Norovirus: a challenging pathogen

Noroviruses account for over 90% of all viral gastroenteritis cases and ~50% of all outbreaks worldwide. Each year in Australia, there are an estimated 1.8 million cases. Casesmaybe sporadic or part of outbreaks, occurring in either the community or healthcare setting. Outbreaks are associated with significant morbidity and some mortality. They incur substantial costs and can be difficult to control in healthcare institutions or other closed settings.Multiple factors (related to virus biological properties, human immune responses or inadequate management modalities) make it a challenging pathogen to control. They include: multiple transmission routes, low infectious dose, environmental survival, spread and persistence, diagnostic difficulty, hand hygiene controversies, imperfect immunity and immune evasion, asymptomatic and prolonged shedding, lack of vaccine and lack of antiviral treatment. The purpose of this article is to promote a better understanding of these factors in order that health professionals may be better equipped to manage the problems posed by noroviruses.Until large-scale effective vaccination and specific treatments become available, the safeguarding of food and water supplies and the rigorous and timely application of outbreak management and infection control measures will remain the key to norovirus disease prevention and control.