Quantitative detection of pathogens in roof-harvested rainwater

Abstract

Roof-harvested rainwater is an alternative water source. Though generally considered acceptable for potable use, the presence of pathogens has been reported in research literature. Various zoonotic pathogens are present in faeces of animals that have access to the roof and, following rain events, pathogens may be transported to rainwater tanks via roof runoff. The microbiological quality of water is traditionally assessed by enumerating faecal indicators such as Escherichia coli and enterococci. Significant limitations in using faecal indicators include their poor correlation with pathogens and faecal indicator concentrations cannot be used to assess public health risk when compared to the direct monitoring of pathogens. Polymerase chain reaction (PCR)-based techniques enable rapid and direct detection/quantification of pathogens in water that are otherwise laborious to culture using traditional microbiological methods.