title: Salmonella enterica Infections in the United States and Assessment of Coefficients of Variation: A Novel Approach to Identify Epidemiologic Characteristics of Individual Serotypes, 1996-2011.
abstract: BACKGROUND
  Despite control efforts, salmonellosis continues to cause an estimated 1.2 million infections in the United States (US) annually. We describe the incidence of salmonellosis in the US and introduce a novel approach to examine the epidemiologic similarities and differences of individual serotypes.
  
  
  METHODS
  Cases of salmonellosis in humans reported to the laboratory-based National Salmonella Surveillance System during 1996-2011 from US states were included. Coefficients of variation were used to describe distribution of incidence rates of common Salmonella serotypes by geographic region, age group and sex of patient, and month of sample isolation.
  
  
  RESULTS
  During 1996-2011, more than 600,000 Salmonella isolates from humans were reported, with an average annual incidence of 13.1 cases/100,000 persons. The annual reported rate of Salmonella infections did not decrease during the study period. The top five most commonly reported serotypes, Typhimurium, Enteritidis, Newport, Heidelberg, and Javiana, accounted for 62% of fully serotyped isolates. Coefficients of variation showed the most geographically concentrated serotypes were often clustered in Gulf Coast states and were also more frequently found to be increasing in incidence. Serotypes clustered in particular months, age groups, and sex were also identified and described.
  
  
  CONCLUSIONS
  Although overall incidence rates of Salmonella did not change over time, trends and epidemiological factors differed remarkably by serotype. A better understanding of Salmonella, facilitated by this comprehensive description of overall trends and unique characteristics of individual serotypes, will assist in responding to this disease and in planning and implementing prevention activities.
authors.affiliation: Epidemic Intelligence Service, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.|Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Boore
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: R Michael
authors.initials: RM
authors.lastname: Hoekstra
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: Martha
authors.initials: M
authors.lastname: Iwamoto
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: Patricia I
authors.initials: PI
authors.lastname: Fields
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Bishop
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, 30333, United States of America.
authors.forename: David L
authors.initials: DL
authors.lastname: Swerdlow
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012478:Salmonella Food Poisoning / Q000453:epidemiology* / Q000821:virology; D012480:Salmonella Infections / Q000097:blood / Q000453:epidemiology* / Q000821:virology; D019779:Salmonella enterica / Q000145:classification* / Q000302:isolation & purification; D012703:Serotyping; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult