Among the many waterborne disease-causing viruses are hepatitis A and Norwalk; the pathogenic protozoa include Cryptosporidium, Entamoeba and Giardia.

• 而主要的水媒病毒为A型肝炎病毒及诺华克病毒；会引起疾病的原生动物，则包括隐孢子虫、内阿米巴原虫、梨形鞭毛虫等。