The state health department warns that paralytic shellfish poisoning, or PSP, is ever present in locally harvested shellfish.
The Alaska Division of Public Health has confirmed a case of PSP on Gravina Island near Ketchikan.
Department spokesman Greg Wilkinson says a woman was hospitalized last week for suspected PSP after eating cockles and clams harvested on the island.
Within a few minutes she experienced numbness in her lips, tingling in fingers and toes and increasing numbness in her legs. She has since been released from the hospital.
Wilkinson says a mixture of the leftover clams and cockles returned a test result showing some of the highest saxitoxin levels ever recorded in Alaska shellfish.
PSP cannot be cooked or cleaned out of shellfish. Only commercially grown shellfish is considered safe because it is tested.