Technique for early detection of localized exposure to an agent active on a biological population include collecting time series for each data type of multiple different data types. The data types are relevant for detecting exposure to the agent. For each data type multiple time series are collected for corresponding multiple locations associated with the data type. Measures of anomalous conditions are generated at the locations for each of the different data types. The measures of anomalous conditions are based on the time series and a temporal model for each data type. Cluster analysis is performed on the measures of anomalous conditions to determine an estimated location, and an estimated extent, of effects from the agent. The techniques allow a surveillance system to avoid diluting the signal of a localized outbreak over too large and area or consuming excessive resources in computing replicas for a matched filter detector.