Prevalence, environmental loading, and molecular characterization of Cryptosporidium and Giardia
Applied and Environmental Microbiology

By: , and 

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Abstract

The risk of disease transmission from waterborne protozoa is often dependent on the origin (e.g., domestic animals versus wildlife), overall parasite load in contaminated waterways, and parasite genotype, with infections being linked to runoff or direct deposition of domestic animal and wildlife feces. Fecal samples collected from domestic animals and wildlife along the central California coast were screened to (i) compare the prevalence and associated risk factors for fecal shedding of Cryptosporidium and Giardia species parasites, (ii) evaluate the relative importance of animal host groups that contribute to pathogen loading in coastal ecosystems, and (iii) characterize zoonotic and host-specific genotypes. Overall, 6% of fecal samples tested during 2007 to 2010 were positive for Cryptosporidium oocysts and 15% were positive for Giardia cysts. Animal host group and age class were significantly associated with detection of Cryptosporidium and Giardia parasites in animal feces. Fecal loading analysis revealed that infected beef cattle potentially contribute the greatest parasite load relative to other host groups, followed by wild canids. Beef cattle, however, shed host-specific, minimally zoonotic Cryptosporidium and Giardia duodenalis genotypes, whereas wild canids shed potentially zoonotic genotypes, including G. duodenalis assemblages A and B. Given that the parasite genotypes detected in cattle were not zoonotic, the public health risk posed by protozoan parasite shedding in cattle feces may be lower than that posed by other animals, such as wild canids, that routinely shed zoonotic genotypes.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Prevalence, environmental loading, and molecular characterization of Cryptosporidium and Giardia
Series title Applied and Environmental Microbiology
DOI 10.1128/AEM.02422-12
Volume 78
Issue 24
Year Published 2012
Language English
Publisher American Society for Microbiology
Contributing office(s) Western Ecological Research Center
Description 11 p.
First page 8762
Last page 8772
Country United States
State California
Other Geospatial Monterey Bay