Expert Advisory Committee: thirteenth session: Ouagadougou, 8-12 June 1992: briefing session, 6 June 1992: notes on EG12 and EAC12 recommandations (follow-up)

ONCHOCERCIASTS CONTROL PROGRAMME IN WEST AFRTCA Expert Advisory Committee Thirteenth session Ouaeadoueou. 8-12 June 1992 Briefing session, 6 June 1992 OCP/EACI3/Briefing paper no. 8 Rev.l NOTES ON EGI2 AND EACI2 RECOMMENDATIONS (follow-up) EG 12 (ECOLOGTCAL GROUP) l. By VCU EGl2. oaracraoh 49: The impact of human activities on the terrestrial and aquatic ecosystems walr discussed by the Ecological Group during its l3th session and a proposal addressed to the CSA for consideration. EGl2. oaraeraoh 50: The workload of the OCP hydrobiology unit led is hydrobiologist to discuss the question of the susceptibility/resistance in aquatic non-target organisms with the national teams in Ghana and Guinea as recommended by the Ecological Group. It emerged from it that there was the need for knoweldge of the species and larval stages of the organisms. While some species are known and could be used for susceptibility tests, a lot remains to be done as regards the larval stages for which studies are currently being carried out by the above-mentioned national teams. As soon as this obstacle is removed, tests will be conducted by these teams in collaboration with the Insecticide Research Unit. EACI2 (EXPERT ADVTSORY COMMTTTEE) 2. By EPI Relating to Epidemiology EACl2. oaraeraoh 76: Further studies to clarify the possible epidemiological effect of migration: A consultant sociologist was engaged to look into the role of migration in the Banifing IV basin where, apart from the fact that entomological and epidemiological results were at variance with each other, there was also a prevalence of infection of 8.3% in one village, Mpetyela which was out of phase with the general trend of less than 3% in all the other villages in the basin. The detailed study revealed the existence of all forms of migrans, viz. immig,rantsr returnees, seasonal workers etC. making up more than 43% of the total population of the study area. These migrants were invariably the infected people in the communities and often the level of their infection was quite appreciable. ln Mpetyela in particular, over 42% of the population were migrants. A study was also carried out this time by an Epi team in collaboration with the VCU in the Zongoiri rapids in the Red Volta river basin in northern Ghana. There also infection was recorded among migrants who had settled in small communities but not among the permanent inhabitants. One set of the immigrants were fishermen originating from the Volta Refion in southern Ghana who were considerably infected and who in fact settle in the area periodically during the dry season ro carry out their fishing activity. Another set of immigrants were Fulani herdsmen from Burkina who had also settled in the area with their cattle. They were however not infected. 08 .05 .92 ! a2 In Kuono on the Sissili however, migration does not appear to play any important role despite considerable movement of the population across the border with Ghana. The reason for the delayed trend in the reduction of the prevalence is therefore the result of a local transmission associated with a new breeding site created by the construction of a dam. EACl2. oaraeraoh 79: Continuation of ophthalmological follow-up studies including assessing the impact of both regular and irregular mectizan treatment: Follow-up studies on the impact of mectizan treatment on ocular onchocerciasis after four rounds of treatment at yearly interval in the Asubende focus confirms the findings that have been reported previously. A significant regression of eye lesions of the anterior segment has occurred and eye lesions of the posterior seg,ment continue to remain stable in their development. Analysis to determine the outcome of the eye lesions of those individuals who take mectizan irregularly appears difficult. This is because, scanty data are available on most of such individuals who as well as not taking the drug do not also attend ophthalmological examination. A study of the forms of a few who attended molx ophthalmological examination show rhat deterioration of eye lesions, mainly of the posterior segment occur in some of the patients. However in view of the lack of data on most of the patients, no statistical analysis can be conducted to allow a proper comparison with that part of the population that takes treatment regularly. It is however worthy of note that the vast majority of the patients are not heavily infected in the eye. Relating to Mectizan EACl2. oaraeraoh 97: Research into drug delivery systems, acceptability and compliance: Other methods of drug delivery have been tried out in the last year. These include drug distribution by the staff of VCU during their activities in the field. VCU staff in Guinea-Conakry, Mali and Sierra Leone have been particularly implicated. Treatment by community participation has been carried out successfully in 25 villages in Mali and in l5 in Senegal. This mode of treatment has proven to be very effective and is intended to be extended to all programme areas. A review of the fixed centres identified for distributing mectizan was carried out with regard to their suitability for accomplishing the relevant task. This was necessary to ensure that mectizan tablets deposited in a fixed centre got used and was not stocked ro g,et expired. Health posts which were not functioning or are located in areas where mectizan distribution is not justified were eliminated. Population awareness campaign and information dissemination have been a very important activity which has been initiated and directed by the Devolution unit and implemented through the VCU staff in the course of their field activities. All these have led to an increase in the efficiency and level of drug distribution in the last year. It is believed that the awareness campaign in particular has enhanced drug acceptability and will encouraS,e that compliance will continue into the future. These additional activities will naturally be evaluated in due course to assess their impact on the existing methods of delivery. Relating to Research Priorities EACl2. oaraeraoh l4l: Development of an immunodiagnostic test: The last March Subcommittee meeting on Immunodiagnostics in Geneva reported on the proSress on the activities of the immunodiagnostic initiative. Though the immunodiagnostic test with a-3- antigen cocktail gives an improved sensitivity over single antigens, the specificity of the test remains poor mainly due to the problem of the definition of a threshold level for a positive test. For the moment immunodiagnosis may be useful in community diagnosis in the sense of demonstrating a change in pattern after an interval. Preliminary results of the evaluation of two different antigen cocktail tests with sera from the Cameroon appear encouraging. The subcommittee recommended the collection of sera in OCP in areas where there will be a risk of recrudescence as well as areas where animal parasite is being transmitted after stopping larviciding. Further it urged OCP to consider getting ready to set up an immunodiagnotic laboratory. Requests for documents EACl2. oaraeraoh I l7: Organization and implementation of passive epidemiological surveillance: Passive surveillance may be seen essentially as a complement to the active surveillance instituted to detect recrudescence of onchocerciasis infection after effective vector control of l4 years duration which has resulted in zero or near zero prevalence of infection in the communities in the area. It will be carried out essentially in the health institutions situated in the area where active surveillance is instituted. Personnel of the health institutions will be trained to carry out the task. The strength of passive surveillance will be the detection of cases of onchocerciasis which the active surveillance survey might have missed because the individuals concerned were absent during the active surveillance survey or the individual turned positive during the interval between two surveys. As part of the organisation of passive surveillance public awareness campaign will be carried out to educate people to report to the nearest health institution in case of symptoms related to onchocerciasis and the communities will be instructed to send all new arrivals to the health institutions for check-up to exclude onchocerciasis which may be introduced into the area. The surveillance of migrants into the community is however an action to prevent the occurrence of recrudescence and not to detect it. The health institutions will be given clear instructions as to which central body diagnosed cases will be communicated to. (See document OCP/EAC.l3.2). EACl2. oaraeraoh I l7: Modes of mectizan distribution in areas not under larviciding: In areas which are not under larviciding in the northern part of the Western extension in Mali and Senegal, distribution of mectizan is being carried out essentially by mobile reams made up of nationals with minimum or no supervision from OCP personnel. The areas being covered have been extended to include communities with very low CMFL (even lower than 4 mf/s). Further, community participation is being encouraged more and more. Drugs are left with the community with specific instructions for the treatment of absentees and those who are temporarily disqualified from treatment such as lactating mothers with babies in the first week or pregnant mothers expected to deliver soon. Health institutions are being encouraged to treat patients who present in the clinic and who are suspected to have onchocerciasis. The activities of the institutions are followed up closely. Public awareness campaigns are conducted vigorously to raise the public perception for the need of pursuing treatment and seeing to it that also the neighbour ges treated. These activities are standard OCP activities with some modification to improve efficiency and coverage. With regards to other modes of mectizan distribution the plan of OCP has been to encourage and stimulate the countries to develop their own alternative mode of mectizan distribution which is suitable and applicable to their countries. In this regard other modes of mectizan distribution that have been developed are either in their early stage or are about to take off. R system of training the communities to undertake their own treatment with mectizan under minimum supervision by health personnel is under way in the Bougouni area in Mali. This approach which has just started and a4 is being run by the nationals, is clearly cheaper to run and appears to be efficient as well. It should be extended to all over Mali eventually. A plan has also been submitted by the national co-ordinators of Senegal designed to integrate mectizan distribution in the onchocerciasis areas in their country into the national plan for priilary health care. This plan which is yet to take off will have similar distribution srrategy as the Expanded Programme on Immunization viz: l) passive distribution from fixed centres2) active distribution through the outreach network using mobylette and3) distribution by mobile teams of the'Grandes End6miis,. The oncho activity will also be combined with schistosomiasis and Guinea worm control activities which are already on-going in the oncho region of Senegal. The supervision of the activities will occur at different levets. The nurse in charge at the health poit ,"itt supervise the rural level. The "M6decin Chel'will supervise the departmental or the regiona[level as applicable whilst the national oncho co-ordinator will supervise at the national level. The proposal contains also provision fortraining of personnel in connection with onchocerciasis, schistosomiasis and Guinea worm control.Information dissemination and public education campaign will also be carried out. 3. By BIS FAel2-parasraoh 86: Testing of model-predictions for recrudescence in the event of recrudescencein the Original Programme area: The model has shown that the best strategy for the detection of recrudescence of infection andits control with mectizan would be to minimize ttre number of epidemiological surveys and the number of treatment failures in case of eventual recrudescence. Pripararions-are in projress in theinitial Programme area to put in place, under devolution, the application of this strategy which is mainly based initially on epidemiological surveillance. Results observed at present in this part of the Programme show that the risk of recrudescence is less than l% and no case of recrudescence has appearedit a monitoring sire. It is therefore too earlyto test the model predictions but a detailea report (OCP/BIS/MOD/l/{4 rhat will take into account the present situation and all the main assumptions, in order to better understand the recrudescencephenomenon, will be presented to EACI3. 4. By OCT EACI2- oaraeraoh 125: Approach to Ciba Geigy regarding difficulties experienced in obtaining data on CGP 6140: Professor T. Freyvogel, member of EAC, approached Dr Poltera of Ciba Geigy as suggested, and the Macrofil project Manager has also visited Ciba Geigy on three recent occasidns to foltw uj the collaboration with Ciba Geigy. The situation with regard to CGP 6140 is now very good. All clinical data from Dr poltera's trials in Latin America have been placed in the hands of Ciba Geigy starisricians for analysis. The Department of Regulatory Affairs at Ciba Geigy will be given the iinal report on clinicai trials ofCGP 6140, and will prepare a submission to the Swiss Regulatory nuthority (IKS). The Macrofilproject Manager has been present at two meetings held in 1992 atCiba Geigy to discuss these matters, and the Regulatory Submission will proceed as soon as possible; if necessary utilizing additionai resources outside the company. ,a 5 EACI2. oaraeraoh 130: OCRC to investigate in onchocercal patients the possible macrofilaricidal effect of high doses of ivermectin: Dr Awadzi, Project Director OCRC, prepared a clinical protocol for such studies which has been reviewed by the Macrofil Steering Committee and submitted to Merck, Sharp and Dohme and SCRIHS at WHO for approval. lt was proposed that single and multiple oral doses of ivermectin at the following levels be utilized:- 400 pslKs, 600 pelKg and 800 pslKs. The Committee's recommendation was that the 400 pelKg studies (used safely in lymphatic filariasis) should proceed immediately, but the MSD position, as discussed verbally, was that the higher dose levels (600 and E00 pglKg might not be approved). Since that time the Macrofil project Manager has reviewed a manuscript submitted for publication, in which a dose of 600 pglKg of ivermectin was used without adverse effecs, against patiens infected with Mansonella oerstans. The company is being urged to make a decision on this matter, and provide the appropriate doses of ivermectin, and required placebo tablets.