Epidemiology of Human Adenoviruses: A 20-Year Retrospective Observational Study in Hospitalized Patients in Bern, Switzerland

Akello, Joyce Odeke; Kamgang, Richard; Barbani, Maria Teresa; Suter-Riniker, Franziska; Leib, Stephen L; Ramette, Alban

The recent emergence of the HAdV14 strains in the USA 15 and Europe (Ireland) 4 calls for a need to fill major gaps in understanding the molecular epidemiology and disease patterns of HAdVs. The predominant HAdV genotypes detected in association with clinical presentation differ among different countries and may change over time. 16 Currently in Switzerland, the knowledge on the molecular epidemiology and clinical presentation of HAdV infection is lacking. This study presents the molecular epidemiology of HAdV and associated clinical findings based on a retrospective observational study from laboratory confirmed HAdV cases collected between 1998 and 2017, at the Institute for Infectious Disease (IFIK), following referral of specimens by clinicians from the largest hospitals and other regional clinics in Bern. Since outbreaks of HAdV have been reported in various countries, 10, 15, [17] [18] [19] we therefore hypothesized that a thorough epidemiological analysis of the Bern HAdV clinical bio-bank, including genotyping and comparison to strains involved in international outbreaks, would provide information on potential outbreaks of HAdV that occurred in the last 20 years in Switzerland and how the epidemiological situation compares to that seen elsewhere in Europe during the studied period. To our knowledge, this is the first study to report HAdV epidemiology from a large clinical dataset over a 20-year period from patients of any age with positive HAdV infection. Overall, the study sheds light on epidemiological trends, risk factors for infection, and molecular epidemiology of HAdV circulating genotypes.