Should you really only eat shellfish when there's an 'R' in the month?

Types of Shellfish Poisoning: How Bad Could It Really Be?

Red tides can cause widespread contamination and death among fish and other sea life.

There are four different types of shellfish sickness. All four types share some common features (such as headache and nausea), but each one has a horrible feature all its very own:

  • When you think of seafood sickness in general, you probably imagine something much like diarrheal shellfish poisoning. It's the old-fashioned, one-day kind, and the preferred form among shellfish connoisseurs. It plays all the popular hits: vomiting, abdominal pain, date-ending diarrhea. It won't kill you, but it may cure you of your shellfish addiction.
  • Whereas diarrheal shellfish poisoning begins its ominous rumblings about half an hour after eating bad shellfish, paralytic shellfish poisoning instead causes numbness and tingling in your mouth. This is a good time to ask the waiter for the check. Soon, the tingling will spread to your arms and legs and you'll feel like you're floating. While some people pay good money for drugs to feel this way, this is the most serious form of shellfish poisoning -- it can paralyze your lungs and kill you in as little as two hours. The fatality rate is as high as 12 percent [source: Pledger].
  • Because doctors couldn't name this next form of poisoning "temporary insanity shellfish poisoning," they named it neurotoxic shellfish poisoning. Suddenly, an ice cube feels hot to you, and a candle flame ice cold. You'll feel a million tiny pinpricks on your skin, your muscles will ache and you'll become dizzy. You won't die, but interestingly, the toxin responsible for this form of poisoning can become aerosolized, meaning you can breathe it in and become sick while walking along the shoreline.
  • Shellfish poisoning isn't an experience you'll soon forget, unless it's the type that destroys your memory -- amnesic shellfish poisoning. It sounds like a plausible defense from a criminal attorney: "My client insisted on harvesting his own shellfish in July, got amnesic shellfish poisoning and can't remember where he was on the night in question." Amnesic shellfish poisoning is most common in the Pacific Northwest. The unfortunate consumer of the bad shellfish will first experience "normal" symptoms of seafood poisoning, but may soon become confused, disoriented and even comatose. The cognitive damage is permanent, affecting short-term memory and even causing dementia.

Now that we've clarified just how pleasant shellfish poisoning is, let's figure out how to avoid it.