title: Reduction and return of infectious trachoma in severely affected communities in Ethiopia.
abstract: BACKGROUND
  Antibiotics are a major tool in the WHO's trachoma control program. Even a single mass distribution reduces the prevalence of the ocular chlamydia that causes trachoma. Unfortunately, infection returns after a single treatment, at least in severely affected areas. Here, we test whether additional scheduled treatments further reduce infection, and whether infection returns after distributions are discontinued.
  
  
  METHODS
  Sixteen communities in Ethiopia were randomly selected. Ocular chlamydial infection in 1- to 5-year-old children was monitored over four biannual azithromycin distributions and for 24 months after the last treatment.
  
  
  RESULTS
  The average prevalence of infection in 1- to 5-year-old children was reduced from 63.5% pre-treatment to 11.5% six months after the first distribution (P<0.0001). It further decreased to 2.6% six months after the fourth and final treatment (P = 0.0004). In the next 18 months, infection returned to 25.2%, a significant increase from six months after the last treatment (P = 0.008), but still far lower than baseline (P<0.0001). Although the prevalence of infection in any particular village fluctuated, the mean prevalence of the 16 villages steadily decreased with each treatment and steadily returned after treatments were discontinued.
  
  
  CONCLUSIONS
  In some of the most severely affected communities ever studied, we demonstrate that repeated mass oral azithromycin distributions progressively reduce ocular chlamydial infection in a community, as long as these distributions are given frequently enough and at a high enough coverage. However, infection returns into the communities after the last treatment. Sustainable changes or complete local elimination of infection will be necessary.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00221364.
authors.affiliation: Orbis International, Addis Ababa, Ethiopia.
authors.forename: Takele
authors.initials: T
authors.lastname: Lakew
authors.forename: Jenafir
authors.initials: J
authors.lastname: House
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Hong
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Yi
authors.forename: Wondu
authors.initials: W
authors.lastname: Alemayehu
authors.forename: Muluken
authors.initials: M
authors.lastname: Melese
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zhou
authors.forename: Kathryn
authors.initials: K
authors.lastname: Ray
authors.forename: Stephanie
authors.initials: S
authors.lastname: Chin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Romero
authors.forename: Jeremy
authors.initials: J
authors.lastname: Keenan
authors.forename: John P
authors.initials: JP
authors.lastname: Whitcher
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Gaynor
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lietman
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017963:Azithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D002675:Child, Preschool; D004334:Drug Administration Schedule; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011247:Pregnancy; D014141:Trachoma / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin