Seafood poisoning rises with warming

Experts estimate that up to 50,000 people worldwide suffer ciguatera poisoning each year, with more than 90 percent of cases unreported. Scientists say the risks are getting worse, because of damage that pollution and global warming are inflicting on the coral reefs where many fish species feed.

Dozens of popular fish types, including grouper and barracuda, live near reefs. They accumulate the toxic chemical in their bodies from eating smaller fish that graze on the poisonous algae. When oceans are warmed by the greenhouse effect and fouled by toxic runoff, coral reefs are damaged and poison algae thrives, scientists say.

Ciguatera has long been known in the South Pacific, the Caribbean and warmer areas of the Indian Ocean. Some South Pacific islanders use dogs to test fish before they eat. But in the past decade, it has spread through Asia, Europe and the United States, where more restaurants are serving reef fish, prized for their fresh taste and exotic cachet.

Should global warming and pollution worsen and boost ciguatera poisonings, as most experts predict, health officials will face a daunting challenge. Currently, there is no reliable way to detect whether a fish has ciguatera. The molecule is extremely complex and differs markedly from region to region. The most important thing is there is no antidote to it.