An outbreak of enterovirus 71 in metropolitan Sydney: enhanced surveillance and lessons learnt.

Objective: To report the findings of the enhanced surveillance set up in New South Wales in response to the recent outbreak of human enterovirus 71 (EV71) infection.

Design And Setting: A two-armed enhanced public health surveillance system including statewide emergency department surveillance and clinical surveillance at the Sydney Children's Hospitals Network.

Participants: Children aged less than 10 years with suspected or confirmed enterovirus infection.

Main Outcome Measures: Epidemiology of the outbreak, including weekly case counts, demographic information, geographic spread of the outbreak, and clinical presentation and progression.

Results: Statewide weekly case counts indicate that an epidemic of EV71 infection occurred in NSW from December 2012 until May 2013. Around 119 children were reported with disease severe enough to warrant admission to a tertiary Sydney children's hospital. Cases were spread throughout the Sydney metropolitan area and there is some evidence of geographic migration of the outbreak. Presenting features included fever, lethargy, myoclonus and skin rash. Only 24% of cases presented with classical hand, foot and mouth disease.

Conclusions: EV71 infection is likely to continue to be a public health problem in Australia. Surveillance of routinely collected emergency department data can provide a useful indication of its activity in the community.