Was Lou Gehrig's ALS Caused by Drinking Water?

Rudyard Kipling called it “Hell’s Half Acre,” a geothermal wonderland where people could fall through the Earth’s thin crust or be poached by steamy hot springs and geysers. Most visitors to Yellowstone National Park’s Midway Geyser Basin stroll the wooden boardwalks, but a few hike a short, steep side trail that reveals a bird’s-eye view of the entire valley, including Grand Prismatic Spring, which can be fully appreciated only from above. Mustard-yellow and vibrant-orange mats spread like tentacles from the turquoise pool. “Not even the most talented artist could imagine something as beautiful as that,” muses Sandra Banack, a biologist who studies cyanobacteria, the microbes that create the colorful mats — and that hold a toxic secret.

Banack works as senior scientist at the Institute for EthnoMedicine in Jackson Hole, Wyoming, alongside the institute’s founder, Paul Cox, a botanist and conservationist. Cox’s long list of achievements includes working to preserve Samoan rain forests, for which he was awarded the 1997Goldman Environmental Prize, and discovering one of the few compounds active against HIV, prostratin, from the Samoan mamala tree. In the early 2000s — when he directed the National Tropical Botanical Gardens in Hawaii and Florida and Banack was a biology professor at California State University, Fullerton — the two made a series of discoveries that led to the founding of the institute.

What started as a study of the island of Guam’s fruit bats and cycads, ancient seed-bearing plants that resemble palms, led to a startling hypothesis: Could cyanobacteria cause neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer’s, and Parkinson’s?

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“We never wanted to announce a problem without some thoughtful solutions,” says Cox. He, Banack, and I met at their small institute, a building tucked on a side street near Jackson Hole’s town square two hours from Yellowstone. The institute’s two-room laboratory is stuffed with equipment and Erlenmeyer flasks filled with emerald goo — cyanobacteria from around the world.

Cyanobacteria, which sometimes form symbiotic relationships with other organisms, live in marine and freshwater habitats and even in dried desert crusts, where they spring to life with the first droplets of rain. The microbes may cover shallow lakes and ocean floors or grow over the top of coral reefs. And under certain conditions, massive blooms erupt, covering the water’s surface in a pea-green scum.

Although frequently called blue-green algae, cyanos are actually bacteria that photosynthesize, or create food from light, which is why early scientists classified them as algae. Modern genetics shows they share no evolutionary lineage with algae; the classification is as scientifically accurate as calling a dog a plant.

Cyanobacteria produce a host of nasty compounds, including neurotoxins that derail nervous systems, hepatotoxins that damage liver function, and tumor promoters. Their blooms have poisoned wildlife and caused massive fish kills. In humans they can cause rashes, numbness, vomiting, and sometimes long-term liver or nerve damage. While “death by pond scum” has never appeared in an obituary, that could change: not only are blooms increasing worldwide, but scientists predict they will worsen as the climate warms and nutrient levels rise, when, for example, fertilizers from America’s breadbasket run into the Mississippi River and down to the Gulf of Mexico. Recently, burgeoning cyano blooms in the Great Lakes have garnered attention.