Browsing by Author "Nahabwe, Christine"

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    Elimination of Simulium neavei–Transmitted Onchocerciasis in Wambabya–Rwamarongo Focus of Western Uganda
    (The American Journal of Tropical Medicine and Hygiene, 2020) Katabarwa, Moses N.; Habomugisha, Peace; Khainza, Annet; Oguttu, David; Byamukama, Edson; Katamanywa, James; Isingooma, Thomson; Bwenume, Fredrick; Nahabwe, Christine; Ngabirano, Monica; Akampurira, Paul; Bernard, Lauri; Unnasch, Thomas R.; Richards, Frank
    Wambabya–Rwamarongo onchocerciasis focus is one of the eight foci Uganda verified using the WHO verification guidelines. The approach for elimination was twice yearly treatment with ivermectin for every round, treating at least 90% of all the eligible population. This was in combination with vector elimination using Abate® (BASF SE, Limburgerhof, Germany) since elimination nationwide policy was launched. From 2008 to 2013, the program distributed ivermectin with a mean treatment coverage of the ultimate treatment goal (UTG) or eligible population of 91.2%, with a range of 85–96%. In 2009, vector elimination based on ground larviciding had a dramatic impact on the Simulium vectors, as the last fly was observed in October 2009. No more Simulium vectors were observed during a period of at least 7 years, including the 3-year posttreatment surveillance (PTS) until the focus was reclassified as eliminated in August 2017. During the PTS period, none of the 10,578 trapped crabs were found infested with the aquatic stages of the vector. The last infested crab was observed in March 2010, and for at least 7 years, no infested crabs were observed. Serological surveys showed that of 2,978 young children examined in 2013, only one was OV16 positive (0.0%;95% CI: 0–0.21). In 2017, after the PT period, all 3,079 young children examined were negative for OV16(95% CI: 0–0.16). Therefore, entomological and ecological results provided evidence that resulted in the reclassification of WambabyaRwamarongo focus from “transmission interrupted” to “transmission eliminated” with no possibility of recrudescence.
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    Historical Elimination of Onchocerciasis from Victoria Nile Focus in Central Uganda Verified Using WHO Criteria
    (The American journal of tropical medicine and hygiene, 2020) Katabarwa, Moses N.; Habomugisha, Peace; Khainza, Annet; Oguttu, David W.; Byamukama, Edson; Katamanywa, James; Nahabwe, Christine; Ngabirano, Monica; Akampurira, Paul; Bernard, Lauri; Unnasch, Thomas R.; Richards, Frank
    Uganda has verified elimination of seven onchocerciasis foci since 2007 when the nationwide onchocerciasis elimination policy was launched. However, the Victoria Nile focus (which was eliminated in the early 1970s) had not been verified. The objective of this study was to verify this focus to the WHO verification guidelines and bring it in line with recently eliminated foci. Vector control with dichlorodiphenyltrichloroethane was the main intervention used at the Victoria Nile from the 1950s to the 1970s. Historical fly collection sites along River Nile were identified for recent fly collection. Relevant health workers near the sites were trained to supervise fly collection activity. With support from communities, fly collectors were identified, trained, and equipped to collect Simulium flies for at least a year. A total of 854 Simulium flies were collected and analyzed by polymerase chain reaction to detect Onchocerca volvulus DNA. The communities and their leaders provided consent for the collection of dry blood spots (DBS) from children younger than 10 years for investigation of recent exposure to the disease.A total of 2,953DBSwere collected and analyzed by OV16 ELISA to detect the presence of IgG4 antibodies recognizing the OV16 antigen. The results showed that none of the flies carried O. volvulus DNA. Similarly, all the children were OV16 negative, showing no exposure to onchocerciasis. All the flies collected were identified as Simulium adersi, which is not a known vector for O. volvulus. The results confirmed that onchocerciasis and its vector Simulium damnosum had been eliminated in the Victoria Nile focus.
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    Serosurveillance to Monitor Onchocerciasis Elimination: The Ugandan Experience
    (The American journal of tropical medicine and hygiene, 2014) Oguttu, David; Byamukama, Edson; Katholi, Charles R.; Habomugisha, Peace; Nahabwe, Christine; Ngabirano, Monica; Hassan, Hassan K.; Lakwo, Thomson; Katabarwa, Moses; Richards, Frank O.; Unnasch, Thomas R.
    Uganda is the only African country whose onchocerciasis elimination program uses a two-pronged approach of vector control and mass drug distribution. The Ugandan program relies heavily upon the use of serosurveys of children to monitor progress toward elimination. The program has tested over 39,000 individuals from 11 foci for Onchocerca volvulus exposure, using the Ov16 ELISA test. The data show that the Ov16 ELISA is a useful operational tool to monitor onchocerciasis transmission interruption in Africa at the World Health Organization (WHO) recommended threshold of < 0.1% in children. The Ugandan experience has also resulted in a re-examination of the statistical methods used to estimate the boundary of the upper 95% confidence interval for the WHO prevalence threshold when all samples tested are negative. This has resulted in the development of Bayesian and hypergeometric statistical methods that reduce the number of individuals who must be tested to meet the WHO criterion.