Artificial UV-B and Solar Radiation Reduce in Vitro Infectivity of the Human Pathogen Cryptosporidium parvum

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• 作者：Sandra J. Connelly ; Elizabeth A. Wolyniak ; Craig E. Williamson ; Kristen L. Jellison
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：October 15, 2007
• 年：2007
• 卷：41
• 期：20
• 页码：7101 - 7106
• 全文大小：96K
• 年卷期：v.41,no.20(October 15, 2007)
• ISSN：1520-5851

文摘

The potential for solar ultraviolet (UV) radiation to act asa significant abiotic control of Cryptosporidium parvum oocystsin nature is unknown. Infectivity of C. parvum followingexposure to artificial UV-B and natural solar radiation, withand without UV wavelengths, was tested under controlledpH and temperature conditions. Percent infectivity ofexposed oocysts was determined by in vitro cell culture.Artificial UV-B exposures of 32 and 66 kJ/m² significantlydecreased oocyst infectivity by an average of 58 and 98%,respectively. Exposure of oocysts to approximately halfand full intensity of full solar spectrum (all wavelengths)for a period of less than 1 day (10 h) in mid-summer reducedmean infectivity by an average of 67% and >99.99%,respectively. Exposure of the C. parvum oocysts to UV-shielded solar radiation (>404 nm) in early autumn reducedmean infectivity by 52%, while full spectrum solar radiation(exposure at all wavelengths) reduced mean infectivityby 97%. The data provide strong evidence that exposureto natural solar radiation can significantly reduce C. parvuminfectivity. Direct effects of solar radiation on oocysts innature will depend on the depth distribution of the oocysts,water transparency, mixing conditions, and perhapsother environmental factors such as temperature, pH, andstress.