Microbiological and physicochemical analysis of coastal waters impacted by point sources pollution in southwestern Morocco

Viral and bacterial contamination of recreational coastal water is a rising public health concern. The aim of our study was to conduct a preliminary evaluation of the presence of indicator virus and pathogens in seawater, sand and mussels at recreational marine beaches in Southern Morocco. Forty six samples (mussels, sand and seawater) were collected from Dar Bouazza region and tested for the presence of enteric viruses by (qPCR) and viral viability by integrated cell culture-PCR (ICC-PCR) assay. The samples were collected from three beaches points and seawater was filtered by HA membrane for viruses concentration. Our results showed that 33% of seawater samples, 50% of mussels samples and 18% of sand samples were tested positive for enteroviruses. Human adenovirus was the most prevalent virus detected (33%) in seawater samples, followed by polyomavirus JC (11%). Mussels were positive for norovirus GI, Norovirus GII and rotavirus A in (36%), (11%) and (33%) of samples respectively. HAV was not present in any samples. The fecal indicator bacteria (FIB) levels exceeded regulatory thresholds in 26% of seawater samples for Escherichia coli and Enterococcus and 9% of them showed the presence of viruses. No correlation was demonstrated between bacterial contamination and virus presence. However, a possible correlation was showed between salinity and virus presence. This data reflected the viral contamination of recreational waters and suggested that human adenoviruses should be an index for human fecal pollution in conjunction with FIB. The presence of enteric viruses in marine samples may constitute a potential public health risk for shellfish consumers and swimmers. Therefore viral parameters should be adapted for monitoring the beach water quality and shellfish safety.