@article{10.1371/journal.pone.0019467, abstract = {

Twitter is a free social networking and micro-blogging service that enables its millions of users to send and read each other's “tweets,” or short, 140-character messages. The service has more than 190 million registered users and processes about 55 million tweets per day. Useful information about news and geopolitical events lies embedded in the Twitter stream, which embodies, in the aggregate, Twitter users' perspectives and reactions to current events. By virtue of sheer volume, content embedded in the Twitter stream may be useful for tracking or even forecasting behavior if it can be extracted in an efficient manner. In this study, we examine the use of information embedded in the Twitter stream to (1) track rapidly-evolving public sentiment with respect to H1N1 or swine flu, and (2) track and measure actual disease activity. We also show that Twitter can be used as a measure of public interest or concern about health-related events. Our results show that estimates of influenza-like illness derived from Twitter chatter accurately track reported disease levels.

}, author = {Signorini, Alessio and Segre, Alberto Maria and Polgreen, Philip M.}, doi = {10.1371/journal.pone.0019467}, interhash = {56b199b8f3a3d085aef43e25b2aca06b}, intrahash = {6c3bc3dabf1b1d0095774e87b14d3ad2}, journal = {PLoS ONE}, month = {05}, number = 5, pages = {e19467}, publisher = {Public Library of Science}, title = {The Use of Twitter to Track Levels of Disease Activity and Public Concern in the U.S. during the Influenza A H1N1 Pandemic}, url = {http://dx.doi.org/10.1371%2Fjournal.pone.0019467}, volume = 6, year = 2011 } @misc{Medus2011, abstract = { The individual-based models constitute a set of widely implemented tools to analyze the incidence of individuals heterogeneities in the spread of an infectious disease. In this work we focus our attention on human contacts heterogeneities through two of the main individual-based models: mobile agents and complex networks models. We introduce a novel mobile agents model in which individuals make displacements with sizes according to a truncated power-law distribution based on empirical evidence about human mobility. Besides, we present a procedure to obtain an equivalent weighted contact network from the previous mobile agents model, where the weights of the links are interpreted as contact probabilities. From the topological analysis of the equivalent contact networks we show that small world characteristics are related with truncated power-law distribution for agent displacements. Finally, we show the equivalence between both approaches through some numerical experiments for the spread of an infectious disease. }, author = {Medus, A. D. and Dorso, C. O.}, interhash = {d2f8fefb3a26400deab44de456bd990c}, intrahash = {8ad77fa71d773ea860280d528fd0b1c2}, note = {cite arxiv:1104.4913 Comment: 19 pages, 7 figures, submitted to PRE}, title = {Diseases spreading through individual based models with realistic mobility patterns}, url = {http://arxiv.org/abs/1104.4913}, year = 2011 }