title: Lack of active Onchocerca volvulus transmission in the northern Chiapas focus of Mexico.
abstract: The northern Chiapas onchocerciasis focus has undergone 11 years of ivermectin mass treatment. No evidence of microfilariae in the cornea and/or anterior chamber of the eye or in skin snips was seen in residents examined in 2006 in two sentinel communities (upper limit of the 95% confidence interval [UL 95% CI] = 0.5% and 0.3%, respectively). In children 10 and under, 0 of 305 were found to harbor antibodies to Ov16, a marker of parasite exposure; 0 of 4,400 Simulium ochraceum s.l. collected in 2005 contained parasite DNA, giving an UL 95% CI for the infective rate of 0.9/2,000, and an UL 95% CI of the seasonal transmission potential of 1.2 L3/person. These data, assumed to be representative of the focus as a whole, suggest that there is no ongoing transmission of Onchocerca volvulus in the northern Chiapas focus. Community-wide treatments with ivermectin were halted in 2008, and a post-treatment surveillance phase was initiated.
authors.affiliation: Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, Tamaulipas, México. drmarodriguez@hotmail.com
authors.forename: Mario A
authors.initials: MA
authors.lastname: Rodríguez-Pérez
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Unnasch
authors.forename: Alfredo
authors.initials: A
authors.lastname: Domínguez-Vázquez
authors.forename: Alba L
authors.initials: AL
authors.lastname: Morales-Castro
authors.forename: Frank
authors.initials: F
authors.lastname: Richards
authors.forename: Graciela P
authors.initials: GP
authors.lastname: Peña-Flores
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Orozco-Algarra
authors.forename: Gibert
authors.initials: G
authors.lastname: Prado-Velasco
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D006801:Humans; D007559:Ivermectin / Q000627:therapeutic use; D008800:Mexico / Q000453:epidemiology; D017181:Onchocerca volvulus / Q000187:drug effects* / Q000276:immunology; D009855:Onchocerciasis / Q000276:immunology / Q000469:parasitology / Q000635:transmission*
chemical_list: D000871:Anthelmintics; D007559:Ivermectin