Biomonitoring of surface and coastal water for Cryptosporidium , Giardia , and human-virulent microsporidia using molluscan shellfish

Surface inland and coastal waters in Ireland were surveyed for the human waterborne enteropathogens; Cryptosporidium parvum , Giardia lamblia, Encephalitozoon intestinalis , Encephalitozoon hellem , and Enterocytozoon bieneusi by utilizing bivalve mussel species, i.e., Mytilus edulis (blue mussel), Anodonta anatina (duck ‘mussel’, actually a unionid clam), and the invasive Dreissena polymorpha (zebra mussel) as biomonitors at twelve sites located in three Irish river-basin districts with various water-quality pressures. Biomolecular techniques were utilized to assess the presence and concentration of these pathogens. At least one pathogen species was detected in shellfish at each site. Cryptosporidium , implicated in several recent Irish gastrointestinal epidemics, was recorded at all sites subjected to agricultural runoff and at one sewage discharge site, linking source-track directly to human and animal fecal wastes. G . lamblia was present at eleven of the twelve sites in a range of concentrations. A coastal bay with raw urban sewage discharge was 100% positive for all analyzed enteropathogens. Overall, the results demonstrate long-term human enteropathogen contamination of Irish waters with consequent public-health risk factors for drinking-water abstraction and water-based activities.