Occupational exposure to pfiesteria species in estuarine waters is not a risk factor for illness.
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.
Morris
J Glenn
JG
Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA. jmorris@epi.umaryland.edu
Grattan
Lynn M
LM
Wilson
Leslie A
LA
Meyer
Walter A
WA
McCarter
Robert
R
Bowers
Holly A
HA
Hebel
J Richard
JR
Matuszak
Diane L
DL
Oldach
David W
DW
D000328:Adult; D000368:Aged; D000818:Animals; D004141:Dinoflagellida / Q000145:classification / Q000502:physiology*; D006801:Humans; D008297:Male; D008396:Maryland; D008875:Middle Aged; D016273:Occupational Exposure; D009792:Oceans and Seas; D011528:Protozoan Infections / Q000469:parasitology; D012307:Risk Factors; D045483:Rivers; D013997:Time Factors; D014768:Virginia