Quantifying Vibrio Infection Risks From Beach Recreation Along U.S. Eastern Seaboard in Year 2100

Marine vibrios, a group of marine bacteria that are opportunist human pathogens, proliferates faster in coastal environments at warmer temperature. Recently, there have been significant concerns of human infection risks during marine beach recreations due to the elevation of seawater temperature in the United States Eastern Seaboard. This study carried out a quantitative microbial risk assessment (QMRA) to estimate health risks associated with V. vulnificus and V. parahaemolyticus infections from water ingestion during recreational activities under varying climate scenarios that predict sea surface temperatures (SSTs) in the next 75 years. Monte Carlo simulations that incorporate Vibrio concentrations at specific SSTs, ingestion dose during recreational activities, and dose-response relationships were applied to predict the probability of infection under varying exposure scenarios. The risk of Vibrio infections along the U.S. Eastern Seaboard was first estimate for the year 2020 based on measured SSTs. The same approach was applied to predict the risk in the year 2100 based on projected SSTs using two IPCC Representative Concentration Pathways (RCP) scenarios: RCP 2.6 and RCP 8.5. The results indicate that the median risks of V. vulnificus and V. parahaemolyticus from recreational activities along the Eastern Seaboard increase significantly from 2020 to 2100, with rises of up to 1,000-fold under RCP 8.5 and up to 100-fold under RCP 2.6. Furthermore, the estimated risks represent a conservative lower-bound of vibrio-related health impacts because wound infection from water contact was not included. This study highlights the growing public health concern and the need for adaptive management strategies.