Watershed use and Giardia cyst presence

Ongerth, Jerry E.; Hunter, Gary; DeWalle, Foppe B.

doi:10.1016/0043-1354(94)00271-8

Cited by 26 publications

(18 citation statements)

References 5 publications

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confidence: 99%

“…The reported frequencies of occurrences of contamination of surface water with Giardia and Cryptosporidium are from 60 to 96% in the United States (12,22) and from 20 to 64% in Canada (11,36). Their levels in surface waters are very low, ranging from 0.5 to 5,000 organisms in 100 liters of water (11,21,22,23,36). It has been proposed that action levels to prevent outbreaks with these protozoa should occur when concentrations in 100 liters of water sampled are Ͼ5 Giardia cysts (37) and 10 to 30 oocysts of Cryptosporidium (6).…”

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Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage

Guy

Payment²,

Krull

et al. 2003

Appl Environ Microbiol

350

244

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The protozoan pathogens Giardia lamblia and Cryptosporidium parvum are major causes of waterborne enteric disease throughout the world. Improved detection methods that are very sensitive and rapid are urgently needed. This is especially the case for analysis of environmental water samples in which the densities of Giardia and Cryptosporidium are very low. Primers and TaqMan probes based on the ␤-giardin gene of G. lamblia and the COWP gene of C. parvum were developed and used to detect DNA concentrations over a range of 7 orders of magnitude. It was possible to detect DNA to the equivalent of a single cyst of G. lamblia and one oocyst of C. parvum. A multiplex real-time PCR (qPCR) assay for simultaneous detection of G. lamblia and C. parvum resulted in comparable levels of detection. Comparison of DNA extraction methodologies to maximize DNA yield from cysts and oocysts determined that a combination of freeze-thaw, sonication, and purification using the DNeasy kit (Qiagen) provided a highly efficient method. Sampling of four environmental water bodies revealed variation in qPCR inhibitors in 2-liter concentrates. A methodology for dealing with qPCR inhibitors that involved the use of Chelex 100 and PVP 360 was developed. It was possible to detect and quantify G. lamblia in sewage using qPCR when applying the procedure for extraction of DNA from 1-liter sewage samples. Numbers obtained from the qPCR assay were comparable to those obtained with immunofluorescence microscopy. The qPCR analysis revealed both assemblage A and assemblage B genotypes of G. lamblia in the sewage. No Cryptosporidium was detected in these samples by either method.

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confidence: 99%

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confidence: 99%

Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage

Guy

Payment²,

Krull

et al. 2003

Appl Environ Microbiol

350

244

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“…The numbers of waterborne outbreaks of Cryptosporidium and Giardia infections have increased in recent years (23), and there is a potential for large outbreaks, such as that seen in Milwaukee, Wis., in which more than 400,000 people were infected with Cryptosporidium (21). Although Cryptosporidium received a great deal of attention after the Milwaukee outbreak, Giardia continues to be the more common of the two organisms in waterborne disease outbreaks (29).…”

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confidence: 99%

“…One of the most common modes of transmission is consumption of feces-contaminated water (17,25,34). It is estimated that 80 to 96% of surface waters in the United States are contaminated with Cryptosporidium and Giardia (16,29). The numbers of waterborne outbreaks of Cryptosporidium and Giardia infections have increased in recent years (23), and there is a potential for large outbreaks, such as that seen in Milwaukee, Wis., in which more than 400,000 people were infected with Cryptosporidium (21).…”

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Occurrence ofCryptosporidiumandGiardiain Wild Ducks along the Rio Grande River Valley in Southern New Mexico

Kuhn

Rock

Oshima

2002

Appl Environ Microbiol

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Fecal samples were taken from wild ducks on the lower Rio Grande River around Las Cruces, N. Mex., from September 2000 to January 2001. Giardia cysts and Cryptosporidium oocysts were purified from 69 samples by sucrose enrichment followed by cesium chloride (CsCl) gradient centrifugation and were viewed via fluorescent-antibody (FA) staining. For some samples, recovered cysts and oocysts were further screened via PCR to determine the presence of Giardia lamblia and Crytosporidium parvum. The results of this study indicate that 49% of the ducks were carriers of Cryptosporidium, and the Cryptosporidium oocyst concentrations ranged from 0 to 2,182 oocysts per g of feces (mean ؎ standard deviation, 47.53 ؎ 270.3 oocysts per g); also, 28% of the ducks were positive for Giardia, and the Giardia cyst concentrations ranged from 0 to 29,293 cysts per g of feces (mean ؎ standard deviation, 436 ؎ 3,525.4 cysts per g). Of the 69 samples, only 14 had (oo)cyst concentrations that were above the PCR detection limit. Samples did test positive for Cryptosporidium sp. However, C. parvum and G. lamblia were not detected in any of the 14 samples tested by PCR. Ducks on their southern migration through southern New Mexico were positive for Cryptosporidium and Giardia as determined by FA staining, but C. parvum and G. lamblia were not detected.Cryptosporidium and Giardia are enteric parasites that infect a wide range of vertebrate hosts, including birds and mammals. Cryptosporidium parvum and Giardia lamblia are the most common pathogenic species of these parasites in humans. In humans, these organisms can cause persistent diarrhea for 1 to 3 weeks. One of the most common modes of transmission is consumption of feces-contaminated water (17,25,34). It is estimated that 80 to 96% of surface waters in the United States are contaminated with Cryptosporidium and Giardia (16,29).

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Persistence of Pathogens in Water

Nasser

2004

Water Encyclopedia

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Natural water sources become contaminated with pathogenic micro‐organisms by the discharge of inadequately treated wastewater. Four major pathogen groups can be found in wastewater: over 100 types of enteric viruses, 7 types of pathogenic bacteria, 10 types of protozoan parasites, and 6 types of helminthes of health significance to humans and animals. The concentration of pathogenic micro‐organisms in wastewater is affected mainly by the amount of precipitation, the season of the year, and the socioeconomic status of the community. For most pathogenic micro‐organisms, the methods of detection are expensive, time‐consuming, and difficult to perform. Therefore, data on the prevalence of pathogenic micro‐organisms in wastewater effluents and natural water sources is limited to types for which a detection technique was developed. The recently developed molecular biology‐based techniques enhanced our capability in detecting human pathogenic micro‐organisms in water sources.

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Watershed use and Giardia cyst presence

Cited by 26 publications

References 5 publications

Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage

Real-Time PCR for Quantification of Giardia and Cryptosporidium in Environmental Water Samples and Sewage

Occurrence ofCryptosporidiumandGiardiain Wild Ducks along the Rio Grande River Valley in Southern New Mexico

Persistence of Pathogens in Water

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