Inactivation of Cryptosporidium parvum Oocysts in Copper Tubing

Autor: Yoshinori Satoh, Takeshi Nakamura, Akira Takahashi, Tomoko Sekiguchi, Yoko Takayama, Takeshi Sasahara, Matsuhisa Inoue, Shunji Okuda, Ritsuko Kikuno
Rok vydání: 2006
Předmět:
Zdroj: Journal of the Japanese Association for Infectious Diseases. 80:377-382
ISSN: 1884-569X
0387-5911
DOI: 10.11150/kansenshogakuzasshi1970.80.377
Popis: We studied whether the infectivity of Cryptosporidium parvum oocysts for suckling mice could be inactivated by copper tubing or by other types of tubing used to construct water distribution systems, including stainless steel, rigid polyvinyl chloride (PVC), PVC-lined steel, polyethylene (PE), cross-linked PE, and polybutene (PB), using glass tubing as the control. Oocysts were incubated in each tubings for 24 hours. The extent of inactivation of infectious oocysts by copper tubing was -1.303 log, which significantly inactivated of infectivity. In contrast, other types of tubing had no significant effect on some oocyst infectivity, although PB did show a maximum inactivation of -0.313 log. 25% of oocysts showed degeneration morphologically after passing through copper tubing, while 0.3% to 1.8% showed degeneration after passing through other tubing. Significant inactivation of infectious oocysts was not caused by water in which copper tubing had been let stand for 24 hours, although it had a cupric ion (Cu2+) concentration of 2.4 mg/L. The direct contact of oocysts with copper surface resulted in a decrease in the recovery percentage of oocysts and generation of hydrogen peroxide (0.5 mg/L) after 24 h of incubation. The percentage of degenerating oocysts was 29%. Such cryptosporidicidal effects of the copper surface on oocysts were completely inhibited by overlaying the surface with a Millipore filter before adding oocysts and incubating oocysts in the presence of catalase, an antioxidant enzyme. These findings suggest that copper tubing inactivates infectious C. parvum oocysts cytotoxically which may be due to oxygen radicals generated by the interaction between Cu2+ and hydrogen peroxide on the tubing surface.
Databáze: OpenAIRE