title: Transmission of Onchocerca volvulus continues in Nyagak-Bondo focus of northwestern Uganda after 18 years of a single dose of annual treatment with ivermectin.
abstract: The objective of the study was to determine whether annual ivermectin treatment in the Nyagak-Bondo onchocerciasis focus could safely be withdrawn. Baseline skin snip microfilariae (mf) and nodule prevalence data from six communities were compared with data collected in the 2011 follow-up in seven communities. Follow-up mf data in 607 adults and 145 children were compared with baseline (300 adults and 58 children). Flies collected in 2011 were dissected, and poolscreen analysis was applied to ascertain transmission. Nodule prevalence in adults dropped from 81.7% to 11.0% (P < 0.0001), and mf prevalence dropped from 97.0% to 23.2% (P < 0.0001). In children, mf prevalence decreased from 79.3% to 14.1% (P < 0.0001). Parous and infection rates of 401 flies that were dissected were 52.9% and 1.5%, respectively, whereas the infective rate on flies examination by polymerase chain reaction (PCR) was 1.92% and annual transmission potential was 26.9. Stopping ivermectin treatment may result in onchocerciasis recrudescence.
authors.affiliation: The Carter Center, Atlanta, Georgia 30307, USA. mkataba@emory.edu
authors.forename: Moses N
authors.initials: MN
authors.lastname: Katabarwa
authors.forename: Tom
authors.initials: T
authors.lastname: Lakwo
authors.forename: Peace
authors.initials: P
authors.lastname: Habomugisha
authors.forename: Stella
authors.initials: S
authors.lastname: Agunyo
authors.forename: Edson
authors.initials: E
authors.lastname: Byamukama
authors.forename: David
authors.initials: D
authors.lastname: Oguttu
authors.forename: Ephraim
authors.initials: E
authors.lastname: Tukesiga
authors.forename: Dickson
authors.initials: D
authors.lastname: Unoba
authors.forename: Patrick
authors.initials: P
authors.lastname: Dramuke
authors.forename: Ambrose
authors.initials: A
authors.lastname: Onapa
authors.forename: Edridah M
authors.initials: EM
authors.lastname: Tukahebwa
authors.forename: Dennis
authors.initials: D
authors.lastname: Lwamafa
authors.forename: Frank
authors.initials: F
authors.lastname: Walsh
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Unnasch
mesh_terms: D000328:Adult; D000818:Animals; D000977:Antiparasitic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003386:Brachyura / Q000469:parasitology; D002648:Child; D004334:Drug Administration Schedule; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D007559:Ivermectin / Q000008:administration & dosage / Q000627:therapeutic use*; D017181:Onchocerca volvulus / Q000187:drug effects*; D009855:Onchocerciasis / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission*; D012843:Simuliidae / Q000469:parasitology; D014454:Uganda / Q000453:epidemiology
chemical_list: D000977:Antiparasitic Agents; D007559:Ivermectin