Large scale treatment with ivermectin in the OCP: plan of action and budget for 1989 and 1990

;.- Onchocerciasis Control Prograue in West Africa LARGE SCALE TREATMENT WITH IVERI{ECTIN IN THE OCP PLAN OF ACTION AND BUDGET FOR 1989 AND 1990 Contents: 1. Introduction 2. Connunity trials of ivermectin in 1987 and 1988.3. Large scale treatnent with ivernectin in 1989 and 1990. 4. Involvenent of national teans. 5. Budget for 1989 and 1990. Appendices: I. A description of the ivernectin treatnent zones, 1g8g and 1990.II. A sumnary table and nap of the treatment zones.III. Methodology for treatnent. IV. Tine table. V. Budget. 07'/04/88 p8,ge 1 1. INTRODUCTION. Since the start of control operations in 1975, the Onchocerciasis Control ProElranne (OCP) has had to rely exclusively on vector control as the sole uethod available for achieving its objective, i.e. to put an end to onchocerciasis as a disease of public health and socio-economic inportance andto assure that there will be no recrudescence of the disease thereafter. However' a second nethod of control has recently emerged. Ivermectin has shown to be an effective nicrofilaricide which is relatively welI tolerated and the drug was registered for hunan use in October 1987 in France under the nane Mectizan. The OCP be8an in 1986 to investigate how ivernectin aight be utilized as a cost-effective operational tool in the control of onchocerciasis and it was concluded that two najor questions needed to be answered before operationalplans could be nade. The first concerned the risk of rare but severe adverse events following ivernectin treatnent, a question which had not been resolvedduring the clinical trials. The second question concerned the potential ofivernectin mass treatnent as a tool for controlling transnission, whether as an adjunct to larviciding or as a replacenent. The OCP enbarked on &n anbitious progrenme of eight connunity trials of ivernectin during 1987 and 1988 in order to answer those questions. 2. COMMUNITY TBIATS q MRIIECTIN IN 1987 AND 1988. Over 40r000 people from endenic onchocerciasis foci in the OCP have beentreated todate with ivermectin and this nunber is large enough to allowprelininary conclusions to be made concerning the safety of the drug. Adverse events following ivernectin treatuent were considerably nore frequent than expected but only few cases required symptonatic treatment under nedical supervision, and alI recovered fully, usually within a few hours following the episode. Based on the available evidence it is presently concluded thativermectin is sufficiently safe for use in Iarge scale distribution providedthat an adequate systen of monitoring of adverse reactions by paranedicalpersonnel is maintained during the first 72 hours following treatnent. The community trials confirned the inportant microfilaricidal effect ofivermectin and treatnent resulted in very dranatic reductions in the intensity of infection in the trial connunities. In one trial area the treatnent wasfollowed by a significant faII in the level of transmission. However, thedata on the effect on transmission in other trial areas are not yet available and answers to this question wilr have to await the results of thepost-treatment entomological evaluation during 1ggg. 3. LARGE SCALE DISTRIBUTION OF IVEBUECTIN IN 1989 AND 1990. An ocP staff meeting was herd in March 19gg to review the pran of operations for the remainder of the third financial phase. This neetingdiscussed at length the possible operational use of chenotherapy during thisperiod and a plan was drawn up for the Iarge scale distribution- of ivernectinduring 1989 and 1990. Since the drug appears sufficiently safe to allow its controlled operational use, it was agreed that it would not be ethical to wait for the renaining trial results before planning further large scale utilization ofivernectin. In the extension areas and reinvaded zones there ere nany communities where the intensity of infection and the risk of blindness isstill very high and it was concluded that priority should be given toivermectin treatment in these high risk conmunities. The meeiing identifiedthe nost endemic zones in the oCP area and designated these for annual large scale ivermectin treatnent. A description of each zone is given in appendixI, and a summary table with a map of the zones is provided in appendix II.Decisions concerning reductions in vector control operations- following theintroduction of large scale ivernectin treatment cannot be taken before thefinal trial resurts on transmission become available early 1ggg. 07 /04/88 pagp 2 Nevertheless, several of the selected ivernectin treatnent zones are areas of major operational importance and it was agreed to extend in such areas theivernectin treatnent in 1990 to a Iarger population than those Iiving in high risk communities alone, in order to nininize the risk of transnission in these zones. The neeting stressed the need for great frexibility in the implementation of the ivermectin progranne for 1989 and 1990 to enable theincorporation of the latest findings fron the ongoing trials. It was also agreed that some of the key trials should be prolonged to study the incidence of adverse events and the reduction in transnission after several rounds ofivernectin treatment. In spite of the general need for further trial results, it was already decided for sone specific OCP areas that control wiII be undertaken using chenotherapy alone. In two isolated zones vector control has always been extraordinarily difficult and expensive while the results have generally been unsatisfactory. Since it is believed that these zones do not constitute a source of reinvasion for other are&s in the OCP, it has been decided to stop vector control in these two foci and to protect the population at risk by chemotherapy. Furthermore, vector control is scheduled to cease in 1990 inIarge parts of the original OCP area, and ivermectin wiII than be the onlypractical tool for the maintenance of control in the few isolated foci where there has been residual transmission during the control period. These foci wilr be kept under annual ivernectin treatnent from 1988 onward. 4. INVOLVEMENT OF NATIONAL TEA}IS. National personnel has been involved in the coununity trials from thebeginning. In the first four trials national participation constituted 502 ofthe personnel who carried out the distribution of the drug and the nonitoring of adverse events. In the renaining four trials, nationals accounted for ZbI of the personnel involved in ivermectin distribution and nonitoring, and theydid the epideniological mapping of the trial a.reas. This fornula will be expanded during the large scale ivernectin treatnents during the next years.At present only 3 national teans in the Western extension are oper&tional: theteans of Guinea, MaIi and Senegal. These teans are presently conpleting the epidemiological map of the Western extension area. National teans wilt betrained in each of the oCP participating countries from 1989 onward. These teans wiII undertake the detailed epideniological napping of the selected treatment zones in preparation of drug delivery under the supervision of OCp staff. The final distribution of the drug and monitoring of adverse eventsfollowing treatment will also be done by the national teans in collaboration with OCP. 5. BUpcET reB 1989 ANp 1990. The budget proposal, for which the detairs are shown in appendix v, covers a period of two ye&rs for a total cost of US $ 3 r2OLr600 broken down asfoI Iows: 1989: US $ 1r7t2,700 1990: US $ 1,488,900 Most of the activities wiII be carried out by the national teams under the supervision and nonitoring of the OCP Professional Staff. OCP General Servicepersonnel wiII also provide support to this operation. The national teanswiII be provided with 202 salary subsidiesr per dien allowa,nces and travellingfacilities. To meet the objective of the progranne, vehicles, uobylettes, Iaboratory equipment and supplies, drugs and medical supplies etc., must be acquired andprovided to the national teams. Most costs related to the acquisition of equipnent wiII take place in early 1989 and wiII not be repeated in 1gg0.Operating costs are those related to the operation and naintenance of vehicles and equipnent. Mapping of the localities to be treated wiII be partly carriedout with the use of helicopters and fixed wing aircraft. 07 /04/88 Appendix I, page 1 DESCRIPTION gE MBIIECTIN TREATI{ENT ZONES. 1989 AXD 1990. A total of 14 zones have been selected for large scale ivernectin distribution in 1989 and 1990. Provisions have also been made for two rore zones which nay be identified as soon as the epiniological nap of the Southern Extension and of Sierra Leone have been coupleted. A description of each of the 14 selected zones is given below using the same nunbering as used in the sunnary table and map of appendix II. l. Upper Niger basin (Guinea). The treatment zone in the Upper Niger basin in Guinea is the Iargest and uost important of aII selected zones. The Upper Niger basin is the uain source of reinvasion by infective simuliids into the original OCP area and this basin is therefore one of the main targets for vector control operations in the Western Extension. The epidemiological situation is anong the worst in the OCP area with very high intensities of infection and high blindness rates. The total population in the zone is estimated at 200,000. About 60,000 people Iive in high risk areas and these have been identified as the terget population for the large scale ivermectin treatnent. Further epideniological napping wiII be required to allow a more accurate identification of the target population and this will be done by the national tean of Guinea. It is hoped that some 602 of the target population wiII already be treated during the dry season of 1988-1989. These people wiII receive their second treatnent during the dry season of 1989-1990 when the remaining part of the target population wiII receive their first dose. Fron then onward the total target population will be treated annually. Because of the operational importance of this area, treatment wiII not be linited to villages with a CMFL of nore than 15 mfs, Iess endemic villages wiII probably also be treated during 1990 in an attenpt to further reduce the risk of transmission. For this purpose a special component of entomological evaluation wiII be included in this zone. The exact approach to be folllowed in 1990 wiII depend on the results fron the epideniological mapping and of the ongoing transmission trials. 2. Upper Ganbia river focus (Senegal). This concerns a hyperendemic focus along the Gambia river downstrean fron the town of Kedougou. This focus was included anong the eight conmunity trials and a first ivermectin treatment will be given in May 1988 as part of the trial. Detailed epideniological napping of this zone by the national tean has shown that disease is most severe around the bend of the river near Mako. The proposed treatment zone is essentially the same as the area which was included in the trial and the total population to be treated wiII not exceed 10 , 000. 3. Upper Bakoye river (Mali,/Guinea). The epidemiological napping by the national tean of MaIi has identified the upper Bakoye river valley, upstream fron the town of Kita, as a focus of severe and hyper endenic onchocerciasis. This focus is therefore alsoproposed as a priority zone for large scale ivermectin treatnent. The focus extends into Guinea, as shown by subsequent epidemiological surveys by the Guinean national team, but the area is rather sparsely populated and it is estinated that the total population in high risk villages will not exceed 10'000 people. However, this needs to be confirmed by more detailed epidemiol8ical mapping of the area. Both the napping and the first round of treatment will be conpleted during the dry season of 1988-1989. 07 /04/88 Appendix I, page 2 4. Tienfala (MaIi). The Tienfale focus along the river Niger is a very special &rea. The breeding sites of S.dannosun s.s. are the huge rapids in the river Niger itself and vector control in this area requires very large anounts of Iarvicides which nakes vector control in this focus disproportionately expensive. It is believed that the area is quite isolated from an entomological point of view and that the Tienfala focus does not constitute a source of reinvasion for other parts of the OCP. Detailed epideniological napping of this &re&, as part of the preparation for one of the connunity trials, has shown that there are several hyperendenic villages located on the Ieft bank of the river. On the riSht bank the prevalence and intensity of infection are uuch lower. The total population in the area is quite small and does not exceed 8000. Given also the good accessabitity of the area and the concentration of the population in villages, it wiII be quite feasible to treat the total population instead of only those in hiSh risk villages. Because of the problens with larvicidingr the relative isolation of the focus and the high feasibilty of mass treatnent with ivernectin, it has been decided to replace vector control in the Tienfala focus by large scale ivermectin treatnent. A first round of treatnent is scheduled for April 1988 as part of the connunity trial, and annual retreatnent wiII be naintained fron 1989 onward. A detailed entomological evaluation wiII be naintained during 1989 and 1990 in order to study the renaining level of transmission and to enable a proper decison to be made as to what should be the target population for ivermectin treatnent for the period after 1990. 5. Itlarahou6 focus (C6te d'Ivoire). During nost of the control period, the effect of vector control operrtions has been unsatisfactory along the Marahou6 river, as also evidenced b3- the results of the epideniological evaluations in several follow-up villages Iocated between Danagloro and Segu6la. There has been little inprovenent in the epidemiological situation in these hyperendenic villages where the population remains heayily infected and at a high risk of developing blindness. It i., for this reason that this part of the OCP has been selected as a priority zone for Iarge scale ivernectin treatment. The zone is not weII defined and Iittle is also known about the distribution of onchocerciasis and of the population density in relation to endemicity. The first step will therefore have to be the detailed epideniological mapping of the zone in order to determine the Iocation and size of the high risk population. The zone is a potential source of reinvasion into the weII protected part of the programne because of its location to the South-West of the central OCP &rea. It is therefore likely that ivermectin treatment in this area wiII be extended to a larger population in 1990 in order to help reducing the risk of importation of infection into the North-East. The exact approach to be followed will depend on the results of the transnission trials and of the mapping of the zone, but this type of extension has been taken into account in the estimates of the population to be treated. 6. Upper Sassandra river (C6te d'Ivoire). This river basin was for many years subiect to heavy reinvasion by infective blackflies from the upper reaches of its affluents located across the border in Guinea. However, the results have improved progressively over the years and fuII control has been achieved since 1986 when the upper Sassandra basin in Guinea cane under control. The initial problems are clearly reflected in the results of the epidemiologiical evaluation. During the first 5 years of control there has been virtually no inprovenent in the very severe epidemiolof,ical situation of the indicator viIlages, but from then onward there has been a definite anelioration in the epidemiological situation. Nevertheless, the intensity of infection in the conmunity was still 07 /04 /88 Appendix I, page 3 unacceptably high during the last surveys in 1985. Further surveys and mapping will be needed to deternine the present status of the area before a final decision is nade to start large scale ivernectin campaigns in this zone. 7. Lower Bandala (C6te d'Ivoire). Vector control has also been difficult in the area between Taabo and Tiessal6 along the Lower Bandana river in COte d'Ivoire. Particularly complicated is vector control at the huge Gauthier falls near the confluence of the Bandama and the N'zi rivers. The area upstrean, around Taabo, is the spot where the first resistance to Abate w&s detected anonEl the savanna species of Simuliun daunosun s.s. The zone is located to the South-l{est of the central OCP area and it is, because of this geographical location, apotential source of reinvasion into the well-protected a,rea. In this sense the zone is conparable to the Marahou6 treatment zone. However, the epidenioloSical situation appears to be quite different as might be expected in an intermediate zone between the forest and the savanna. The linited information available for the pre-control period suggests that high intensities of infection and onchocercal blindness were only found in the direction of Taabo, and that the disease had a considerably lower level of endenicity around Tiessal6. OnIy one village has been followed up during the control period and the results for this village confirn that control has been incomplete even though there has been a definite improvenent in the epideniological situation. More extensive epidemiological mapping needs to be done before detailed plans can be made for Iarge scale ivernectin treatment in this area and it will probably be necessary to include an ophthalnological conponent in order obtain a better understanding of the distribution of the blindingr sav&nna forn of onchocerciasis in this zone, As in the Marahou6 zoner ivermectin treatnent will in 1990 probably be extended to a larger target population than those living in high risk villages alone in an attenpt to minimize the risk of transmission. 8. Pendie (Burkina Faso). The Pendie focus along the Dienkoa river is the only area in Burkine Fasofor which the epideniological evaluation has shown that significant transnission has occurred during the control period. Transnission has probably occurred during several years between 1980 and 1985, and the epideniological trend in this focus is therefore out of phase with the sumounding areas where the reservoir of infection is rapidly dying out. To avoid that this focus becones a source of recrudescence of infection once vector control operations wiII have ceased in the central OCP area, it will be necessary to develop a special intervention strategy for the Pendie focus based on chemotherapy. It is for these re&sons that this focus has been selected for a connunity trial in 1988. Vector control has been interruptedin 1987 in order to study the pre-treatnent level of transnission in this focus as indicated by entonological paraneters. the total population which night be a source of transnission in the area will be treated with iveruectinin April 1988. Following the treatnent vector control will once nore be interrupted and the difference in the level of transnission with that observedin 1987 will be studied in detail. The Pendie focus provides a unique opportunity to study the potential of ivernectin mass treatnent for the control of recrudescence of transnission in an area which was initially under satisfactory control but where transnission has relapsed and the results of this study ere expected to give sone of the most inportant indications of how ivernectin can be used for the naintenance of control after cessation of larviciding after a prolonged period of successful vector control. Since the present study wiII only provide answersfor the effect on transuission following one single round of treatment, it has been decided to continue to study the residual level of transmsissionfollowing the second and third treatnent rounds. 07 /04/88 Appendix I, page 4 9. Bui (Ghana). Vector control has always been difficult along the Black Volta near Bui, which contains one of the largest breeding sites in West-Africa, and both entomological and epidemiological evaluation data have shown that transnission has not satisfactorily been interrupted by the Iarviciding operations in this area. The location of the Bui focus just South of the core area of the OCP makes it the nost dangerous potential source of reinvasion into well-protected areas, and notably into the Red and White Volta basin in Ghana and Burkina Faso. It was because of these special characteristics that the Bui focus was selected as an area for a connunity trial in 1987 and 1988. The first round of treatnent was already executed in August 1987 when the population Iiving in the first line villages was treated, and during the second round, which is scheduled for May 1988, treatnent wiII be extended to the population living in second and third Iine villeges. Because of the nultitude of factors which influence the entonological situation in this focus it is certainly not an ideal focus for a conmunity trial of the effect of ivernectin on transnission. However, because of it major operational inportance, ivermectin treatment wiII have to be maintained in this special focus together with a careful evaluation of the remaining risk of transnission. 10. Asubende (Ghana). A very inportant connunity trial was undertaken in the Asubende focus along the river Pru in the Southern extension in Ghana, where the first round of treatnent was given in October 1987. This focus was identified as one of the nost appropriate areas for a trial of the effect on transnission because of its relative isolation free fron any significant reinvasion of infective blackflies fron other sources and because entonological baseline data of high quality were available for a period of seven years without vector control. This nade it possible to provide a fairly reliable estinate of the reduction in the intensity of transnission brought about by large scale ivernectin treatnent and it was estimated that the first round of treatnent had resulted in a reduction of 70-75A. The level of endenicity was very high in this focus and this was the reason for a much higher incidence of adverse reactions than has been observed in the other community trials undertaken sofar. The most important infornation collected on adverse reactions originates therefore also fron the Asubende focus. Because of the unique conditions in this focus, it has been decided to treat during the next two years the total population Iiving within a radius of 20 kn from the breeding site, as was done during the comnunity trial, instead of Iimiting the treatment to the inhabitants of high risk communities only. The monitoring of adverse reactions and the entonological evaluation will also be maintained at similar levels as during the trial. It is expected that this will provide extremely inportant infornation on the risk of adverse reactions at retreatnent and on the reduction in the level of transmission as a result of the cumulative effect of several rounds of ivernectin treatment. 11. Kulpawn/Sissili problem foci (Ghana). Epideniological evaluations have shown that control has not always been satisfactory along the Kulpawn and Sissili rivers where localized transnission has occurred during certain years. This has also been demonstrated by the results of the entomological evaluation for 1982 and 1985, even though the entomological evaluation data are Iimited as the Kulpawn area is inaccessible during the rainy season. FoIlowing the first epideniological evidence of Iocalized transmission for the village of Goreba-Somun along an affluent of the White Volta just South of the Kulpawn river, a large number of epidemiologicaL surveys have been undertaken in order to determine the extent of the problem. Only one other problem village was detected along the Kulpawn river, and it was concluded that the transnission problens have probably only 07 /04/88 Appendix I, page 5 been very localized. The two problen villages identified sofar wiII be kept under ivermectin treatnent starting 1988 in order to reduce the level of infection in the connunity as much as possible before a decision is taken to cease vector control in the central OCP area. The total Kulpawn/SissiIi area wiII be kept under special epideniological surveillance and any other problen village which night be identified at a later stage wiII be directly included in the ivernectin treatnent programne. 12. Asukawkaw/Dodofie focus (Ghana). This is an area along the Asukawkaw river in the Southern extension in Ghana for which it is known that it concerns a focus of severe savanna onchocerciasis with high blindness rates. Quite sone epideniologicalinfornation is already available and these data show that the disease isparticularly severe around Dodofie. However, it wiII stiII be necessary to undertake further epideniological napping in order to deternine the Iimits of the focus and identify all high risk connunities to be included in the large scale treatnent. 13. Kara basin (Togo/Benin). This treatnent zone conprises selected villages along the upper Kara river basin as weII as along the upper M6 and upper K6ran rivers in both Togo andBenin. This region, though belonging to the area under vector control, has always been subject to heavy reinvasion by infective sinuliids, and the results of the epideniological evaluation have shown that the vector control operations have brought little benefit to the population in the high risk villages. This area was chosen for a connunity trial during 1988 and the villages to be included are essentially those which have been treated during the first round of treatment, though a few nodifications wiII be nade based on the infornation acquired during the comnunity trial. 14. Sota river basin (Benin). Though the Sota river valley is part of the original OCP area, it has hadIittle benefit from local larviciding because of heavy reinvasion by infective sinuliids. In the two indicator villages which have been followed up during the control period there has been no iuprovement in the epideniological situation and the disease renains todate as severe as it was before the start of vector control. It is uncertain if the situation wiII greatly inprove whenlarviciding operations wiII becone effective in the Southern extension area because it is quite possible that an inportant proportion of the fIies, which are responsible for transnission in this particular valley, originates fron sources outside the programme area. Contrary to all other surrounding rivers in that part of the OCP, the Sotais a perennial river where S.damnosun s.s. nay breed for nost of the year. Because of this, Iarviciding is comparatively very expensive, not only because of the larvicide requirements, but also because of the Iong ferry tine for the spraying aircraft to this isolated river. Since vector control is very costlyin the Sota river valley, and has little effect on transnission, it would seembetter to cease local larviciding and replace this by large scale ivermectin treatnent in order to protect the population living in the high risk villages,if not from reinfection, than at least fron onchocercal norbidity. It isbelieved that the Sota valley is relatively isolated entonologically and that such a decision wilI not result in reinvasion of infective blackflies from theSota river into the weII-protected central area of the OCP. Nevertheless, such a major change in the control strategy needs to be carefully nonitoredinitially and it is therefore planned to intensify the entomological evaluation in this valley during the years of 1989 and 1990 when vector control will be fulIy replaced by large scale ivermectin treatnent. 07 /04/88 Appendix II, page 1 Estinated * number to be treated a sutrMARy QF IVERMECTIN TREATMENT ZoNES FoR 1989 AND 1990. Proposed priority zones Country Fi rst treatment round 1. Upper Niger basin 2. Ganbia river focus 3. Bakoye basin 4. Tienfala 5. Marahoue 6.u r Sassandra 8. Pendie 9. Bui 10. Asubende ll.Kulpawn/SissiIi problen foci 12. Asukawkaw/Dodof ie focus 13.Kara basin 14.Sota river basin 15.Other Southern extension foci 16.Sierra Leone foci Guinea Senegal MaI i/Gu inea MaI i C6te d'Ivoire C6te d'Ivoire C6te d'Ivoire Burkina Faso Ghana Ghana Ghana Ghana Togo/Benin Benin TogolBenin Sierra Leone 5 ,000 4,000 15,000 2,000 5,000 15 ,000 10,000 30,000 ** 20,000 ** 88/8e 87 /se 88/8e 87 /ge 88/89 89/90 88/90 87 /88 87 /88 87 /88 88/8e 89/90 87 /88 88/89 89/e0 89/90 50,000 10,000 10,000 7,000 .6nd\Y, 30,000 t( on+ ],sro ?,t'o ?, f,oo \, \5o \b , ooct (9;-" /r, 'uo @7, Tiessal6 15,0 5f, o@ Total 253 ,000 * ; The estinates are for nost zones based on very linited infornation and these figures should at this stage only be seen as indications till the epidemiological mapping of the zone has been conpleted. **: Treatnent zones in the Southern Extension and in Sierra Leone have not yetbeen selected. These population estinates are therefore conpletelyfictive and have only been included for budget purposes. o I a @o(,=@z >mCM I u)=az >rnC> qj$ r . . *Io o NI m ooa>ot?O-iiliiiEi F:{i!Ai; 2 -t:'io;'; E s i ; ! -- : i i; ii i E: t: !:*t l u El:E:-;-g3E;;l-'m : E l o N o\a'oc 8' g3: 4o..q aGdo-.c+ aod-9;oi?:e9 NO arJa3 ::3 !o4;E= :'; oa :3oo ,o 9' a - +a ro C) { o z. o 'rl m 7' rn C){ z. {v m -{ =mz -{ No z. ma 'rt ov (o @(o z.I :(o(o o U) m z m 6, r o2 a4 I ? z 3 ozI s i I I I I I g c t I m f, o s an aJ N o a) \ z m I u, I I i @ . D o II t I + + I I I I I I t-, I I I I I I I I I I I I I I I I I I I L- t m o{o I a o ! m , f o z r D a ,tl N o z 6 o ! FI ! I o2 z m I f Itt o trl r o c FIo z z c) o a a o I I a -,\ a m @oC a I 6) - z I t I t I I I I \ IL_ I , t t -r-- j I a E' 6)o I( = ID6 ooq s8c o I t @ #=oz NOm z> m(,{om!,mz!!oJ!lOm -Dz>I!< Loi!-D OF n' t:, Emqb -{ I I I I I I I I I( I I I t I z \ o m --_T z 6, m f, 6 o ! o : o o! t o: o a o az .II XI Io z a o I 5 + I I I I I + I l I J @ I t , 07 /04/88 Appendix III, page 1 iTETHODOLOGY FOR TABGE SCALE IVERMECTIN TREATMENT 1. Epidemiological mapping of the extension areas. A stratified random sample of villages has been surveyed in nost of the Western extension area in order to describe the distribution and severity of onchocerciasis as a basis for the selection of priority zones for large scale ivermectin treanent. This work has been executed by the national teans. In the Southern extension epidemiological napping wiII start next year following the same procedure as developed in the Western extension. 2,1. Detailed mapping of the selected treatment zones. AII available geographical, entonological' denographical and epideniological information has to be sunmarised in a map with a scale of 1:200,000. An aerial and terrestrial survey wiII be conducted to update the nap unless detailed and recent aerial photographs are available. More detailed epideniological data are collected by conducting surveys in a sanple of villages located along the river banks and at varying distances from the river. The data to be collected in these surveys are the census data for the ropulation, the prevalence of onchocerciasis infection and the Connunity Microfilarial Load (CMFI). The CMFL is the geometric nean of nicrofilariae per skin snip among the total population above 20 years of age of a given village. This work is acconplished by national teams trained and supervised by OCP personnel. 2.2. Selection of the target population. The objective of the nass distribution in a given area deternines the criteria for the selection of the target population. If the goal of the exercise is the control of morbidity, aII villages with a CMFL of nore than 15 nfs nust be treated because above this cut off point, the risk of onchocercal blindness has been shown to become important. If a reduction of transnission is the aim treatment is extended to all villages which are thought to contribute substantially to transmission. 2,3, Treatment and nonitoring. The drug is distributed by teams conposed by a nurse, a census clerk and an tssistant. A nedical officer supervises two or more teams. The nurses are also in-charge of the monitoring of adverse events following treetment. A senior nedical officer of the OCP is in-charge of the supervision and monitoring of the whole area. With exception of this medical officer and sone OCP support staff, aII personnel involved in the exercise is national. The national onchocerciasis tean wiII be involved in aII ivernectin distribution in the country concerned, but local health personnel fron the treatnent zone will also be trained and involved in the distribution of the drug and the monitoring of adverse events. The exclusion criteria established by the manufacturers will be strictly observed. The population treated wiII be follor+ed f.or 72 hrs to nonitor for severe adverse events following treatnent and to provide nedical care and symptomatic treatnent when required. OnIy in a few special areas will extended monitoring will be undertaken by experienced OCP personnel in order to study the expected reduction in the frequency and severity of adverse events as a result of the reduction in nicrofilarial loads in the population following repeated ivermectin distributions. 2,4, Evaluation of large scale treatment. For each treatment viIlage, information wilI be collected on the censuspopulation and the treatment coverage by age and sex, and on the reasons why t.he drug could not be given to the non-treated part of the population. After the ivermectin distribution a sample of villages with known pre-treatment 07 /04/88 Appendix III, page 2 epideniological infornation wiII be surveyed again to assess the change in the prevalence and CMFL and to evaluate retrospectively the efficacy of drug delivery in the are&. Pre and post treatnent surveys will follow exactly the same nethodology and will be both executed by national teans. 2,5. Reporting The results of the treatnent of each area wiII be reported annually by the OCP. The report of the first distribution will be the nost inportant because it will include the results of the epidemiological mapping of the area and the detailed plan for distribution and nonitoring together with details on the hunan and naterial resource requirenents. Reporting wiII concentrate on thedetails of coverage, reported severe adverse events following treatnent and on the impact of large scale treatnent on the prevalence and nicrofilarial loads in the treatment zone. Timetable for I9E9 and 1990 Appendix IV, page I I 989 I 990 1. Upper Niger Detailed epid.oapping Treateent + Eonitoring FIy catching + dissection Analysis + reporting 2. Canbia River Senegal Treatment + nonitoring + reportingAnalysis 3. Bekoye Detailed epid.aapping TreatDent + ronitoring Analysis + reporting 4. Tienfala Treatnent + aonitoring FIy catching + dissection Analysis + reporting 5. l,larahoue Detailed epid.oapping TreetDent + nonitoring Analyais + reportlng 6. Upper Sassandra Detailed epid.Eapping Treat[ent + Eonitoring Analysia + reporting 7. Tiassale Detailed epid.Dapping Treatrent + lonitoring Analysis + reporting 6. Pendie Treatr€nt + tonitoring lly catching + dlssection Anelyeis + reporting 9. Bui freatrent + oonitoring fIy catching + dlssection Analysls + reportlng 10. Asubende Treat[ent + Donitoring Fly catching + diaaection Analysis + reporting JFI,IAI,IJJASOND + + + ++ +++++++++l++ +++ + + + +++ +++++++ + + + + + + + + +++++ + + ++t++ + + JPHAMJJASOND +++++ + +++++l+++++i + + + + +++ +++++++ + + + +++++ + +++++ + + ++ ++ + + +++ ++ +++ + ++ + ++ + + I+ + + + + +t+l+ +++++t+ +t ++++++ ++ + + + + + + + I i + Tinetable for 1989 and 1990 Appendix IV, page 2 I 969 I 990 11. Kulpavm-Siesili Detailed epid.aapping Treattrent + oonitoring Analysis + reporting 12. Asukawkaw focus Detailed epid.rapping TreatDent + aonitoring Analysis + reporting 13. 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