Mounkaila Noma

Impact of long-term treatment of onchocerciasis with ivermectin in Kaduna State, Nigeria: first evidence of the potential for elimination in the operational area of the African Programme for Onchocerciasis Control

BackgroundOnchocerciasis can be effectively controlled as a public health problem by annual mass drug administration of ivermectin, but it was not known if ivermectin treatment in the long term would be able to achieve elimination of onchocerciasis infection and interruption of transmission in endemic areas in Africa. A recent study in Mali and Senegal has provided the first evidence of elimination after 15-17 years of treatment. Following this finding, the African Programme for Onchocerciasis Control (APOC) has started a systematic evaluation of the long-term impact of ivermectin treatment projects and the feasibility of elimination in APOC supported countries. This paper reports the first results for two onchocerciasis foci in Kaduna, Nigeria.MethodsIn 2008, an epidemiological evaluation using skin snip parasitological diagnostic method was carried out in two onchocerciasis foci, in Birnin Gwari Local Government Area (LGA), and in the Kauru and Lere LGAs of Kaduna State, Nigeria. The survey was undertaken in 26 villages and examined 3,703 people above the age of one year. The result was compared with the baseline survey undertaken in 1987.ResultsThe communities had received 15 to 17 years of ivermectin treatment with more than 75% reported coverage. For each surveyed community, comparable baseline data were available. Before treatment, the community prevalence of O. volvulus microfilaria in the skin ranged from 23.1% to 84.9%, with a median prevalence of 52.0%. After 15 to 17 years of treatment, the prevalence had fallen to 0% in all communities and all 3,703 examined individuals were skin snip negative.ConclusionsThe results of the surveys confirm the finding in Senegal and Mali that ivermectin treatment alone can eliminate onchocerciasis infection and probably disease transmission in endemic foci in Africa. It is the first of such evidence for the APOC operational area.

Rapid epidemiological mapping of onchocerciasis (REMO): its application by the African Programme for Onchocerciasis Control (APOC)

Abstract One of the fundamental challenges that the African Programme for Onchocerciasis Control (APOC) has had to face is how to identify the endemic communities where its mass ivermectin-treatment operations are to be carried out in conformity with its stated objective of targetting the most highly endemic, aVected and at-risk populations. This it has done by adopting a technique, known as the rapid epidemiological mapping of onchocerciasis (REMO), that provides data on the distribution and prevalence of onchocerciasis. Integration of the REMO data into a geographical information system (GIS) enables delineation of zones of various levels of endemicity, and this is an important step in the planning process for onchocerciasis control. Zones are included in (or excluded from) the APOC-funded programme of community-directed treatment with ivermectin (CDTI), depending on whether or not their levels of onchocercal endemicity reach the threshold set by APOC. This review describes the application of the REMO/GIS technique by APOC in its operations, and identifies the remaining related challenges.

African Programme for Onchocerciasis Control 1995–2015: Model-Estimated Health Impact and Cost

Background Onchocerciasis causes a considerable disease burden in Africa, mainly through skin and eye disease. Since 1995, the African Programme for Onchocerciasis Control (APOC) has coordinated annual mass treatment with ivermectin in 16 countries. In this study, we estimate the health impact of APOC and the associated costs from a program perspective up to 2010 and provide expected trends up to 2015. Methods and Findings With data on pre-control prevalence of infection and population coverage of mass treatment, we simulated trends in infection, blindness, visual impairment, and severe itch using the micro-simulation model ONCHOSIM, and estimated disability-adjusted life years (DALYs) lost due to onchocerciasis. We assessed financial costs for APOC, beneficiary governments, and non-governmental development organizations, excluding cost of donated drugs. We estimated that between 1995 and 2010, mass treatment with ivermectin averted 8.2 million DALYs due to onchocerciasis in APOC areas, at a nominal cost of about US

Monitoring community-directed treatment programmes for sustainability: lessons from the African Programme for Onchocerciasis Control (APOC)

257 million. We expect that APOC will avert another 9.2 million DALYs between 2011 and 2015, at a nominal cost of US

The challenges of community-directed treatment with ivermectin (CDTI) within the African Programme for Onchocerciasis Control (APOC)

221 million. Conclusions Our simulations suggest that APOC has had a remarkable impact on population health in Africa between 1995 and 2010. This health impact is predicted to double during the subsequent five years of the program, through to 2015. APOC is a highly cost-effective public health program. Given the anticipated elimination of onchocerciasis from some APOC areas, we expect even more health gains and a more favorable cost-effectiveness of mass treatment with ivermectin in the near future.

The geographic distribution of onchocerciasis in the 20 participating countries of the African Programme for Onchocerciasis Control: (2) pre-control endemicity levels and estimated number infected

Abstract Community-directed treatment is a relatively new strategy that was adopted in 1997 by the African Programme for Onchocerciasis Control (APOC), for large-scale distribution of ivermectin (Mectizan®). Participatory monitoring of 39 of the control projects based on community-directed treatment with ivermectin (CDTI) was undertaken from 1998–2000, with a focus on process implementation of the strategy and the predictors of sustainability. Data from 14,925 household interviews in 2314 villages, 183 complete treatment records, 382 focus-group discussions, and the results of interviews with 669 community leaders, 757 trained communitydirected drug distributors (CDD) and 146 health personnel (in 26 projects in four countries) were analysed. The data show that CDD dispensed ivermectin to 65.4% of the total population (71.2% of the eligible population), with no significant gender differences in coverage (P > 0.05). Treatment coverage ranged from 60.2% of the eligible subjects in Cameroon to 76.9% in Uganda. There was no significant relationship between the provision of incentives to CDD and treatment coverage (P > 0.05). The frequency of treatment refusal was highest in Cameroon (29.2%). Although most (72.1%) of the communities investigated selected their CDD on the basis of a community decision at a village meeting, only 37.9% chose their distribution period in the same way. There is clearly a need to improve communication strategies, to address the issues of absentees and refusals, to emphasise community ownership and to de-emphasise incentives for CDD. The investigation of the ‘predictor indicators’ of sustainability should enable APOC to understand the determinants of project performance and to initiate any appropriate changes in the programme.

African Programme for Onchocerciasis Control 1995-2015: updated health impact estimates based on new disability weights

Abstract The principal strategy adopted by the African Programme for Onchocerciasis Control (APOC), for the control of onchocerciasis in the 19 countries of Africa that now fall within the programme’s remit, is that of communitydirected treatment with ivermectin (CDTI). Halfway through its 12-year mandate, APOC has gathered enough information on the main challenges to guide its activities in Phase 2. An analysis of reports and other documents, emanating from consultants, scientists, monitors and national and project-level implementers, indicates that there are three broad categories of challenge: managerial; technical; and socio–political. Under these three categories, this review identifies the most pertinent concerns that APOC must address, during Phase 2, to enhance the prospects of establishing sustainable systems for ivermectin distribution. The major challenges include: (1) maintaining timely drug-collection mechanisms; (2) integrating CDTI with existing primary-healthcare services; (3) strengthening local health infrastructure; (4) achieving and maintaining an optimal treatment coverage; (5) establishing and up-scaling community self-monitoring; (6) designing and implementing operations research locally; (7) ensuring the adequacy of community-directed distributors; (8) increasing the involvement of local non-governmental develop organizations in the programme; (9) achieving financial sustainability; (10) implementing equitable cost-recovery systems; and (11) engaging in eVective advocacy. The implications of the challenges and suggestions about how they are being (or could be) addressed are also highlighted in this brief review, which should be of value to other programmes and agencies that may be contemplating the adoption of this unique strategy.

Integrated rapid mapping of onchocerciasis and loiasis in the Democratic Republic of Congo: impact on control strategies.

BackgroundThe original aim of the African Programme for Onchocerciasis Control (APOC) was to control onchocerciasis as a public health problem in 20 African countries. In order to identify all high risk areas where ivermectin treatment was needed to achieve control, APOC used Rapid Epidemiological Mapping of Onchocerciasis (REMO). REMO involved spatial sampling of villages to be surveyed, and examination of 30 to 50 adults per village for palpable onchocercal nodules. REMO has now been virtually completed and we report the results in two articles. A companion article reports the delineation of high risk areas based on expert analysis. The present article reports the results of a geostatistical analysis of the REMO data to map endemicity levels and estimate the number infected.MethodsA model-based geostatistical analysis of the REMO data was undertaken to generate high-resolution maps of the predicted prevalence of nodules and of the probability that the true nodule prevalence exceeds the high risk threshold of 20%. The number infected was estimated by converting nodule prevalence to microfilaria prevalence, and multiplying the predicted prevalence for each location with local data on population density. The geostatistical analysis included the nodule palpation data for 14,473 surveyed villages.ResultsThe generated map of onchocerciasis endemicity levels, as reflected in the prevalence of nodules, is a significant advance with many new endemic areas identified. The prevalence of nodules was > 20% over an area of 2.5 million km2 with an estimated population of 62 million people. The results were consistent with the delineation of high risk areas of the expert analysis except for borderline areas where the prevalence fluctuated around 20%. It is estimated that 36 million people would have been infected in the APOC countries by 2011 if there had been no ivermectin treatment.ConclusionsThe map of onchocerciasis endemicity levels has proven very valuable for onchocerciasis control in the APOC countries. Following the recent shift to onchocerciasis elimination, the map continues to play an important role in planning treatment, evaluating impact and predicting treatment end dates in relation to local endemicity levels.

The African Programme for Onchocerciasis Control: impact on onchocercal skin disease

Since 1995, the African Programme for Onchocerciasis Control (APOC) has coordinated mass treatment with ivermectin in sixteen sub-Saharan countries with the aim to control morbidity due to infection with Onchocerca volvulus, a filarial nematode. The authors predicted trends in prevalence of infection, visual impairment,blindness, and troublesome itch due to onchocerciasis in APOC countries for the period 1995–2015, based on extensive data on pre-control infection levels, population coverage of ivermectin mass treatment, and the association between infection and morbidity . They also estimated the associated health impact, expressed in disability-adjusted life years (DALYs). However, the estimated health impact was based on disability weights from the 2004 update of the Global Burden of Disease (GBD) study, which have been criticized for being based solely on the opinions of health professionals . The published GBD 2010 study addressed the criticism by providing updated disability weights based on household surveys in Bangladesh, Indonesia, Peru, and Tanzania, an open internet survey, and a telephone survey in the United States . As a result of this populationbased approach, the disability weights for visual impairment, blindness, and troublesome itch have changed considerably and should better reflect our ideas and beliefs as a society of what constitutes health.

Evaluation of the diethylcarbamazine patch to evaluate onchocerciasis endemicity in Central Africa.

BACKGROUND Onchocerciasis can be effectively controlled by annual mass treatment with ivermectin in endemic communities. However, in communities that are endemic for loiasis there may be significant risk of severe adverse reactions after ivermectin treatment. Planning of control requires therefore mapping of these two infections using rapid assessment tools developed for each disease. These tools were initially implemented independently till the feasibility of combining them was demonstrated. This paper reports the results of integrated mapping in four epidemiological zones in the Democratic Republic of Congo and its implications on operational decision-making on ivermectin treatment. METHODS Rapid assessment surveys were conducted between 2004 and 2005 using both rapid epidemiological mapping of onchocerciasis (REMO) and rapid assessment procedure for loiasis (RAPLOA). The survey results were subjected to a spatial analysis in order to generate for each of the two diseases maps of the estimated prevalence of infection throughout the four zones. RESULTS Surveys were undertaken in 788 villages where 25,754 males were examined for palpable onchocercal nodules and 62,407 people were interviewed for history of eye worm. The results showed major differences in the geographic distribution of the two diseases. Loiasis was highly endemic in some areas, where special precautions were required, but not in others where routine ivermectin treatment could proceed. CONCLUSION Integrated rapid mapping of onchocerciasis and loiasis reduces both time and cost of surveys and greatly facilitates operational decision-making on ivermectin treatment in areas where loiasis might be co-endemic.