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Title:Inactivation kinetics and mechanisms of rotavirus: the roles of sunlight, temperature, and sensitizers
Author(s):Romero-Maraccini, Ofelia
Director of Research:Nguyen, Thanh H.
Doctoral Committee Chair(s):Nguyen, Thanh H.
Doctoral Committee Member(s):Mariñas, Benito J.; Shisler, Joanna L.; Liu, Wen-Tso
Department / Program:Civil & Environmental Eng
Discipline:Environ Engr in Civil Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Solar disinfection
Abstract:Rotavirus is the leading cause of diarrhea hospitalizations and deaths among young children worldwide, responsible for an estimated 453,000 deaths each year. The only proven route of rotavirus transmission is via the fecal–oral route, yet all documented rotavirus waterborne outbreaks have been associated with direct fecal contamination of a water supply or improper water treatment. Rotaviruses can remain infectious after undergoing typical wastewater treatment, and thus can contaminate drinking water sources, such as rivers. The transmission route and resilience of rotaviruses strengthen the importance of effective potable water treatment technologies against rotaviruses in developing countries. Solar disinfection is a cost-effective and promising alternative for water and wastewater treatment in less-developed countries lacking reliable water treatment technologies. However, the solar inactivation mechanisms of rotaviruses have not been investigated. Improved knowledge of the photochemical and molecular mechanisms leading to rotavirus inactivation by solar and thermal treatments will help in the development and design of new technologies to detect and control rotaviruses in water. The objectives for this study were: 1) to investigate the natural sunlight conditions that induced rotavirus inactivation such as the effects of sunlight fractions, organic matter, temperature; 2) to determine how different types of organic matter influenced rotavirus inactivation by their photochemical contributions; and 3) to determine the molecular determinants causing inactivation of rotavirus upon heat and solar irradiation treatments. Our results showed that rotaviruses were inactivated upon solar irradiation, especially with full spectrum irradiation that contains UVB light. When the UVB fraction of sunlight was blocked, rotavirus inactivation greatly decreased when compared to full spectrum irradiation. However, independent of the sunlight fraction used, irradiation of natural organic matter triggered a photochemical production of radicals that indirectly inactivated rotavirus. These photo-chemically produced radicals were likely hydroxyl radicals and excited triplet state species. Our molecular work showed that rotavirus inactivation was linked to genome damage by solar irradiation, regardless of the sunlight fraction, while thermal treatment caused primarily protein damage. The presence of organic matter augmented rotavirus inactivation by causing protein damage, likely targeted by the indirectly-produced radicals.
Issue Date:2014-09-16
Rights Information:Copyright 2014 Ofelia Romero-Maraccini
Date Available in IDEALS:2014-09-16
Date Deposited:2014-08

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