HealthMap is a system that monitors disease outbreaks around the world by processing over 20,000 news and unstructured web sites every hour using text clustering, matching, filtering and other algorithms. It provides a "heat index" alert system to identify potential disease outbreaks based on the number and recency of reports from different locations. While most alerts currently come from English language sources, the system also covers Spanish, French and Russian. It is used as a public health monitoring and response tool by various organizations and sees 500-600 daily users. Future work aims to improve algorithms, add more languages and collaborate with other health networks.

1. Disease Outbreak Monitoring on the Web Clark Freifeld Research Software Developer Harvard Medical School Children’s Hospital Informatics Program

2. www.healthmap.org

4. HealthMap Article Processing Acquisition >20,000 sites Every hour; 24/7 Clustering Text Matching Similarity Score Categorization 1700 disease patterns 5000 location patterns Bayesian Filtering 6 million phrases 91% accuracy

5. Multi-Stream Alarming: Heat Index Meta-alert composite score, based on Number of sources providing information at a particular location Recentness of alert Marker algorithm Exponentially weighted alerts Increase heat (redness) for more recent event and higher impact low high Freifeld et al. J Am Med Informatics Assn. 2008.

6. Limitations of English-language Alerts by country 1-USA: 4351 2-UK: 1018 3-Canada: 880 4-China:737

7. English

8. Spanish

9. French

10. Russian

11. Case Study: Legionnaire’s in Spain June 30th Google (ES) Alert Alert #1 July 2nd ProMED-mail Alert Alert #2 July 4th Google (EN) Alert Alert #3

12. Early Stats > 200 alerts per day 80,000 alerts so far Alerts in 201 countries 175 disease categories 4 four languages English (60%) Spanish (20%) French (11%) Russian (9%)

13. Usage 500-600 visits per day 100,000 unique visitors since 9/06 launch Top visitors: cdc.gov dhs.gov med.navy.mil, af.mil state.fl.us state.id.us

14. Public Health Resource

15. Various implementations International Society for Infectious Disease Liberty Science Museum, NYC HHS Command Center

16. Tool for general population

17. Future Directions Improve existing filtering algorithms More sensitive, noisy sources More filters: number of cases, species affected More languages Collaborative networks Other areas: Environmental health Chronic disease Violence, conflict zones Pharmaceuticals Your ideas

18. Acknowledgments Children’s Hospital Informatics Program @ Harvard-MIT HST John Brownstein, PhD Ken Mandl, MD MPH Ben Reis, PhD Mikaela Keller, PhD Isaac Kohane, MD PhD Carlo Venis (Wabash) Roger Araujo (Peru NMRCD) David Blazes (Peru NMRCD) Aranka Anema (UBC) Larry Madoff (ProMED) Funding Google Foundation National Library of Medicine (NLM) Centers for Disease Control and Prevention Canadian Institutes of Health Research (CIHR)

19. Contact [email_address] www.healthmap.org www.chip.org