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Notice to Readers: Possible Estuary-Associated Syndrome

Pfiesteria piscicida (Pp) is an estuarine dinoflagellate that has been associated with fish kill events in estuaries along the eastern seaboard and possibly with human health effects (1,2). CDC, in collaboration with other federal, state, and local government agencies and academic institutions, is conducting multistate surveillance, epidemiologic studies, and laboratory research for possible estuary-associated syndrome (PEAS), including possible Pp-related human illness.

The surveillance system tracks PEAS rather than Pp-related illness because a Pp toxin(s) has not been identified and therefore a biomarker of exposure has not been developed. Detection of Pp or fish with lesions in water has been used as evidence of suspected Pp toxin(s) (3). However, Pp has been found in waters where there were no reports of harm to fish or persons. In addition, lesions on fish can result from various biologic, physical, and environmental factors. Therefore, detecting Pp or observing fish with lesions may not be indicative of the presence of putative Pp toxin(s).

PEAS surveillance criteria resulted from a series of CDC-sponsored multistate workshops and differ from criteria developed in 1997 (3). Persons are considered to have PEAS if 1) they report developing symptoms within 2 weeks after exposure to estuarine water; 2) they report memory loss or confusion of any duration and/or three or more selected symptoms (i.e., headache, skin rash at the site of water contact, sensation of burning skin, eye irritation, upper respiratory irritation, muscle cramps, and gastrointestinal symptoms) that--with the exception of skin rash at the site of water contact and sensation of burning skin--persist for greater than or equal to 2 weeks; and 3) a health-care provider cannot identify another cause for the symptoms.

It is unclear whether persons exposed to Pp while swimming, boating, or engaging in other recreational activities in coastal waters are at risk for developing illness. PEAS is not infectious and has not been associated with eating fish or shellfish caught in waters where Pp has been found. However, persons should avoid areas with large numbers of diseased, dying, or dead fish and should promptly report the event to the state's environmental or natural resource agency. In addition, persons should not go in or near the water in areas that are closed officially by the state and should not harvest or eat fish or shellfish from these areas. Persons who experience health problems after exposure to estuarine water, a fish-disease event, or a fish-kill site should contact their health-care provider and state or local public health agency.

Several states have established PEAS information lines: Delaware, (800) 523-3336; Florida, (888) 232-8635; Maryland, (888) 584-3110; North Carolina, (888) 823-6915; South Carolina, (888) 481-0125; and Virginia, (888) 238-6154.

Reported by: AL Hathcock, PhD, Delaware Dept of Health and Social Svcs. B Hughes, PhD, Florida Dept of Health. D Matuszak, MD, Maryland Dept of Health and Mental Hygiene. JS Cline, DDS, North Carolina Dept of Health and Human Svcs. R Ball, MD, South Carolina Dept of Health and Environmental Control. S Jenkins, VMD, Virginia Dept of Health. Health Studies Br and Surveillance Br, Div of Environmental Hazards and Health Effects, Div of Environmental Health and Laboratory Sciences, National Center for Environmental Health, CDC.


  1. Smith CG, Music SI. Pfiesteria in North Carolina: the medical inquiry continues. North Carolina Medical Journal 1998;59:216-9.
  2. Grattan LM, Oldach D, Tracy JK, et al. Learning and memory difficulties after environmental exposure to waterways containing toxin-producing Pfiesteria or Pfiesteria-like dinoflagellates. Lancet 1998;352:532-9.
  3. CDC. Results of the public health response to Pfiesteria workshop--Atlanta, Georgia, September 29-30, 1997. MMWR 1997;46:951-2.

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