Fig. 4: Enhancing epidemic response with targeted surveillance.
From: Human behavior-driven epidemic surveillance in urban landscapes
a The SEIR model is augmented with a surveillance system that records positive tests from exposed and infectious individuals. b The solid line represents the natural (without interventions) epidemic curve. The dotted lines correspond to the epidemic curves shown in f (commented below). In panel c we show the time evolution of detected cases for different concentrations of testing resources on critical links. The dashed horizontal line signifies the threshold, nalarm, which triggers containment actions. The Early Warning Time (EWT) - the interval spanned from the initial infections to the time when nalarm detections occur - is plotted against the degree of test concentration L for d various numbers of available tests, ntests, and for e distinct basic reproduction numbers, \({{\mathcal{R}}}_{0}\). Panel f shows the mitigated epidemic curves upon the imposition of containment measures that reduce \({{\mathcal{R}}}_{0}\) by 50% at time t = EWT (these curves are also represented with dashed lines in panel b for illustrating the mitigation effect with respect to the uncontrolled scenario). The shaded areas in panels d–f represent the 95% confidence interval in the results obtained from 100 distinct simulations.
