{"title":"Cryptosporidium parvum inactivation from short durations of treatment with ozonated water produced by an electrolytic generation system.","authors":"Makoto Matsubayashi, Asako Haraguchi, Manami Morisaki, Hiromi Ikadai, Isao Teramoto, Yasutoshi Kido, Akira Kaneko","doi":"10.1007/s00436-024-08390-z","DOIUrl":null,"url":null,"abstract":"<p><p>Cryptosporidium is a waterborne pathogen that causes diarrhea in vertebrates and humans (mainly C. hominis and C. parvum). Ozone (O<sub>3</sub>) is a powerful disinfectant due to its high oxidative characteristics, and it is used to inactivate microorganisms in drinking water. As an alternative to the gas dissolution system for producing ozone from oxygen, a simpler electrolytic ozone generation system has recently been developed. In the present study, the efficacy of the ozonated water produced by this system in inactivating Cryptosporidium parasites (C. parvum) was evaluated at different current intensities (which change the ozone concentrations) and short exposure times (15-60 s). Oocyst viability and integrity was assessed using vital dye staining, excystation assays, and scanning electron microscopy (SEM). SEM data revealed that oocyst walls were damaged by exposure to ozone molecules even at low concentrations (< 0.01 mg/l for 1 min) (current intensity 0.2 A), but that the excystation assay could not differentiate between deformed oocysts (dead) and partially excysted oocysts (alive). Exposure to ozonated water produced with a low current intensity (0.3 A) for 15 and 120 s resulted in the inactivation of 96.2% (CT value < 0.003) and 99.4% (CT value < 0.020) of the oocysts, respectively. Thus, it was estimated that a CT value more than 0.020 was required to inactivate > 99% of the C. parvum oocysts. These results suggested that the electrolytic ozone generation system may be more effective than gas dissolution ozone generation; however, further studies using additional approaches are needed to obtain clearer evidence.</p>","PeriodicalId":19968,"journal":{"name":"Parasitology Research","volume":"123 11","pages":"371"},"PeriodicalIF":1.8000,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Parasitology Research","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s00436-024-08390-z","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PARASITOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Cryptosporidium is a waterborne pathogen that causes diarrhea in vertebrates and humans (mainly C. hominis and C. parvum). Ozone (O3) is a powerful disinfectant due to its high oxidative characteristics, and it is used to inactivate microorganisms in drinking water. As an alternative to the gas dissolution system for producing ozone from oxygen, a simpler electrolytic ozone generation system has recently been developed. In the present study, the efficacy of the ozonated water produced by this system in inactivating Cryptosporidium parasites (C. parvum) was evaluated at different current intensities (which change the ozone concentrations) and short exposure times (15-60 s). Oocyst viability and integrity was assessed using vital dye staining, excystation assays, and scanning electron microscopy (SEM). SEM data revealed that oocyst walls were damaged by exposure to ozone molecules even at low concentrations (< 0.01 mg/l for 1 min) (current intensity 0.2 A), but that the excystation assay could not differentiate between deformed oocysts (dead) and partially excysted oocysts (alive). Exposure to ozonated water produced with a low current intensity (0.3 A) for 15 and 120 s resulted in the inactivation of 96.2% (CT value < 0.003) and 99.4% (CT value < 0.020) of the oocysts, respectively. Thus, it was estimated that a CT value more than 0.020 was required to inactivate > 99% of the C. parvum oocysts. These results suggested that the electrolytic ozone generation system may be more effective than gas dissolution ozone generation; however, further studies using additional approaches are needed to obtain clearer evidence.
期刊介绍:
The journal Parasitology Research covers the latest developments in parasitology across a variety of disciplines, including biology, medicine and veterinary medicine. Among many topics discussed are chemotherapy and control of parasitic disease, and the relationship of host and parasite.
Other coverage includes: Protozoology, Helminthology, Entomology; Morphology (incl. Pathomorphology, Ultrastructure); Biochemistry, Physiology including Pathophysiology;
Parasite-Host-Relationships including Immunology and Host Specificity; life history, ecology and epidemiology; and Diagnosis, Chemotherapy and Control of Parasitic Diseases.