Prudent detection is a cornerstone in the control and
prevention of infectious diseases. Traditional infectious
disease surveillance systems are typically characterised
by a bottom-up process of data collection and information
flow; these systems require a patient to recognise
illness and seek treatment and a physician or laboratory
to diagnose the infection and notify the relevant authority
[1,2]. For emerging infectious disease events, this
process is reported to take, on average, 15 days from onset
to detection and a further 12–24 hours for the World
Health Organization to be notified [3]. The development
and implementation of more efficient systems for gathering
intelligence on infectious diseases has the potential
to reduce the impact of disease events. Internet-based
surveillance systems are one such system [4].
Internet-based surveillance systems produce estimates
of disease incidence through analysis of various digital
data-sources. Targeted sources include internet-search
metrics, online news stories, social network data and blog/