Pan african programme for onchocerchiasis control outside the OCP sub-region: technical and organizational considerations, November 1994

Onchocerciasis Control Programme in West Africa Programme de Lutte contre I'Onchocercose en Afrique de I'Ouest JOINT PROGRAMME COMMITTEE Office of the Chairman JOINT PROGRAMME COMMITTEE Fifteenth session Yamoussoukro- 29 Nov.-l December laa4 COMITE CONJOINT DU PROGRAMME Bureau du President JPCIs/INF/DOC.5 ORIGINAL: ENGLISH November 1994 JPC - CCP ! a Provisional agenda item l3 PAN AFRICAN PROGRAMME FOR ONCHOCERCIASIS CONTROL OUTSIDE THE OCP SUB-REGION ! Technical and organizational considerations November 1994 The World Bank ffi0an ocercla e CONTENTS Executive summary Preamble The burden of onchocerciasis Options for control Vector control Luge scale ivermectin treatment for morbidity control Focal vector eradication Current status of onchocerciasis control in Africa The OCP Outside the OCP Programme Strategy Programme objective Programme operations Preparatory operational research Financing of operations Costs of the Programme Organizational framework AIINEX I. The Distribution of Onchocerciasis and the Magnitude of the Problem. AIINEX 2. Vector control and vector eradication ANNEX 3. Orgarnzations presently involved in ivermectin distribution outside the OCP ANNEX 4. OperationalResearch in preparation for a Pan African Control Progtamme. I 4 5 7 7 7 I 9 9 9 l0 l0 11 t2 t2 t2 .13 l5 l9 24 28 II Executive summary A Pan African Programme for Onchocerciasis Control will be created. Its goal will be the elimination of onchocerciasis throughout Africa. Building upon the success of the Onchocerciasis Control Programme in West Africa (OCP), which is on the verge of eliminating the disease from I I West African countries, the new Programme will achieve its goal by implementing sustainable control in the remaining l6 cotmtries in Africa where the disease is still a public health problem. Whereas the OCP used vector control as the principal method for control, the new Programme will control the disease in the non-OCP countries by establishing community-based treatment prograrnmes with the drug ivermectin, supplemented with vector eradication in a few isolated foci. Onchocerciasis remains a serious public health problem in much of tropical Africa. It affects 17.6 million people, of whom l5 million, or more than 8502, now live outside the area of the OCP. The most severe consequence of onchocerciasis is blindness, which may afflict over one third of the adult population of the most affected communities. Other important problems are severe skin disease and maddening itching which cause great suffering to millions of people. The infection is probably respqnsible for an important amount of epilepsy and for growth retardation. In the West African savanna zone onchocerciasis is a severely blinding disease. It was also responsible for the depopulation of fertile river valleys in the OCP countries and hence had become a major impediment to economic development. For these reasons the large scale vector control operations of the OCP, based on the aerial application of insecticides and aiming at the virtud elimination of the disease, were considered economically justified. OCP has been successful in eliminating onchocerciasis as a public health and socioeconomic problem. Outside the OCP area, onchocerciasis remains a major cause of blindness in the central and easterly parts of the savanna belt of the Northern Tropics, which cross parts of Nigeria, Cameroon, CAR, Chad and Sudan - - areas where some 6.5 million persons are infected. However, in these parts of the savanna belt, onchocerciasis does not appear to be the cause of major depopulation of fertile lands. Partly for this reasorL large-scale vector control operations are not likely to be as cost-effective as they have been in the OCP area. Onchocercal blindness rates are also high in some parts of Zaire. Onchocerciasis is a less important cause of blindness in the other endemic areas of Africa outside the OCP countries. However, in these areas, where 8.6 million infected people live, skin problems and some of the other systemic consequences such as epilepsy, are often very severe. Recent research findings clearly show that the people of highly endemic communities consider onchocerciasis, especially the grave and unrelenting itching, to be one of their main health problems and the cause of much misery. In East Africa the vectors of onchocerciasis, and consequently the disease, have been eradicated from six small foci by ground based insecticiding operations. There is evidence that other isolated foci exist where this may also be feasible and highly cost-effective. 2 3 4 5 6 7 No safe drug for community-based treatment of onchocerciasis was available until ivermectin wai registered for human use in 1987. The availability, free of charge from the manufacturer, of this effective and extremely safe drug presents a unique oppornrnity to follow up the success of the OCP and control the disease as a public health problem throughout the African Region. To control onchocerciasis as a public health problenr, ivermectin needs to be given at least once per year to the population of all seriously affected communities. Experience to date indicates that ivermettin treatment is very popular among endemic populations and that communities can effectively take responsibility for their own treatments. It should be possible, therefore, to control onchocerciasis at very low cost and with active community involvement. Community self-treatment with ivermectin may also provide an important entry point for other community based health interventions and thus help to develop a pr.rii."t basis for strengthening primary health care in some of the poorest and most underserved communities in the world. A number of important issues remain to be resolved. They include the location of all high risk communitiei requiring treatment, the effect of treatment on onchocercal skin disease, indicators for treaim.ri in areas where skin disease is the'main complication of onchocerciasis, sustainable approaches to community self-treatment, simple methods for monitoring control, and the macrofilaricidal potential of ivermectin at higher and/or more frequent lor.r. The UNDPAilorld Banlc/WHO Special Programme for Research and Tr"i^ning in Tropical Diseases has accelerated and expanded its onchocerciasis operational ,"."*.Ih progi"rnrn. in order to resolve most of these issues, and other research organizatitns ate investigating some of these problems independently' The endemic countries, working closely with a well-coordinated consortium of international Non-Governmental Development Organizations (NGDO's), have made an important start with ivermectin-based control. Over three years they have built up progr.**.s which in 1994, will cover about l5 percent of the infected people outside the bCF *,rntries, and include mainly those in the worst affected areas. This coverage is near the upper limit of what can be achieved with currently available resources. In several endemic countries there exists an effective collaboration between governments and NGDO,5. There is a need to expand this collaboration and to create an overall planning mechanism which brings togetherihe governments of all endemic countries, NGDO's and international organizo:tions. this wili ensure that the control of onchocerciasis in all endemic countriis outside the OCP is approached and coordinated in the most rational, cost-effective and sustainable manner. The control of onchocerciasis as a public health problem throughout the non-OCP countries in Africa will require initially a timeJimited, regional programme. Its principal objective will be to establisir cost-effective approaches to ivermectin-based control which can be sustained by the endemic communities and countries themselves. The programme will also be responsible for providing technical and financial support for local vector eradication in isolated foci. 8 9 10. ll t2 -3- 13. The prograrnme will be based on a partnership between participating governments, NGDO's and other parties operational in the field, bilateral donors and international agencies. The governing body will be the Joint Action Fonim (JAF) on which these parties will be represented. The co-sponsors will constitute the Committee of Sponsoring Agencies, which will act as executive secretariat for the programme. A Technicd Cons.rltative Committee will review all ivermectin delivery projects. The fiscal agency will be the World Bank which has established a separate trust fund for this Purpose. There will be no obligation whatsoever on the donors of OCP to provide,funding for the new progftrrnme. 14. The executing agency will be WHO. The programme's headquarters would be located in Africa. The programme, supported by its statutory bodies, would provide guidelines and advice to ivermectin based control projects, ensure coordination, organize operational research and training, provide independent monitoring and evaluation of control, ensure financial oversight, and be responsible for advocacy of the programme. Ivermectin delivery will be done through Ministries of Health and NGDO's on the basis of technical service agreements. A liaison offce would be maintained at WHO headquarters in Geneva to facilitate liaison with the NGDO's. I a -4- Preamble r An unique opportunity exists to establish a development partnership and to move forward expeditiiusly- ioward ihe goal of eliminating onchocerciasis as an important development constraint. Thir opporn nity is created by the knowledge base and remarkable achievements of the Onchocerciasis Control Programme in West Africa (OCP), the availability of an effective drug free of charge, the demonstrited willingness of Ministries of Hedth and a coalition of Non- Govemmental Dwelopment Organizations (NGDOs) to become actively involved in distributing the drug and the recognition by gorernments, donors and sponsoring agencies of the importance of onchocerciasis as a major impediment to development throughout the African continent. The proposed Pan-African Piogramme for Onchocerciasis Control outside the OCP sub-region is iesigned as a parhership berween affected African countries, multilateral and bilateral agencies, and NGDOs. The newprogramme holds promise of not only controlling a significant parasitic disease, but also demonstrating the effectiveness of a new partnership approach for implementing sustainable solutions to major regional development problems' The ultimate goal ofthepan-African Programme is to eliminate onchocerciasis-as a public health and socio-economic problem throughout Africa. The control strategy would be multi-faceted but would rely primarily upon ivermectin-based control which can be sustained by the communiti.r "nd ttre enaemii countries themselves through their primary hedth care systems. Where primary health care services are inadequate, community-based ivermectin distribution prograflrmes would serve as a catalyst for the development and strengthening of primary health care services. The programme will also rely upon local vector eradication as a control tool where such an approach is feasible and cost-effective. 52. The burden of onchocerciasis Onchocerciasis is caused by infection with the nematode wonn Onchocerca volvulus for which man is the only known reservoir. The adult worns are usually found in zubcutaneous nodules and have an average longevity of around l0-l I years. The adult female worn produces millions of microfilariae which migrate to the skin and the eyes of the human hos.. The microfilariae are the main cause of the clinical manifestations of the disease. These include dermatitis, resulting in very severe itching, depigmentation and atrophy of the skirl and lymphadenitis which may lead to hanging groin and elephantiasis of the genitals. The most severe manifestations of onchocerciasis are irreversible ocular lesions of both the anterior and posterior segment of the eye, resulting in impaired vision and finally in total blindness. There is increasing evidence suggesting that onchocerciasis is an important risk factor for epilepsy and that it is responsible for hypo-sexual dwarfism in certain areas (e.g the Nakalanga syndrome in Uganda). The parasite is transmitted by a blackfly of the genus Simulium, which ingests microfilariae during a bloodmeal on man. In the fly, some of these microfilariae develop into infective larvae which can be transmitted to another person during a subsequent bloodmeal and develop into new adult worms. The blackfly breeds in rapids in fast flowing water and consequently the transmission is most intense, and the disease most severe, in the river valleys. The epidemiologit:al pattern of onchocerciasis, and in particular the severity of ocular disease, varies considerably between geographical zones. Well documented is the difference in ocular pathology between the West African savanna and forest areas. While onchocercal blindness can be rampant in hyper endemic communities in the savanna belt of the Northern Tropics, there is less damage to the eyes in forest villages with a comparable intensity of infection. However, the situation in other parts of Africa is different. In theZure basin severe blinding and less blinding onchocerciases are found in both forest and savannq while in East Africa onchocercal blindness is rare in both savanna and forest. It is believed that the explanation lies in the existence of various O. volwtlus strains of different pathogenicity. The severity of onchocerciasis is closely related to the intensity and the duration of infection. In the West African savanna, onchocerciasis is socially inapparent when the Community Microfilarial Load (CMFL) remains below 4-5 microfilariae per skin snip (mfls). However, onchocerciasis becomes an important public health problem when the CMFL reaches l5-20 mfls and blindness will affect more than 5o/o of the population when the CMFL exceeds 40 mfls. With such high blindness rates, the disease becomes insupportable and threatens the survival of the village itself. The disease has led to the depopulation of many relatively fertile river valleys in the Volta River Basin and several neighbouring rivers in the West African savanna. In this poor part of the world, onchocerciasis was not only an important public health problem but also a major obstacle to socio-economic development. Outside the savanna belt of the Northern Tropics and with the exception of certain areas in Zure, onchocercalblindness is a less serious health problem, even though there remains a need -6- to further investigate the blinding potentiat of onchocerciasis and the impact of the disease in terms of visual disability in some areas. However, the disease is still a significant public health problem as other complications of the disease can be highly prevalelt-. R"9"lt research has rhorm that onchocercal skin lesions can affect more than one-third of the adult population of hyperendemic communities, ranging from unsightly and itchy papular onchodermatitis to gross alpigmentation of the shins (leopard skin). In such communities more than half the adult pop,itation suffers from severe itching due to onchocerciasis. For the affected population this maddening itching is the most severe complication of onchocerciasis which seriously affects their wellbiing and which they perceive as an important health problem. In Africa some 17.5 million people are infected vithOnchocercavolwrlns. About 15 million of the infected, or more than gsX, live now outside the OCP countries (see Annex l)' Of those, an estimated 6.4 million infected live in areas with severe blinding onchocerciasis and 8.6 million infected in areas with parasite strains which are less damaging to the eye but which are responsible for severe skin diiease. Outside the OCP there are some 217,000 persons blind as a rlsult of the disease (according to figures obtained by WHO in 1993, which did not include blindness estimates for all endemic countries), with an estimated incidence of 35,000 new cases of blindness per year before the start of ivermectin distribution. At present there are no reliable estimates foi the burden of skin disease and severe itching but it is probable that it causes suffering in millions of peoPle. MAP 1: Countries in Africa with endemic onchocerciasis I: CNDEUrcGP@I.IXTRIES ["TI ENT,EI.IC OOT,NTRIES OIJT$I,E TI{E OCP N enoeutcrw uitcERTAll 73. Options for control At present, the only feasible method of eliminating onchocerciasis in Africa is by intensive vector control or by vector eradication. While the latter is the ideal solutiorU it is technically feasible only in relatively small foci. Since 1987, the drug ivermectin has been available and has proved excellent for morbidity control. 3.1. Vector control Vector Control implies the long term application of larvicides. This is necessary because the whole focus is not covered and on cessation of lanviciding the vector will invade from uncontrolled areas.Vector control to intem.rpt transmission has been the means employed in the highly successful OCP operations in West Africa. The aerial application of larvicides, as done by the OCP, is large scale, requires highly skilled operations and management, and hence can be costly as a whole. Nevertheless, this approach has a high benefit/cost ratio in the I I country West African savanna area owing to two factors; l) substantial economies of scale associated with operational research, the pooling of expertise, and high quality centralized management; and 2) the importance of onchocerciasis as a cause of the depopulation of large tracts of arable land. The savanna belt ofthe Northern Tropics, east of the OCP area (Nigeriq Cameroon, Chad, CA& Sudan), has similar vectors and similar onchocerciasis epidemiology to the OCP (see annex l). The only technically feasible means of controlling the vectors would be a large-scale aerial larviciding operation similar to that carried out by the OCP. Even excluding Sudan, where lack of security precludes anti-vector measures, such a programme, confined to savanna areas, would cost in the order ofUS$500 million for a 14 year programme (see annex 2 for details). The area coverd although affected by the blinding form of onchocerciasis, does not appear to suffer the severe socio-economic effect of depopulation to the same extent as did the central OCP countries before that programme began; and certainly not to the extent of justifying the expenditure estimated in Annex 2. In other areas, particularly where the disease is likely to spread, small scale vector control operations may be both desirable and cost effectivdfeasible (see annex 2). 3.2. Large scale ivermectin treatment for morbidity control The introduction of ivermectin in 1987 provided for the first time a feasible chemotherapy for large scale treatment of onchocerciasis. Ivermectin is an effective microfilaricide which greatly reduces micofilarial loads. Since the microfilariae cause the severe morbidity of onchocerciasis, ivermectin treatment is a very effective tool for morbidity control. Ivermectin is a very safe drug. This was convincingly demonstrated during large community trials between 1987 and 1989 when some 100,000 persons from hyper-endemic communities were treated and closely monitored for 72 hours after treatment. Since theq millions of infected people have been treated with ivermectin and only transient and generally minor side effects, which were easily managed at the local level, have been reported. There remains some uncertainty as to the safety of ivermectin treatment in cases with heavy co-infection with Lu -8- loa and further investigations into this question are ongoing. Although ivermectin is very effective against the microfilariae, it has only limited adverse actions on the adult worm. A few months after treatment, when the adult female worrn recommences its reproductiorL skin microfilarial loads will start to rise again and treatment will need to be repeated before the microfilarial load reaches unacceptable levels. Several studies have shown that annual treatment is sufficient to prevent the development of ocular lesions and blindness. Less clear are the results on the effect of ivermectin treatment on onchocercal skin lesions and itching and further research is needed to determine the appropri'ate treatment interval for the control of onchodermatitis. Ivermectin treatment greatly reduces transmission of the parasite, but does not intemrpt it and the adult worn may liie foi as long as 14-15 years. Annual large scale treatment will therefore have to continue for a very long time. Current predictions with a simulation model indicate that annual treatment at the current lJvel of coverage may have to continue for several decades before the parasite reservoir has sufficiently collapsed to break the chain of transmission. The main chalienge facing ivermectin-based tontrol, therefore, is to develop and implement simple methodi of ivermectin delivery which can be sustained by the communities themselves. Fortunately, the first experiencet *itt community-based approaches indicate that communities can be giuen the responsibility of ivermectin delivery and that they often even achieve a better *.r"r"gI than mobile teams. (ine of the main priorities for operational r:s:ar9tL therefore, is to furttrertevelop community-selftreatment approaches in which there is minimal need for external support (seaAnnex 4). Community self:tieatment may also provide an important entry point for other community based healtir interventions and thus develop a practical basis for strengthening primary health care in some of the poorest and most underserved communities in the world. 3.3. Focal vector eradication Focal vector eradication implies that the whole focus is covered at once resulting in the total eradication of the vector or., . very short time scale. This is termed "short-sharp eradication". In other cases eradication may be aihieved over a longer time frame (not more than 3 years) as the population gradually deilines to a critical level from which it collapses. This is termed ,'eradi""tion by attrition'i and can be achieved where the vector belongs to the S- neavei group' Both operations can be accomplished at relatively low costs. The situation in East Africa is very different to that in the Northern Tropics. The vectors, even those in the S. donnosum campler tend to have poor powers of dispersal. There-are many rivers and streams snritable for vectoibreeding, which are occupied by non-man-biting forms, while the vectors are confined to relatively small pockets. Thus there is considerable potential for the spread of onchocerciasis and this is occtrrring at present in Malawi. Members of the S' neavei group have strictly limited population sizes a-nd low rates of population increase owing to their i.p.nd.n.e on frlshwater cribs. In East Africa vector control remains a valid, cost-effective ophor,, even in the era of ivermectin distribution. Subject to feasibility studies, and careful pre- control evaluation, short-sharp eradication should be attempted in selected foci in Burundi, Malawi, Tanzania and Uganda and eradication by attrition at least in Uganda, (see Annex 2)' It is proLable that vector iontrol would also be cost effective in some foci in Ethiopia but these have yet to receive detailed entomological investigation' 4. Current status of onchoc 4.1. The OCP area In the OCP area onchocerciasis has been brought longer considered a public health problem eliminated from the centre of the OCP. The aerial application of insecticides to the principal means of onchocerciasis control in the successfully concluded in Burkina Faso and Niger, and Togo, and in S.E. Mali. It has not been used in continues in the other countries on a selective basi Over most of the OCP are4 ivermectin control, but in Senegal and Guinea Bissau it is people are being treated annually with ivermectin in 4.2. Outside the OCP area Currently, large-scale ivermectin distribution thirteen of the sixteen endemic countries in organizations responsible for the distribution are countries assisted by several non-governmental a number of NGDOs which have established a (NGDO Group), UMCEF/I.ligeria and several By far the largest share of ivermectin distribution 3 million persons treated in 1994, is supported prografirmes rapidly and consistently over the past Taking into account that ivermectin distribution has areas, more than 2 million of those treated may treatment coverage ofabout l5% ofthose infected the maximum distribution effort that can be the national governments and the NGDOs, and worst affected countries. The main methods currently employed in African countries outside the OCP are (a) large "passive" distribution. The former is carried out trained individuals living in the community called usually have minimum direct supervision implications with distribution by CBDs and use vehicles or motor cycles and are paid per di distribution which requires populations to attend However, there are some exceptions which low cost and satisfactory coverage rates -9- ciasis control in Africa. complete control. The disease is no the area and the parasite has been virrually rivers of the Simulium vectors remains the OCP. However, vector control has been the northern parts of Ivory Coast, Ghana and Guinea Bissau. Vector control is being carried out as an adjunct to vector sole means of control. Close to 2 million the OCP area. onchocerciasis is being carried out in outside the OCP (see Annex 3). The the Ministries of Health of the endemic internati on al or ganizations. These include group for ivermectin distribution Technical Co-operation Organizations. the OCP, some 957o of the estimated the NGDO Group which has built up its years. carried out mainly in the worst affected been actually infected. This amounts to a the OCP area. It also represents about with the resources currently available to the current limited access to some of the distribution prografirmes in endemic active distribution or (b) clinic-based or by mobile teams of para-medicals or by Distributors (CBDs), who the activity is strictly monitored. Cost are far less than by mobile teams which Coverage of communities by clinic-based to fetch their drug tends to be low. -10- 5. Programme Strategy and Operations Onchocerciasis has been brought under full control in the OCP where the disease is no longer a public health problem. Outside the OCP are4 an important start has been made with ivermectin-based control. However, only about l5% ofthe infected people are culrently treated and this coverage is near the upper limit of what can be achieved with the currently available resourc€s and wiih the present approaches to control. Vector eradication is not being attempted anyvhere, even though this may be cost-effective in some foci. r With the presently available intervention tools, it should be possible-to control onchocerciasis as a publt healttr.problem throughout Africa. To achieve that goal, however, a new approach will be required wittrin a regional frameworh building on the factors which were responsible for the succeis of onchocerciisis control by the OCP, and the recent initiatives of the Ministries of Health and NGDOs to institute ivermectin based control activities in the countries outside the OCP. Crucial to the success of the OCP have been (i) clear, feasible objectives; (ii) detailed operational plans; (iii) proper monitoring and evaluation; (iv) problem solving caiacjU; (v) incorporation bf tfr. i.iuitr of operational research into the day-to-day management of the Programme. The control of onchocerciasis throughout the non-OCP countries in Africa will require initially a regional programme with the same characteristics. 5.f . Programme objective and stratery As large scale vector control is not considered cost-effective outside the OCP, and vector eradicition only applies to limited foci, the new regional programme- will have to rely on ivermectin treatment as its main intervention tool. This consideration has important implications for the selection of the objective and strategy of the programme. To control onchocerciasis as a public health problem, ivermectin needs to be given at least once per year to the population of all seriously affected communities. Ivermectin is very effective '"gainrt the microfilariae which cause the severe manifestations of the disease, but an important limitation of the drug is that it has relatively few, and as yet poorly understood, adverse effects on the adult worm *ti.t can live for as long as 14 years. Furthermore, large scale ivermectin treatment, although it can reduce transmissioq does not intemrpt it, and the population of endemic areas under large scale ivermectin treatment continues to be re-infected, albeit at a significantly reduced rate.-Consequently, ivermectin treatment will have to be given annually for aieriod oidecades to ensure thi longterm control of the disease. L The long term control of onchocerciasis as a public health problem is the ultimate goal' Howwef it willnot be the programme objective ai this would imply that the programme would have to continue its operation, io. an unspecified period of time and that it would have no clearly defined end-point. Fortunately, a relevant prograrnme. Experience to date endemic populations and it appears own treatments. It should be community involvement and at The main strategy of the based ivermectin delivery systems countries themselves without PROGR,4MME OBJECTIW: To establish, within a perid ive rme c ti n tre atment t h r ou gh ou t disease by vector control in Attsinment of this objective will health and soci*economic 5.2. Programme operations The programme expands and sr.rpported by governments, NGDO's activities so as to strengthen programme will collaborate closely in the field, and encourage the links Within this context, the programme further develop standard monitoring of ii. augment support to the lv v advice, assistance and funds for small scale projects. - ll - objective which only calls for a time limited that treatment is very popular among can effectively take responsibility for their to ensure control of onchocerciasis with active low cost, and with little or no external support. therefore, be to develop and establish community- which can be by the endemic communities and external after the programme has come to an end. l0 years, and se lf-saslainab le communi ty-based remaining areas in Africa and to eliminate the the gul of throughou, of onchocerciasis as a public Afica activities in countries which are already being other It will build flexibly on the existing achievements at national and community levels. The national NGDO's and other parties active these undertake following: and for the design, execution and ivermectin di governments NGDO's to enable them to develop and implement community-based ivermectin deli Programme objectives and to move towards achieving the iii. carry out applied and operational research support of control and to modify the approaches to control when required. provide independent monitoring and of ivermectin delivery programmes in goal ofregional control ofthe disease.relation to the progamme objective and the provide or strengthen the necessary training to control. staff involved in ivermectin-based vi. identify limited fociwhich might be amenable vector eradication, and provide technical l. -12- 5.3. PrcparatorT opcrational research There remain a number of important issues which need to be resolved urgently. They include the location of high risk communities requiring ivermectin treatment, the effect of ivermectin treatment on onchocercal skin disease and itching, indicators for large scale treatment in areas where skin disease is the main complication of onchocerciasis, sustainable approaches to community self-treatment with ivermectin, simple methods for monitoring control, and investigations into the macrofilaricidal potential of ivermectin give_n at higher and/or more frequent doses. The UNDpAilorld gankiWttO Special Programme for Research and Training in Tropical Diseases (TDR) has recently accelerated and expanded its onchocerciasis operational r.r".rih programme in order to help resolve most of those issues as early as possible (see Annex 4), and 'ottrir organizations, including ORSTOM and RBF, are investigating some of these problems independently. 5.4. Financing of oPerations The programme would provide matching financing to governments and/er cooperating NGDO's oorting TCC approved projects. In gineral, the executing party wguld be required to provide at least 25yo of total project financing to quali$ for trust fund financing of the remaining amount. Other levels'of trust fund Jupport could be considered in exceptional cases on recommendation of the TCC. Matching dn"rce could be channelled directly to the cooperating NGDO with the agreement of the government concerned' 5.5. Costs of the Programme Based on the costings of the current NGDO activities, projected ivermectin distribution costs prepared by Walsh[ and the need for the programme to undertake operational researctr, monitoring an evaluation, as well as limiied vector eradication, an annual budget of approxima=tely l0 million US dollars may be needed. However, the actual costs of the programme is yet to be determined. twalsh, J.F. (1993). Review of human onchocerciasis in Africa outside the OCP countries with recommendations on control. Unpublished report to the World Bank' 6, Organization The programme will be based on a partnership other parties operational in the field, the donors fiamework must reflect this partnership. It is proposed to use an effective framework of tested governance structures of the existing OCP The programme would be comprised of the agency and the fiscal agent. The programme would be governed by a Joint would consist of members from among the contributors; (b) the participating countries; (c) participating non-governmental organizations and contributing to the prografirme resources or progranrme. The JAF shall have among its responsibilities to and budgets, assess global financing requirements, programme policies. The JAF would meet annually two-yearly intervals. The cosponsors of the programme would be the and the Bank. The cosponsors would constitute the and meet quarterly in conjunction with the OCP/C executive secretariat of the new programme. It regarding funding allocations in the context of collaboration and consistency in the operations of CSA would take all interim decisions on behalf programme's budget or changes in overall policies management would report through the CSA to the consult with the CSA on the package of proposals for financing for that specific fiscal year. The executing agency of the progtamme would be be located in Africa. The programme staffwould based control, assist with the preparation and coordination between all actors involved, organize national stafr organize and provide independent financial and administrative oversight of the control and public relations of the programme. -13- framework participating govemments, NGDO's and international agencies. The organizational and governance, patterned after the parties, the cosponsors, the executing Forum (JAF), similar to the JPC, which parties being: (a) the financial cosponsors of the programme; (d) or non-profit organizations technical and/or.scientific support to the and approve the proposed plan ofactions take decisions with regard to overall the first two years and subsequently at as for OCP, being, UNDP, WHO, FAO of Sponsoring Agencies (CSA), meetings. The CSA would act as the oversee global operations, take decisions financing availabilities, and ensure close new programme and OCP. Finally, the the JAF, such as those regarding the approval of the JAF. The programme . The programme management would the TCC (see below) has recommended The programme's headquarters would guidelines and support to ivermectin of project proposals, ensure researcll support training of and evaluation of control, ensure ons, and be responsible for advocacy -14- Ivermectin delivery will be done through the Ministries of Health and NGDO's on the basis of technical service agreements for ivermectin delivery projects. In order- to facilitate the development and iriplementation of these projects, the progfimlme Yo-'l-d organize regular coordination meetings with Ministries of Healt[ the members of the NGDO Group, and other organizations underiaking ivermectin delivery. To facilitate liaison with the NGDOs, a liaison off.. would be maintained at the Prevention of Blindness unit at the wHo headquarters in Geneva. The prograrrme shall be supported by a Technical Consultative Committee (TCC) of l0 membericomprised offive independent scientists, two technical representatives ofNGDOs, one represeniative-of the Carter Center, one representative of the Medizan Expert Committee, and o* r"pr"r"ntative ofthe Expert Advisory iommittee of the OCP. The independent members of the TCC would be selected by the CSe. fhe functions of the TCC would be primarily to review ivermectin delivery projects, including the review of guidelines for project proposals, the technical content -a U,rag.t'of propoJed projects and the implementation of funded projects. The Committee would maki apprbpriate recommendations on these projects to the programme' The TCC would meet at least rwice per year. The fiscal agent for the programme will be the World Banh having established a specific Trust Fund. The trust fund would be governed by the guidelines of the World Bank and resemble the trust fund presently held for th; OCP. It needslo be stressed here, however, that the funding arrangements for OCp *a the new programme, including the trust- funds,- would be totally ,.p.r"tr, and separate accounts held for each progralnme. No obligation will be on the donors prbrriaing funding for ocP to also provide funding for the new programme. ANNEX I. The Distribution Magnitude of t Human onchocerciasis in Africa is widely di woodland and forest zones north of the equator from l4'N in the OCP countries to 13"N across Howwer, in the Nle valley the disease occurs as far as far as 15"N. It occurs throughout West Afric4 are slow flowing and unsuitable as vector breeding foot of Mount Cameroon and bathers and flies. The disease appears to be patchily distributed and Congo. It also occurs on the island of Bioko. result of the lack of systematic survey work in tho Although there are probably several discrete foci in territory, extending into northern Angola as far Burundi and Uganda to about 30"8. Isolated foci and Tanzania. The disease was formerly present disease may still exist in the foothills of Mount Onchocerciasis is known to be endemicin2T of the (see Map l). In addition it is probably marginally Mozambique and Rwanda). Eleven of the endemic Africa. They are not considered in this document listed in Table I with their crude onchocerciasis of infected people are to be found in Zure, descending order. However, most blindness from Zure, Cameroon, Chad and CAR These, togaher communities. Certainly all have districts in which of the total population of some communities. Factors affecting the patterns of distribution of In Africa the distribution of onchocerciasis is vectors. There are virilally no extensive areas where absence of disease, except Zambia This was substantial uninhabited regions infested with S. such areas inZure. The key elements which influence the distribution determine the presence or absence ofthe vectors and, elements include the amount of rainfall and its metamorphic and non-porous, or sedimentary and forest or savanna. -15- Onchocerciasis and the Probliem. in a broad band throughout the savanna l5"W to 40"E. The northern limit ranges and 10" 30N from Cameroon to Sudan. as 20"N (Abu Hiunad) and in Ethiopia on the coastal plains where the rivers In Cameroon it reaches the coast at the at sea are liable to be bitten by the vector of 2"N in Equatorid Guinea, Gabon apparent patchiness may, in part, be a countries onchocerciasis occurs in most of the as 10"S, and eastwards into western further east in Uganda and in Malawi western Kenya ryhere a small pocket of adjacent to Uganda. I countries of Africa south of the Sahara in three other countries (Keny4 are covered by the OCP in West remaining sixteen endemic countties are As can be seen the largest numbers Cameroon, Uganda and Ethiopia in asis probably occurs in Nigeri4 Sudaru probably have the worst afflicted rate of onchocercal blindness exceeds 502 almost entirely by the distribution of the vectors of the disease occur in the so in the recent past when there were s.l. in Uganda and almost certainly the disease are, therefore, those which present, precisely which vectors. These , whether the underlying rocks are s and whether the natural vegetation is - 16- The panerns of disease and the broad epidemiological picture is also determined by the different strains of the parasite. There are at least two strains in West Atica. One strain, 6'pical of the wooded savanna readily causes blindness, the other, typical of the rainforest, is much less damaging to the eye. Eisewhere parasite strains have not been studied, but it is likely that the situation is different as blinding onchocerciasis is known to occur in some forest foci of Zaire. Different strains may prove to1" asso"iated with other manifestations of the disease, such as dwarfisnL epilepsy, and severe skin disease. Thc epidemiological zones of Africen Onchocercirsis As a consequence ofthe differences in vectors and strains of the parasite African onchocerciasis can be divided into four broad categories in four distribution zones (see map 2). These are: Zone I the savanna woodland belt or the Northern Tropics II the West and Equatorial African rainforest m the Zaire basin fV the East African Highlands. Zone I - the svannawoodland belt of the Northern Tropics . This Zone extends from Senegal to Sudan (including the OCP area). Onchocerciasis is of the severely blinding type and the epidemiological pattern is similar to that found in the OCP area. Outsidi the oCp countries about 4.78 ;i[ion people are infected and 160,000 blind from onchocerciasis. The CAR is almost certainly thi most seriously affected country outside the OCp. The vet:tors are highly migratory, and typically breed in large rivers. There is no fossibility of eradicating thEm and localized vectoi control will not normally be cost-effective. Zone II - the lYest and Equatorial African rainforest This Zone extends, with intemrptions, from Guinea Bissau to Gabon. Onchocerciasis is of the 'less blinding' type. Outside thi oCP area about 2.42 nrllion people a-re infected and 17,500 blind from onchocerciasis. The epidemiological pattern is similar to that found in southern Ivory Coast, though in the Equatorial iorest onchocerciasis is diffi'rse with fairly high prevalence rates couplld wii-tr tow pur"rit" loads. The key vectors !f:d in small forest covered streams with cannot be detected from overflying airciaft. Aerial based vector control is not technically feasible, and ground controlwould be problematical and not cost-effective. Zone III - the kire Basin This Zone includes the onchocerciasis areas of N. Angola, Congo andZure, though theZake rainforest is contiguous with that of the rest of Equatorial Africa. The epidemiological pattern is complex and piobably unlike that of west Afriia. There are foci of btinding onchocerciasis within the forest, and some less blinding onchocerciasis foci in the savanna. There are thought to be about 4.71 million people infectJa and 40,000 blind from onchocerciasis, though these figures are very tentative. thovector situation is very complex and not well understood' There are probably some small isolated foci which could be eliminated by anti-vector action but with present knowledge, and lack of political stability, vector control is not feasible. -17 - Zone IV - the hst African Highlands This Zone extends from Ethiopia to Malawi. Onchocerciasis is generally of the less blinding type. There are over 3.08 million people infeced but only few blind from onchocerciasis. Skin disease seems particularly severe in some foci, and onchocerciasis is associated with exceptionally high rates of epilepsy in several countries and with dwarfism in Uganda. Thus the epidemiology of the disease is rather dissimilar to that found in Zones I and II. The disease is highly focal, sometimes dependent on forest cover, and the vectors d.o not aPpear to be .igr"tory. A number of imall isolated foci are knowrU and the disedse has already been eradicated from six of these. There is a real possibility of cost-effective anti-vector action in all of the endemic East African countries. Table l: Estimates of the number of people infected and blind due to onchocerciasis by country in Africa outside the OCP area. Country Total population (millions) Number infected wrthO.volwlus Ns. blind due to onchocerciasis Chad Sudan Nigeria Cameroon c.A.R. Gabon Congo Equatorial Guinea Zure Angola Liberia Ethiopia Malawi Burundi Uganda Tanzania 5.7 25.8 99.0 I 1.8 3.0 1.2 2.3 0.4 35.6 10.0 2.6 49.2 8.8 5.5 18.8 27.3 870,000 620,000 3,302,000 1,300,000 390,000 60,000 50,000 60,000 4,565,000 100,000 600,000 929,000 150,000 143,000 1,200,000 650,000 20,000 10,000 100,000 26,000 19,000 ? 600 ? 37,500 2,000 2,600 ? ? ? ? ? Total 307 14,989,000 217 700 - t8 - MAP 2. ONCEOCERCIASIS EPIDEIYIIOLOGICAL ZONES 0cP Zone I OOO Kr Savanna Belt of Northern lroPlcsFI II Ralnforest III Zalre Baeln [ry-lI -' I IF East Afrlcan Hlghlantls Descrt Foci (not consld.ered. ln RePort) JFW ilt -19- ANNEX2. Vector control and vector eradication. The arguments in favour of carrying out vector control are set out in separate documents2. It is worthwhile bearing in mind that: - while chemotherapy is effective, unsophisticated and relatively cheap, and brings benefit to those who receive treatment, it gives no direct benefit to those who remain untreated. In contrast, though vector control (larviciding) is more sophisticated, and is generally considered relatively costly, it is also more effective on the long term because it tends towards elimination of the parasite reservoir following the intemrption of transmission and brings immediate benefit to all the population living within the treated area. - Although the individual benefit is not as dramatic as in the case of treatment with drugs, nevertheless, the reduction in the biting nuisance is usually perceived as a major advantage by local communities. It is also clear, from work in the OCP, that in as little as 5 years there are perceptible ophthalmological benefits. The goals ofvector control, in combination with the mass distribution of ivermectin, may be the immediate intemrption oftransmission or, where this is not considered feasible, a rapid reduction of transmission to levels lower than can be achieved by ivermectin distribution alone, with a view to the eventual cessation in the development of the more serious symptoms of the disease. i. Control to interrupt transmission This implies that the whole area of the focus is not covered by the control action, or that the action taken does not result in the complete suppression of vector breeding within the control area. Either the vector is ever present with concomitant transmission, or the vector and transmission are eliminated only seasonally, with the vector invading periodically. If control is carried out at high intensity and for a long period, the transmission cycle may be intemrpted for a period exceeding the reproductive life span of the parasite. When this happens the disease may be eliminated as a socio-economic and public health problem. Should vector control be stopped the fly will probably invade from untreated areas, without the disease reappearing. This is what has been achieved in the central area of the OCP. It is eradication of the parasite by attrition. In the savanna belt of the Northern Tropics (Zone [), outside the OCP are4 the vectors are widespread, highly migratory, capable of rapid population growth and present in all suitable habitats. They can only be controlled effectively by large scale insecticiding using aircraft. Vector eradication is not feasible. To achieve irreversible results the transmission cycle must be broken for a period exceeding the fecund life span of the parasite (up to 14 years). 2walsh, J.F. (1993). Reviewof human onchocerciasis in Africa outside the OCP countries with recommendations on control. Unpublished report to the World Bank Walsh J.F. (1994). The control of human onchocerciasis in Africa outside the OCP countries: suggestions for vector control. Unpublished report to the World Bank. -20 - An aerial control operation lasting 14 years and covering this savanna belt eastwards from the eastern boundary oi the OCP (he BeninA.{igeria frontier), but excluding southern Sudan, has been costed on the basis of the OCP operations. The onchocerciasis infected savanna belt from the BeninA.{igeria frontier to NE Central African Republic @vers 979,000 km2 (see Table 2),i.e., an area about one-third larger than the original 7-country OCP. In the original OCP flight hours flown per 1000 km2 were 12.8 in 1976, l0'0 in lg7g, g.0 in lgg0 and g.g in tgaz. on this basis the flight hours and costs for an aerial operation covering the savanna area east of the OCP are given in Table 3.' Table 2. Details of a Nigeria-cameroon-cAR-chad Project Area* Country Surface Area km2 Population Infected Blind from Onchocerciasis Cameroon CAR Chad a 157,000 175,000 95,000 552,000 500,000 260,000 870,000 2,500,000 20,000 17,000 20,000 93,000 TOTAL 979,001 4,130,000 150,000 Figures taken from 1993 WHO Expert Committee Report, which probably underestimate* the CAR situation. Table 3. The Flight Hours and Costs for a 14 year Control Operation in the Savanna Belt east of the OCP Area Operational years Flight Hours/1000 km2 furnual Costs (million us $) Total Costs (million USI)- Ito3 4to6 7to12 13 to 14 10.0 9.0 8.0 7.0 9.79 8.81I 7.832 6.853 29.37 26.433 46.992 13.706 Grand total I16.501 -21 - Assessing insecticide usage is more problematical but a figure of 300 litres of temephos per 1000 km2 per year at a price of US Dollars 2O1itre has been used based on the middle period of OCP operations. This gives an annual consumption of 293,700 litres at a cost of US Dollar 5,874,000 per annurL for a 14 year Programme cost of US Dollar 82,236,000 For the period 1986-91 in the original OCP the Aerial Operations + Lawicides totdled US Dollar 65,229,499 from a total budget of US Dollar 177 million, or 36.8802. If that were to be repeated in the "OCP II" area the cost of a 14 year Programme would be U.S Dollar 538,874,000 In fact Aerops could well be more efficient than the original OCP, but this has been partly discounted inFlight HourVl00O km2 figures. Aerops might also be a larger proportion of the overall budget. However, no allowance has been made for the preliminary 2 years of start-up time and pre-operational activity, or for a wind-down year. It is also clear that a Programme of this size would have to be phased in over 2, perhaps 3, years. Thus a realistic cost could not be less than US Dollar 500 million. Given that onchocerciasis is not a major cause of the depopulation of fertile lands in these countries such an expenditure would be hard to justify economically. In certain circumstances small scale ground based landciding may provide a cost-effective approach to onchocerciasis control. This is particularly likely to be the case where there is a danger of onchocerciasis spreading and where the severity of the disease, or the excessive biting rates of the flies, cause local depopulation. A good example of the likely benefits of ground based control is that of the Nyamagasani valley. in Uganda the Lubilya river forms the border of Kasese District andZure. It is part of a large onchocerciasis focus in which the vector is S. damnontn s.l. The adjacent valley to the east in Ugand4 the Nyamagasani valley, was formerly part of this focus. However in the early 1970s larviciding eliminated the vector from this and other valleys to the northeast. On the cessation of control the Nyamagasani and its tributaries were colonized by a non-man-biting form of the S. damnosttm complex. This was the situation until 1990 when the disease was no longer a noticeable problem. However, by 1993 the vector species had returned and as there is still a small number of people in the area infected with onchocerciasis it is likely that transmission will resume. There is also the danger of the vector spreading further. Vector control would be cheap, technically simple, and probably need only be intermittent. By any standard it is likely to be considered cost effective. At the same time proximity to a large focus inZure means that irreversible eradication is unachievable. ii. Short-Sharp eradication This implies an all out attack on the whole area covered by the vector, to prevent breeding for a period which exceeds that of the ma:rimum life span of the vector. Provided the focus is fully isolated, and the project is properly planned and executed, 8 to 12 larviciding applications should lead to the eradication of the vector and ultimately the disappearance of the disease. The advantages of short-sharp eradication are an immediate cessation of transmission, no danger of resistance developing to insecticide or drug, virtually no environmental damage, irreversibility and cheapness. Once the eradication of a vector has been achieved in an isolated focus, (and it has been achieved in Keny4 Uganda andZure), future political instability or waning interest -'r) - by local populations, national authorities, or donor organizations will have no effect. Despite a long pl.ioa of civil war and instability the eradication of onchocerciasis from part of the Ruwenzori area and the Victoria Nile basin, Uganda \ilas not reversed. Short-sharp eradication is scientifically feasible in the island focus of Bioko (Zone II) and is probably so and likely to be cost-effective in the following mainland foci of East Africa (Zone TV): i. Thyolo, Malawi ii. Tulanytr, Tanzania iii. Bwakira" Tanzania iv. Anra-Terego,Uganda. v. Mahoma-Nsonge,Uganda. vi. Rutanq Burundi Eradication of the vectors would almost certainly be feasible in the Eastern and Western Usambara foci, Tanzania, and the Bugoma focus, Uganda. However, evidence suggests that these foci may be dying out as a result of deforestation. If so, control would probably not be cost- effective. Throughout East Africa vectors of the S. damnosum complex tend to occur in small pockets ,urround"d by non-man-biting populations, or unsuitable terrain. The species involved appear to be very sldentary. eko ai th.r. rp".ies tend to inhabit rivers and large streams, their breeding ,it., "r" relatively accessible foi the application of lanicides, and eradication is likely to be a ieasible option. Tlie Thyolo, Tukuyu, Bwakira and Mahoma-Nsonge foci are dl of this tlPe. Teams in each of the three countries, Malawi (Thyolo), Tanzania (Tularytr), and Uganda (Mohoma-Nsonge) could develop their skills on these priority targets and when successful could iransfer with equipment and rlmaining supplies to other, and in the case of Tanzania and Uganda, more difficult, foci to plan and execute control. iii. Eradication by Attrition In East Africa the vector in many foci is a member of the S. newei group. All require the presence of freshwater crabs to which their larvae and pupae become attached. As a result S' neavei is not usually found at the high densities which can be achieved by the freeJiving S.damnosttn complex. In addition S. ieavei seems to have difficulty in rebuilding populations from low levels. Past experience has shown that small scale control operations, which did not adequately cover a focui could have marked effects on such vectors, if continued for several months oirepeated for six to eight weekly rycles intermittently. Short-sharp eradication is likely to be difficulty to achieve in S. neavei foci, unless these are very small, as in the case of the Usambaras and Bugomq as these vectors often live in very small forest streams with very difficult access and in which larvicides do not carry well. However, owing to low populationdensities and low powers of population growth these species tend to die out b-elow criiicat levels far short of zero, a situation completely different to that experienced -23 - with the S. donnorum complex. The result is that eradication by attrition is likely to be an option in S. neavei foci. Something of this type was approached by very limited larviciding activities in the West Nile, Budongo and Mount Elgoq S. neavei foci of Uganda in the 1950s and 1960s. Eradication by attrition should be considered for most larger S. neavei foci in East Africa. As in the case of short-sharp eradicatiorl feasibility studies are required to assess the possibilities of this approach in the Budongo, Inuara and Mount Elgon foci of Uganda. This approach may also be effective in Ethiopia and Zure. Eradication by attrition offers the advantage of.liUle danger ofresistance, little environmental damage and low insecticide costs where control is intermittent. Transmission rapidly declines to low levels. All these o<amples, including the Usambaras and Bugomq require feasibility studies and, where appropriate, preliminary costings. Subject to a positive decision on feasibility in each focus it would be necessary to carry out up to two years of pre-control ecological study and quantitative evaluation. -24 - ANNEX 3. Organizations presently involved in ivermectin distribution outside the OCP Currently, large-scale ivermectin distribution against onchocerciasis is being carried out in thirteen out ofsixteen countries in Africa outside OCP. Those responsible for the distribution are the following: Ministries of Health National Crovernments in endemic African countries outside the OCP have recognized the public health importance of onchocerciasis in areas where it occurs and its devastating nature in the populations in certain foci. Many have invited NGDOs to assist them in setting up ivermectin a.iirn..y prograrnmes (IDPs) .ni h.r" signed memoranda of understanding with them. Their contribution towards the programm.s so iar has been mainly in kind, in the form of seconding personnel as well as oftering Uuitdings and other office furnishing to the programmes. In Nigeri4 some states have made,r"ii.l.r "r"il"ble whilst some Local Government Authorities have even paid allowances to health staffinvolved in ivermectin distribution in the past. National Governments, though restrained in contributing more funds beiause of limited budgets, in the light of comp.iing plorities, are keen to have efficient ivermectin distribution strategies developi which they ci atrord to maintain in future. They are anxious to have such strategies integrated into their PHC systems which urgently need strengthening. Three countries, Carieroon, Nigeria and Uganda, have completid or are in the process of developing national plans for onchJcerciasis control with the assistance of the NGDO coordinating group. Governments need to find other means of financing their IDPs and their health systems. Some countries, such as Cameroon are trying out cost recovery for services delivered during ivermectin distribution according to the "Bamalo Initiative". There is no charge for the drug itself which is given free by the iranufacturer. This approach, however, needs to be studied further as it hiriders a higtr level of coverage of the t"rg.t population in its present form. Cost-effective strategies *.h * community-selftreatment wilh adequate link to and surpervised by the District Medical Team needs to be developed as another affordable method. Non-Governmental Development Organization Coordination Group for Ivermectin Distribution (NGDO Group) Several Non-Governmental Development Organizations engaged in prevention of blindness activities in developing countries have come together in a coordination Soup associated with the WHO programme Ior the Prevention of Blindness@Bl). The group has sponsored the post of a coordinating officer within PBL' The objectives of the members of this NGDO group are the following: . to coordinate effectively their activities to be able to better assist endemic countries in the planning, implementation and evaluation of ivermectin distribution programmes -25 - a a to promote worldwide interest and support for the use of ivermectin against onchocerciasis in endemic countries and to facilitate and seek $.lpport for important operational research in order to further develop large-scale ivermectin distribution programmes. The NGDO Group is conceived as an open ended group and is at present made up of Africare, Christoffel Blindenmission (CBM), Helen Keller International (I{trqD, International Eye Foundation (IEF), Organization pour la Pr6vention de la Cecite (OPC), River Blindness Foundation (RBF) and Sight Savers collaborating with the Mectizano Donation Program and the WHO Programme for the Prevention of Blindness and the Filariasis Unit of the Division of Control of Tropical Diseases. The NGDO Group works with and assists Ministries of Health of endemic countries in the distribution of ivermectin to control onchocerciasis. Ten out of sixteen endemic African countries are currently receiving such assistance (see table 4). Despite their different ways of operating, these NGDOs are collaborating closely and are sharing their experiences in the technical training of health workers, development of health education materials and the promotion of financial and administrative management. They conduct regular meetings to exchange and share experiences and information and to develop common strategies. Seminars have been conducted in Central and East Africa to bring together Field Managers from different countries in the subregions for exchange and sharing of experiences. Regular in-country meetings are conducted with the Ministries of Health for the same purpose. As it is unlikely that funds can be found to maintain the activity for an indefinite period of time, the preoccupation ofthe NGDO Group has been the development of cost-effective ivermectin distribution to ensure sustainability of programmes. Considerable efforts by the NGDO Group in collaborating with governments in the setting up of IDPs, have resulted in rapid expansion of ivermectin distribution. However, further expansion has had to be delayed because of inadequaste financial resources. Four million dollars will be spent collectively in 1994 by the NGDO Group. The Group has identified a funding gap of nearly 8 million dollars as the amount required to enable it to maintain its present activities and undertake a moderate expansion over the next three years. The Group has been developing formulas which should help it better utilize its resources effectively. This includes coalition building at the national level which has been started in Nigeri4 and is soon to be so in Cameroog together with the International Coalition which aims to mobilize additional resources for the Group. a -26 - Table 4: Organizations distributing ivermectin in countries outside the OCP area Other involved organizations Other organizations which have been assisting Ministries_of Health of various endemic countries in ivermEctin distribution, but which are not members of the NGDO group are: . UNICEF/tligeria which has been offering the Federal Ministry of Health logistics and financial assistance for ivermectin distribution in 7 States. . The Belgian Technical Cooperation (ABOS) which has been assisting the Ministry of Health in Burundi in ivermectin distribution in all endemic foci in the country. Estimated number treated in 1994Other Organizatiqq Member of NGDO groupCountry Angola 40,000Belgium Cooperation 200,000GTZEL_E_E, RBF' Burundi Cameroon 300,000C.A.R. RBF 200,000Africare, RBF RBF Chad of Barcelona French 30 000 000 IEF French C Guinea I 000 000I Gabon Liberia Malawi 1,000,000 < 1,000_ Nigeria Sudan lqq,9.-0_q._.. 80q,q.-0..q.....GTZ 50,000 UNICEF CBM CBM, RBF. Sieht Savers LIONSIEFS Tarvania Africare, RBF, Sight RBF RBF Il*e*4s Zure 2,820,000TOTAL University a-27 - The French Technical Cooperation, which is supporting the University of Gabon in ivermectin distribution in the country. i The Spanish Technical Cooperatioq through the University of Madrid, which is assisting the Ministry of Health in Equatorial Grinea in ivermectin distribution. The German Technical Cooperation (GTZ), which is assisting the Mnistries of Health in Cameroon and Uganda in ivermectin distribution. a a -28 - ANNEX 4. Operational Research in preparation for a Pan African Control Progn'amme. 1. Introduction The control strategy for the Pan African Programme for onchocerciasis control outside the OCP subregion wifl bJmorbidity control through large scale ivermectin treatnient zupplemented by vector eradication in foci *ir"r" this may bi cost-effective. The main aim of the programme will be to bring ivermectin treatment to those who need it most and to build up a sustainable delivery system in-all endemic countries. The Task Force on Onchocerciasis Operational Research of the UNDpAVorld Banl/WHO Special Programme for Research and Training in Tropical Diseases (TDR) has been requested to acceleraG and expand its operational research activities in order to develop the technical basis for such a regional Programme' 2. Objectives In order to provide the technical basis for a regional control Programqe for onchocerciasis control in thonon-OCp countries, the TDR Task Force on Onchocerciasis Operational Research has adopted the following objectives: l. To better determine the geographical distribution and public health importance of onchocerciasis in the non-OCP countries. Z. To develop simple, cost-effective and sustainable methods for ivermectin delivery and for monitoring of ivermectin-based control. 3. To determine the feasibility of vector eradication in circumscribed foci. 3. PIan of activities In order to achieve the above objectives, the Task Force will undertake the following activities' 3.1. Distribution and public health importance of onchocerciasis in Africa 3.Ll Rapid Epidemiological Mapping qf endemicitv blt country For most countries outside the OCP there is insufficient information on the geographical distribution ofonchocerciasis infection and on the location of high risk communities where large scale ivermectin treatment is most urgently needed. There is therefore an urgent need for epidemiological mapping of onchocercLsis io provide a basis for rational planning of control' Classical methods foi eiiaeriological mapping based on skin snip surveys in all communities potentially at risk are not appropriat-e as thqtwould be too time-consuming and costly to perform it rough6rt all affected couniries. Instead the method of Rapid Epidemiological Mapping of oncho-cerciasis (REMO) willbe used. This method was recently developed under a Task Force a ^-29 - initiative in Cameroon and was successfully field tested in 1993. The REMO method is currently being used for the nation-wide rnapping of onchocerciasis in Nigeria and further REMO mapping of Cameroon is ongoing. REMO will be done in all those endemic non-OCP countries where it is likely that following the mapping, large scale ivermectin treatment can be instituted where indicated. The REMO mapping of countries where it will not be possible to launch large scde ivermectin treatment because of political unrest or other reasons, will be delayed to a future date when the prospects for control will have improved. Though the REMO method has proven its validity for endemic areas where S. domnosum s.l.is the vector, there remains uncertainty about its usefulness for foci of the vector S. nearyi in East Africa. Therefore, the REMO method will be field tested, and modified if required, in Uganda before the end of 1994. 3.1.2 Relation between public health imPortance and endemiciU The nation-wide application of REMO will provide information on the population infected by endemicity level. For West African savanna areas these estimates can bc directly translated into estimates of the number blind due to onchocerciasis because of the well established relationship between the prevalence of blindness and endemicity. However, no such information exists for the relationship between the prevalence of onchocercal skin disease and endemicity. It will therefore be necessary to undertake special studies of this relationship in order to be able to translate the results ofttre REMO mapping in terms of disease burden due to onchocerciasis and to provide objective cnteria for inclusion of comrnunities in large scale ivermectin treatment programmes. Studies of this relationship will be undertaken in eight sites in East, West and Central Africa using a standard methodology for the classification of onchocercal skin disease and its psycho-social implications. This methodology is currently being developed by the Task Force in a multi-country study of the psycho-social importance of onchocercal skin disease. Studies of the relationship with endemicity need to be undertaken in multiple sites because of the variation in disease pattern due to differences in parasite strains. The studies will be supported with DNA probe classifications of parasites using the recently developed probes which are now in operational use in the OCP. 3.1.3 Baseline.for ewhation olthe impact olcontrol The results of the above surveys and the skin disease studies currently undertaken by TDR will provide baseline information to allow the future evaluation of the epidemiological impact of control. However, these detailed surveys will only be undertaken in a limited number of sites and not all endemic countries will be involved. Since it will be necessary to demonstrate in the future for each participating country the health benefit of the interventions, additional baseline surveys are required in those countries not involved in the studies. It is important that such surveys are done in a standardized manner and as soon as possible before the first round of ivermectin treatment is given. t I -30- 3.2. Ivermectintreatmentstrategies The currently recommended ivermectin treatment strategy for the contlol on onchocercal blindness is annual large scale treatment of the total eligible population in high risk communities. Information available to date suggests that this stratery is effective in controlling onchocercal eye disease. However, two issues need still to be resolved before decisions can be made on tieatment strategies for the non-OCP area. These are the effect of ivermectin treatment on onchocercal skin disease, and the development of sustainable methods of ivermectin treatment. i.2.1 Elfect qf ivermectin treatment on skin disease Very little is known of the effect of ivermectin treatment on onchocercal skin disease, including its iffect on itching which is commonly very severe and one of the most serious symptoms for the af[ected population. The limited studies done have not been conclusive and have mainly focused on the- observed but not on the perceived improvement after treatment. The little evidence available to date suggests that ivermectin treatment has a positive effect on onchodermatitis but indicate tharinnual treatment may not be sufficient. It is therefore planned to undertake four studies of the effect of ivermectin treatment at annual versus 6-monthly intervals and by using the new dermatological and psycho-social methodology currently being developed andiestedln the ongoing multi-centre study of onchocercal skin disease. Two study sites will be selected from East Afri"a and two from West Africq again for reasons of differences in disease patterns and parasite strains. 3.2.2 Communi9 seV'treatment strategies One of the main priorities of the Task Force is the development of simple, cost-effective and sustainable meth;ds for repeated treatment of the populations of high risk communities. promising approaches fromihe point of view of sustainability, are delivery methods in which ttre community itself takes the responsibility for the organization and execution of the treatment. During the last two years some preliminary experiments with such approaches have been undertakerU notably in Mali under the auspices of the OCP and Sight Savers' Community self-treatment appears promising, but there remain many questions about its acceptability in different cultures and socio-economic settings and in-counlries which do not have in the background a strong organization such as the OCP. Therefore, the Task Force will soon launch a multi-country rtuay on community self-treatment of onchocerciasis in Africa. Following advertisement i; endemic countries, applications were received from 33 multi- disciplinary teams from l0 countries. Seven teams were selected and invited to a protocol de,,neiopment workshop which was held in June 1994 in Bamako. The field research will start before the end of 1994. 3.2.3 RaPid melhods.for monitoring olcontrol Once onchocerciasis control by large scale ivermectin treatment has been launched, it will be necessary to carefully monitor the control operations, and particularly the treatment coverage of the targ;t population. In anticipation of this need, and recognizing once again the financial and logistiJ consiraints in the endemic countries concerned, the Task Force has launched research .l a I- 3l - on the development of rapid methods for monitoring control. A multi-country study is currently going on in Nigeria where methods are being tested which are independent from the drug delivery system. Two methods based on mailed questionnaires are being tried out, one addressed to school-teachers and the other for use by local enumerators of the Mnistry of Economic Affairs. The results of the pilot study are very promising and the main study is in full swing in 20 Local Cvovernment Areas. The final results will be reported during a meeting in October 1994 in Kaduna, Nigeria. If indeed these methods prove effective, it will be important to further develop them and similar methods for use in other endemic countries ealmarked for ivermectin based control. 3.3. Focal vcctor eradication Focal vector control is not possible in most of West Africa because of active and long distance migration of the vectors of the S. domnosttn complex. However, in six foci in East Afric4 and one in theZure basin, the vector was eradicated following the application of DDT in the 1940s and 1950s. It is believed that there are several other foci in Africa where vector eradication may be achieved by a vector control effort of not more than l-2 years, without the risk of subsequent reinvasion of the focus by vectors from elsewhere. This would then provide a definite solution to the problem of onchocerciasis in such foci, and because of the short period of vector control, probably a very cost-effective solution. Therefore, studies of the feasibility of vector eradication will be undertaken in a number of foci in East and Central Africa in which it is thought that this approach may work. 3.4. Reporting of the results and recommendations A GIS data base ofthe epidemiological mapping data will be set up and used to prepare detailed maps of the distribution of onchocerciasis in the non-OCP countries. Before the end of 1996, the Task Force will submit a final report with details on the distribution and public health importance of onchocerciasis in Afric4 the results of the studies on the effect and delivery of ivermectin, and with recommendations on ivermectin treatment strategies in the non-OCP countries and on the feasibility of localized vector eradication. This report and any relevant additional information will be made available to the new control programme. a I )