c Pathogenic enteric viruses are responsible for a wide range of infections in humans, with diverse symptoms. Raw and partially treated wastewaters are major sources of environmental contamination with enteric viruses. We monitored a municipal secondary wastewater treatment plant (New Orleans, LA) on a monthly basis for norovirus (NoV) GI and GII and enterovirus serotypes using multiplex reverse transcription-quantitative PCR (RT-qPCR) and microbial indicators of fecal contamination using standard plating methods. Densities of indicator bacteria (enterococci, fecal coliforms, and Escherichia coli) did not show monthly or seasonal patterns. Norovirus GII was more abundant than GI and, along with enterovirus serotypes, increased in influent during fall and spring. The highest NoV GI density in influent was in the fall, reaching an average of 4.0 log 10 genomic copies/100 ml. Norovirus GI removal (0.95 log 10 ) was lower than that for GII, enterovirus serotypes, and male-specific coliphages (1.48 log 10 ) or for indicator bacteria (4.36 log 10 ), suggesting higher resistance of viruses to treatment. Male-specific coliphages correlated with NoV GII densities in influent and effluent (r ‫؍‬ 0.48 and 0.76, respectively) and monthly removal, indicating that male-specific coliphages can be more reliable than indicator bacteria to monitor norovirus GII load and microbial removal. Dominant norovirus genotypes were classified into three GI genotypes (GI.1, GI.3, and GI.4) and four GII genotypes (GII.3, GII.4, GII.13, and GII.21), dominated by GI.1 and GII.4 strains. Some of the seasonal and temporal patterns we observed in the pathogenic enteric viruses were different from those of epidemiological observations. E nteric viruses are responsible for a wide range of infections in humans with diverse symptoms. Infected individuals shed millions of virus particles in their feces or body fluids, which eventually enter sewage systems. Enteric viruses may naturally occur in aquatic environments as well, but human activities, in particular, sewage discharge, is the primary source of environmental contaminants (1-3). Among the pathogenic enteric viruses, norovirus (NoV), enterovirus (EV), adenovirus, astrovirus, and rotavirus have been found frequently in municipal wastewaters worldwide (1, 4-6). Several gastroenteritis outbreaks have been linked directly or indirectly to human exposure of raw or partially treated sewage-contaminated water or foods (2).Municipal wastewaters usually undergo a secondary treatment before being discharged into the environment. The process involves a mechanical treatment for removing solids followed by biological and chemical treatments, nutrient removal, and discharge (7). Primary-treated (physically processed) wastewater or the effluent water that does not undergo a disinfection process may still harbor infectious enteric viruses, similar to the raw sewage (4, 8). To protect water quality and public safety, fecal coliforms and Escherichia coli have been used to monitor fecal pollution in wastewater dis...