title: Do differences in risk factors, medical care seeking, or medical practices explain the geographic variation in campylobacteriosis in Foodborne Diseases Active Surveillance Network (FoodNet) sites?
abstract: BACKGROUND
  In the United States, considerable geographic variation in the rates of culture-confirmed Campylobacter infection has been consistently observed among sites participating in the Foodborne Diseases Active Surveillance Network (FoodNet).
  
  
  METHODS
  We used data from the FoodNet Population Surveys and a FoodNet case-control study of sporadic infection to examine whether differences in medical care seeking, medical practices, or risk factors contributed to geographic variation in incidence.
  
  
  RESULTS
  We found differences across the FoodNet sites in the proportion of persons seeking medical care for an acute campylobacteriosis-like illness (range, 24.9%-43.5%) and in the proportion of ill persons who submitted a stool sample (range, 18.6%-40.7%), but these differences were not statistically significant. We found no evidence of geographic effect modification of previously identified risk factors for campylobacteriosis in the case-control study analysis. The prevalence of some exposures varied among control subjects in the FoodNet sites, including the proportion of controls reporting eating chicken at a commercial eating establishment (18.2%-46.1%); contact with animal stool (8.9%-30.9%); drinking water from a lake, river, or stream (0%-5.1%); and contact with a farm animal (2.1%-12.7%). However, these differences do not fully explain the geographic variation in campylobacteriosis.
  
  
  CONCLUSIONS
  Future studies that quantify Campylobacter contamination in poultry or variation in host immunity may be useful in identifying sources of this geographic variation in incidence.
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia 30333, USA. eailes@cdc.gov
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ailes
authors.forename: Elaine
authors.initials: E
authors.lastname: Scallan
authors.forename: Ruth L
authors.initials: RL
authors.lastname: Berkelman
authors.forename: David G
authors.initials: DG
authors.lastname: Kleinbaum
authors.forename: Robert V
authors.initials: RV
authors.lastname: Tauxe
authors.forename: Christine L
authors.initials: CL
authors.lastname: Moe
mesh_terms: D000818:Animals; D002167:Campylobacter / Q000276:immunology / Q000302:isolation & purification*; D002169:Campylobacter Infections / Q000453:epidemiology* / Q000382:microbiology / Q000628:therapy; D016022:Case-Control Studies; D002487:Centers for Disease Control and Prevention, U.S.; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000382:microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000628:therapy; D006801:Humans; D015994:Incidence; D007223:Infant; D010342:Patient Acceptance of Health Care / Q000523:psychology*; D011159:Population Surveillance; D010818:Practice Patterns, Physicians' / Q000592:standards*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology