Synchronized Detection of Adenovirus F41 in Wastewater and Fecal Samples Confirms a Small Outbreak in Santiago, Chile

We conducted systematic surveillance of circulating viruses in two cities in Chile through regular wastewater analysis between 2018 and 2021. Samples were concentrated, nucleic acids were extracted, and the samples were analyzed by massive sequencing. After bioinformatic processing, we detected a significant number of Adenovirus F41 genomes in samples collected during a specific period (January-March 2020), particularly in treatment plants from Santiago de Chile. To confirm whether the virus was circulating in the city during that period, we analyzed stool pools collected at one of the city's main pediatric hospitals. We detected Adenovirus F41 sequences only in the same period as in wastewater. Phylogenetic analysis showed that the virus detected in wastewater and stool samples was almost identical and classified as Lineage 2B. These results demonstrated the effectiveness of wastewater surveillance for detecting enteric viruses in the community, shed light on the efficiency of treatment processes, and revealed a small outbreak of a virus strain previously reported in Europe.