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

OBJECTIVES: To assess the long-term impact of the African Programme for Onchocerciasis Control on itching and onchocercal skin disease (OSD). METHODS: Seven study sites in Cameroon, Sudan, Nigeria and Uganda participated. Two cross-sectional surveys were conducted of communities meso- and hyper-endemic for onchocerciasis before and after 5 or 6 years of community-directed treatment with ivermectin (CDTI). Individuals were asked about any general health symptoms including itching and underwent full cutaneous examinations. Onchocercal skin lesions were documented according to a standard classification. RESULTS: Five thousand one hundred and ninety three people were examined in phase I and 5,180 people in phase II. The presence of onchocercal nodules was a strongly significant (P < 0·001) risk factor for all forms of onchocercal skin disease: APOD (OR 1·66); CPOD (OR 2·84); LOD (OR 2·68); reactive skin lesions (OR 2·38) and depigmentation (OR 3·36). The effect of community-directed treatment with ivermectin was profound. At phase II, there were significant (P < 0·001) reductions in the odds of itching (OR 0·32), APOD (OR 0·28); CPOD (OR 0·34); reactive skin lesions (OR 0·33); depigmentation (OR 0·31) and nodules (OR 0·37). Reduction in the odds of LOD was also significant (OR 0.54, P < 0.03). CONCLUSIONS: This first multi-country report of the long-term impact of CDTI reveals a substantial reduction in itching and OSD. APOC operations are having a major effect in improving skin health in poor rural populations in Africa.

Prevalence and distribution of ocular onchocerciasis in three ecological zones in Nigeria.

The African Programme for Onchocerciasis Control (APOC) sponsored a baseline study in Nigeria between 1998 and 1999 on the prevalence and distribution of Onchocerciasis. The randomly selected 1,064 subjects in the baseline study underwent detailed eye examination in Cross River (rain forest), Taraba (savanna) and Kogi (forest-savanna) States. This paper compares and contrasts the public health significance of ocular onchocerciasis in these ecological zones. A blindness prevalence of 2.4% was recorded in the study, onchocerciasis being responsible for 30.2% of the bilaterally blind subjects. Onchocerciasis-induced blindness prevalence was relatively high in the rain forest and forest savanna zones of Cross River and Kogi States, Cross River having the highest site-specific prevalence (50.0%), followed by Kogi (41.7%). Taraba recorded only 27.3%. Other conditions identified included glaucoma, optic nerve disease and cataract rates of which were also found to be high among the population (6.9%, 6.5 % and 8.9% respectively). Anterior segment onchocercal lesions, punctate and sclerosing keratitis were the predominant features of the infection in the savanna zone (14.1% and 6.3% respectively), while posterior segment lesions were much more common in the forest zone. The need to sustain the present efforts to control onchocerciasis through mass ivermectin treatment is recommended.

Utility and effectiveness of computerised motion sensitivity screening tests in rural onchocercal community survey.

BACKGROUND: Non-invasive tool of community diagnosis for onchocercal endemicity needs to be identified and ascertained for their utility and effectivity in order to facilitate the control of onchocerciacis in sub-Saharan Africa OBJECTIVE: To determine the utility and effectiveness of the Wu-Jones Motion Sensitivity Screening Test (MSST) in detecting optic nerve diseases in onchocercal-endemic rural Africa. METHODS: MSST was applied to sampled subjects in the selected communities of Raja in Sudan; Bushenyi in Uganda; Morogoro in Tanzania; and of Ikom, Olamaboro and Gashaka in Nigeria. Basically, six points within the central field of vision were repeatedly tested at 1/3 meter from the screen of a laptop computer in a room darkened. Motion sensitivity was expressed as a percentage of motion detected in the individual eye and this was averaged for the community. RESULTS: A total of 3,858 eyes of 2,072 patients were examined. Seventy-six percent of the subjects completed the test, at an average test time of 120.4 (66.7) seconds. The overall mean motion sensitivity of all eyes tested was 88.49 (17.49%). At a cut-off point of 50%, 6.4% of all subjects tested were subnormal, while at 70% cutoff, 13.3% were subnormal. The highest proportion of 50% cutoff sub-normality was recorded at Morogoro at 12.7%. CONCLUSION: Motion Sensitivity Screening Test was widely accepted and easily administered to the rural and largely illiterate subjects studied. Our data suggest that the proportion of severe field defects by MSST in a community, with cutoff at 33%, best correlates with optic nerve disease prevalence, while proportion of defect from a higher cut-off level at about 50%, best correlates with overall ocular morbidity.

Utility and Effectiveness of Computerised Motion Sensitivity Screening Tests in Rural Onchocercal Community Survey

BACKGROUND: Non-invasive tool of community diagnosis for onchocercal endemicity needs to be identified and ascertained for their utility and effectivity in order to facilitate the control of onchocerciacis in sub-Saharan Africa OBJECTIVE: To determine the utility and effectiveness of the Wu-Jones Motion Sensitivity Screening Test (MSST) in detecting optic nerve diseases in onchocercal-endemic rural Africa. METHODS: MSST was applied to sampled subjects in the selected communities of Raja in Sudan; Bushenyi in Uganda; Morogoro in Tanzania; and of Ikom; Olamaboro and Gashaka in Nigeria. Basically; six points within the central field of vision were repeatedly tested at 1/3 meter from the screen of a laptop computer in a room darkened. Motion sensitivity was expressed as a percentage of motion detected in the individual eye and this was averaged for the community. RESULTS: A total of 3;858 eyes of 2;072 patients were examined. Seventy-six percent of the subjects completed the test; at an average test time of 120.4 (66.7) seconds. The overall mean motion sensitivity of all eyes tested was 88.49 (17.49). At a cut-off point of 50; 6.4of all subjects tested were subnormal; while at 70cutoff; 13.3were subnormal. The highest proportion of 50cutoff sub-normality was recorded at Morogoro at 12.7. CONCLUSION: Motion Sensitivity Screening Test was widely accepted and easily administered to the rural and largely illiterate subjects studied. Our data suggest that the proportion of severe field defects by MSST in a community; with cutoff at 33; best correlates with optic nerve disease prevalence; while proportion of defect from a higher cut-off level at about 50; best correlates with overall ocular morbidity

The elimination of the onchocerciasis vector from the island of Bioko as a result of larviciding by the WHO African Programme for Onchocerciasis Control.

The island of Bioko is part of the Republic of Equatorial Guinea and is the only island in the World to have endemic onchocerciasis. The disease is hyperendemic and shows a forest-type epidemiology with low levels of blindness and high levels of skin disease, and the whole population of 68,000 is estimated to be at risk. Control of onchocerciasis began in 1990 using ivermectin and this yielded significant clinical benefits but transmission was not interrupted. Feasibility and preparatory studies carried out between 1995 and 2002 confirmed the probable isolation of the vector on the island, the high vectorial efficiency of the Bioko form of Simulium yahense, the seasonality of river flow, blackfly breeding and biting densities, and the distribution of the vector breeding sites. It was proposed that larviciding should be carried out from January to April, when most of the island's rivers were dry or too low to support Simulium damnosum s.l., and that most rivers would not need to be treated above 500 m altitude because they were too small to support the breeding of S. damnosum s.l. Larviciding (with temephos) would need to be carried out by helicopter (because of problems of access by land), supplemented by ground-based delivery. Insecticide susceptibility trials showed that the Bioko form was highly susceptible to temephos, and insecticide carry was tested in the rivers by assessing the length of river in which S. damnosum s.l. larvae were killed below a temephos dosing point. Regular fly catching points were established in 1999 to provide pre-control biting densities, and to act as monitoring points for control efforts. An environmental impact assessment concluded that the proposed control programme could be expected to do little damage, and a large-scale larviciding trial using ground-based applications of temephos (Abate 20EC) throughout the northern (accessible) part of the island was carried out for five weeks from 12 February 2001. Following this, a first attempt to eliminate the vectors was conducted using helicopter and ground-based applications of temephos from February to May 2003, but this was not successful because some vector populations persisted and subsequently spread throughout the island. A second attempt from January to May 2005 aimed to treat all flowing watercourses and greatly increased the number of treatment points. This led to the successful elimination of the vector. The last biting S. damnosum s.l. was caught in March 2005 and none have been found since then for more than 3 years.

[African programme for onchocerciasis control (APOC): entomological aspects of Onchocerca volvulus transmission by Simulium neavei in the Basin of Sankuru (Eastern Kasai, Democratic Republic of Congo)]. / Aspects entomologiques de la transmission d'Onchocerca volvulus par Simulium neavei dans le bassin du Sankuru (Kasaï oriental, République Démocratique du Congo).

As part of a study to evaluate the long-term impact of community-directed treatment with ivermectin (CDTI), baseline entomological data on the transmission of onchocerciasis in the forest zone of the Eastern Kasai Province were collected from July 1998 to January 1999. Species of the Simulium neavei complex were the only vectors found in the site during the study. Nuisance activity was low with a mean biting rate of only 32.5 bites/man/day. The mean parturity rate was 29.4%, the mean rate of infected females was 14.5% and the mean number of infective Onchocerca larvae per 1000 parous flies was 659. These findings clearly show that the S. neavei population at the study site has high vector capability and constitutes a large microfilarial reservoir. The entomological features found in the study area are consistent with a hyper-endemic zone.

[Onchocerciasis in the area of Lastourville, Gabon. Clinical and entomological aspects]. / L'onchocercose dans la région de Lastourville, Gabon. Aspects cliniques et entomologiques.

The African Programme for Onchocerciasis Control (APOC) has implemented a series of surveys aimed at evaluating the long-term impact of its activities. The region of Lastourville (Gabon) is one of the selected sites for this study. A total of 886 persons was examined for skin lesions, and 459 out of them participated in detailed ocular examinations. Blackflies were collected during one year and dissected. Although the focus was found to be hypoendemic (prevalence of nodules: 7.7%), the frequency of onchodermatitis was relatively high. The lesions of the anterior segment of the eye were rare, but the prevalence of optic nerve disease, and of choroido-retinal lesions reached 5.2 and 2.7%, respectively. The annual transmission potential (2,171 infective larvae per man) was high, when compared with the results recorded in the human population. This may be due to the presence of Onchocerca spp. of animal origin in the blackflies. These results indicate that in the area of Lastourville, though regarded as the main focus of onchocerciasis in Gabon, the disease is relatively mild.

[African Programme for Onchocerdasis Control (APOC): Onchocerca Simulium squamosum in two regions in the Republic of Cameroon]. / Programme africain de lutte contre l'onchocercose (APOC): intensité de la transmission d'Onchocerca volvulus par Simulium squamosum dans deux régions de la République du Cameroun.

In 1998, the African Programme for Onchocerciasis Control (APOC) decided to launch a long-term impact assessment of its operations. This paper reports the baseline entomological data collected throughout a whole year in two sites of Cameroon (Kahn and Bolo). The Simulium populations of the two study sites were characterized by parous rates of 7.2% and 33.5% respectively and infectivity by O. volvulus of 31 and 190 infective larvae per 1000 parous flies respectively The Annual Transmission Potentials (ATP) were respectively 523 and 9972 infective larvae per man and per year in Kahn and in Bolo. The Simulium populations studied in both sites, even though the ATP in Kahn is 19 times lower than that of Bolo, showed a pattern of an onchocerciasis hyperendemic zone in terms of vector capacities and entomological indices.

[African Program for Onchocerciasis Control (APOC): Onchocerca volvulus transmission by Simulium damnosum s. l. in two regions of the Central African Republic]. / Programme africain de lutte contre l'onchocercose (APOC): transmission d'Onchocerca volvulus par Simulium damnosum s. l. dans deux régions de la République Centrafricaine.

Entomological baseline data were collected in the villages of Zinga and Boali-Falls in Central African Republic (CAR) in view of the long term impact assessment of community-directed treatment with ivermectin (CDTI). Morphological determinations revealed that flies caught in both sites belong to the sub-group Sou/Sq. In Boali, the nuisance was relatively high with biting rates averaging 243 bites/man/day, with a parous rate of 61.6% and a crude annual transmission potential (ATP) of 8,259 infective larvae/man/year; and the average number of infective larvae per 1,000 parous flies was 177. In Zinga, the mean biting rate was 191 bites/man/day, with a parous rate of 51.6%, a crude ATP of 3,422, and 86 infective larvae per 1,000 porous flies. In conclusion, the vectorial capacity and the entomological indices recorded are characteristic of high onchocerciasis transmission zones. However, some of the infective larvae found, maybe of animal origin, need identification to better determine the real level of endemicity.

A multi-centre study of community-directed ivermectin distributors' (CDDs') involvement in other healthcare and development programme activities in Cameroon, Togo, Sudan, Nigeria and Uganda.

A multi-centre study to determine whether community-directed distributors (CDDs) are capable of carrying out additional healthcare and developmental activities in their communities was carried out in Cameroon, Nigeria, Sudan, Uganda and Togo to ascertain the potential effects of their involvement on the implementation of community-directed treatment with ivermectin (CDTI). Both quantitative and qualitative methods were used to collect data from households, community-directed distributors, community leaders, and health workers. The results showed no major decrease in the CDDs' performance in CDTI: on the contrary, the involvement of CDDs in other health and development activities motivated them to perform their CDTI functions better. However, the results did not show any significant increase in therapeutic coverage of ivermectin distribution. The expansion of the CDDs' experience to include additional healthcare and development related activities would be of interest to onchocerciasis control programmes--it will strengthen CDTI sustainability through greater integration.

The achievements and challenges of the African Programme for Onchocerciasis Control (APOC).

The main strategy of APOC, of community-directed treatment with ivermectin (CDTI), has enabled the programme to reach, empower and bring relief to remote and under-served, onchocerciasis-endemic communities. With CDTI, geographical and therapeutic coverages have increased substantially, in most areas, to the levels required to eliminate onchocerciasis as a public-health problem. Over 20 million people received treatment in 2000. APOC has also made effective use of the combination of the rapid epidemiological mapping of onchocerciasis (REMO) and geographical information systems (GIS), to provide information on the geographical distribution and prevalence of the disease. This has led to improvements in the identification of CDTI-priority areas, and in the estimates of the numbers of people to be treated. A unique public-private-sector partnership has been at the heart of APOC's relative success. Through efficient capacity-building, the programme's operations have positively influenced and strengthened the health services of participating countries. These laudable achievements notwithstanding, APOC faces many challenges during the second phase of its operations, when the full impact of the programme is expected to be felt. Notable among these challenges are the sustainability of CDTI, the strategy's effective integration into the healthcare system, and the full exploitation of its potential as an entry point for other health programmes. The channels created for CDTI, could, for example, help efforts to eliminate lymphatic filariasis (which will feature on the agenda of many participating countries during APOC's Phase 2). However, these other programmes need to be executed without compromising the onchocerciasis-control programme itself. Success in meeting these challenges will depend on the continued, wholehearted commitment of all the partners involved, particularly that of the governments of the participating countries.

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

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, affected 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.

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

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 community-directed 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-govemmental develop organizations in the programme; (9) achieving financial sustainability; (10) implementing equitable cost-recovery systems; and (11) engaging in effective 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.

Partnership and promise: evolution of the African river-blindness campaigns.

This article describes the evolution of the partnership, between various health and developmental agencies, that has sustained the campaign against river blindness in Africa. The international community was oblivious to the devastating public-health and socio-economic consequences of onchocerciasis until towards the end of the 1960s and the beginning of the 1970s. Then a 'Mission to West Africa', supported by the United Nations Development Programme, and a visit to the sub-region by the president of the World Bank culminated, in 1974, in the inauguration of the Onchocerciasis Control Programme in West Africa (OCP). OCP was a landmark event for the World Bank as it represented its first ever direct investment in a public-health initiative. The resounding success of the OCP is a testimony to the power of the partnership which, with the advent of the Mectizan Donation Programme, was emboldened to extend the scope of its activities to encompass the remaining endemic regions of Africa outside the OCP area. The progress that has been made in consolidating the partnership is discussed in this article. The prospects of adapting the various strategies of the African Programme for Onchocerciasis Control, to entrench an integrated approach that couples strong regional co-ordination with empowerment of local communities and thereby address many other health problems, are also explored.

Gender issues in the community-directed treatment with ivermectin (CDTI) of the African Programme for Onchocerciasis Control (APOC).

This paper reviews the issues relating to compliance and participation among the men and women of three countries within the remit of the African Programme for the Control of Onchocerciasis (APOC): Cameroon, Nigeria and Tanzania. Project-monitoring data from 109 focus-group discussions, 6069 household-survey respondents and 89 interviews with ivermectin distributors were analysed to gain an insight into the attitudes and behaviours of men and women in relation to ivermectin treatment and their participation in the programme. Although there are no statistically significant gender differences in coverages for ivermectin treatment, culturally prescribed gender relationships influence the ways in which men and women express and experience treatment-related behaviours. Gender roles also affect participation in the programme. Decision-making in communities on the selection of distributors tends to follow socio-cultural hierarchies based upon patriarchy and gerontocracy. Relatively few ivermectin distributors (21%) are women. Although they receive less support than their male counterparts, the female distributors are just as willing to continue ivermectin distribution in the community, and they perform as well or better than men in this regard. The terms 'community-directed', 'community participation' and even 'compliance' obfuscate important gender differences that are inherent in the implementation of onchocerciasis control. Development of strategies that recognize these gender differences will have important implications for long-term adherence to treatment and for the overall quality and sustainability of the programme.

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

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 community-directed 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.

APOC's strategy of community-directed treatment with ivermectin (CDTI) and its potential for providing additional health services to the poorest populations. African Programme for Onchocerciasis Control.

Since its inauguration in 1995, the African Programme for Onchocerciasis Control (APOC) has made significant progress towards achieving its main objective: to establish sustainable community-directed treatment with ivermectin (CDTI) in onchocerciasis-endemic areas outside of the remit of the Onchocerciasis Control Programme in West Africa (OCP). In the year 2000, the programme, in partnership with governments, non-governmental organizations and the endemic communities themselves, succeeded in treating 20,298,138 individuals in 49,654 communities in 63 projects in 14 countries. Besides the distribution of ivermectin, the programme has strengthened primary healthcare (PHC) through capacity-building, mobilization of resources and empowerment of communities. The community-directed-treatment approach is a model that can be adopted in developing other community-based health programmes. The approach has also made it possible to bring to the poor some measure of intervention in some other healthcare programmes, such as those for malaria control, eye care, maternal and child health, nutrition and immunization. CDTI presents, at all stages of its implementation, a unique window of opportunity for promoting the functional integration of healthcare activities. For this to be done successfully and in a co-ordinated manner, adequate funding of CDTI within PHC is as important as an effective sensitization of the relevant policy-makers, healthworkers and communities on the value of integration (accompanied by appropriate training at all levels). Evaluation of the experiences in integration of health services, particularly at community level, is crucial to the success of the integration.