Onchocerciasis control in Mali: achievements and prospects after OCP

ONCHOCERCIASIS CONTROL IN MALI Achievements and Prospects after OCP 2002 1 I. 1.1 INTRODUCTION Onchocerciasis in West Africa before OCP Onchocerciasis prevails in Africa, America and in the Arabian peninsula. It was estimated that in the world: Approximately 122,9 million people are exposed to onchocerciasis. More than 17,7 million people were infected with the disease. More than 270 000 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 northem parts of Benin, Togo, Cdte 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 C6te 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 1 235 000 km2 with almost 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 worrn 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 governments 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. After approval of the mission report of the "Support Programme to Governments" 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. 1.2. Control Strateqies 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 fwo strategies were combined. I I 2 o I \1.3. Results obtained in the OCP area Onchocerciasis is now eliminated as a problem of public health in all the OCP area. In sorne limited foci however, there is the need to improve on the results achieved. I Nearly 40 million people are protected today from onchocerciasis and more than 18 n'rillion 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 Oueme in Benin, the Pru in Ghana, the Mafou and the Tinkisso in Guinea. II. ONCHOCERCIASIS IN MALI BEFORE OCP Onchocercal endemicity prevails in Mali in 5 areas, spanning the original area (Sikasso, Segou, Mopti, Koulikoro on the right bank) and the surface of western extension (left Koulikoro left bank and Kayes) of the OCP Programme. Twenty-five circles are concerned and cover an area of approximately 350,472 km2, where more than 5,000,000 people live. At the beginning of control operations in 1977, the preliminary epidemiological data indicated hyper-endemic foci: prevalence 80% (89,6% at Niako on the Baoule in 1977), Community Microfilarial Load (CMFL) > 10 by skin snip test, Annual Transmission Potential (ATP) > 100, with rates of blindness of l2o/o in the original area, and variable from 3 to 10% in the Western extension. The Annual Transmission Potential (ATP reached 998, whereas the Annual Biting Rate was 29.000 bites per man. III. CONTROL STRATEGIES 3.1. Vector control It is based on the aerial larviciding, used in rotation. The larviciding operations began in March 1977 (Phase III of OCP) on the basins of the Baoule, Kankelaba, Bagoe and the Bani before addressing the Niger in 1989. 3.2. Treatment with ivermectin It is the second control strategy used by the Programme. Ivermectin was introduced in Mali for mass treatment in 1988. On the outset, distribution was carried out by mobile teams made up of health workers. ! 3 I t3.3. Trainine To ensure the maintenance of Oncho control gains, by the Participating Countries, the OCP undertook the training of nationals academically, as well as in-service training particularly on control strategies. 3.4. Other strateeies Information, Education and Communication (IEC), epidemiological and entomological surveillance also constitute strategies for the control of the disease. IV. RESULTS OBTAINED IN MALI On the entomological level Today, the transmission of the disease is almost nil on the entire river basins, which are under control (the Niger and tributaries, Farako, Lotio, Banifing IV, Kankelaba, Baoule, Bafing, Bakoye, Faleme, the Senegal and its tributaries). The risk of reappearance of infection of onchocerciasis has been reduced to the minimum. The Annual Transmission Potential (ATP) is lower than 100 (standard < 100) out of the 5 catching points, regularly monitored on the basin of the Niger and its tributaries. The rate of infectivity is lower than I infectious female for 1000 caught females (standard < 1 per 1000 flies). On the epidemiological level Prevalence rates and the Community Microfilarial Loads (CMFL) are very low - zero in the majority of the evaluated villages. In 2001, out of 88 evaluated villages, 66% had aprevalence of |Yo. Only 8 o/ohad a prevalence higher than 5 Yo. Treatment with Ivermectin In 2001 the geographical and therapeutic coverage rates of the villages under ivermectin were 98,7Yo and 78,6oh respectively. In 2002, out of I 562 144 listed persons, I 246 167 (80%) were treated in? 892 villages, out of the planned 3 508 (82%). Training More than 78 Malians benefited from an OCP scholarship, including 38 in entomology, 12 in epiderniology, 6 in parasitology, 7 in public health, 5 in ophthalmology, 5 in hydrobiology, 3 in administration and2 in management of health services. V. OBSERVATION 5.1. Streneths Very satisfactory epidemiological and entomological results in the entire basins under surveillance. 4 Existence of the national teams trained, and able to carry out the epidemiological and entomolo gical evaluations. Ordering of ivennectin, as an essential drug, by the Ministry of health. The eligible endemic zones are under TIDC. Training and involvement of the socio-medical personnel and communities in the activities of onchocerciasis control. Existence of educational material for the communities. Follow-up of activities through the periodic district quarterly meetings, semi-annual meetings of the regions, and the annual review at the central level. Financing of onchocerciasis control activities, through the plans of operation, which benefrt from substantial support from NGOs (SSI, OPC and HKI) and WHO/AFROPOC. 5.2. Weaknesses Instability of some distributors. Illiteracy of some distributors (support available now for their work). Delay in the routing of results of treatment with ivermectin from the village to the health centres, and from the latter to the regional and central level. Dearth of supervisions from the regions towards the circles, from the latter towards the health centres, and from the latter towards the villages. Refusal of certain communities to undergo skin snip tests (the DEC patch will be practised in future, in lieu and place of the skin snip test). Insufficiency of epidemiological surveillance equipment at the regional level. Decrepitude of logistics at the central level. Insufficiency of national financial resources allocated to the maintenance of gains. vI. CONDITIONS TO SUSTAIN AND IMPROVE OCP ACHIEVEMENTS - Reinforcement of the capacities of the decentralized structures to undertake the evaluation and monitoring for the early detection of any recrudescence through: . equipping (with sufficient material and logistics). . Staff training of health personnel of the various levels concerned . The continuous follow-up/supervision of health personnel and distributors. - Effective integration of ivermectin into the essential drug management structures, particularly at the level of regional depots and the health areas, which are yet to do so. - Reinforcement of the system of collection and analysis of data at the various levels - Development of partnership with organizations and development stakeholders interested in the nuisance control. - Support to the NOCP through the supply of equipment and logistics, to enable it to assist the regions and the circles as part of efforts to maintain and build up the gains of onchocerciasis control in Mali. 5