UV inactivation of adenovirus type 4 measured by integrated cell culture qPCR

Recent changes to water quality regulations may increase the prevalence of ultraviolet (UV) disinfection in water treatment applications. Adenoviruses currently pose a tremendous challenge to UV disinfection due to the high dose requirements for inactivation. This study validates a strategy combining cell culture and quantitative polymerase chain reaction (qPCR) for direct quantification of infectious adenoviruses in disinfection studies. Using primary liver carcinoma cell monolayers grown in well trays or flasks, post-infection washing, and a 24-hr incubation period, the time and material requirements for the infectivity assays were reduced significantly in comparison to traditional assays based on cytopathogenic effects. With this integrated cell culture quantitative PCR (ICC-qPCR) strategy, a standard curve was used to quantify infectious adenoviruses and ultimately determine relative inactivation for a disinfection study. Using ICC-qPCR, UV doses of approximately 10, 34, 69, and 116 mJ/cm(2) corresponded to 1, 2, 3, and 4-log inactivation of adenovirus 4 in water, respectively. The results indicate that the new ICC-qPCR strategy represents a practical alternative for the quantification of adenoviruses in disinfection studies.