title: Successful interruption of transmission of Onchocerca volvulus in the Escuintla-Guatemala focus, Guatemala.
abstract: BACKGROUND
  Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of Escuintla-Guatemala in Guatemala, based on World Health Organization criteria for the certification of elimination of onchocerciasis.
  
  
  RESULTS
  We conducted evaluations of ocular morbidity and past exposure to Onchocerca volvulus in the human population, while potential vectors (Simulium ochraceum) were captured and tested for O. volvulus DNA; all of the evaluations were carried out in potentially endemic communities (PEC; those with a history of actual or suspected transmission or those currently under semiannual mass treatment with ivermectin) within the focus. The prevalence of microfilariae in the anterior segment of the eye in 329 individuals (> or =7 years old, resident in the PEC for at least 5 years) was 0% (one-sided 95% confidence interval [CI] 0-0.9%). The prevalence of antibodies to a recombinant O. volvulus antigen (Ov-16) in 6,432 school children (aged 6 to 12 years old) was 0% (one-sided 95% IC 0-0.05%). Out of a total of 14,099 S. ochraceum tested for O. volvulus DNA, none was positive (95% CI 0-0.01%). The seasonal transmission potential was, therefore, 0 infective stage larvae per person per season.
  
  
  CONCLUSIONS
  Based on these evaluations, transmission of onchocerciasis in the Escuintla-Guatemala focus has been successfully interrupted. Although this is the second onchocerciasis focus in Latin America to have demonstrated interruption of transmission, it is the first focus with a well-documented history of intense transmission to have eliminated O. volvulus.
authors.affiliation: Centro de Estudios en Salud, Universidad del Valle de Guatemala, Guatemala City, Guatemala.
authors.forename: Rodrigo J
authors.initials: RJ
authors.lastname: Gonzalez
authors.forename: Nancy
authors.initials: N
authors.lastname: Cruz-Ortiz
authors.forename: Nidia
authors.initials: N
authors.lastname: Rizzo
authors.forename: Jane
authors.initials: J
authors.lastname: Richards
authors.forename: Guillermo
authors.initials: G
authors.lastname: Zea-Flores
authors.forename: Alfredo
authors.initials: A
authors.lastname: Domínguez
authors.forename: Mauricio
authors.initials: M
authors.lastname: Sauerbrey
authors.forename: Eduardo
authors.initials: E
authors.lastname: Catú
authors.forename: Orlando
authors.initials: O
authors.lastname: Oliva
authors.forename: Frank O
authors.initials: FO
authors.lastname: Richards
authors.forename: Kim A
authors.initials: KA
authors.lastname: Lindblade