After 70 years of fighting an age-old scourge, onchocerciasis in Uganda, the end is in sight

Abstract

Onchocerciasis causes severe itching, serious skin disease and ocular damage leading to visual impairment or permanent blindness. It is associated with hanging groin, epilepsy, Nakalanga dwarfism and, most recently, nodding disease. This disease affected communities in 17 transmission foci in 37 districts of Uganda, where about 6.7 million people are once at risk. The efforts against onchocerciasis in Uganda commenced in the late 1940s, when vector control was launched using dichlorodiphenyltrichloroethane; by 1973, Simulium damnosum had been eliminated in the Victoria focus. Success outside of the Victoria focus was short-lived due to changes in government priorities and the political upheavals of the 1970s and 1980s. With the return of political stability, annual treatment with ivermectin through mass drug administration was launched in the early 1990s. Control of the disease has been successful, but there has been failure in interrupting transmission after more than 15 years. In 2007 Uganda launched a nationwide transmission elimination policy based on twice-per-year treatment and vector control/elimination, with a goal of eliminating river blindness nationwide by 2020. By 2017, 1 157 303 people from six foci had been freed from river blindness. This is the largest population ever declared free under World Health Organization elimination guidelines, providing evidence that elimination of river blindness in Africa is possible.

Onchocerciasis-Associated Epilepsy with Head Nodding Seizures—Nodding Syndrome: A Case Series of 15 Patients from Western Uganda, 1994

“…52 In this field, Uganda can be considered as an exemplary model having achieved elimination of onchocerciasis in several foci, including the Itwara focus. 15,53 This is providing an opportunity to test the hypothesis that the removal of the putative cause of NS will lead to the disappearance of the condition in the area. This would provide additional evidence that NS is specifically linked to onchocerciasis.…”

Prevalence and incidence of nodding syndrome and other forms of epilepsy in onchocerciasis-endemic areas in northern Uganda after the implementation of onchocerciasis control measures

“…Biannual CDTI was implemented in 2013. The average CDTI coverage in northern Uganda progressively improved from 33% in 2011 to 70% after 2015 [22]. In December 2012, the Government of Uganda launched vector control programs consisting of periodic ground larviciding of blackfly breeding areas in the three districts [22][23][24].…”

“…The average CDTI coverage in northern Uganda progressively improved from 33% in 2011 to 70% after 2015 [22]. In December 2012, the Government of Uganda launched vector control programs consisting of periodic ground larviciding of blackfly breeding areas in the three districts [22][23][24]. Aerial spraying was done as a one-off activity along the rivers Pager, Aswa and Agago which run through Kitgum, Pader and Lamwo districts resulting in a dramatic decrease of the blackfly population [24].…”

Data-driven modelling and spatial complexity supports heterogeneity-based integrative management for eliminating Simulium neavei-transmitted river blindness

“…We show that overall the least effective scenario is low coverage annual MDA without VC resulting in requiring variously between 15-31 years to achieve transmission interruption in these sites even at 80% MDA coverage (Table 5), while the most effective strategy is high coverage biannual MDA with VC needing only between 3-7 years of control ( Table 5). The Uganda Onchocerciasis program is beginning to consider switching to the use of biannual MDA currently 55 , and the results here show that this change may bring about major savings in the durations of interventions required for achieving onchocerciasis elimination in the country, with the model predictions showing that up to some 7-17 years could be saved in the present sites with this approach compared to application of annual MDA alone ( Table 5). Although the intervention forecasts made here require to be assessed with follow-up data in the present sites for evaluating their plausibility, it is critical to note that the projections depicted in Table 5 lie within the 15-19 years found empirically to be needed for reducing mf prevalence to near elimination levels in the field using annual MDA 7,[56][57][58][59] .…”