Cryptosporidium Source Tracking in the Potomac River Watershed

Abstract

To better characterize Cryptosporidium in the Potomac River watershed, a PCR-based genotyping tool was used to analyze 64 base flow and 28 storm flow samples from five sites in the watershed. These sites included two water treatment plant intakes, as well as three upstream sites, each associated with a different type of land use. The uses, including urban wastewater, agricultural (cattle) wastewater, and wildlife, posed different risks in terms of the potential contribution of Cryptosporidium oocysts to the source water. Cryptosporidium was detected in 27 base flow water samples and 23 storm flow water samples. The most frequently detected species was C. andersoni (detected in 41 samples), while 14 other species or genotypes, almost all wildlife associated, were occasionally detected. The two common human-pathogenic species, C. hominis and C. parvum, were not detected. Although C. andersoni was common at all four sites influenced by agriculture, it was largely absent at the urban wastewater site. There were very few positive samples as determined by Environmental Protection Agency method 1623 at any site; only 8 of 90 samples analyzed (9%) were positive for Cryptosporidium as determined by microscopy. The genotyping results suggest that many of the Cryptosporidium oocysts in the water treatment plant source waters were from old calves and adult cattle and might not pose a significant risk to human health.

Identification of Cryptosporidium Species and Genotypes in Scottish Raw and Drinking Waters during a One-Year Monitoring Period

“…A 15-month study in the Potomac River watershed that analyzed a total of 92 water samples has reported the identification of 15 Cryptosporidium species/genotypes in 50 Cryptosporidium-positive samples by PCR-RFLP and sequencing, of which C. andersoni was the most common species (41 PCR-positive samples) compared to wildlife genotypes (14 samples). C. andersoni was the species presenting the highest level of contamination inferred from the rates of PCR amplification of 5 replicates compared to the wildlife species/genotypes identified by the same study (30). Likewise, C. andersoni, C. baileyi, and the Cryptosporidium skunk genotype were predominant species in samples from the Oldman River, Canada (14).…”

Cryptosporidiumspecies in Australian wildlife and domestic animals

“…In addition, many studies have reported that C. andersoni, which is predominantly a parasite of adult cattle, C. ubiquitum, which is a common Cryptosporidium species in sheep and C. parvum are the dominant Cryptosporidium species detected in watersheds and raw and drinking water (Yang et al 2008;Ruecker et al 2007;Nichols et al 2010;Smith and Nichols, 2010). In addition, the high density of cattle and sheep across Australia, which contribute a large volume of manure to catchments indicate that they are the main species that present a risk to public health in Australian catchments.…”

Cryptosporidium testudinis sp. n., Cryptosporidium ducismarci Traversa, 2010 and Cryptosporidium tortoise genotype III (Apicomplexa: Cryptosporidiidae) in tortoises

“…Fresh faecal samples were collected from the floor (box, terrarium) immediately after defecation and each sample was placed into a separate plastic tube without fixative. Yang et al (2008) NS -origin of the host (country) was not specified in the manuscript.…”