Dr. Alex Keenan from the Health Protection Agency gives a short introduction into epidemiology and surveillance.

1. An Introduction to Epidemiology pt 01 Dr Alex Keenan, Epidemiology and Surveillance Analyst, Cheshire & Merseyside HPU 27 th April 2010

7. Surveillance Systems Database Policy makers PCTs / LAs / SHAs Health Practitioners Dissemination Laboratory / clinic Data Analysis Specialist Laboratory Supplementary data

9. Weekly Surveillance Data

10. Campylobacter – Weekly Surveillance (1)

11. Campylobacter – Weekly Surveillance (2)

13. Campylobacter – Weekly Surveillance (3)

14. Temporal Distribution

15. Measles – Outbreak (1)

16. Measles – Outbreak (2)

31. Clusters can be… In Time e.g. cases of legionella In Place e.g. meningococcal cases in same school class In Person e.g. cases of breast cancer in a family The term cluster denotes the suspicion of an increased frequency of some event occurring, not that any increase has been demonstrated

34. Figure. Measles cases by date of onset of rash. Region of Madrid, March 2006. (Cases reported until 16th March, 2006) Example of propagated outbreak (see www.eurosurveillance.org/ew/2006/060330.asp)

35. Example of Point Source Outbreak

45. Epidemiological Curve

47. Single Variable Analysis <0.01 6.45 – 32.47 15.70 Rice <0.01 6.99 – 31.84 15.40 Chicken Curry <0.01 1.99 – 7.22 3.61 Vegetable Samosa <0.01 3.12 – 12.56 6.21 Beef Cutlet <0.01 2.80 – 10.52 6.05 Chicken Lollipop <0.01 2.60 – 9.77 4.87 Spring Roll 0.34 0.71 – 2.67 1.30 Sex 0.056 0.99 – 1.04 1.02 Age p – value Confidence Interval Odds Ratio

49. Multivariate Analysis <0.0001 4.34 – 36.88 12.63 Rice 0.003 1.54 – 8.51 3.63 Chicken Curry p- value Confidence Interval Odds Ratio