Protozoan pathogens Blastocystis and Giardia spp. in roof-harvested rainwater: the need to investigate the role of the common brushtail possum (Trichosurus vulpecula) and other potential sources of zoonotic transmission

Abstract

Abstract Globally, protozoan pathogens are an increasingly important cause of reported disease outbreaks, with the majority of documented outbreaks between 2004 and 2010 reported in Australia. While the microbiological contamination of roof-harvested rainwater (RHRW) has been well studied, limited information is available regarding contamination with protozoan pathogens. In this study, rainwater (n = 134) and possum fecal samples (n = 20) were screened for the presence of several protozoan pathogens, including Blastocystis spp., Cryptosporidium spp., Giardia spp., Dientamoeba fragilis, and Entamoeba histolytica using the multiplex real-time polymerase chain reaction. While Cryptosporidium spp. was only detected in two possum fecal samples (10%) and Giardia spp. was only detected in three RHRW samples (2.23%, n = 134), Blastocystis spp. was detected in both possum feces (25%) and RHRW (5.22%) samples. Dientamoeba fragilis and Entamoeba histolytica were not detected in any samples. These findings highlight protozoan pathogens as a potentially important area of focus for rainwater quality assessment. Furthermore, while possums are suggested as a potential source of Blastocystis spp. in RHRW, sources of this pathogen in RHRW warrant further investigation.