Rethinking disinfection of iGiardia/i cysts with ultraviolet light: old light through a new window.

Wallis, P. M.; Campbell, A. T.

doi:10.1079/9780851996127.0239

Cited by 2 publications

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“…Similarly, those disinfectants, such as ultraviolet irradiation and ozone (Wallis & Campbell 2002), that are effective in inactivating waterborne Cryptosporidium and Giardia (oo)cysts are expected to prove useful for other waterborne protozoa (Smith & Grimason 2003).…”

Section: Removal/destruction In Water Treatmentmentioning

confidence: 99%

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Karanis

Kourenti

Smith

2006

Journal of Water and Health

714

403

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At least 325 water-associated outbreaks of parasitic protozoan disease have been reported.North American and European outbreaks accounted for 93% of all reports and nearly two-thirds of outbreaks occurred in North America. Over 30% of all outbreaks were documented from Europe, with the UK accounting for 24% of outbreaks, worldwide. Giardia duodenalis and Cryptosporidium parvum account for the majority of outbreaks (132; 40.6% and 165; 50.8%, respectively), Entamoeba histolytica and Cyclospora cayetanensis have been the aetiological agents in nine (2.8%) and six (1.8%) outbreaks, respectively, while Toxoplasma gondii and Isospora belli have been responsible for three outbreaks each (0.9%) and Blastocystis hominis for two outbreaks (0.6%). Balantidium coli, the microsporidia, Acanthamoeba and Naegleria fowleri were responsible for one outbreak, each (0.3%). Their presence in aquatic ecosystems makes it imperative to develop prevention strategies for water and food safety. Human incidence and prevalence-based studies provide baseline data against which risk factors associated with waterborne and foodborne transmission can be identified. Standardized methods are required to maximize public health surveillance, while reporting lessons learned from outbreaks will provide better insight into the public health impact of waterborne pathogenic protozoa.

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Section: Removal/destruction In Water Treatmentmentioning

confidence: 99%

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Karanis

Kourenti

Smith

2006

Journal of Water and Health

714

403

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“…Cysts survive for months in water supplies (Jarroll, 1988) and transmission from infective faeces occurs via contaminated water or by adult-to-adult contact (Rabbani & Islam, 1994). Treatment with antigiardial agents (nitroimidazoles, nitrofurans or acridine dyes) fails in about 20 % of cases (Ellis et al, 1993b) and cysts are highly resistant to water-treatment procedures (Jakubowski & Craun, 2002;Wallis & Campbell, 2002).…”

Section: Introductionmentioning

confidence: 99%

Menadione kills trophozoites and cysts of Giardia intestinalis

et al. 2004

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Production of reactive oxygen species by redox cycling in the presence of low levels of oxygen has been studied as a possible approach to anti-protozoal chemotherapeutic strategy. Incubation of the diplomonad flagellate Giardia intestinalis with 2-methy-1,4-naphthoquinone (menadione), under anaerobic conditions, gave UV absorption changes characteristic of reduction to menadiol; partial reversal was observed on admitting O 2 . Under microaerobic conditions, similar to those on the surface of the jejunal mucosa, trophozoites consumed O 2 rapidly in the presence of menadione; reaction products included singlet O 2 (monitored by single photon counting of O 2 -dependent low-level chemiluminescence) and H 2 O 2 (measured by the formation of Complex I of microperoxidase). Trophozoites became swollen and incapable of regulatory volume control; these irreversible responses led to loss of motility, cessation of flagellar activity and cell death. Comparison of the sensitivities of trophozoites to metronidazole and menadione gave LC 50 values (mg ml "1 ) of 1?2 and 0?7, respectively; corresponding values for cysts (measured by in vitro excystation capacities) were >50 and 1?3. Menadione (LD 50 in mice, 0?5 g kg "1 ) is therefore a potentially more useful and general anti-giardial agent than metronidazole, as it is active against cysts as well as trophozoites.

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Rethinking disinfection of iGiardia/i cysts with ultraviolet light: old light through a new window.

Cited by 2 publications

References 0 publications

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Waterborne transmission of protozoan parasites: A worldwide review of outbreaks and lessons learnt

Menadione kills trophozoites and cysts of Giardia intestinalis

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