Onchocerciasis control in Côte d'Ivoire: achievements and prospects after OCP

ONCHOCERCIASIS CONTROL IN COTE D'IVOIRE Achievements and Prospects after OCP , 2002 1 ,I. INTRODUCTION 1.1. Onchocerciasis in West Africa before OCP ' Onchocerciasis prevails in Africa, America and in the Arabian peninsula. ' It was estimated that in the world: Approximately I22,9 million people are exposed to onchocerciasis. More than L7,7 million people were infected with the disease. More than270 000 people were blind and at least 500,000 had visual impairment cased by onchocerciasis. Africa is the continent most affected, with more than 16.9 million (95%) victims. West Africa was not only particularly affected but most of all it had the most significant foci of the most serious form of the disease. These foci were located particularly in the northern parts of Benin, Togo, C6te d'Ivoire, Ghana, east of Mali, the south of Niger and were disseminated in the whole of Burkina Faso. It is in these areas known as the original area, covering 654,000km2 that the Onchocerciasis Control Programme in West Africa (OCP) was started. The Programme then extended to the foci south of COte d'Ivoire, Benin, Togo and Ghana, then to the west of Mali, Guinea, Guinea-Bissau, Senegal and Sierra Leone. Today, the whole of the Programme area covers | 235 000 km2 with alrnost 40 million people. Before the beginning of the control operations, there existed more than 3 million onchocercal patients out of which approximately 135,000 were blind. Onchocerciasis is a parasitic disease. It is caused by a filarial (a worm) known as Onchocerca volvulus. The adult wonn which develops only in man produces microfilariae which is transmitted to other men by the bite of a tiny fly commonly called "simulie", the vector of the disease. Onchocerciasis prevails only in rural areas, in the settlements located along the rivers with fast flowing current. The simulie reproduces in these rivers, hence the name "river blindness" which is still interchanged with the name onchocerciasis. The most exposed communities are those located approximately ten kilometres on both sides of the rivers. Blindness, the nuissance and other consequences of onchocerciasis are factors for the deterioration of the living conditions of these communities and the cause of the abandonment of the fertile riverain lands by the villagers. An agreement signed in 1973 between the participating govemments and WHO defined the limits, the objectives, the of consultative structures and management of the Programme as well as the modalities for control operations and evaluation procedures. I I I After approval of the mission report of the "Support Programme to Govemments" in January 1974, the budget necessary for the implementation of the onchocerciasis control prograrnme in the Volta basin was voted. WHO was then designated as the Executing Agency. In a fit of intemational solidaity, 22 countries and institutions financed the activities of OCP for nearly three decades. 2 n D I.2. Control Stratesies used The main strategy used is vector control to which ivermectin treatment was added in 1987. In certain areas, vector control was the method used and in others ivermectin treatment only. In some others on the other hand, the two strategies were combined. 1.3. Results obtained in the OCP area Onchocerciasis is now eliminated as a problem of public health in all the OCP area. In some limited foci however, there is the need to improve on the results achieved. Nearly 40 million people are protected today from onchocerciasis and more than 18 million children born since the beginning of the Programme have escaped the risk of onchocercal blindness. 600,000 cases ofblindness have been prevented Presently, more than 25 million hectares of riverain lands have been redeemed and is being re-populated and developed. This will enable about 17 million people to be nourished. It is to be noted however that, at some points, the results need to be improved. These are the tributaries of the Oti in Togo, the Ou6m6 in Benin, the Pru in Ghana" the Mafou and the Tinkisso in Guinea. U ONCHOCERCIASIS IN THE REPUBLIC OF COTE D'IVOIRE BEFORE OCP The initial limits of the Onchocerciasis Control Programme in C0te d'Ivoire, included the most significant foci of savannah Onchocerciasis, as they were known in 1975. These foci included: - The north-eastern part of the country (Bouna- Bondoukou) on the Black Volta - The Upper Comoe, from the border of Burkina Faso to Groumania (Serebou) and the areas of Nassian, Dabakala and Prikro - The Upper Bagoe in the Department of Boundiali - The Upper Baoule in the Department of Odienne. The prevalence rates in these original areas sometimes exceeded 75o/o, the Community Microfilarial Load varied between 15 and 43,per biopsy, whereas the rate of blindness reached t0%. The Annual Transmission Potential (ATP) ranged between 0 and 2 2Il and the Annual Biting Rate (ABR) varied between 0 and 62 596 per man. Following the invasion of the south of the country by infective blackflies, the progralnme area was extended to this part in 1979 (southern extension), especially the hyper-endemic zones in the basins of the Sassandra, the N'Zi-Bandama, Black Volta, Bou-Bandama and the Comoe. a 3 I ,A REMO study carried out in the forest zone in 1998, and which showed an average rate of nodule carriers of about 20o/o, extended the prograrnme to the districts of Alepe, Aboisso, Danane, Soubre, Tabou and Sassandra. III CONTROL STRATEGIES 3.1. Vector control It is based on the insecticide rotational aerial larviciding The operations of aerial larviciding began in February 1975 (Phase I of OCP) in the basins of the N'Zi, the Comoe and the white Bandama. They then extended to the south of the country in 1979, on the basins of the Sassandra, the N'Zi-Bandama, the Black Volta, the Bou- Bandama and the Comoe. 3.2 Ivermectin treatment It is the second control strategy used by the Programme. Ivermectin was introduced in Cote d'Ivoire for mass treatment in 1988. At the beginning, distribution was carried out by mobile teams, made up of health workers of the country and the personnel of OCP. Since 1997 distribution is done in more than 1700 villages, by the communities themselves, through village volunteers. 3.3. Training To ensure the maintenance of control gains by participating countries, OCP undertook the training of nationals, both at the academic level and on the job, especially on control strategies. 3.4. Other strateeies Information, Education and Communication (IEC), epidemiological and entomological monitoring also constitute strategies of control of the disease. 4 \OBJECTIVE OF THE PROCRAMME RESULTS OBTAINED REMARKS reduce the prevalence to less than 5oZ. AREA BEFORECONTROL CURRENT RESULTS Area where no control activity is undertakenORIGINAL AREA Rate of prevalence higher than 60% Average blindness rate 4,8%o The overall prevalence rate lies between 0 and 5% although the evaluations carried out in 2000 and 2001 showed a suspicions trend on the Upper N'Zi in the villages of NAMAYEREDOUGOU (6,7%)and KOBADARA (9,2%) and on white Bandama in2002 at NAGOTINGOKAHA (8,88%). SOUTHERN EXTENSION AREA Prevalence rate ranging between 20 and30Yo The prevalence rate is between 5Yoandl5%o Area under CDTI since 1994 FOREST ZONE Prevalence ranging between 30 and 65% (REMO r998) Area under CDTI since 2002 Iv. RESULTS tN COTE D'IVOIRE IN 2OO2 On the epidemiological level On the entomological level N.B : ATP : Annual Transmission Potential Rate of infectivity: percentage of infective blackflies for 1000 captured females. 5 OBJECTIVE OF THE PROGRAMME AREA RESULTS OBTAINED REMARKS Reduce the incidence to 0%. BEFORE CONTROL CURRENT RESULTS Area where no control activity is undertakenORIGINAL AREA Reduction of99%o SOUTH EXTENSION AREA Reduction of more than 90% Area under CDTI since1994 FOREST ZONE Prevalence ranging between 30 and 65% (REMO l9e8) Area under CDTI since 2002 INDICATOR RESULTS REMARKS ATP BEFORE CONTROL CURRENT RESULTS Between 1000 and 2500 in the original area Lower than 100 On all the points RATE OF INFECTIVITY Original area: 0 at BADIKAHA on the White Bandama South Extension area :Between 0,0623 at AMOUAKOUKRO on the Comoe and 0,1575 at ASSEREKRO on the Kan/N' Zi 2000 data aOn treatment with ivermectin Due to the late delivery of Ivermectin by MDP (September 2001), treatment could not take place in 2001 . For2OO2, all the Districts in the extension area, as well as those of the forest zone were provided with Ivermectin and the treatment is ongoing. The partial results that the Management of the Programme received are encouraging in the Southem extension: * tlre therapeutic coverage rates vary from 60 to 72oh * the geographical coverage rates vary from 60 to 100%' - On training On the whole, 34 Ivorian nationals benefited from a training scholarship, particularly in entomology (24), hydrobiology (4), epidemiology (3), ophthalmology (2), management of health services (1). The doctors and nurses were trained on control strategies, and the village volunteers on CDTI. V OBSERVATIONS Streneths Existence of a constituted multidisciplinary team of entomologists, epidemiologists and technician specialists. 100% of the endemic medical districts are covered by CDTI The doctors of the endemic districts, the nurses and the Community Health Workers (CHWs) were trained on onchocerciasis control strategies. The development and the provision of sensitization material for Doctors, nurses, CHWs and the Communities are effective in the forest zone. Existence at the headquarters of the Programme of a team for evaluation and data management of epidemiological surveillance. Existence of an inspection channel on each basin. Existence in the villages of entomological follow-up of trained village catchers. Weaknesses Irregular official budgetary executions. Insufficiency of logistics (vehicles, fuel and lubricants) or Irregular supervision and follow-up for lack of financial means and logistics. Integration of the former Ivorian technician entomologists of OCP in the national team not yet effective. Low level of involvement of the Districts and health centres in the process of entomological surveillance. The despatching of catching equipment to the DNA laboratory in Ouagadougou is not yet autonomous. Detay in the collection, the compilation and the transmission of data. Absence of incentives for the CHWs 6 , \VI Staff training not completed in the 12 Districts of the forest zone. The decentralization of epidemiological surveillance not yet effective in the districts. Frequent transfers of the already trained health workers. Data on onchocerciasis epidemiological surveillance not integrated in the national health information system. Cu.ry out an annual treatment of all the eligible villages in all the basins, except those of the Comoe and the N'Zi-Bandama, where treatment is biannual Cover 100% of the eligible villages and hamlets with CDTI. Obtain at least 65Yo of therapeutic coverage per village, district and basin Recycle nurses every 2 years and CHWs at least every other year. Carry out regular activities of follow-up and supervision in the Districts (by the central level), health centres (by the district level) and Community (by the health centres). Seek ways and means of motivating health workers and the Community distributors to ensure the sustainability of the system. Make ivermectin available in all the villages * Epidemiological surveillance Gradually decentralize epidemiological surveillance in the districts. Equip the districts in epidemiological surveillance equipment (Holtz grips, magnifying glasses, ringed blades, DEC patch test, etc...) and in fuel needed for the follow-up and the supervision of activities. * Entomological surveillance Identify a reliable channel for sending samples from the Community level to the DNA laboratory, through the health centre, the District and the Headquarters of the Programme. * Data Management Carry out the district staff training on the cross analysis of epidemiological surveillance data.. Set up a continuous feedback system for the benefit of the main actors involved in control activities. * Mobilization of financial resources Maintain and widen the financing of activities by the Ministry of Public health. Carry out advocacy with NGOs so that they may support the activities of control of Onchocerciasis, in particular CDTI in the long-term. CONDITIONS TO SUSTAIN AND IMPROVE CDTI GAINS 7 tI * Availability of human and material resources Reinforce the staff of the programme management by recruiting on its budget, a mechanic, 3 drivers, 1 technician/entomologist. Ensure the maintenance of computer hardware and acquire new materials. 8