NATIONAL ENTOMOLOGICAL TEAMS OF THE WESTE RN EXTENSION AREA OF THE ONCHOCERCIASIS CONTROL PROGRAM (OCP) FROM 1986 TO 1990 .1. OPERATIONAL STRUCTURES, FUNCTIONING AND FUTURE

The western extension area of the Onchocerciasis Control Programme in West Africa (OCP) covers five countries: Guinea, Guinea-Bissau, Mali ( western part), Senegal and Sierra Leone. From 1986 to 1990, national t eams employed by the respective governments have been regularly collec ting entomological data on the vectors of onchocerciasis in these coun tries. As in the initial programme area of the OCP, the entomological surveillance network was composed of entomological sectors and subsect ors (the latter are called ''operational bases'' in the western extens ion). In 1990, 308 staff in 47 capture teams were employed for the ent omological surveillance activities in seven sectors and twenty-five op erational bases. They included a national coordinator in the overall m anagement of available resources. The national teams worked under the technical responsibility and supervision of WHO/OCP but with no employ ee/employer relationship between them and WHO, since they were employe d and their salaries were paid by the governments. The OCP, however, p aid additional lump sum allowances to each worker, as well as daily su bsistence allowances when away from their duty station. vehicles, ento mological equipment, office supplies and furniture, fuel and lubricant s were provided by WHO/OCP. Despite the difficulties encountered in th e field, which when often great, and their lower salaries (compared wi th colleagues paid by WHO/OCP), the technical workers in the national teams performed well by OCP standards, with results as satisfactory as those obtained by the WHO/OCP teams in the rest of the programme area s. The main reasons for the efficiency and dynamism of the national en tomological teams are described. The future of these teams after OCP h as ceased its activities is also discussed. From 1986 to 1990, the col lection of entomological data was carried out by national teams in the five countries of the western extension area of the Onchocerciasis Co ntrol Programme in west Africa (Guinea, Guinea Bissau, Mali, Senegal a nd Sierra Leone). As in the initial programme area, the entomological surveillance network of the western extension area was responsible for , among other things, the provision of pre-larviciding data on the den sities and transmission potential of the vectors of onchocerciasis. Th is article gives an overview of the entomological activities of these national teams, underlining their blackfly-catching and dissection eff orts and presenting data on the main entomological indices with a view to subsequent entomological indices with a view to subsequent entomol ogical indices with a view to subsequent comparisons during or after t he control campaigns. Thus, 1 152 539 S. damnosum females were collect ed by the national entomological teams from May 1986 to December 1990 in 21 695 days of catching and 695 800 flies were dissected. This effo rt has allowed the selection of 186 catching points for the calculatio n of an annual biting rates (ABRs) and the annual transmission potenti als (ATPs) which are used as baseline data for the western extension z one. The results show that, in the absence of any continued and succes sful vector control operation, less than 5% of the points present ABRs below 1000, while for more than 69% of them the ABRs exceed 8000. As far as the transmission is concerned, only 13% of the points have reve aled ATPs below the epidemiological threshold of 100. For more than 44 % of the sites, ATPs exceeding 800 have been recorded.