| Occupational Exposure to Pfiesteria Species in Estuarine Waters Is Not a Risk Factor for Illness J. Glenn Morris Jr.,1 Lynn M. Grattan,2 Leslie A. Wilson,1 Walter A. Meyer,1 Robert McCarter,1 Holly A. Bowers,3 J. Richard Hebel,1 Diane L. Matuszak,1,4 and David W. Oldach3 1Department of Epidemiology and Preventive Medicine, and 2Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, USA; 3Institute for Human Virology, University of Maryland Biotechnology Institute, and Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA; 4Maryland Department of Health and Mental Hygiene, Baltimore, Maryland, USA Abstract
Background: Exposure to the dinoflagellate Pfiesteria has, under certain circumstances, been associated with deficits in human learning and memory. However, uncertainties remain about the health risk of chronic, low-level exposures (as seen among occupationally exposed commercial fishermen) , particularly in light of studies suggesting that Pfiesteria strains are widespread in the estuarine environment in the U.S. mid-Atlantic region. Methods: We selected an initial cohort of 152 persons, including 123 persons with regular, occupational exposure to the Chesapeake Bay ; 107 of the cohort members were followed for the full four summer "seasons" of the study. Cohort members were questioned biweekly about symptoms, and data were collected about the areas of the bay in which they worked. These latter data were matched with data on the presence or absence of Pfiesteria in each area, based on polymerase chain reaction analysis of > 3,500 water samples. Cohort members underwent neuropsychological testing at the beginning and end of each summer season. Results: No correlation was found between work in an area where Pfiesteria was identified and specific symptomatology or changes on neuropsychological tests. Conclusions: Although high-level or outbreak-associated exposure to Pfiesteria species (or specific strains within a species) may have an effect on health, routine occupational exposure to estuarine environments in which these organisms are present does not appear to pose a significant health risk. Key words: commercial fishermen, dinoflagellates, environmental toxins, neuropsychological testing, occupational health, Pfiesteria. Environ Health Perspect 114:1038–1043 (2006) . doi:10.1289/ehp.8627 available via http://dx.doi.org/ [Online 18 April 2006]
Address correspondence to J.G. Morris Jr., Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Room 934, 10 S. Pine St., Baltimore, MD 21201 USA. Telephone: (410) 706-4580. Fax: (410) 706-4581. E-mail: jmorris@epi.umaryland.edu We acknowledge the able assistance of D. Haslow, J. Besso, D. McWilliams, P.J. Twilley, M. King-Dagen, C. Fishburn, M. Lawson, C. Williamson, J. Young, S. Crockett, C. Wilson, J. Graber, and K. Volpini, who played critical roles in the study. Field sampling was made possible through an invaluable collaboration with the Maryland Department of Natural Resources in a program led by R. Magnien, D. Goshorn, P. Tango, and B. Michael. O. Selnes provided key consultation on the neuropsychological studies. We thank the study participants, whose continuing interest and dedication made the study possible. These studies were conducted with funding awarded to the Maryland Department of Health and Mental Hygiene by the Centers for Disease Control and Prevention (grant U50/CCU315411) . The authors declare they have no competing financial interests. Received 2 September 2005 ; accepted 18 April 2006.
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