Medical Mystery: Does Cyanobacteria play a role in brain diseases like Alzheimer's?
Florida has become the stage for a drama involving research into a possible link between brain diseases like Alzheimer’s and a toxin produced by common algae. The story so far:
Act 3 - Dolphins and Dementia
Larry Brand of UM's Rosenstiel school of marine science: "We now know that the cyanobacterias as a group produce well over 1,000 different, weird compounds. The vast majority we haven't investigated so we don't even know what effects they may be having on us." [Photo: Daniel Portnoy]
A laid-back Texan with a doctorate from Woods Hole Oceanographic Institution and MIT and 30 years at UM, Brand is an algae guru. He didn't know Mash but read her paper. "Here I am working on cyanobacteria blooms here in Florida and, hmmm, that's a possibility" — maybe Americans were consuming it in fish and crustaceans that had ingested it from algae in lakes, ponds, rivers and seas, he thought.
Brand studied fish caught near algae blooms and was shocked by the results. Some samples showed nothing. But others were chock full of BMAA. Pink shrimp from Florida Bay and fish from the Caloosahatchee River had concentrations almost as high as the Guam fruit bats. One blue crab from Biscayne Bay had levels twice that of the Guam bats.
Brand also got startling results after studying brains from the carcasses of bottlenose dolphins — apex predators in which the effects of a biotoxin were most likely to be magnified. "All but one of them had high levels of BMAA similar to what you see in Alzheimer's patients. The one that had essentially no BMAA was hit by a boat," he says.
Standing in the Rosenstiel school library, Brand bends over a map showing algae bloom occurrences in Florida. He says people are creating big increases in blooms by dumping more and more nutrients into local waters. Toxins from algae can make us sick from eating tainted fish and breathing tainted air. "Undoubtedly, it's going to be causing increasing human health problems," he says.
People — and their fertilizers, sewage and domestic animal waste — are making the world a friendlier place for toxin-producing algae. Limiting fertilizer use in Florida to stop blooms is a contentious issue, however. Proposed EPA limits on fertilizer, manure and sewage in Florida waterways prompted state officials, agriculture companies and other businesses to file legal challenges, saying the limits will cause great harm to government, whose treatment plants will have to comply, and to the economy. A federal appeals court in August rejected the challenge.