TITLE:
Using Host-Specificity of Cryptosporidium to Understand Contaminant Sources, Seasonality, and Human Health Risk in Three Watersheds of Differing Land-Use
AUTHORS:
Janis L. Thomas, Katarina D. M. Pintar, Peter M. Wallis, Norman F. Neumann
KEYWORDS:
Cryptosporidium, Genotyping, Source Tracking, Health Risk, Water Contamination
JOURNAL NAME:
Journal of Environmental Protection,
Vol.7 No.3,
February
26,
2016
ABSTRACT:
Three tributaries of the Grand River
watershed (Ontario, Canada), each representing different watershed types
(urban, agricultural/rural, and mixed land-use) were examined to understand the
spatial, temporal, and host-source distribution of the waterborne pathogen, Cryptosporidium.
Cryptosporidium was frequently found throughout the study (73%, 65/89) with
occurrence and concentrations observed to be similar among the varying
watershed types. However, applying advanced genotyping techniques, marked
differences in dominant host sources could be observed in each watershed. The
agricultural/rural and mixed land-use watersheds were dominated by genotypes
typically associated with cattle (i.e., C. andersoni), while
the urban watershed had the highest diversity of Cryptosporidium genotypes with
a variety of wildlife as the common source of contamination (e.g., muskrat and
cervine genotypes). A similar seasonal trend observed in the urban,
agricultural, and mixed land-use watershed suggests that factors beyond
specific land use activities (e.g. autumn manure spreading) may influence the
timing and concentration of Cryptosporidium in these
streams. Corresponding genotyping results provided additional insight into
source inputs during these seasonal peaks, indicating that wildlife may be
important seasonal contributors to Cryptosporidium contamination in these streams. Despite the abundance of Cryptosporidium in these watersheds, most of the genotypes
observed were of limited human health importance. This study provides evidence
regarding the significance of including genotyping results into studies
examining waterborne Cryptosporidium. Using this technique
can provide a greater understanding of the risk to the population using water
sources, as well as provide insight into the probable sources and timing of
contamination. This ancillary information can contribute to implementation of
targeted management strategies to further protect sources of drinking water and
recreation areas.