title: Interruption of the transmission of Onchocerca volvulus in the Kashoya-Kitomi focus, western Uganda by long-term ivermectin treatment and elimination of the vector Simulium neavei by larviciding.
abstract: Uganda is the only country in sub-Saharan Africa whose onchocerciasis elimination programme extensively uses vector control and biannual treatment with ivermectin. The purpose of this study was to assess the impact of combined strategies on interrupting onchocerciasis transmission in the Kashoya-Kitomi focus. Mass Drug Administration annually (13 years) followed by biannual treatments (6 years) and ground larviciding (36 cycles in 3 years) with temephos (Abate®, EC500) against Simulium neavei were conducted. Routine fly catches were conducted for over seven years in six catching sites and freshwater crabs Potamonautes aloysiisabaudiae were examined for immature stages of Simulium neavei. Epidemiological assessments by skin snip were performed in 2004 and 2013. Collection of dry blood spots (DBS) from children <10 years for IgG4 antibodies analysis were done in 2010 and 2013. Treatment coverage with ivermectin improved with introduction of biannual treatment strategy. Microfilaria prevalence reduced from 85% in 1991 to 62% in 2004; and to only 0.5% in 2013. Crab infestation reduced from 59% in 2007 to 0% in 2013 following ground larviciding. Comparison of total fly catches before and after ground larviciding revealed a drop from 5334 flies in 2007 to 0 flies in 2009. Serological assays conducted among 1,362 children in 2010 revealed 11 positive cases (0.8%; 95% CI: 0.4%-1.2%). However, assessment conducted on 3246 children in 2013 revealed five positives, giving point prevalence of 0.15%; 95% CI: 0.02%-0.28%. Four of the five children subjected to O-150 PCR proved negative. The data show that transmission of onchocerciasis has been interrupted based on national and WHO Guidelines of 2012 and 2016, respectively.
authors.affiliation: Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda. Electronic address: tlakwo@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Lakwo
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, P.O. Box 304120, D-20324 Hamburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Garms
authors.affiliation: Kamwenge District Local Government, P.O. Box 1408, Kamwenge, Uganda.
authors.forename: J
authors.initials: J
authors.lastname: Wamani
authors.affiliation: Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda.
authors.forename: E M
authors.initials: EM
authors.lastname: Tukahebwa
authors.affiliation: Buhweju District Local Government, P.O. Box 10, Kabwohe, Uganda.
authors.forename: E
authors.initials: E
authors.lastname: Byamukama
authors.affiliation: Envision/RTI- Neglected Tropical Diseases Control Programme, Kampala, Uganda.
authors.forename: A W
authors.initials: AW
authors.lastname: Onapa
authors.affiliation: Kabarole District Local Government, P.O. Box 38, Fort Portal, Uganda.
authors.forename: E
authors.initials: E
authors.lastname: Tukesiga
authors.affiliation: Kyenjojo District Local Government, Medical Department, P.O. Box 1002, Kyenjojo, Uganda.
authors.forename: J
authors.initials: J
authors.lastname: Katamanywa
authors.affiliation: Rubirizi District Local Government, P.O. Box 239, Bushenyi, Uganda.
authors.forename: S
authors.initials: S
authors.lastname: Begumisa
authors.affiliation: The Carter Center, Uganda office, P.O. Box 12027, Kampala, Uganda.
authors.forename: P
authors.initials: P
authors.lastname: Habomugisha
authors.affiliation: Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda.
authors.forename: D
authors.initials: D
authors.lastname: Oguttu
authors.affiliation: The Carter Center, Uganda office, P.O. Box 12027, Kampala, Uganda.
authors.forename: E
authors.initials: E
authors.lastname: Byamukama
authors.affiliation: The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA 30307, USA.
authors.forename: F
authors.initials: F
authors.lastname: Richards
authors.affiliation: University of South Florida, Global Health Infectious Disease Research, College of Public Health, Tampa, FL, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Unnasch
authors.affiliation: The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA 30307, USA.
authors.forename: M
authors.initials: M
authors.lastname: Katabarwa
mesh_terms: D000818:Animals; D000977:Antiparasitic Agents / Q000627:therapeutic use*; D002648:Child; D006801:Humans; D007300:Insect Control / Q000379:methods*; D007303:Insect Vectors; D007306:Insecticides; D007559:Ivermectin / Q000627:therapeutic use; D008842:Microfilariae / Q000187:drug effects; D017181:Onchocerca volvulus; D009855:Onchocerciasis / Q000517:prevention & control* / Q000635:transmission; D012843:Simuliidae / Q000187:drug effects; D000002:Temefos; D014454:Uganda / Q000453:epidemiology
chemical_list: D000977:Antiparasitic Agents; D007306:Insecticides; D007559:Ivermectin; D000002:Temefos
keywords: Interruption; Ivermectin; Larviciding; Long-term treatment; Onchocerca volvulus; S. neavei; Uganda