Screening environmental indicators for viral monitoring

Aquatic ecosystems are critical screening points for human viruses as the discharge of viral pathogens in treated sewage is a reality. Thus, the present study aims to select promising aquatic matrices for viral monitoring.

A total of 41 samples comprising secondary outlet effluents, intertidal sediments, digestive gland of riverine and estuarine bivalve molluscs with different feeding behaviours, gut content of marine fish, and faecal droppings of marine birds were considered to screen genomes of the ubiquitous human polyomavirus JC (JC virus) and norovirus genogroup II (GII). To deep knowledge regarding prevention of foodborne viral infections, the efficiency of common 48-h depuration treatment of bivalves was also evaluated.

Results confirmed the presence of JC virus and norovirus GII genomes in outlet effluents and estuarine bivalves, which highlight the importance of additional disinfection methods (tertiary treatments) in wastewater treatment plants. Considering pathogenic viruses, we advance that wild estuarine suspension-feeding benthic bivalves such as cockles are good starting candidates to define environmental indicators, and that norovirus GII is considered a promising virus for routine bivalve monitoring. Results also show that 48-h depuration treatments of bivalves are not a safe option to reduce viral concentration, and, thus, increase regulatory depuration times or complement depuration with other disinfection technologies to minimize the risk of viral outbreaks through bivalve consumption are suggested.