Occurrence and molecular genotyping of Cryptosporidium spp. in surface waters in Northern Ireland

Lowery, Colm; Moore, John E.; Millar, B. Cherie; McCorry, Kieran; Xu, Jing; Rooney, Paul J.; Dooley, James

doi:10.1046/j.1365-2672.2001.01440.x

Cited by 29 publications

(21 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The SSU rRNA PCR-based method detected Cryptosporidium oocysts in 86% of samples or 82% of all samples and subsamples analyzed, whereas the latter detected oocysts in only 62% of the samples or 70% of all samples and subsamples, despite the fact that many samples and subsamples had more than 0.5 ml of packed pellet volume analyzed by microscopy. Previously, other studies have also shown that PCRbased methods have higher sensitivities than microscopy-based methods such as method 1622/1623 for detecting Cryptosporidium oocysts in water (5,9,10,12,13,24). In the present study, the higher detection rate by PCR occurred largely in samples where microscopy failed to detect any oocysts.…”

Section: Discussionsupporting

confidence: 57%

Detection of Cryptosporidium Oocysts in Water: Effect of the Number of Samples and Analytic Replicates on Test Results

Xiao

Alderisio²,

Jiang

2006

Appl Environ Microbiol

View full text Add to dashboard Cite

Due to the small number of Cryptosporidium oocysts in water, the number of samples taken and the analyses performed can affect the results of detection. In this study, 42 water samples were collected from one watershed during 20 storm events over 1 year, including duplicate or quadruplicate samples from 16 storm events. Ten samples from four events had three to eight subsamples. They were processed by EPA method 1623, and Cryptosporidium oocysts present were detected by immunofluorescent microscopy or PCR. Altogether, 24 of 39 samples (47 of 67 samples and subsamples) analyzed by microscopy were positive for Cryptosporidium. In contrast, 36 of 42 samples (62 of 76 samples and subsamples) were positive by PCR, including 10 microscopy-negative samples (13 microscopynegative samples and subsamples). Six of the 24 microscopy-positive samples were negative by PCR, and all samples had one or less oocyst in a 0.5-ml packed pellet volume calculated. Discordant results were obtained by microscopy and PCR from six and three of the storm events, respectively, with multiple samples. Discordant microscopy or PCR results were also obtained among subsamples. Most of the 14 Cryptosporidium genotypes were found over a brief period. Cryptosporidium-positive samples had a mean of 1.9 genotypes per sample, with 39 of the 62 positive samples/subsamples having more than one genotype. Samples/subsamples with more than one genotype had an overall PCR-positive rate of 73%, compared to 34% for those with one genotype. The PCR amplification rate of samples was affected by the volume of DNA used in PCR.

show abstract

Section: Discussionsupporting

confidence: 57%

Detection of Cryptosporidium Oocysts in Water: Effect of the Number of Samples and Analytic Replicates on Test Results

Xiao

Alderisio²,

Jiang

2006

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…However, the data on the annual occurrence of Cryptosporidium sp. in humans in England (8.9 cases per 100,000 persons) (Lowery et al 2001) is higher than in Spain (0.2 cases per 100,000 persons) (Anonymous 2003). This difference may be the result of the prevalence in Spain being underestimated (Montemayor et al 2005).…”

Section: Resultsmentioning

confidence: 94%

Occurrence of Cryptosporidium hominis in pigeons (Columba livia)

Abreu-Acosta

Foronda

López

et al. 2009

Acta Parasitologica

View full text Add to dashboard Cite

show abstract

“…Recent studies (3,6,8,10,13,14,24) have shown that the use of molecular methods, such as PCR-RFLP, has some advantages over the traditional IFA detection method. This and the previous study (31) clearly indicate that detection of Cryptosporidium in storm water samples by PCR is more sensitive than the IFA method.…”

Section: Discussionmentioning

confidence: 99%

“…This and the previous study (31) clearly indicate that detection of Cryptosporidium in storm water samples by PCR is more sensitive than the IFA method. Other studies have also shown that PCR has higher sensitivities in the analysis of both clinical and environmental samples (3,6,8,10,13,14,24). It is possible that some oocysts present in storm samples were not stained by immunofluorescence due to the loss of surface antigens as a result of long exposure to the adverse environment.…”

Section: Discussionmentioning

confidence: 99%

Distribution of Cryptosporidium Genotypes in Storm Event Water Samples from Three Watersheds in New York

Jiang

Alderisio²,

Xiao

2005

Appl Environ Microbiol

255

216

View full text Add to dashboard Cite

To assess the source and public health significance of Cryptosporidium oocyst contamination in storm runoff, a PCR-restriction fragment length polymorphism technique based on the small-subunit rRNA gene was used in the analysis of 94 storm water samples collected from the Malcolm Brook and N5 stream basins in New York over a 3-year period. The distribution of Cryptosporidium in this study was compared with the data obtained from 27 storm water samples from the Ashokan Brook in a previous study. These three watersheds represented different levels of human activity. Among the total of 121 samples analyzed from the three watersheds, 107 were PCR positive, 101 of which (94.4%) were linked to animal sources. In addition, C. hominis (W14) was detected in six samples collected from the Malcolm Brook over a 2-week period. Altogether, 22 Cryptosporidium species or genotypes were found in storm water samples from these three watersheds, only 11 of which could be attributed to known species/groups of animals. Several Cryptosporidium spp. were commonly found in these three watersheds, including the W1 genotype from an unknown animal source, the W4 genotype from deer, and the W7 genotype from muskrats. Some genotypes were found only in a particular watershed. Aliquots of 113 samples were also analyzed by the Environmental Protection Agency (EPA) Method 1623; 63 samples (55.7%) were positive for Cryptosporidium by microscopy, and 39 (78%) of the 50 microscopy-negative samples were positive by PCR. Results of this study demonstrate that molecular techniques can complement traditional detection methods by providing information on the source of contamination and the human-infective potential of Cryptosporidium oocysts found in water.Waterborne cryptosporidiosis has been reported worldwide and remains one of the prominent public health concerns (22). Cryptosporidium spp. are a threat to water supplies because they are resistant to chlorine disinfections, have a small infectious dose, and are harbored by many animal species (4). Farm animals and humans have been considered major sources of contamination of Cryptosporidium oocysts in surface water (15,20,36). Thus, controlling agricultural and human sewage discharge is important in watershed protection. However, wildlife are also commonly infected (1,18,21,26) and can be a source of water contamination with Cryptosporidium oocysts (25). Controlling wildlife contamination remains largely beyond the reach of water management efforts.With the exception of C. hominis (previously known as the C. parvum human genotype or genotype I) (17), which almost exclusively infects humans, C. parvum (previously known as the C. parvum bovine genotype or genotype II) can infect not only humans but also ruminants and perhaps a few other animals (27). Some researchers believe the natural ecology of C. parvum probably involves at least two cycles; one is a zoonotic cycle in agricultural settings involving humans and farm animals, particularly dairy cattle and sheep (2,29,30), and the other is a cycle wi...

show abstract

Occurrence and molecular genotyping of Cryptosporidium spp. in surface waters in Northern Ireland

Cited by 29 publications

References 20 publications

Detection of Cryptosporidium Oocysts in Water: Effect of the Number of Samples and Analytic Replicates on Test Results

Detection of Cryptosporidium Oocysts in Water: Effect of the Number of Samples and Analytic Replicates on Test Results

Occurrence of Cryptosporidium hominis in pigeons (Columba livia)

Distribution of Cryptosporidium Genotypes in Storm Event Water Samples from Three Watersheds in New York

Contact Info

Product

Resources

About