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Background: Onchocerciasis is a neglected tropical disease with 217.5 million people globally at risk of having the infection. In both settled and semi-nomadic communities of Massangam Health District in Cameroon, Sightsavers has been carrying out test-and-treat with doxycycline and twice-yearly ivermectin distribution. This paper focuses on the cost of test-and-treat with doxycycline in the two community contexts of settled and semi-nomadic. Methods: For the valuation, a combination of gross or micro-costing was used to identify cost components, as well as bottom-up and top-down approaches. The opportunity costs of vehicle and equipment use were estimated and included. Not included, however, were the opportunity costs of building use and Ministry of Public Health staff salaries. We only captured the incremental costs of implementing test-and-treat activities as part of a functional annual community-directed treatment with the ivermectin programme. Results: We estimate the economic cost per person tested and cost per person treated in Massangam to be US$135 and US$667 respectively. Total implementation cost in the settled community was US$79,409, and in the semi-nomadic community US$69,957. Overall, the total economic cost of implementing the doxycycline test-and-treat strategy for onchocerciasis elimination in Massangam came to US$168,345. Financial costs represented 91% of total costs. Conclusions: Unit costs of test-and-treat in both settled and semi-nomadic communities are higher than unit costs of community-directed treatment with ivermectin. However, it is critical to note that a two-year implementation shows a significantly larger reduction in infection prevalence than the preceding 20 years of annual community-directed treatment with ivermectin. Test-and-treat with doxycycline may be a cost-effective intervention in places where the prevalence of microfilaria is still high, or in hard-to-reach areas where community-directed treatment with ivermectin and MDA coverage are not high enough to stop transmission or where marginalised populations consistently miss treatment. Author summary: Onchocerciasis, also known as river blindness, is a neglected tropical disease (NTD) caused by a parasitic nematode, Onchocerca volvulus. It is transmitted to humans through the bites of infected blackflies of the genus Simulium, which breed in fast-flowing rivers and streams. To eliminate transmission, a yearly distribution of ivermectin is conducted in infected areas. This medication kills the microfilaria but not the adult nematode, which is killed by doxycycline. Despite over 20 years of ivermectin mass distribution, the disease is still prevalent in the Massangam Health District in Cameroon. Therefore, alternative strategies have been discussed to stop transmission, including treatment of positive tested persons with doxycycline in both settled and nomadic communities. This paper estimated the total cost of implementation at US$168,345 in Massangam district, in order to compare it with the current elimination strategy and to demonstrate the potential effectiveness of the intervention–especially in high infection, hard-to-reach and loa loa co-infection settings. [ABSTRACT FROM AUTHOR]

We trialed strategies to reach semi-nomadic population with interventions targeting onchocerciasis including a combination of community knowledge and Geographical Information System (GIS) technology; nomad-specific sensitization; and mobile outreach. The interventions included ivermectin (ivm) mass drug administration (MDA) and treating infected individuals (found upon skin snip microscopy test) with doxycycline for 35 days. Microscopy-negative snips were further tested by Polymerase Chain Reaction (PCR). After 8 months, individuals immigrating or emigrating constituted 47% of the initial population; 59% of individuals not born in the area have immigrated during the last five years; 28% (age>9) reportedly never taken ivm; 72% (compared to 51% previously) of eligible population (age ≥ 5 years) took ivm; and 47% (age > 8, not pregnant, not breastfeeding, not severely ill,) participated in the test. A high prevalence of onchocerciasis,15.1%, was found upon microscopy & PCR test; 9/10 tested by skin snip microscopy and PCR at follow-up were all negative. Microfilaria prevalence and intensity upon skin snip microscopy reduced significantly from baseline following the intervention (8.9% to 4.1%, p = 0.032; 0.18 to 0.16, p = 0.013, respectively). The strategies considerably increased reach to nomadic camps. Treating with doxycycline in combination with ivm is feasible and has led to a significant reduction in infection level within one year among the semi-nomads. Being potentially curative in one intervention round, this combination should be considered for population group faced with challenges of achieving adequate coverage and adhesion to ivm MDA over prolonged period (>10 years). Author summary: Community knowledge, satellite imagery, semi-nomadic sensitization and outreach strategies were employed to deliver ivermectin and doxycycline treatments against onchocerciasis in semi-nomadic population. Doxycycline was offered only when skin snip examination revealed infection. We found that about 50% of the population has either left or joined the community within 8 months; 59% of people not born in the area arrived during the last 5 years; 28% of those older than 9 years reported never taking ivermectin; 72% (compared to 51% previously) of eligible population (≥5 years) took ivermectin; and 47% participated in skin snip test. A high proportion of participants– 15% were infected. All the infected individuals were treated, and no infection was found in almost all those retested (9/10). This study highlights high rate of onchocerciasis and the challenges of offering continuous treatment for a prolonged period (>10 years) to a mobile population. It further demonstrates that combining ivermectin and doxycycline is preferrable in mobile population as it is curative and can be given only one time. [ABSTRACT FROM AUTHOR]

The main onchocerciasis elimination strategy is annual Community-Directed Treatment with ivermectin (CDTi). However, as a response to persistent high infection prevalence in Massangam Health District in Cameroon, two rounds of alternative treatments including biannual CDTi, ground larviciding and test and treat with doxycycline (TTd) were implemented. This led to a significant prevalence reduction from 35.7% to 12.3% (p<0.001) as reported by Atekem and colleagues. Here we report on the acceptability of TTd component based on qualitative and quantitative data. The TTd involved microscopic examination for microfilaria in skin biopsy and those infected were offered doxycycline 100 mg daily for 35 days by community-directed distributors (CDDs). Participation level was significantly high with 54% of eligible population (age > 8, not pregnant, not breastfeeding, not severely ill,) participating in the test in each round, increasing to 83% over the two rounds. Factors associated with non-participation included mistrust, being female; being younger than 26 years; short stay in the community; and belonging to semi-nomadic sub population due to their remote and disperse settlement, discrimination, their non selection as CDD, and language and cultural barriers. Treatment coverage was high -71% in round 1 and 83% in round 2. People moving away between testing and treatment impacted treatment coverage. Some participants noted mismatch between symptoms and test result; and that ivermectin is better than doxycycline, while others favoured doxycycline. CDD worried about work burden with unmatching compensation. Overall, TTd participation was satisfactory. But can be improved through reinforcing sensitisation, reducing time between test and treatment; combining TTd and CDTi in one outing; augmenting CDDs compensation and/or weekly visit; exploring for frequently excluded populations and adapting strategies to reach them; and use of a sensitive less invasive test. Author summary: Doxycycline was offered to people to treat river blindness in Massangam health district after test indicating they are infected. The test, conducted twice, involved taking a small piece of skin for examination. Those infected were given doxycycline for 35 days by community volunteers. Among those who were eligible for the test, 54% were tested each time, increasing to 83% for both rounds. Participation was influenced by trust level; and varied by sex, age, and duration of community stay. Semi-nomadic population participated less than permanent residents because of their remote locations, language and cultural barriers, perceived discrimination by the permanent resident population. Doing test before ivermectin treatment impacted test result. Delay in starting treatment led to some infected people moving away. Almost all those starting treatment completed it each time. Some beneficiaries prefer the usual ivermectin treatment. For the volunteers, delivering treatment was demanding in terms of effort and time. Overall, the level of participation was satisfactory but could be improved through more sensitisation, reviewing volunteer compensation, inclusion of the frequently excluded population, combining doxycycline and ivermectin treatments, and developing a sensitive less invasive test. [ABSTRACT FROM AUTHOR]

Background: Alternative strategies are recommended to accelerate onchocerciasis elimination in problematic areas including areas where annual ivermectin (IVM) distributions are unable to interrupt transmission. The aim of this study was to accelerate progress towards elimination in the Massangam health district, West Region of Cameroon where impact evaluations demonstrated ongoing transmission of onchocerciasis infection and high microfilaria (mf) prevalence despite more than 20 years of annual IVM distribution. Methodology/Principal findings: Parasitological, entomological, and breeding site surveys were conducted in 2015 delineating a focus of high transmission and identified three communities with high mf prevalence. Individuals in these communities were screened for mf yearly for a period of two years and those positive treated each year with doxycycline 100mg daily for five weeks. In addition, surrounding communities were given biannual IVM. Temephos-based applications were performed once a week for 10 consecutive weeks on Simulium damnosum s.l. breeding sites. Parasitological and entomological assessments were conducted after two years of implementation and findings compared with 2015 baseline. Alternative strategies accelerated progress towards elimination through a significant mf reduction (χ2: 40.1; p<0.001) from 35.7% (95%CI: 29.0–42.8) to 12.3% (95%CI, 9.0–16.4). Reductions were furthermore recorded over a longer period, with a reduction of prevalence of 29.0% under AIS in 2017–2019 compared to 14.6% with IVM in 2011–2015; and by 23.2% following the two years of alternative strategies compared to 20.3% reduction over 15 years of treatment with IVM (1996–2011). Entomological assessment demonstrates that transmission is still ongoing despite the reduction in mf which is expected in an environment with complex breeding sites and open transmission zones, i.e., where migration of flies or humans to and from neighbouring areas is common. Conclusion/Significance: This study provides evidence that alternative strategies are feasible and effective and should be considered in areas where transmission is sustained throughout long term uninterrupted MDA with IVM. However, there is need to consider wider transmission zones, and further explore optimal timing of larviciding with treatment to impact transmission. Author summary: Elimination of onchocerciasis has been shown to be possible when ivermectin (IVM) is given continuously every year for about 15–17 years. However, areas where continuous IVM distribution has not achieved this objective, alternative methods are needed. Massangam health district in Cameroon is one of such areas despite more than 20 years of annual distribution. This study aimed to fast-track elimination through alternative intervention strategies (AIS). This included testing and treating those having onchocerciasis with doxycycline in communities where the infection was high, giving IVM twice a year to surrounding community members and reducing the density of flies that carry the worms by pouring chemical in river sites having fly larvae once a week for 10 weeks. The effect of these activities was measured and compared with previous data. The AIS significantly reduced the percentage of those having the disease from 35.7% to 12.3%. A 23.2% reduction was also observed with two years of AIS compared with 20.3% reduction with IVM over 15 years. Thus, AIS are practical and useful and should be considered in areas where IVM has not successfully stopped the spread of onchocerciasis. [ABSTRACT FROM AUTHOR]

This correction notice states that Alexandre Chailloux should be included as the third author in the article titled "Ivermectin and doxycycline treatments against Onchocerciasis: Adaptations and impact among semi-nomadic population in Massangam Health District, Cameroon." The correction provides Chailloux's affiliation and outlines his contributions to the article. The correct citation for the article is also provided. The notice is reported by various authors involved in the study. [Extracted from the article]