kaipara Harbour.
Please see the latest 17 January 2013 Media Release regarding shellfish biotoxins.
If you are thinking of eating shellfish you have gathered from somewhere in the Auckland region remember to always check whether the area from which the shellfish are gathered is currently safe from toxic shellfish poisoning.
Scientists have tried to identify the triggers for the algae that cause the toxic shellfish poisoning, but haven't yet identified the key factors. Marine biotoxins are one potential hazard related to shellfish. Please see the ARPHS Shellfish fact sheet for more information.
Paralytic Shellfish Poisoning (PSP) Symptoms
Symptoms of PSP usually occur within 12 hours of consuming shellfish and include:
- Numbness and tingling around the mouth, face or extremities.
- Difficulties in swallowing or breathing.
- Dizziness, double vision.
- In severe cases, paralysis and respiratory failure.
If anyone becomes ill after eating shellfish contact a doctor immediately and please contact Auckland Regional Public Health Service, Telephone (09) 623 4600. Please also keep the left over shellfish so it can be tested.
Toxic Shellfish Poisoning
There are four main kinds of toxic shellfish poisoning. The chemicals that cause toxic shellfish poisoning are produced by certain species of toxic algae and released into the shellfish when they eat the algae. One of these types of toxic shellfish poisoning is paralytic shellfish poisoning.
What is paralytic shellfish poisoning?
Paralytic shellfish poisoning is caused by a group of chemicals called the saxitoxins and gonyautoxins. These chemicals are produced by algae and released into the shellfish when the algae are eaten. The chemicals all differ in their toxicity to humans, and can be changed depending on the species of shellfish. Stomach acids in animals and humans can also alter the toxicity.
The toxins can also be released into the sea from the algae but there are no known problems from recreational contact with water (e.g. swimming).
At what levels of toxicity are people at risk of illness and death?
The risk of illness depends on many factors for example:
The toxins present in the shellfish.
Type of toxins present in shellfish.
A person’s state of health.
A person’s genetic make-up.
The toxins remain even when the shellfish is cooked.
Monitoring and testing
Shellfish and seawater samples around New Zealand are tested each week to ensure they are not contaminated with biotoxin. Public warnings are issued when shellfish are not safe to eat. Monitoring of toxin levels will continue in the region and the public will be notified of any changes.
For more information on shellfish, please contact Auckland Regional Public Health Service, Telephone (09) 623 4600.
Further information is also available on the following: