Tracking host sources of Cryptosporidium spp. in raw water for improved health risk assessment.
Recent molecular evidence suggests that different species and/or genotypes of Cryptosporidium display strong host specificity, altering our perceptions regarding the zoonotic potential of this parasite. Molecular forensic profiling of the small-subunit rRNA gene from oocysts enumerated on microscope slides by U.S. Environmental Protection Agency method 1623 was used to identify the range and prevalence of Cryptosporidium species and genotypes in the South Nation watershed in Ontario, Canada. Fourteen sites within the watershed were monitored weekly for 10 weeks to assess the occurrence, molecular composition, and host sources of Cryptosporidium parasites impacting water within the region. Cryptosporidium andersoni, Cryptosporidium muskrat genotype II, Cryptosporidium cervine genotype, C. baileyi, C. parvum, Cryptosporidium muskrat genotype I, the Cryptosporidium fox genotype, genotype W1, and genotype W12 were detected in the watershed. The molecular composition of the Cryptosporidium parasites, supported by general land use analysis, indicated that mature cattle were likely the main source of contamination of the watershed. Deer, muskrats, voles, birds, and other wildlife species, in addition to sewage (human or agricultural) may also potentially impact water quality within the study area. Source water protection studies that use land use analysis with molecular genotyping of Cryptosporidium parasites may provide a more robust source-tracking tool to characterize fecal impacts in a watershed. Moreover, the information is vital for assessing environmental and human health risks posed by water contaminated with zoonotic and/or anthroponotic forms of Cryptosporidium.
Ruecker
Norma J
NJ
Alberta Provincial Laboratory for Public Health (Microbiology), and Department of Microbiology and Infectious Diseases, University of Calgary, 3030 Hospital Drive NW, Calgary, Alberta, Canada T2N 4W4.
Braithwaite
Shannon L
SL
Topp
Edward
E
Edge
Thomas
T
Lapen
David R
DR
Wilkes
Graham
G
Robertson
Will
W
Medeiros
Diane
D
Sensen
Christoph W
CW
Neumann
Norman F
NF
D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D003458:Cryptosporidium / Q000235:genetics*; D005243:Feces / Q000469:parasitology; D014644:Genetic Variation; D005838:Genotype; D008969:Molecular Sequence Data; D009864:Ontario; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D021521:Ribotyping; D045483:Rivers / Q000469:parasitology*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D012335:RNA, Ribosomal