CrumpByronCEOASRecreationalSwimmersExposure_AppendixA.pdf
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Abstract
Vibrio vulnificus and Vibrio parahaemolyticus are ubiquitous in the marine–estuarine environment, but the
magnitude of human non-ingestion exposure to these waterborne pathogens is largely unknown. We evaluated
the magnitude of dermal exposure to V. vulnificus and V. parahaemolyticus among swimmers recreating in Vibrio-populated
waters by conducting swim studies at four swimming locations in the Chesapeake Bay in 2009 and
2011. Volunteers (n = 31) swam for set time periods, and surface water (n = 25) and handwash (n = 250)
samples were collected. Samples were analyzed for Vibrio concentrations using quantitative PCR. Linear and
logistic regressions were used to evaluate factors associated with recreational exposures. Mean surface water
V. vulnificus and V. parahaemolyticus concentrations were 1128 CFU mL⁻¹ (95% confidence interval (CI): 665.6,
1591.4) and 18 CFU mL⁻¹ (95% CI: 9.8, 26.1), respectively, across all sampling locations. Mean Vibrio concentrations
in handwash samples (V. vulnificus, 180 CFU cm⁻² (95% CI: 136.6, 222.5); V. parahaemolyticus, 3 CFU cm⁻²
(95% CI: 2.4, 3.7)) were significantly associated with Vibrio concentrations in surfacewater (V. vulnificus, p < 0.01;
V. parahaemolyticus, p < 0.01), but not with salinity or temperature (V. vulnificus, p = 0.52, p = 0.17;
V. parahaemolyticus, p = 0.82, p = 0.06). Handwashing reduced V. vulnificus and V. parahaemolyticus on subjects'
hands by approximately one log (93.9%, 89.4%, respectively). It can be concluded that when Chesapeake Bay
surface waters are characterized by elevated concentrations of Vibrio, swimmers and individuals working in
those waters could experience significant dermal exposures to V. vulnificus and V. parahaemolyticus, increasing
their risk of infection.Keywords: Vibrio parahaemolyticus, Exposure assessment, Vibrio vulnificus, Waterborne illness, Chesapeake Bay, Recreational exposureKeywords: Vibrio parahaemolyticus, Exposure assessment, Vibrio vulnificus, Waterborne illness, Chesapeake Bay, Recreational exposur