Inactivation of an Enveloped Surrogate Virus in Human Sewage

Data are needed to provide guidance for handling of human sewage potentially containing infectious Ebola virus. The purpose of this research was to determine inactivation of enveloped viruses in sewage using bacteriophage Phi 6 as a surrogate. Sewage was spiked with Phi 6 and held at 22 or 30 degrees C, and the viral titer was measured over time Inactivation was much more rapid at 30 degrees C than at 22 degrees C. At 30 degrees C, inactivation was approximately linear and reached 1.7 log(10) in 24 h, 5 log(10) by 48 11, and >7 log(10) within 72 h. At 22 degrees C, the time to 5 log(10) inactivation was 6 days and nonlinear. In sewage, Phi 6 should be considered as a potential model for survival and inactivation of enveloped human viruses. The results suggest that enveloped viruses can undergo 6-7 log inactivation M sewage M 3-7 days, depending on temperature. Longer holding times may be desirable out of an abundance of caution at lower temperatures.