Using UV to inactivate Cryptosporidium

Clancy, Jennifer L.; Bukhari, Zia; Hargy, Thomas M.; Bolton, James R.; Dussert, Bertrand W.; Marshall, Marilyn M.

doi:10.1002/j.1551-8833.2000.tb09008.x

Cited by 152 publications

(85 citation statements)

References 5 publications

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“…All of these viruses have been associated with outbreaks involving drinking water (1,10,12). UV light disinfection is being increasingly used in the treatment of both wastewater and potable drinking water since such treatment does not produce disinfectant by-products and is effective against Cryptosporidium oocysts (2). The goal of this study was to compare the ways inactivation by UV light varies among the enteroviruses and a nonenteric adenovirus.…”

mentioning

confidence: 99%

“…For ease of calculation, it was determined that the petri dish must contain 14 ml of solution in order to achieve a 1-cm distance from the bottom of the petri dish to the surface of the viral suspension. This experimental design allows for an accurate irradiance measurement when low-pressure UV lamps are used (2). A different petri dish was used for each exposure period.…”

mentioning

confidence: 99%

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Comparative Inactivation of Enteroviruses and Adenovirus 2 by UV Light

Gerba

Gramos

Nwachuku

2002

Appl Environ Microbiol

253

191

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The doses of UV irradiation necessary to inactivate selected enteric viruses on the U.S. Environmental Protection Agency Contaminant Candidate List were determined. Three-log reductions of echovirus 1, echovirus 11, coxsackievirus B3, coxsackievirus B5, poliovirus 1, and human adenovirus type 2 were effected by doses of 25, 20.5, 24.5, 27, 23, and 119 mW/cm2, respectively. Human adenovirus type 2 is the most UV light-resistant enteric virus reported to date

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mentioning

confidence: 99%

mentioning

confidence: 99%

Comparative Inactivation of Enteroviruses and Adenovirus 2 by UV Light

Gerba

Gramos

Nwachuku

2002

Appl Environ Microbiol

253

191

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“…Although some water treatment processes remove oocysts, any oocysts that break through represent a potential threat to human health due to their relative chlorine resistance. Various methods of disinfection have been investigated by a number of research groups; these methods include UV light (4,10,11,13,14,23,35), ozone (5,18,22,29), chlorine dioxide (8,12,22,30,34), mixed oxidants (MIOX) (6,40), and chlorine (7,22,17). Many disinfection studies have used animal infectivity or surrogate in vitro assays to determine the viability of oocysts after disinfection.…”

mentioning

confidence: 99%

Cell Culture-Taqman PCR Assay for Evaluation of Cryptosporidium parvum Disinfection

Keegan

Fanok

Monis

et al. 2003

Appl Environ Microbiol

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Cryptosporidium parvum represents a challenge to the water industry and a threat to public health. In this study, we developed a cell culture-quantitative PCR assay to evaluate the inactivation of C. parvum with disinfectants. The assay was validated by using a range of disinfectants in common use in the water industry, including low-pressure UV light (LP-UV), ozone, mixed oxidants (MIOX), and chlorine. The assay was demonstrated to be reliable and sensitive, with a lower detection limit of a single infectious oocyst. Effective oocyst inactivation was achieved (>2 log 10 units) with LP-UV (20 mJ/cm 2 ) or 2 mg of ozone/liter (for 10 min). MIOX and chlorine treatments of oocysts resulted in minimal effective disinfection, with <0.1 log 10 unit being inactivated. These results demonstrate the inability of MIOX to inactivate Cryptosporidium. The assay is a valuable tool for the evaluation of disinfection systems for drinking water and recycled water.Cryptosporidium is recognized as a frequent cause of waterborne disease in humans (3). The disease has been documented worldwide, with speculation that many undiagnosed cases of gastroenteritis may have been caused by this parasite (21,38). Two means of transmission have been shown to be contaminated drinking water in distribution systems (25,28) and swimming pools (17). Cryptosporidium oocysts are resistant to standard chlorine-based disinfection procedures that are a key barrier in the transmission of other waterborne pathogens in potable water. Although some water treatment processes remove oocysts, any oocysts that break through represent a potential threat to human health due to their relative chlorine resistance. Various methods of disinfection have been investigated by a number of research groups; these methods include UV light (4, 10, 11, 13, 14, 23, 35), ozone (5, 18, 22, 29), chlorine dioxide (8,12,22,30,34), mixed oxidants (MIOX) (6, 40), and chlorine (7,22,17). Many disinfection studies have used animal infectivity or surrogate in vitro assays to determine the viability of oocysts after disinfection. Animal bioassays are considered the "gold standard" for assessing Cryptosporidium oocyst infectivity, and the neonatal mouse model has been used extensively in the assessment of oocyst disinfection. However, this model has limited applications for the assessment of waterborne oocysts because type 1 (human) Cryptosporidium parvum cannot infect mice. The human genotype can be cultured in gnotobiotic pigs (41), and this model has been used to assess drug efficacy (37).Significant developments in determining oocyst infectivity have included cell culture (CC) assays for type 1 oocysts (20) and for type 2 oocysts (14,15,20,31,36,39). These methods have used culturing of oocysts in HCT-8 (human ileocecal adenocarcinoma) cells. Evaluation of these methods has shown the CC assay with the HCT-8 cell line to be equivalent to the gold standard neonatal mouse infectivity assay (32,35). Shim et al. (35) demonstrated that CC assays provide a level of sensitivity similar to t...

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“…Interestingly, the quality of w ater is one of the many defining factors in its application (Wright and Cairns, 1998). Amid it being a cost effective disinfection technology, there is evidence, UV provides no residual effect in w ater tow ards the protection against post treatment contamination (Clancy et al, 2000;Said and Otaki, 2013). A study by Choi and Choi (2010) has show n the technology has an effect on dissolved organic matter structure (DOM) in distribution systems including an increase in biodegradability (Frimmel, 1998;Drikas et al, 2004).…”

Section: Effect Of Uv Irradiation On W Ater Quality and Its Applicatimentioning

confidence: 99%

Evidence based review of Legionella elimination in building water systems

Sedzro¹,

Banu²,

Akrong³

2017

Int. J. Water Res. Environ. Eng.

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Legionnaires disease can be acquired through exposure to Legionella pneumophila, a gram-negative bacteria ubiquitous in both natural and engineered water systems. Over the years, a number of disinfection techniques notably, chlorination, ozonation, thermal, UV and copper-silver ionization have been employed across different kinds of engineered water systems with diverse measures of success. Available evidence portends, most of the aforementioned techniques often have to be combined to achieve long-term efficacy. Remarkably, albeit the extensive research and reportage on Legionnaires outbreak in the developed world, very few studies have been carried out with regards to Africa. We reviewed existing literature on the application of the aforementioned techniques in buildings. Our study concurs with earlier studies; most of the disinfection techniques will have to be combined to achieve the desired efficacy. We found very scanty studies on Legionella or reportage of its outbreak within Africa. Our study also found very little in terms of any of the techniques been applied with the specific aim of reducing Legionella proliferation in engineered water systems within Africa. This is alarming, especially, on a continent where several communities have little or no access to quality water and healthcare. In light of the above, stronger measures such as sensitization, pro perly managed water distribution systems, as well as policies aimed at enforcing national and international guidelines on Legionella control is recommended.

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Using UV to inactivate Cryptosporidium

Cited by 152 publications

References 5 publications

Comparative Inactivation of Enteroviruses and Adenovirus 2 by UV Light

Comparative Inactivation of Enteroviruses and Adenovirus 2 by UV Light

Cell Culture-Taqman PCR Assay for Evaluation of Cryptosporidium parvum Disinfection

Evidence based review of Legionella elimination in building water systems

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