title: Whooping cough dynamics in Chile (1932-2010): disease temporal fluctuations across a north-south gradient.
abstract: BACKGROUND
  The spatial-temporal dynamics of Bordetella pertussis remains as a highly interesting case in infectious disease epidemiology. Despite large-scale vaccination programs in place for over 50 years around the world, frequent outbreaks are still reported in many countries.
  
  
  METHODS
  Here, we use annual time series of pertussis incidence from the thirteen different regions of Chile (1952-2010) to study the spatial-temporal dynamics of Pertussis. The period 1975-1995 was characterized by a strong 4 year cycle, while the last two decades of the study period (1990-2010) were characterized by disease resurgence without significant periodic patterns.
  
  
  RESULTS
  During the first decades, differences in periodic patterns across regions can be explained by the differences in susceptible recruitment. The observed shift in periodicity from the period 1952-1974 to the period 1975-1995 across regions was relatively well predicted by the susceptible recruitment and population size. However, data on vaccination rates was not taken into account in this study.
  
  
  CONCLUSIONS
  Our findings highlight how demography and population size have interacted with the immunization program in shaping periodicity along a unique latitudinal gradient. Widespread B. pertussis vaccination appears to lead to longer periodic dynamics, which is line with a reduction in B. pertussis transmission, but our findings indicate that regions characterized by both low birth rate and population size decreased in periodicity following immunization efforts.
authors.affiliation: Departamento de Ecología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, 6513677, Chile. mlima@bio.puc.cl.|Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile. mlima@bio.puc.cl.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Lima
authors.affiliation: Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile. sergio.estay@gmail.com.|Inst. de Ecología y Evolución, Facultad de Ciencias. Univ. Austral de Chile, Casilla 567, Valdivia, Chile. sergio.estay@gmail.com.
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Estay
authors.affiliation: Departamento de Epidemiologia, Ministerio de Salud, Santiago, Chile. rodrigo.fuentes@minsal.cl.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Fuentes
authors.affiliation: Departamento de Epidemiologia, Ministerio de Salud, Santiago, Chile. paolarubilarr@gmail.com.
authors.forename: Paola
authors.initials: P
authors.lastname: Rubilar
authors.affiliation: MIVEGEC, UMR CNRS 5290-IRD 224-UM1-UM2, 911, Avenue Agropolis BP 64501, 34394, Montpellier Cédex 5, France. helene.broutin@ird.fr.
authors.forename: Hélène
authors.initials: H
authors.lastname: Broutin
authors.affiliation: School Public Health, Georgia State University, Atlanta, GA, USA. gchowell@gsu.edu.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Chowell-Puente
mesh_terms: D000293:Adolescent; D000328:Adult; D001886:Bordetella pertussis / Q000472:pathogenicity; D002648:Child; D002675:Child, Preschool; D002677:Chile / Q000453:epidemiology; D006801:Humans; D017589:Immunization Programs; D007223:Infant; D032541:Mass Vaccination; D008875:Middle Aged; D010567:Pertussis Vaccine; D011156:Population Density; D062211:Spatio-Temporal Analysis; D014917:Whooping Cough / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D055815:Young Adult
chemical_list: D010567:Pertussis Vaccine