Surveillance of Enteric Viruses, Enterococci, and PMMoV in Sargassum-Impacted Coastal Waters in the Mexican Caribbean
摘要
The atypical arrival of Sargassum spp. along the Mexican Caribbean coast has raised environmental and public health concerns. This study assessed the occurrence of enteric viruses—Human adenovirus (HAdV), Norovirus genogroups I and II (NoV GI, GII), Aichi virus (AiV)—and the viral indicator Pepper mild mottle virus (PMMoV) in seawater during Sargassum tides (2020–2021) and in Sargassum-free conditions (2022). Seawater samples (15 L) were collected seasonally and processed using ultrafiltration and adsorption-elution methods, followed by nucleic acid extraction and quantification via qPCR/RT-qPCR. Enterococci were detected in all samples collected during Sargassum tides, where 87% (7/8) of the samples met recreational water quality standards (< 200 MPN/100 mL). NoV GI and GII were detected in all Sargassum-associated samples (102–103 and 101–103 genome copies/L, respectively), while HAdV and AiV were found in 50% of samples (101–102 GC/L). In contrast, in Sargassum-free seawater, HAdV and NoV GII were detected in 66% of the samples (102 to 104 GC/L, respectively), NoV GI was detected only in 33% of the samples (102 GC/L), and AiV was not detected. PMMoV was consistently present, with higher concentrations during Sargassum tides (102–104GC/L) compared to Sargassum-free periods (up to 102 GC/L). A significant difference was observed in the viral concentration profile detected in Sargassum tides compared to Sargassum-free seawater. These findings suggest that Sargassum tides may influence the occurrence and concentration of fecal-associated viruses in coastal waters. The detection of enteric virus genomes in recreational seawater highlights potential public health risks and underscores the need for integrated coastal monitoring strategies in regions affected by macroalgal influxes.