Norovirus Sydney 2012: The chunder from down under
Norovirus is the leading cause of acute gastroenteritis globally with the primary symptoms of infection including vomiting and diarrhea. Typical of most single stranded RNA viruses, norovirus demonstrates a broad genetic diversity and can infect a wide range of mammalian hosts; however, the majority of human infections are caused by variants of a single genetic lineage – GII.4. The molecular epidemiology of the norovirus GII.4 lineage has been characterised by a continual turnover of novel variants that often precede large global epidemics. The emergence and evolution of these novel GII.4 variants has been attributed to rapid evolution and antigenic variation in response to herd immunity as well as frequent recombination between circulating strains. In this presentation, I will reflect on the recent molecular epidemiology of norovirus infections in Australia and globally, and then discuss the significant impact and origins of a recently emerged GII.4 virus, known as Sydney 2012, that has grabbed headlines across the globe (for the wrong reasons).