A year after a spate of reports that Pocomoke River watermen were becoming ill from pfiesteria, a Maryland medical team’s findings have been published in a well-known journal, strengthening the claim that the toxic microorganism that kills fish can cause attention and memory loss in humans.
Doctors and neurologists who worked with the team in examining the watermen and others apparently affected by Pfiesteria piscicida reported in the Aug. 15 issue of The Lancet that their findings support a new clinical syndrome apparently caused by pfiesteria’s toxins.
Nineteen people exposed to the river showed “deficits in learning and selective and divided attention” when compared with a control group picked by age, sex and occupation. The longer the exposure at the time pfiesteria was active, the worse the problems seemed to be, the team reported. The research had been reported earlier, but had not undergone close scrutiny by other scientists until The Lancet’s peer review board studied it before publishing the article.
“When the media and the public looked at it last year, it became a matter of public opinion,” said Lynn Grattan, a neuropsychologist at the University of Maryland, who wrote the paper and administered last year’s tests. “When it appears in the medical journal, it takes it out of the realm of public opinion.”
Dr. J. Glenn Morris Jr., who headed the team, agreed. “We have moved from public controversy to hard scientific data,” he said. “This puts the spotlight on the human health issues, where it belongs.”
Watermen on the Pocomoke began complaining of health problems — fatigue, headaches, diarrhea, weight loss — as early as 1996, when they began seeing fish with lesions and sores in their nets.
Last year, the problems returned and a fish kill in August closed the river. Pfiesteria and another microorganism of the same type were implicated. At the same time, the medical team began meeting with watermen and other area residents who had complained of illnesses.
While no consistent physical symptoms could be found, the team found a correlation between exposure to the river at the time the toxins were active to memory loss and a lack of attention.
In The Lancet article, the researchers describe people forgetting where they were driving to and watermen forgetting to put needed supplies on their boats.
The 19 people tested had a much harder time remembering words from lists, matching numbers and letters on a diagram, and placing pegs in a grooved board than the control group.
The report said follow-up studies showed most people recovered after three months, and the rest by six months.
Meanwhile, two North Carolina Health Department employees who expressed their skepticism about pfiesteria’s threat to human health have been demoted.
Dr. Stan Music, a former public health section chief, was demoted by Dr. Dennis McBride shortly after he arrived as the new state health director this spring. And this month, longtime epidemiologist Dr. Greg Smith was transferred from his job as an environmental hazard sleuth.
The two men most recently authored a N.C. Medical Journal article saying no conclusive evidence exists that pfiesteria is dangerous.