title: Salmonella enterica Serovar Napoli Infection in Italy from 2000 to 2013: Spatial and Spatio-Temporal Analysis of Cases Distribution and the Effect of Human and Animal Density on the Risk of Infection.
abstract: BACKGROUND
  Salmonella Napoli is uncommon in Europe. In Italy however, it has been growing in importance since 2000. To date, no risk factors have been identified to account for its rise. This study aims at describing the epidemiology, spatial and spatio-temporal patterns of S. Napoli in Italy from 2000 to 2013, and to explore the role of several environmental correlates, namely urbanization, altitude and number of livestock farms, on the risk of S. Napoli infection among humans.
  
  
  METHODS
  Data were obtained from Enter-Net Italy, a network of diagnostic laboratories. The data were aggregated at the municipality level. Descriptive epidemiology, multivariate regression models, spatial and spatio-temporal analyses were performed on the number of cases and incidence rates.
  
  
  RESULTS
  S. Napoli showed an expanding trend at the national level, and an increasing number of cases. Compared to the other main serovars in Italy, the risk of S. Napoli infection was higher in the age group <1 year, and lower in the other age groups. Although urbanization and the number of farms were associated with the risk of S. Napoli infection to some extent, their role in the epidemiology of the disease remains inconclusive. S. Napoli cases showed a positive global spatial autocorrelation as well as a significant spatio-temporal interaction. Twenty-four spatial and spatio-temporal clusters were identified, seven purely spatial and 17 spatio-temporal, mainly in north-western Italy. Most of the clusters were in areas characterized by urban and industrial settlements surrounded by agricultural land and an abundance of freshwater bodies.
  
  
  CONCLUSIONS
  Our results point to the presence, in a number of areas in Italy, of a Salmonella of public health concern originating in the environment. This highlights the increasing relevance of environmental, non-food-related sources of human exposure to enteric pathogens.
authors.affiliation: Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Graziani
authors.affiliation: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Ida
authors.initials: I
authors.lastname: Luzzi
authors.affiliation: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Owczarek
authors.affiliation: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Dionisi
authors.affiliation: Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Busani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors; D012480:Salmonella Infections / Q000453:epidemiology* / Q000382:microbiology; D019779:Salmonella enterica / Q000302:isolation & purification* / Q000378:metabolism; D065288:Serogroup; D062211:Spatio-Temporal Analysis; D055815:Young Adult