Enterovirus detection in storm drain-impacted waters along the shoreline of the Southern California Bight

Assays for the detection of enteroviruses by reverse transcriptase-polymerase chain reaction (RT-PCR) were performed on coastal seawater samples taken at 15 randomly selected freshwater outlet sites along the shoreline of the Southern California Bight (SCB). All of the sites from which these samples were taken are influenced year-round by urban runoff and many are proximal to highuse sandy beaches that are recreational “hot spots” in southern California. Reverse transcriptase-PCR (RT-PCR) is a primer-based molecular biology technique that can be used to detect specific groups or types of viruses based upon the complementarity of primer sequences with conserved sequences in viral genomes. Pan-enterovirus primers were used for the detection of enteroviruses, the family of which includes poliovirus, Coxsackievirus, and echovirus. The results of our analyses showed that the concentration methods and RT-PCR protocol can be used consistently to detect enterovirus genomes from 20l samples of coastal seawater. Results were presence-absence for enterovirus detection. In addition, a most probable number (MPN) approach was used to estimate the number of viral genomes present in each sample. Of the 15 samples taken, 7 were positive for enteroviruses. Results of the virus estimates did not demonstrate a strong significant logistical or rank correlation to total and fecal coliforms, or enterococci (p > 0.05). However, a weak logistical correlation was observed between fecal coliforms and the detection of enteroviruses. Our results demonstrate that enteroviruses, which are indicative of local human fecal contamination, are found in nearly half of the freshwater outlets in southern California. Since enteroviruses are known to be causative agents of disease in humans from recreational water contact, the analysis of their presence will assist managers in protecting the public health at high-risk locations (e.g., high-use sandy beaches) or during certain seasons of the year. INTRODUCTION The beaches of southern California are popular destinations for recreation, water contact sports, and relaxation. However, serious concerns have been raised by the public, government agencies, and the scientific community about ocean water quality, particularly in areas heavily impacted by urban runoff. In southern California, the main sources of urban runoff are freshwater outlets (more specifically, the concrete-lined drains and rivers that empty the watershed of the entire region). Many of these freshwater outlet locations directly impact “high-use” sandy beaches that are vital to the economy of the region. Although waterborne illnesses in humans can be caused by protozoa, bacteria, and viruses, methodological limitations have until recently forced monitoring to focus only on the use of bacterial indicators such as total and fecal coliforms and enterococci. However, the time required to produce results with bacterial indicator analysis can delay management action (e.g., beach closure or posting) following a deterioration in water quality from activities such as a storm event or illicit dumping. Also, indicator bacteria cannot always be cultured effectively when introduced into aquatic environments; traditional plate counts often dramatically underestimate actual bacterial concentrations (Byrd et al. 1991). As a result, human pathogenic viruses are not monitored routinely in coastal waters and no guidelines or thresholds have been established for viral indicators. Viruses have been shown to cause a significant portion of the waterborne diseases transmitted to humans through water contact, mostly from the ingestion of sewagecontaminated water and contaminated seafood (Fogarty et al. 1995). Large numbers of viruses are excreted in the