title: Investigating source water Cryptosporidium concentration, species and infectivity rates during rainfall-runoff in a multi-use catchment.
abstract: Protozoan pathogens present a significant human health concern, and prevention of contamination into potable networks remains a key focus for drinking water providers. Here, we monitored the change in Cryptosporidium concentration in source water during high flow events in a multi-use catchment. Furthermore, we investigated the diversity of Cryptosporidium species/genotypes present in the source water, and delivered an oocyst infectivity fraction. There was a positive and significant correlation between Cryptosporidium concentration and flow (ρ = 0.756) and turbidity (ρ = 0.631) for all rainfall-runoff events, despite variable source water pathogen concentrations. Cell culture assays measured oocyst infectivity and suggested an overall source water infectious fraction of 3.1%. No infectious Cryptosporidium parvum or Cryptosporidium hominis were detected, although molecular testing detected C. parvum in 7% of the samples analysed using PCR-based molecular techniques. Twelve Cryptosporidium species/genotypes were identified using molecular techniques, and were reflective of the host animals typically found in remnant vegetation and agricultural areas. The inclusion of molecular approaches to identify Cryptosporidium species and genotypes highlighted the diversity of pathogens in water, which originated from various sources across the catchment. We suggest this mixing of runoff water from a range of landuses containing diverse Cryptosporidium hosts is a key explanation for the often-cited difficulty forming strong pathogen-indicator relationships.
authors.affiliation: South Australia Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia. Electronic address: brooke.swaffer@sawater.com.au.
authors.forename: Brooke A
authors.initials: BA
authors.lastname: Swaffer
authors.affiliation: South Australia Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia.
authors.forename: Hayley M
authors.initials: HM
authors.lastname: Vial
authors.affiliation: Australian Water Quality Centre, GPO Box 1751, Adelaide, SA 5001, Australia.
authors.forename: Brendon J
authors.initials: BJ
authors.lastname: King
authors.affiliation: South Australia Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Daly
authors.affiliation: South Australia Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Frizenschaf
authors.affiliation: Australian Water Quality Centre, GPO Box 1751, Adelaide, SA 5001, Australia.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Monis
mesh_terms: D000075368:Anoctamins; D018118:Chloride Channels; D003458:Cryptosporidium / Q000235:genetics / Q000502:physiology*; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D005618:Fresh Water / Q000469:parasitology*; D005838:Genotype; D009391:Nephelometry and Turbidimetry; D033661:Oocysts / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011156:Population Density; D011891:Rain; D013021:South Australia; D014872:Water Movements; D060753:Water Quality / Q000592:standards*; D014881:Water Supply
chemical_list: C575623:Ano2 protein, rat; D000075368:Anoctamins; D018118:Chloride Channels
keywords: 18s; Drinking water; Genotyping; PCR; Pathogen; gp60