Astrovirus VA1 in patients with acute gastroenteritis

Human astroviruses (AstVs) are usually associated with acute gastroenteritis. In recent years, atypical animal-like AstVs have been identified, but their pathogenic role in humans has not been determined. Starting from 2010, there has been a growing evidence that AstVs may also be associated with encephalitis in human and animal hosts. Some human atypical AstV strains (VA1, MLB1/MLB2) display neurotropic potential, as they have been repeatedly identified in patients with AstV-related encephalitis, chiefly in immunosuppressed individuals. In this study, a VA1-like AstV was identified from a single stool sample from an outbreak of foodborne acute gastroenteritis occurred in Italy in 2018. On genome sequencing, the virus was related to the VA1-like strain UK1 (99.3% at the nucleotide level). Similar viruses were also found to circulate in paediatric patients hospitalized with AGE in the same time span, 2018, but at low prevalence (0.75%, 3/401). Gathering epidemiological data on atypical AstVs will be useful to assess the risks posed by atypical AstV infections, chiefly in medically fragile patients.