Do Residents Believe that Onchocerciasis Transmission Was Eliminated? Results of A Post-Treatment Surveillance Knowledge, Attitude, and Practices Survey in Three Foci of Uganda.

In Uganda, 15 of 17 foci have interrupted transmission of onchocerciasis (river blindness) and stopped mass drug administration (MDA) of ivermectin. This 2016 study describes the results of a knowledge, attitude, and practices survey regarding river blindness among participants (N = 1,577) 3-5 years after ivermectin MDA was halted in three foci: Imaramagambo halted in 2012, Kashoya-Kitomi in 2013, and Mt. Elgon in 2011. The study showed high levels of composite knowledge (focus-specific range: 66.8-81.2%) related to river blindness transmission, signs, symptoms, and treatment. However, 38.1% of respondents did not know that blackflies transmitted river blindness. Notably, 72.2% claimed they had not been informed why MDA was stopped, 56.3% did not believe river blindness had been eliminated, and 83.1% wanted ivermectin MDA to resume. During the 3-5 year post-treatment surveillance period, only 27.7% (438 of 1,577) reported being informed of what to do once treatments stopped, with the most knowledgeable hailing from the Mt. Elgon focus (47.9%). This study reinforces the need for programs to intensify health education and information dissemination when MDA is stopped. Programs must remind residents that although biting insects may persist, they no longer transmit river blindness. Incorporating messages about the elimination of river blindness into community health education campaigns can help improve the community's perceptions related to the disease's absence and the ending of a long-standing MDA intervention.

Elimination of Simulium neavei-Transmitted Onchocerciasis in Wambabya-Rwamarongo Focus of Western Uganda.

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 PTS period, all 3,079 young children examined were negative for OV16 (95% CI: 0-0.16). Therefore, entomological and serological results provided evidence that resulted in the reclassification of Wambabya-Rwamarongo focus from "transmission interrupted" to "transmission eliminated" with no possibility of recrudescence.

Historical Elimination of Onchocerciasis from Victoria Nile Focus in Central Uganda Verified Using WHO Criteria.

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 2,953 DBS were 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.

Comparison of Reported and Survey-Based Coverage in Onchocerciasis Programs over a Period of 8 Years in Cameroon and Uganda.

Mass drug administration (MDA) with ivermectin must reach a high treatment coverage (90% of the eligible population) if onchocerciasis is to be eliminated. Questions have been raised as to whether reported treatment figures reaching such high coverage are reliable. Sample surveys are proposed as the method of choice for "validating" reported coverage figures. The purpose of this study was to compare the district-level MDA coverage reported by programs with contemporaneous surveys of randomly selected respondents living in those same districts. Over an 8-year period, 19,219 households were selected using multistage random sampling; 38,433 adult male and female heads of those households were asked about their recent ivermectin MDA treatment experience. District coverage reports were considered "accurate" if they fell within the 95% CIs determined by the corresponding district's survey. Ninety-eight treatment rounds were evaluated over an 8-year period. Overall, the reported coverage of 96.5% (range: 68-100%) was significantly higher than the 92.5% surveyed coverage (range: 62.1-99.6%, 95% CI: 91.9-93.2%). However, only 20% of districts reported significantly higher coverage than surveys, 68% of district program reports were judged as accurate, and 12% of districts reported significantly lower coverage figures than their corresponding surveys. Eighty-eight percent of districts reported coverage ≥ 90% threshold for success, compared with 97% of surveys that included 90% in their 95% CIs. We conclude that when analyzed statistically at the district level, most surveys verified the reported coverage.