Pfiesteria Found In East
Coast Fish Now Linked
to Memory Disorder
PHILADELPHIA (Reuters) - Researchers reported the first scientific evidence of a human health threat from Pfiesteria piscicida Thursday, saying the toxic microbe found in waterways along the U.S. East Coast was responsible for a new neurological syndrome.
Writing in The Lancet medical journal, Maryland researchers blamed the single-cell dinoflagellate for problems among 24 commercial fishermen, sportsmen and environmental workers exposed to contaminated water on Chesapeake Bay's Eastern shore last year.
The syndrome, though temporary, was marked by several disturbing symptoms including impaired memory, disorientation and learning difficulties. The symptoms were most severe among those with the highest exposure to Pfiesteria-contaminated water. But in each case, health problems began to fade after three months and were gone after six.
In separate but unpublished studies, the team of scientists from the University of Maryland and Johns Hopkins University also found evidence linking Pfiesteria to changes in brain metabolism and said contact led to skin lesions among those with the most pronounced neurological difficulties.
The health problems appeared to be caused by unidentified toxic chemicals secreted by the microorganism.
"These are extremely potent toxins," said Dr. Glenn Morris, the University of Maryland epidemiologist who heads the team.
"What this does is to open up a completely new field of research. We don't know what the toxins are or how they act.
And we don't know how they are transmitted to the brain."
Although Pfiesteria has long been identified in the press as causing health problems including memory loss, politicians and policymakers in some states have denied any threat to the public and concentrated instead on the millions of fish that have developed lesions or died in massive fish kills in contaminated waters.
New outbreaks already have been reported this year in North Carolina and Maryland.
In North Carolina, where memory problems from Pfiesteria exposure were first reported among lab workers in 1990, two epidemiologists from the U.S. Centers for Disease Control and Prevention and the state health department recently reported "no findings of any consequence" with regard to the microbe and public health.
One of those lab workers was JoAnn Burkholder of North Carolina State University, the nation's leading Pfiesteria researcher, who has suffered 11 bouts of pneumonia over the past three years and suspects her respiratory problems are due to the microbe.
Pfiesteria's emergence as a toxic organism has stirred health concerns and political controversy in state capitals along the East Coast from Delaware to the Carolinas, as well as in Congress. Outbreaks are being monitored by officials in six states and studied by both the CDC and the U.S. Environmental Protection Agency.
Operators of so-called factory farms, which raise poultry and other animals, have come under fire from environmentalists who say nitrate-rich runoff from the huge operations has allowed Pfiesteria to flourish.
And in Maryland, where a major outbreak of Pfiesteria forced state officials to close three Chesapeake tributaries last year, the seafood industry saw sales plunge by more than $40 million as consumers panicked over a supposed threat to local fisheries.
"To date, there is no evidence that eating fish causes a human health problem," said neuropsychologist Lynn Grattan, who authored the Lancet article.
What the Maryland scientists did find was that some sufferers would set out by car on an errand only to forget where they were going and what they had planned to do once they got there. Watermen, who had both the greatest exposure to contaminated water and the most severe symptoms, forgot basic fishing equipment before setting off in their boats.
Researchers, saying people's ability to take in new information was most greatly impaired, speculated that further study could shed new light not only on Pfiesteria but on the learning process in general.

DOVER, Del. (AP) - A medical journal has lent credibility to research that suggests a toxic microorganism deadly to fish also can cause memory and attention loss in humans.
The Lancet journal reported in its Aug. 15 issue that doctors and neurologists have examined people who complained of medical problems after coming into contact with the toxic organism Pfiesteria on the Pocomoke River.
Pfiesteria is a harmless one-celled organism unless something triggers it to change form and emit a poison that attacks fish, allowing the organism to feed on them until they die.
According to the research, 19 people exposed to the Pocomoke River showed ``deficits in learning and selective and divided attention'' when compared to 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.
While the research had been reported earlier, it had not undergone close scrutiny by other scientists before The Lancet's peer review board studied it.
``We have moved from public controversy to hard scientific data,'' said Dr. J. Glenn Morris Jr., who headed the medical research team. ``This puts the spotlight on the human health issues, where it belongs.''
Men who work along the Pocomoke began complaining of health problems such as fatigue, headaches, diarrhea, weight loss as early as 1996 - the same time fish began appearing with lesions and sores in their nets.
Last year, the problems returned, and Pfiesteria and another microorganism were implicated. Thousands of fish were killed and the river was shut down by government officials. At that 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.
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 in six months.