The blue-green algae blooms invading Lake Champlain this summer can cause nasty stomach problems and skin irritation — and even liver damage in people who accidentally swallow the water. But researchers say there might be longer-term health consequences for people who come into contact with the blooms.
One Vermont doctor is studying the link between blue-green algae and what he says are abnormally high rates of Lou Gehrig’s disease in towns along the shores of Lake Champlain.
Dr. Elijah Stommel is a neurologist at Dartmouth-Hitchcock Medical Center, and a national leader in the treatment of patients with amyotrophic lateral sclerosis – commonly known as ALS, or Lou Gehrig’s disease.
Clusters of ALS
“It’s one of the worst diseases I think that is out there,” Stommel says. “It tends to strike people down in their best years, most productive years. And really we don’t have a handle on how to treat it, or even what’s causing it.”
There is no cure for ALS, a neuro-degenerative disease that slowly robs patients of physical movement. But about seven years ago, Stommel began turning his attention to its cause. And the Thetford resident is among the researchers who now suspect a link between blue-green algae blooms and a fatal disease thrust into the national spotlight last year by the Ice Bucket Challenge.
“In the literature, and in our own experience, we’ve been able to document clusters of ALS,” Stommel says.
According to Stommel, these “clusters” include several hotspots in Vermont. And their exact locations are notable for their proximity to portions of Lake Champlain, and other water bodies, that are prone to summer algae blooms.
“There’s probably an area of increased incidence in the St. Albans area of Vermont, and there may well be one in the Shelburne, Vermont, area and possible in the Sunapee area. And there may also be one in Windsor, Vermont,” Stommel says.
Skepticism among officials
It’s a controversial claim, and one that state health officials dispute.
“We have investigated potential clusters in the past,” says Lori Cragin, state epidemiologist at the Vermont Department of Health. “But they haven’t turned out to be clusters.”
Cragin says she’s familiar with work by Stommel and others that purports to show abnormally high rates of ALS in pockets across New England. But she says they don’t take into account all the other factors that could be responsible for the statistical deviations. And she notes that the mortality rate of ALS in Vermont on the whole is 2.7 deaths per 100,000 residents, about what you’d expect in a state of this size.
“The studies that are out there are a starting point,” Cragin says. “But they are very limited and with many methodological weaknesses.”
Stommel admits he needs more data to establish a causal link between blue-green algae blooms and ALS. But he says the mapping techniques used to isolate the alleged clusters are sound.
“We have some more recent data suggesting that poor water quality seems to overlap with areas of increased incidence of ALS,” Stommel says.
It isn’t the blue-green algae itself that Stommel blames for the increased incidence, but a toxin, called BMAA, that’s produced by the blooms. The foundation for this thesis lies in a body of research in which scientists discovered high levels of BMAA in the brains of people who died of ALS.
How exactly BMAA makes its way into the human body is still a mystery. Some scientists are exploring a path through the food chain – BMAA has been found in fish and crustaceans pulled from polluted waters. Stommel is exploring whether the toxin can get into the air, through wave action or other means, and inhaled by nearby residents.
Stommel now serves on the advisory council of the Lake Champlain International, a nonprofit organization dedicated to improving water quality in the state’s largest body of water. James Ehlers, executive director of LCI, says Stommel’s work is a wake-up call, and that the state ought to be devoting more attention to what he says could be a serious public health threat.
“The state and state-funded institutions need to be cooperating with this first-class research, especially when they’re trying to discern whether these high occurrences of ALS, these clusters that far exceed national standards, are located within our state borders,” Ehlers says.
A peer's review
Dr. Daniel Perl, a former professor of pathology at the University of Vermont College of Medicine, doesn’t share Ehlers’ alarm.
Perl says the foundational basis for Stommel’s theory has its roots in a flawed scholarly article from 2002 that gave rise to the BMAA-ALS hypothesis.
Perl says he was was on a research team funded by the National Institutes of Health that later examined the link between BMAA and ALS. He says there’s no compelling evidence that the toxin is capable of damaging the brain’s neurons in a manner consistent with what happens in ALS patients. Perl also says Stommel and other researchers have yet to determine with any epidemiological rigor that ALS “clusters” have popped up near polluted waterways.
“You know, you have to start by saying, ‘Is this a potential cause of the disease?’ If it’s not, then who cares how you get exposed to it?” Perl says.
Support from the CDC
Stommel says the data is too compelling to ignore. The Centers for Disease Control apparently concurs.
Stommel is currently in the midst of a CDC-funded study in which he and his colleagues are probing the histories of people with ALS in Vermont to better understand the extent of their exposure to blue-green algae blooms.
Stommel and his research colleague and fellow Dartmouth-Hitchcock employee, Dr. Tracie Caller, are using patient questionnaires in an attempt to determine how people might be exposed to cyanobacterial toxins, specifically BMAA.
“We’re exploring the history of patients with ALS and trying to ascertain what kind of work they did, what kind of diet they ate, where they lived, and see if there’s any clear correlation, and link that with actual sample collections – blood, hair samples, nail samples, for cyanobacterial toxins, and other things, like heavy metals,” Caller says.
Those questionnaires are now being distributed to patients in Vermont, through health care providers.
Every year, Stommel attends a meeting of researchers exploring the link between BMAA and ALS.
“Every year that I go to the meeting I’m more and more convinced that this is a real issue, and that the BMAA is a likely culprit as an environmental risk factor for ALS,” Stommel says.
Living with ALS
For people like Curtis Conover, that research is more than academic. A few years ago, Conover began experiencing some odd tightness in his hamstrings. During a doctor’s visit on Christmas Eve in 2012, Stommel told him he has ALS.
Conover handled the news well. He’s still able to enjoy walks with his wife and kids, though stairs have become something of an enemy.
“I view it as a second life,” Conover says. “There was the life that Curtis had when he was healthy and he could do everything. And there was the life from that point on. So that’s the way I view it.”
Conover is especially appreciative of efforts to find a cause, which he hopes may lead to a cure.
“You know, God forbid that anybody gets that disease. Little did I know that I’d have it, and yet still have a pretty positive outlook of hopefully, 'I can hang in with this thing long enough that they can find a cure,'” Conover says.
Too soon to worry?
The Department of Health has posted a notice on its website informing people of the research into BMAA and neurodegenerative diseases like ALS. But she says there’s no reason at this point for anyone to worry they’re at increased risk of getting those conditions.
“Worrying people unnecessarily is a concern that we would have, and this is just too limited and too preliminary to need to do that,” Cragin says.
Cragin says the state however is considering adding ALS to the list of reportable diseases, a move that would increase the amount of data available to researchers like Stommel.
“That said, it is a devastating disease that deserves more research and more investigations,” Cragin says. “And so by putting it on our list and getting more information characteristics of people that are diagnosed with ALS, we could potentially explore that, or have it available for researchers to look at.”