title: Sentinel surveillance of influenza-like illness in two hospitals in Maracay, Venezuela: 2006-2010.
abstract: BACKGROUND
  Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela.
  
  
  RESULTS
  We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month--86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second--higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected.
  
  
  CONCLUSIONS
  Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza virus in the post-pandemic phase.
authors.affiliation: Laboratorio Regional de Diagnostico e Investigacion del Dengue y otras Enfermedades Virales, Instituto de Investigaciones Biomedicas de la Universidad de Carabobo, Maracay, Venezuela. gcomach@yahoo.com
authors.forename: Guillermo
authors.initials: G
authors.lastname: Comach
authors.forename: Nimfa
authors.initials: N
authors.lastname: Teneza-Mora
authors.forename: Tadeusz J
authors.initials: TJ
authors.lastname: Kochel
authors.forename: Carlos
authors.initials: C
authors.lastname: Espino
authors.forename: Gloria
authors.initials: G
authors.lastname: Sierra
authors.forename: Daria E
authors.initials: DE
authors.lastname: Camacho
authors.forename: V Alberto
authors.initials: VA
authors.lastname: Laguna-Torres
authors.forename: Josefina
authors.initials: J
authors.lastname: Garcia
authors.forename: Gloria
authors.initials: G
authors.lastname: Chauca
authors.forename: Maria E
authors.initials: ME
authors.lastname: Gamero
authors.forename: Merly
authors.initials: M
authors.lastname: Sovero
authors.forename: Slave
authors.initials: S
authors.lastname: Bordones
authors.forename: Iris
authors.initials: I
authors.lastname: Villalobos
authors.forename: Angel
authors.initials: A
authors.lastname: Melchor
authors.forename: Eric S
authors.initials: ES
authors.lastname: Halsey
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D006761:Hospitals; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D008957:Models, Genetic; D010802:Phylogeny; D011446:Prospective Studies; D018571:Sentinel Surveillance; D017422:Sequence Analysis, DNA; D014687:Venezuela