- 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- In separate but unpublished studies,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
- 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
- "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
- 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
- By DAVID MORGAN, Reuters
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.