Molecular epidemiology of noroviruses and sapoviruses and their role in Australian outbreaks of acute gastroenteritis

Abstract

Every winter since 2004, (except 2005) there have been outbreaks of acute gastroenteritis across Australia, caused by norovirus (NoV). These outbreaks are frequently seen in aged-care facilities, hospitals and cruise ships. Why has this become the norm and what has happened in virological terms to cause this? A single genetic lineage of NoV has emerged as the major cause of pandemic and epidemic viral gastroenteritis. The first reported pandemic of acute gastroenteritis occurred in 1996, discovered through the advent of molecular detection assays. Following a second pandemic in 2002, NoV-associated pandemics of gastroenteritis have occurred with increasing frequency. Here we describe the current molecular epidemiological trends of human NoV, and its milder cousin, sapovirus (SaV), and explain why, in particular, NoV has become the biggest player in the field of viral gastroenteritis. With encouraging results from the first vaccine trial recently reported and continuing research towards the development of vaccines and antiviral agents, we ask whether better weapons to fight and deter gastroenteritis viruses will be available in the future?