Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Multistate Outbreak of Salmonella Saintpaul Infections Linked to Raw Produce (Final Update)

Posted August 28, 2008

This outbreak appears to be over. However, Salmonella is an important cause of human illness in the United States. More information about Salmonella, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page.

Current Epi Curve

This outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epi curve. Please see the Timeline for Reporting of Salmonella Cases for more details on the reporting process.

The epidemic curve (epi curve) shows progression of an outbreak over time.  The horizontal axis represents the date when a person became ill, also called the date of onset . The vertical axis is the number of persons who became ill on each date. These are updated as new data come in, and thus are subject to change.  The epi curve is complex and incomplete. Several issues are important in understanding it.

  • There is an inherent delay between the date that an illness starts, and the date that the case is reported to public health authorities.  It typically takes 2-3 weeks for Salmonella infections. That means that someone who got sick last week is very unlikely to have been reported yet, and someone who got sick three weeks ago may just be reported now. Please see the Salmonella Outbreak Investigations:Timeline for Reporting Cases.

  • Some background cases of illness are likely to occur that would have occurred even without an outbreak.  This makes it difficult to say exactly which case is the first in an outbreak.   Epidemiologists typically focus on the first recognized cluster or group of cases rather than the very first case. Due to the inherent reporting delay, the cluster is sometimes not detected until several weeks after the persons became ill.
  • For some cases, the date when they became ill is not known because it takes time before someone from the health department can do an interview to ask for this information. Sometimes the interview never occurs.  If the date that the person brought the specimen to be tested to the laboratory is known, we may estimate the date of illness onset as three days before that.      
  • It can be difficult to determine when cases start to decline because of the reporting delay.  This can become clearer as time passes.

  • It can be difficult to say when the outbreak is over, because of the reporting delay. The delay means that the curve for the most recent three weeks always looks like the outbreak could be ending even during an active outbreak. The full shape of the curve is only clear after the outbreak is over.
Interpretation of Epidemic Curves During an Active Outbreak

« Read the full Outbreak Investigation

Previous Epi Curves

Epi Curve: August 22, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 22, 2008.

Epi Curve: August 20, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 20, 2008.

Epi Curve: August 15, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 15, 2008.

Epi Curve: August 12, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 12, 2008.

Epi Curve: August 8, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 8, 2008.

Epi Curve: August 6, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 6, 2008.

Epi Curve: August 4, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 4, 2008.

Epi Curve: August 1, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of August 1, 2008.

Epi Curve: July 30, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 30, 2008.

Epi Curve: July 29, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 29, 2008.

Epi Curve: July 28, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 28, 2008.

Epi Curve: July 25, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 25, 2008.

Epi Curve: July 24, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 24, 2008.

Epi Curve: July 23, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 23, 2008.

Epi Curve: July 22, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 22, 2008.

Epi Curve: July 21, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 21, 2008.

Epi Curve: July 18, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 18, 2008.

Epi Curve: July 17, 2008

Interpretation of Epidemic Curves During an Active Outbreak as of July 17, 2008.
 
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
  • Contact CDC–INFO
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #