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How Many People Got Sick?
Illness Is Real, But Rare

By Michael W. Fincham

Comparison of Diseases in
Maryland, 1997-2006


# Cases Reported

Legionellosis (caused by aquatic bacterium) 671
Lyme Disease 7692
Rabies 4090
PEAS (Possible Estuarine-Associated Syndrome) <30 to 57?

Source: Legionellosis, Lyme Disease and Rabies, tallied from cases reported by the Centers for Disease Control (CDC); Possible Estuarine-Associated Syndrome (PEAS), estimated from cases cited in articles published in Lancet and Environmental Health Perspectives and on interviews with Glenn Morris, University of Maryland School of Medicine and Ritchie Shoemaker, family practice physician, Pocomoke City.

The syndrome never had a name that stuck for long. It's been called "the Pfiesteria thing," the Pocomoke syndrome, the Estuarine-Associated Syndrome, and finally the Possible Estuary-Associated Syndrome, or PEAS.

It started with 13 cases from the Pocomoke River, a number that would never grow much larger over the years, in part because the definition of the disease was never very clear. Ten years later, it's not even clear how many people in Maryland really got sick.

In August 1997, eight watermen, four state workers, and a housewife from the Pocomoke River were all diagnosed with odd mental symptoms including concentration problems and loss of short-term memory. The diagnosis came from a medical team recruited from the University of Maryland and Johns Hopkins University and led by Dr. Glenn Morris.

Something in the water seemed to be making them sick, and the suspected cause was exposure to waters with sick fish and with some kind of toxin — perhaps released by Pfiesteria or by other dinoflagellates that could be releasing a toxin in the water.

Scientists, however, were unable to identify a toxin, so officials with the U.S. Centers for Disease Control (CDC) chose not to label this as a Pfiesteria-related syndrome. They first defined these Pocomoke cases as Estuary-Associated Syndrome (EAS) and then as Possible Estuary-Associated Syndrome (PEAS). They also asked states along the coast to expand their existing surveillance systems and to report back on people affected by PEAS-like symptoms.

So how many people over 10 years have gotten sick with this syndrome? Neither state nor federal agencies have an official count. "The surveillance system for PEAS kind of fell apart," says Lorraine Backer, of the CDC. "There wasn't¬ a lot going on, and the states just stopped reporting to us," she says. "So we don't really have a good handle on what the final vetted numbers were for Maryland."

The unofficial numbers seem to be: not very many. Current estimates come from two Maryland doctors who first diagnosed sick watermen in 1997 and now disagree about the nature of the diagnosis and the number of people affected.

If you listen to Ritchie Shoemaker, the outspoken family practice physician from Pocomoke City, you get a number somewhere north of 50 cases. He lists 37 cases he diagnosed for a 2001 research study, and he estimates he has since then treated an additional 20 PEAS patients. That brings his total to 57 cases, not a large number spread over 10 years.

If you listen to Glenn Morris, the leader of the university-based research team, you get a lower estimate, somewhere south of 30. In 1998, the university team published a study listing only 19 cases from exposures in Maryland waters. Since then, the team has diagnosed more cases, but Morris now has his doubts that all those new cases came from exposure to a toxic algal bloom. "What I would be most comfortable saying is that there were less than a dozen (new cases)," he now says. "And it could be zero."

So whom do you listen to? The small-town doctor or the university researcher? It was Ritchie Shoemaker, ironically enough, who first pushed the medical establishment to examine those watermen who said the river was making them sick. A decade later, Shoemaker is still pushing to publicize the syndrome, but now he is pushing against Morris and the university team that originally confirmed his claims.

Their disagreements center on disease definition and diagnostic technique. For his diagnosis Shoemaker relies on an interview, a series of lab tests, and an eye test called Visual Contrast Sensitivity (VCS). Morris prefers neurocognitve testing, but he has his doubts about any diagnostic tool, including VCS. Until a toxin is purified and tested, there will be no gold standard for identifying its presence in the region's rivers or in a person's bloodstream. "There isn't a definitive diagnostic test," says Morris. "It's not like you can draw a blood sample and say, 'Yep, he's got it.'"

Absence of evidence, of course, is not evidence of absence. Toxic blooms do break out and people can get sick. According to Morris, the university researcher, the Pocomoke syndrome — whatever the cause — is real, but rare. According to Shoemaker, the small-town researcher, even a single case of illness is worrisome: it means others can become ill also and never realize the river could be making them sick.

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