Human Pathogenic Viruses in the Marine Environment

Indigenous marine virus strains outnumber any form of life in the sea, usually occurring in billion amounts per liter (Danovaro et al., 2001; Fuhrman, 1999). However, although transspecific propagation of viruses may take place, the virus–host relationship tends to be quite constrained, and consequently human viruses are the only viral agents of public health concern in the marine environment. Pathogenic viruses are routinely introduced into marine and estuarine waters through the discharge of treated and untreated sewage, since urrent water treatment practices are unable to provide virus-free wastewater effluents (Rao & Melnick, 1986). It is estimated that the number of cases of gastrointestinal illness annually reported worldwide accounts for billions (Oh et al., 2003; Parashar et al., 1998). A good deal of these diarrheal cases are to some extent the result of the fecal contamination of the marine environment (Cabelli et al., 1982; Fattal & Shuval, 1989; Koopman et al., 1982; Moore et al., 1994), while enterically transmitted hepatitis outbreaks, i.e. hepatitis A and E, have been reported to be associated to water and shellfish (Bosch et al., 1991, 2001; Halliday et al., 1991; Melnick, 1957; Reid & Robinson, 1987). The maintenance and assessment of the virological quality and safety of marine water systems employed for recreating and seafood harvesting is of seminal importance in the prevention of diseases transmitted through the fecal–oral route, and may lead to significant reductions of economic losses due to the closures of tourists resorts and shellfish harvesting areas. For this purpose, it is imperative to trace and characterize the type and origin of fecal contaminants in order to assess the associated health threat and the required corrective measures.