title: Pandemic influenza A (H1N1) 2009: epidemiological analysis of cases in a tropical/semi-arid region of Brazil.
abstract: BACKGROUND
  The year 2009 marked the beginning of a pandemic caused by a new variant of influenza A (H1N1). After spreading through North America, the pandemic influenza virus (H1N1) 2009 spread rapidly throughout the world. The aim of this study was to describe the clinical and epidemiological characteristics of cases of pandemic influenza in a tropical/semi-arid region of Brazil.
  
  
  METHODS
  A retrospective study analyzed all suspected cases of pandemic influenza (H1N1) 2009 reported in the Ceará State through the National Information System for Notifiable Diseases during the pandemic period between 28 April, 2009 and November 25, 2010.
  
  
  RESULTS
  A total of 616 suspected cases were notified, 58 (9.4%) in the containment phase and 558 (90.6%) in the mitigation phase. Most cases were of affected young people resident in the City of Fortaleza, the largest urban center in the State of Ceará. The most frequent symptoms presented by the cases with confirmed infection were fever, cough, myalgia, arthralgia, and nasal congestion. Mortality rate was 0.0009/1,000 inhabitants and lethality was 5.6%. Deaths were observed only in the mitigation phase. Mortality rates were similar for both sexes but were higher in the age group under 5 years.
  
  
  CONCLUSIONS
  The study suggests that the influenza A (H1N1) pandemic in this tropical/semi-arid region had a lower magnitude when compared to states in the Southern and Southeastern regions of Brazil.
authors.affiliation: Departamento de Saúde Comunitária, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil. robertojusta@ufc.br
authors.forename: Roberto da Justa
authors.initials: Rda J
authors.lastname: Pires Neto
authors.forename: Daniele Rocha Queiroz
authors.initials: DR
authors.lastname: Lemos
authors.forename: Luciano Pamplona de Góes
authors.initials: LP
authors.lastname: Cavalcanti
authors.forename: Alberto Novaes
authors.initials: AN
authors.lastname: Ramos Junior
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Alencar
authors.forename: Mônica Cardoso
authors.initials: MC
authors.lastname: Façanha
authors.forename: Madalena Isabel Coelho
authors.initials: MI
authors.lastname: Barroso
authors.forename: Dina Cortez Lima Feitosa
authors.initials: DC
authors.lastname: Vilar
authors.forename: Manoel Dias da
authors.initials: MD
authors.lastname: Fonseca Neto
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D062306:Geography, Medical; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D058873:Pandemics; D012189:Retrospective Studies; D014329:Tropical Climate; D055815:Young Adult