Skip to main content
    • Aa
    • Aa

Attributing sporadic and outbreak-associated infections to sources: blending epidemiological data

  • D. COLE (a1), P. M. GRIFFIN (a1), K. E. FULLERTON (a1), T. AYERS (a2), K. SMITH (a3), L. A. INGRAM (a4), B. KISSLER (a5) and R. M. HOEKSTRA (a2)...

Common sources of shiga toxin-producing Escherichia coli (STEC) O157 infection have been identified by investigating outbreaks and by case-control studies of sporadic infections. We conducted an analysis to attribute STEC O157 infections ascertained in 1996 and 1999 by the Foodborne Diseases Active Surveillance Network (FoodNet) to sources. Multivariable models from two case-control studies conducted in FoodNet and outbreak investigations that occurred during the study years were used to calculate the annual number of infections attributable to six sources. Using the results of the outbreak investigations alone, 27% and 15% of infections were attributed to a source in 1996 and 1999, respectively. Combining information from both data sources, 65% of infections in 1996 and 34% of infections in 1999 were attributed. The results suggest that methods to incorporate data from multiple surveillance systems and over several years are needed to improve estimation of the number of illnesses attributable to exposure sources.

Corresponding author
*Author for correspondence: Dr D. Cole, DVM, PhD, Lead, Analytics Team, Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne and Environmental Diseases, 1600 Clifton Rd, NE, MS C-09, Atlanta, GA 30333, USA. (Email:
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

1. EScallan , Foodborne illness acquired in the United States – major pathogens. Emerging Infectious Diseases 2011; 17: 715.

7.HD Kassenborg , Farm visits and undercooked hamburgers as major risk factors for sporadic Escherichia coli O157:H7 infection: data from a case-control study in 5 FoodNet sites. Clinical Infectious Diseases 2004; 38: S271278.

9. JBenichou . A review of adjusted estimators of attributable risk. Statistical Methods in Medical Research 2001; 10: 195216.

10. PBruzzi , Estimating the population attributable risk for multiple risk factors using case-control data. American Journal of Epidemiology 1985; 122: 904914.

11. SGreenland , JMRobins . Conceptual problems in the definition and interpretation of attributable fractions. American Journal of Epidemiology 1988; 128: 11851197.

13. RMurphree , Characteristics of foodborne outbreak investigations conducted by Foodborne Diseases Active Surveillance Network (FoodNet) sites, 2003–2008. Clinical Infectious Diseases 2012; 54: S498S503.

14. MJKnol , What do case-control studies estimate? Survey of methods and assumptions in published case-control research. American Journal of Epidemiology 2008; 168: 10731081.

16.S Greenland . Attributable fractions: bias from broad definition of exposure. Epidemiology 2001; 12: 518520.

17. BRockhill , BNewman , CWeinberg . Use and misuse of population attributable fractions. American Journal of Public Health 1998; 88: 1519.

18. KSteenland , BArmstrong . An overview of methods for calculating the burden of disease due to specific risk factors. Epidemiology 2006; 17: 18.

19.K Mølbak , J Neimann . Risk factors for sporadic infection with Salmonella Enteritidis, Denmark, 1997–1999. American Journal of Epidemiology 2002; 156: 654661.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Epidemiology & Infection
  • ISSN: 0950-2688
  • EISSN: 1469-4409
  • URL: /core/journals/epidemiology-and-infection
Please enter your name
Please enter a valid email address
Who would you like to send this to? *