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Onchocerciasis Control Programme in West Africa I Programme de Lutte contre I'Onchocercose en Afrique de I'Ouest JOINT PROGRAMME COMMITTEE JPC . CCP COMITE CONJOINT DU PROGRAMME Office of the Chairman Bureau du Pr6sident JOINT PROGRAMME COMMITTEE JPC15.2 Fifteenth session ORIGINAL: FRENCH Yamoussoukro. 29 November - I December 1994 September 1994 Provisional aeenda item 5 PROGRESS REPORT OF THE WORLD HEALTH ORGANIZATION FOR 1994 (1 September 1993 - 3l August 1994) Table of contents Page SUMMARY 4 VECTOR CONTROL 6 Climatic conditions 6 Aircraft fleet and aerial operations 7 Treated areas 9 Insecticides and control strategy 9 Hydrology and teletransmission 10 Surveillance and entomological evaluation network 11 Entomological activities of national teams in the south-western extension area 1l Results obtained L2 Transmission t2 Post-control entomological studies t2 Monitoring of the aquatic environment . 13 MRMECTIN (MECTIZANR) DISTRIBUTION AND EPIDEMIOLOGICAL ACTTVITIES l3 lvermectin treatment 13 Epidemiological evaluation . 15 Evaluation in areas where only larviciding is undertaken 15 Evaluation in the areas of both laniciding and ivermectin distribution 16 Migration studies t7 Ophthalmological evaluations 17 BIOSTATISTTCS AND TNFORMATION SYSTEMS . t7 INTERDISCPLTNARY RESEARCH 18 lnsecticides 18 Vector and parasite identification 20 ldentification of vectors 20 Identification of parasites by the DNA-probe technique . 20 Epidemiological modelling 2l Immunodiagnosis 22 JPC15.2 Page 2 Macrofil Chemotherapy Project 23 Potential macrofi laricidal compounds 23 Potential resistance to ivermectin . 23 DEVOLUTION 23 Institutional framework for devolution and the roles of the main actors 24 Training . 24 Public awareness and population mobilization effort by OCP 27 Meeting on evaluation and programming of devolution activities in the countries 27 Meeting on the strengthening of epidemiological surveillance for integrated endemic disease control in West Africa building on the OCP experience . 28 Criteria for the assessment of the capability of the Participating Countries to carry out the detection and control of recrudescence effectively . 29 ADMINISTRATION AND SUPPORT SERVICES 3l Objectives, organization and functioning of services 31 Administrative costs 32 Budget and Finance . 32 Personnel 32 Supply and services 33 Transport and communications 34 PUBLIC RELATIONS, INFORMATION AND DOCUMENTATION ACTTVITIES 34 With the World Health Organization 34 With the Participating Countries 35 With the statutory bodies 35 With the Donors 36 With the aerial spraying contractor 36 With the scientific community 36 With the general public 37 Public relations and documentation 38 lnternal meetings 39 Collaboration with non-goverrlmental organizations (NGOs) 39 Jrc15.2 Page 3 FIGI.JRES IN ANNEX Page Fig.l VCU plan of operations for 1994 N Fig.Z Annual transmission potentials (June 1993-May 1994) - all species infected by Onchocerca s.p. 4t Fig.3 Annual transmission potentials (June 1993 - May 1994) - all species infected by Onchocerca volvulus 42 Fig.4 Annual transmission potentials (June 1993 - May 1994) - savanna species infected by Onchocerca volvulus 43 Fig.5 Location of post-control entomological study catching points - 1990-1994 4 Fig.6 Zones of large-scale ivermectin treatment in 1993-1994 . 45 Fig.7 Ivermectin treatment coverage based on the OCP mode of distribution 6 Fig.8 Pre-control prevalence of skin microfilariae in villages from the original OCP area 47 Fig.9 Prevalence of skin microfilariae in villages from the original OCP area - 1993-1994 48 Fig.10a, Fig. tOb and Fig.10c Changes in the prevalence of mf and CMFL at Galamankourou (Mali), Gbeniki and Lougou (Benin) 49 Fig.11 Computerized mapping - projection of catching points in the OCP area 50 Fig.L2 Results of simulations of combined larviciding and ivermectin 51 Fig.13 Total OCP staff 52 JPC15.2 Page 4 SI.]MMARY (a) In the eastern Programme area, the 1993 rainy season started quite late. However, the situation returned to normal after the heavy rains in July and August. In the western atea, the hydrological regime of the 1993 rainy season was more or less the same as in 1992. [n the two arqu, the 1994 dry season was severe. The rains started in May in the southern areas and in June in the northern part of the Programme area. (b) The number of larviciding helicopters ranged between eleven in the 1993 rainy season and five in the 1994 dry season. During the 1994 rainy season, nine helicopters were expected to be used because of a better distribution of the guaranteed flight hours and supplementary flight hours. (c) The more and more precise nranagement of aerial operations, the cessation of the sprayings in some areas and the decrease in the larvicide coverage in the areas under ivermectin treatment made it possible to save 1244 flight hours, i.e., about US$ 886,000 and 1 17 ,825 litres of insecticides, i.e. some US$ 1,100,000, during the period of May 1993 to April 1994, compared to the Period of May 1992 to April 1993. (d) The insecticide rotation system has functioned perfectly. The acceptance by the Ecological Group at the beginning of 1994 of a seventh operational insecticide, etofenprox or Vectron, will make possi|le much more flexibility and efficiency in the larvicide spraying while controlling the appearance of a possible resistance. (e) The entomological evaluation network has continued to be reduced in the original area as and *hen larviciding ceases. After the closure of three subsectors at the end of 1993, two new subsectors will be closed down at the end of 1994. (0 The entomological results on the transmissionare quite satisfactory in the whole Programme area. Out of the 212 catching points monitored regularly, 92% have an Annual Transmission Potential (ATP) below 100. Only one point has an ATP of 119 if only the transmission due to the savanna species is considered. (g) The post-control entomological studies conducted in 1993-1994 show that out of the eight poin6 srudied,lhe rate of infectivity of the parous females is between 0 and 0.57 infective female per 1000 parous, which makes any resumption of transmission unlikely. (h) The aquatic monitoring activities covered mainly the short-term evaluation of etofenprox or Vectron and that of the long+erm impact of pyraclofos, permethrin and carbosulfan on fishes and the non-target invertebrates. Vectron has proved to be 70 to 200 times less toxic than pennethrin on fishes, six io ten times less toxic on shrimps and 10 to 20 times less toxic on the non-target aqutic insects, still compared to permethrin. For the long-term monitoring, the Ecological Group_ has observed that the increasing impacts of the socioeconomic development of the onchocerciasis-freed valleys on the aquatic environment no longer made it possible to study the possible impact of the larviiiOes used by OCP. It has therefore requested the extension of its terms of reference to the study of the environment of the valleYs. (i) There has been a progressive increase in the distribution of ivermectin. Close to two tnittion persons living in 700b uill"ges received treatment. The coverage in terms of percentage of treated ieople p"r c"*us population was of the average of 7O%. Delivery of ivermectin through community-self-treatment has been encouraging and is now carried out in five countries in fifteen river basins. The coverage through this delivery is around 75%. APart from three reported cases of hypotension, no further serious adverse reactions were noted during the treatment period' JPC1s.2 Page 5 0) Several non-governmental organizations (NGOs) are now involved in the ivermectin distribution in most of the Participating Countries through large-scale, passive and mobile service distribution, in addition to the community self-treatrnent. (k) Epidemiological evaluations were carried out in the zones of the original Programme area, where larviciding is the only control measure with a view to evaluating the impact as well as helping in decision-making on the cessation of larviciding in certain river basins. The results, on the whole, were very good in most of the areas evaluated. (l) In the areas of both larviciding and ivermectin treatment, several villages were evaluated with the view of selecting parasitologically negative individuals who do not receive ivermectin to form a cohort to be followed up to determine the incidence of infection in such areas. (m) In certain river basins in the original area where larviciding has stopped, epidemiological evaluations were carried out by the national teams in the context of devolution with a view to detecting any possible recrudescence of infection. The results were very good in most situations. (n) The ophthalmological and parasitological assessment of the medium- and long-term effects of large-scale ivermectin treatment after five years of annual treatment showed satisfactory results. The skin microfilarial load has decreased markedly and there have been appreciable improvements in lesions of the anterior segment of the eye. The overall results show a beneficial effect of ivermectin treatment on the ocular disease in the population. (o) Migration studies carried out on the Black Volta basin (Bui area) in Ghana showed a higher proportion of the infection in migrants. (p) As part of the activities of the Biostatistics and Information Systems Unit (BIS), the integrated analysis of the results of the entomological and epidemiological evaluation has been continued, using epidemiological modelling as much as possible. One of the most important results is the analysis of simulations of the combination of vector control and ivermectin distribution which has shown that a period of 12 years is sufficient to reduce the risk of recrudescence to less than 1 %. In order to better prepare the nationals for epidemiologicd analysis, emphasis has been laid on training. During this training, longirudinal data collected during epidemiological surveillance were analysed with them in order to verify any possible recrudescence of infection. BIS has also continued to help the other OCP units in the use of computer science.