Genetic diversity and quantification of human mastadenoviruses in wastewater from Sydney and Melbourne, Australia.

Human mastadenoviruses (HAdVs) are DNA viruses that can cause a wide range of clinical diseases, including gastroenteritis, respiratory illnesses, conjunctivitis, and in more severe cases hepatitis, pancreatitis and disseminated diseases. HAdV infections are generally asymptomatic or self-limiting, but can cause adverse outcomes within vulnerable populations. Since most HAdV serotypes replicate within the human gastrointestinal tract, high levels of HAdV DNA are excreted into wastewater systems. In this study, we identified the genetic diversity of HAdV at a population level using wastewater samples collected from Sydney and Melbourne from 2016 to 2017, with the use of next generation sequencing (NGS) technologies. In addition, HAdV DNA levels were quantified using quantitative polymerase chain reaction (qPCR) based methods to better understand the health risks involved if wastewater contamination occurs. An average of 1.8 × 107 genome copies of HAdV DNA was detected in one litre of wastewater collected in Sydney and Melbourne, over the two-year study period. A total of six major groups of HAdV were identified in wastewater samples using MiSeq, which included 19 different serotypes. Of those, the most prevalent was F41 (83.5%), followed by F40 (11.0%) and A31 (3.7%). In contrast, five groups of HAdV were identified in clinical samples with F41 as the most dominant serotype, (52.5% of gastroenteritis cases), followed by C1 and C2 (each responsible for 15.0%), and B3 was the fourth most common serotype (7.5%). This study demonstrated the practicability of using amplicon based NGS to identify HAdV diversity and quantify HAdV genome levels in environmental water samples, as well as broadening our current understanding of circulating HAdV in the Australian population.