title: Epidemiology, seasonality, and burden of influenza and influenza-like illness in urban and rural Kenya, 2007-2010.
abstract: BACKGROUND
  The epidemiology and burden of influenza remain poorly defined in sub-Saharan Africa. Since 2005, the Kenya Medical Research Institute and Centers for Disease Control and Prevention-Kenya have conducted population-based infectious disease surveillance in Kibera, an urban informal settlement in Nairobi, and in Lwak, a rural community in western Kenya.
  
  
  METHODS
  Nasopharyngeal and oropharyngeal swab specimens were obtained from patients who attended the study clinic and had acute lower respiratory tract (LRT) illness. Specimens were tested for influenza virus by real-time reverse-transcription polymerase chain reaction. We adjusted the incidence of influenza-associated acute LRT illness to account for patients with acute LRT illness who attended the clinic but were not sampled.
  
  
  RESULTS
  From March 2007 through February 2010, 4140 cases of acute LRT illness were evaluated in Kibera, and specimens were collected from 1197 (27%); 319 (27%) were positive for influenza virus. In Lwak, there were 6733 cases of acute LRT illness, and specimens were collected from 1641 (24%); 359 (22%) were positive for influenza virus. The crude and adjusted rates of medically attended influenza-associated acute LRT illness were 6.9 and 13.6 cases per 1000 person-years, respectively, in Kibera, and 5.6 and 23.0 cases per 1000 person-years, respectively, in Lwak. In both sites, rates of influenza-associated acute LRT illness were highest among children <2 years old and lowest among adults ≥50 years old.
  
  
  CONCLUSIONS
  In Kenya, the incidence of influenza-associated acute LRT illness was high in both rural and urban settings, particularly among the most vulnerable age groups.
authors.affiliation: Influenza Program,  Kenya Medical Research Institute/Centers for Disease Control and Prevention Public Health and Research Collaboration,  Kenya.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Katz
authors.forename: Emmaculate
authors.initials: E
authors.lastname: Lebo
authors.forename: Gideon
authors.initials: G
authors.lastname: Emukule
authors.forename: Henry N
authors.initials: HN
authors.lastname: Njuguna
authors.forename: Barrack
authors.initials: B
authors.lastname: Aura
authors.forename: Leonard
authors.initials: L
authors.lastname: Cosmas
authors.forename: Alan
authors.initials: A
authors.lastname: Audi
authors.forename: Muthoni
authors.initials: M
authors.lastname: Junghae
authors.forename: Lilian W
authors.initials: LW
authors.lastname: Waiboci
authors.forename: Beatrice
authors.initials: B
authors.lastname: Olack
authors.forename: Godfrey
authors.initials: G
authors.lastname: Bigogo
authors.forename: M K
authors.initials: MK
authors.lastname: Njenga
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Feikin
authors.forename: Robert F
authors.initials: RF
authors.lastname: Breiman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D007630:Kenya / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology; D009960:Oropharynx / Q000821:virology; D011024:Pneumonia, Viral / Q000453:epidemiology* / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012424:Rural Population; D012621:Seasons; D055815:Young Adult