Sailors' baffling discomfort suggests ciguatera
To the editor:
I was interested to read recently in your magazine about ciguatera poisoning ("Voyagers deal with the risk of ciguatera," Issue 119, January/February 2002). Having had first-hand experience of this affliction, I thought your readers might benefit from our observations.
Our party of four visited the Bahamas and experienced ciguatera fish poisoning. Though we knew we had all been having odd symptoms and strange sensations during our holiday, we did not suspect the cause until I returned home and saw a headline on the cover of an Ocean Navigator magazine in the pile of mail that had accumulated during my absence. The headline referred to an article on a new test for ciguatoxin, and the article described our symptoms exactly! Had it not been for this, I doubt that we would ever have known the cause of our discomfort — none our doctors knew about ciguatera.
The symptoms that we found most characteristic of the poisoning were tingling in the feet and the reversal of hot and cold sensations, for example a cold beverage "burned" the lips and tongue, a hot one felt cold. In particular, on our return to Canada, breathing cold air through one's nose was very painful. One also felt an overwhelming sense of muscular weakness, like walking through molasses all the time. This was the most debilitating symptom and could be very dangerous aboard a boat; it was very hard to get any work done. The profound sensitivity to hot and cold beverages was the most obvious symptom. I was particularly struck by the effect of caffeine, chocolate and alcohol in enhancing the symptoms. On reflection, alcohol had given us a distant early-warning signal of the poisoning, which may have been cumulative, because the first symptoms of tingling feet and paresthesia of the tongue occurred in the evenings after a few drinks.
Recovery took a long time, at least six to eight weeks, and quite curiously, as one recovered and as the symptoms fell below a detectable level, taking alcohol or caffeine restored them. I could follow my recovery by testing my response to caffeine. Alcohol and caffeine enhanced different symptoms; alcohol induced profound sleepiness and paresthesia, while caffeine produced an overwhelming fatigue.
We ate no barracuda, and indeed, the only source of toxin was some large grouper that we bought from a fish wholesaler who gave us a ride in his truck from the market. There was so much fish that we ate it on two successive nights!
Because the toxin accumulates up the food chain, the Bahamian rule of thumb makes sense: you should never eat a fish that is larger than your plate. It seems that this simple rule might have saved us and would save many sailors and other visitors to the islands considerable discomfort. n
Robert Painter lives in Richmond Hill, Ontario.