Epidemiological activities and ivermectin distribution in the Kulpawn, Mole, Black Volta (Bui) basins and south west of Ghana

/J EPIDEMIOLOGICAL ACTTVITIES AND IYERMECTIN DISTRIBUTION IN THE KULPAWN, MOLE, BI.ACK VOLTA (BUI) BASINS AND SOUTH WEST OF GHANA EPrlJr.rNE 199s IVERMECTIN TREATMENT IN THE KULPAWN AND MOLE BASINS Introduction Vitlages in the Kulpawn and Mole basins (White Volta) in Ghana (see map) have been placed on ivermectin distribution since 1990 and 1993 respectively due to the relatively less satisfactory epidemiological results from the two basins. The ivermectin distributionwas restricted to only 5 villages in the Kulpawn basin in the initial stages L990-1992. In 1993 treatment was extended to other villages in the basin. Ivermectin treatment in the Mole started in 1993 when it was discovered that two of the villages in the basin had relatively high prevalence rates of infection of 25.8Vo and.39.9Vo In addition, there were several children who were found to be infected. Both basins have been on larviciding to date, a period of at least 18 years. The estimated population for the nvo basins is about 19000. Present epidemiological situation The latest epidemiological results are available from an evaluation carried out in January 1994 in 10 villages in the Kulpawn basin. The prevalence of infection ranged from l0Vo-20Vo. New infections were detected in adults as well as in children. These results were not in conformity with what would have been expected -zeto or near zero prevalence- after the 18 years of vector control as well as ivermectin treatment for the past 5 years. Despite the less than satisfactory results the general tendenry is a decline in the prevalence. No evaluations have been carried out in the Mole basin recently but the results from the previous evaluation carried out three years ago were satisfactory, except in two villages where the prevalence was relatively high. These results suggest that transmission might still be going on in the basins. Entomological data from the Kulpawn area is inadequate due to difficulty in reaching prospective breeding sites for fly catches. In spite of these results a decision has been taken to curtail larviciding, but to intensify ivermectin treatment in the two basins. Plan of action Ivermectin distribution has been increased from once a year, to twice a year treatment with effect from January 1995 in the Kulpawn basin. Treatment has been extended to include all the 23 villages in the basin. AII effort is now made to achieve an optimum coverage. The coverage for the last two treatment cycles wereTl.SVo and80.6Vo The Mole basin has also been placed on twice a year ivermectin treatment as from June 1995. In both basins the epidemiological situation will be reviewed after two years together with that in the Bui area. Increase in community participation will be aimed at to further improve the coverage of treatment, both of persons treated and the number of villages covered, in the two basins. The eventual objective will be to place the two areas on an effective community self- treatment with strong supervision from the national team/coordinator. 2Further action to be taken OCP area Ivermectin treatment distribution will be extended as from June 1995 to include all the villages south of the Black Volta to the level of Ayerade village (see Map). At the initial diitribution to the extended area, opportunity will be taken to update the map and to have a complete census of the number of villages to be involved. Ayerade village sits at the most southern limit of the OCP operational area. Ivermectin treatment will be given at least 3 times a year in the villages. A fourth treatment in a year is planned should the area be accessible during the rains. To this end, increase in community participation will be aimed at. More individuals("agents") in the communities under question will be requested to take part in the large-scale distribution. The practice of leaving adequate ivermectin tablets with such "agents" after each last-scale treatment to be given to those who would have missed treatment during the rounds, will be intensified. It is envisaged that eventually the entire treatment in the various villages or groups in the area will be undertaken solely by such "agents". They will be supervised by the Bui health centre staff who themselves would have taken part in the treatment. The national coordinator will assume overall supervision of this form of treatment as in other places in the country. Area to the south of the OCP zone In order to reduce the "contamination" from the south of Ghana into the Bui area, a proposal to the Ghana Government to institute ivermectin distribution in the Bia, Tano, Ofin and Pru basins in South-west of Ghana is suggested. In preparation for this, an epidemiological evaluation is planned for September 1995. Twenty first line villages situated in these basins will be selected for evaluation, to assess the prevalence and intensity of infection prior to ivermectin distribution. Microfilaria collected from the infected individuals will be sent to the Bouak6 laboratories for DNA identification. Future plans. Prior to instituting the four times a year ivermectin distribution in the Bui area in early 199{ nodules were removed from a number of individuals to assess the viability of the adult worms. The examinations for adult worm viability are being carried out at the Onchocerciasis Chemotherapy Research Center (OCRC) in Hohoe, Ghana. Two years after the four times a yeat treatment in the Bui area,i.e after 8 treatments within a period of 2 years, more nodules will be removed for examination. 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