Study of an Onchocerciasis Control Programme in Nigeria

ta 6 { STI]DY OF AN ONCHOCERCIASIS CONIT,OL PROGRAITIME IN NIGERIA 1. INTRODUCTION Since the start of OCP operations in seven countries of West Africa, the Federal Republic of Nigeria has made a request to also join this prograrme. At the fourth session of the Joint Coordinating Conmittee (Kuwait, December 1977) it was stated (page 13, 6.26 of the Independent Chairmanrs report): "In the case of Nigeria, if it wished to become a contributing Party, it should be invited to consult the World Bank. If it wished to be a particlpating Country, much more information would be requested, the major technical consideration being whether it should joln OCP or operate its own progranme. I.lHo should be invited to discuss with Nigeria what its relationship to oCp should be". Subsequently the Government of Nigeria has decided to operate its own prograume and, after several meetings between Nigerian Authorities and MIO (Regional Office for Africa;headquarters), it was decided that WHO should provide the Federal Government with a plan of action for an Onchocerciasis ConErol Prograrme, the prirnary objective being the protection ofthe Federal Capital Territory (aUu5a area). Since March 1978, I,HO has undert.aken the folloring actions: the Regional Director made available $ 150 OOO from hls Development Fund for supporting activities in 1978. Thls sr:m is in addition Eo g 30 OOO conrributed by the Director- General; - a WHO Onchocerciasis Mission, composed of Regional Offlce and headquarEers experts visited Nigeria and made recorrnendations to the Federal Government on the organization of Ehe necessary preliminary studies. By a letter dated 13 April the Federal Ministry of Health of Nigeria indicated the Governmentrs acceptance of the reconmendations of the WHO Mission and requested I{HO collaboration in the implementation of the reconmendation I the services of a WHO ophthalmologist, already posted in Kaduna (projecr NIE/ESD OOl) has been offered to Nigeria as temporary coordinator of the National OnchocerciasisControl Campaign until such time a suitable national is available to assLme that role; Dr R. W. Crosskey, of the British Muserm (Nat. Hist..), who has considerable knowledge and experience of the onchocerciasls situation in Nigeria, and has prepared as a result of a coutission by the Organtzation a coryrehenslve review of what is known about onchocerciasis and its vectors in Nigeria (see page 2, footnote) ; the WHO ream based in Kaduna (fnf/VfC.O24) has been reoriented and reinforced: - the three entomologists have been trained, by OCP, in the fields of taxonomy, aerial surveys and entomological evaluation; - Dr Dunbar, the leading cytotaxonomist working on onchocerciasi.s vectors, has beeh recruited and will join Kaduna next December; arrangements have also been finallzed for consultancy services by an entomologist, an epidemiologist and an economist; WORLD HEALTH ORGANIZATION ORGANTSATION MONDIALE DE LA SANTE vBcf78 Ce document ne constttue pas une publication. ll ne doit faire l'objet d'aucun compte rendu ou r6sumC ni d'aucune citation sans I'autonsatron de I'Organisatron Mondiale de la Sant6. Les opinions exprim6es dans les artrcles signds n'engagent que leurs auteurs. The issue of thrs document does not constitute formal publrcation. lt should not be reviewed, abstracted or quoted without the agreement of the World Health Organization. Authors alone are responsible for views expressed rn signed articles. vBcf78.6 Page 2 t - archives of the previous activities on onchoccrciasis in Nigeria have been traced and a part of it has been found by the Project Leader of the WIIO Research Unit based in Kaduna; the creation of a Regional Centre for training of medical and veterinary entomologists(University of Jos) has been negociated and a project proposal submitted to Ehe Special Progranrme for Research and Training. On its slde, the Government of Nigeria had to undertake the following actions esEablishment of a base for the National Onchocerciasis Control Campaign; subcontracting of ecological baseline studies and collection of hydrological data to the University of Ife; subcontracting the socioeconomic studies to the Nigerian Institute for Social and Econouic Research (NfsgR) ; subcontracting the collection of epideniological data to the Nigerian Institute for Trypanosomiasis Research (NITR) ; submission of a request to UNDP for financial support for the aerial survey of Simulium breeding sites. I r T 12. ONCHOCERCIASIS AND lTS VECIORS IN NIGERIA Simulir.m damnosum s.1. and onchocerciasis has been known in Nigeria for 70 years. Austen(1909) published the first records of the fly, recording its capture in 1906 at the Cross River. Independently, and coincidently in the same year, Parsons (1909) recorded the occurrence of the disease pathogen, then known as Filaria vglfglE, in four Nigerians seen at Lokoja but coming from Kabba, Onitsha and Tola. 2.1 The disease (see map 3) Despite these very early data, it is not before the opening of eye clinics in rural dispensaries in the Northern Region (1950s), that the ophthalmologist F. H. Budden, started to obEain systematic daEa on the incidence of blindness in rural comnunities. It was quickly discovered that severe ocular onchocerciasis occurred in many parts of Northern Nigeria and that cuEaneous onchocerciasis was much more widespread than had been imagined. Since then, the best and indeed the only thorough study of the epidemiology of onchocer- ciasis in the former Northern Region of Nigeria (the States of Bauchi, Benue, Borno, Gongola, Kaduna, Kano, Kwara, Niger, Plateau and Sokoto) is that published by Budden (1956). This includes the results of whole population surveys in 15 selected vi1lages, where the prevalence and intensity of O. volvulus infection were studied , and where a careful assessment was made of the ocular lesions and of the amount of blindness associated with Ehe disease. It is also based on Ehe resulEs of surveys of the blind in a much larger number of villages with the object of revealing the prevalence of onchocerciasis as a cause of blindness. Budden estimated, at that time (1956), that there were about 20 OOO persons blinded by onchocerciasis out of a population of 17 nillion in the Northern Region of Nigeria. 1 E*ttacts of Dr R. W. Crosskeyrs report (see chapter I): 'rAn appraisal of current knowledge of Simulium damnosum s.1. in the Federal Republic of Nigeria in relation to the development of an Onchocerciasis Control Campaignr'. This report is presently being edited. The bibliography of this report is shown in Annex 1. Three of the five maps are shown as maps 1, 2 and 3. I v 8.6 3 wcfT gePa t Estiuates of population growths since then, place the population of the same area in 1978 at about 43 milIion. Allowing for the fact that population grorth in the areaa worst affected by onchocerciasis is likely to have been below average, it may be Ehat there are now some 30 OOO-4O OO0 persons blinded by onchocerciasis in the northern states. Ttris, in turn, irylies that there will be a like nr-mber who are not econ@ricaIly blind but who suffer from severe visual iryairment resulting from onchocerciasis. Data on onchocerciasis obtained since Buddenrs survey are almost entirely confined to microfilarial prevalence figures. Most of the available figures have been collected during surveys for hr-uan tr)panosomiasis and almost all of them are likely to underestimate the true prevalence rate, and none gives any information on the intensity of infection. Map 3 shows the known distribution of the disease. 2.2 lhe vectors (naps 1 and 2) Identi ty The only vectors of huoan onchocerciasis knovrn in Nigeria belong to the Simulium damnosrm cmplex. Up to now, the studies on the members of the complex in hlest Africa have been almost entirely confined to the countries of the oCp (mostly Ivory Coast and Ghana), Guinea and Liberia. Ttrere have been no comparable studies in Nigeria, beyond the fact that S. sirban'm and S. d66nssrrm s.str in the Abuja area (Vajime & Dunbar, 1 975 and in soue It is Iikely that onchocerciasis is transni tted in nor tvro species (as elsewhere i.n savanna West Africa) and and nothing is known for the country . , the chief vector species, both occur rivers of mid-Borgu (Vaiime, unpublished). thern savanna Nigeria nainly by these that S. squanosrm is involved i-n trans- mission in southern Nigeria, but this needs confirnation. The more southerly species,S. yahense, S. sanctipauli and s soubrense , probably occur in Nigeria and may also be involved as vectors. Lack of information on the identities of the consti.tuent, species in S. damnosum s.1. major gap in knowledge of the vectors in Nigeria. Dis tribution rsa I i I I Ttre available data on the distribution of vector breeding sites (collected by Crosskey, Davies & t'Ialsh) are useful and sufficienE in quantity and quality to al1ow preliminary 1naps tobe prepared (rnaps 1 and 2). However, little or nothing is known of vector breeding sites on the systens, where only rapid prospections (if any) have been made: following river - headwaters of Kaduna river and its southern affluents; - headwater rivers of the Bunaga and Gongola systems; - headwater rivers of the Hawal and yedseran systems; - headwater rivers of the Gurara system; - south-flowing river systems from the southern margins of Jos-plateau; - Pai river system; vBcf 78.6 Page 4 - southern affluents of Che Benue river in Gongola State; - headwaters of the Katsina Ala system. Bioecology, transoission In addition to the broad geographical distribution described above sone rnore j-ntensive studies were made on the bioecology and host-parasite relations of the vectors at Abuja and Lokoja (Crosskey, L975b, 1958a1 Lewis, 1958, 1960) as well as in the Kainji area (I,Ialsh, 1970). VecEor control Several control schemes have been carried out in different. areas of Nigeria (O5i river, 1953 ; Mimi river, 1958 ; Kaduna river, 1956 ; Hawal river, 1963 ). However, the two most iryortant caryaigns were irylemented in the Abuja area (Abuja Control scheme) and around the Kainji dam site. 1 The Abuja scheoe has been well docr-mented since t.he publication of its resulEs (Crosskey, 1958b; Crosskey & Crosskey, 1959; Davies, 1963b, 1965,1966, 1968; Davies et a1., L962). It is most important to eryhasize in the present report that Abuja was chosen, against the llawal valley region, on the grounds that it rdas representative of the kind of difficult non-isolated area that would have to be tackled sooner or later, and that it had good comuni- The primary objective of the schemecations and accurate lar scale maps were available. rras to determine whether in the circuostances, it would be possible to obtain significant vecEor control by annual larviciding of the breeding sites. Secondary aims were to determine - should successful fly control be achieved - wheEher it had the expected effect on the incidence and prevalence of onchocerciasis in the area and whether control could be made simple and cheap enough to place on a 1ocal footing. Larviciding began in 1956 and a very high degree of "realtt vector control was achieved and maintained over several years. However, from the post-control studies of Davies on the cutaneous aspect of onchocerciasis it is clear that while there rras a substantial drop in prevalence over most of the conErol area, the effect on incidence in children was disappointing; transmission continued despite Ehe extremely low vecEor densities resu1ting frorn highly effective control (estimated to be an annual average of. 95% control). The effects of the vector control schemes on ocular onchocerciasis have been investigated by Rodger (1973), who could form no definite conclusi.ons but considered it possible that the absence of onchocercal blindness in villages along the Tapa ri.ver (the southern-most controlled river in the project area) was attributable to the scheme. 2. The construction of a dam across the Niger at Kainji at the beginning of the 1960s, required the fornation of a Unit, financed by the Niger Dams Authority, to carry out control meaaures against S. damnosum s.1. Control was necessary to ensure EhaE construction work was not adversely affected by the biting nuisance, and that the work force would not contract onchocerciasis. Larviciding began in 1961 and was continued until 1968 when the dam was completed. Walsh (1968) esEioates that fly density was reduced at Kainji by almost 92"L. There was no biting nuisance on the site; no one is known to have contracted onchocerciasis at Ehe construction site and over 50 OOO 1ocal people were afforded some protection. A very full account of the scheme is given by Walsh (1970). I I , a a l Iwcf78.6 Psge 5 2.3 The socioeconomic qspects Apart from the studles carried out by Bradley (1976) in the Hawal valley, no specific inforrnation on the socioeconomics of onchocerciasis is known from Nigeria. There is hotrever a clear indication that the effects of thls disease are corryerable to those known fron other countries included in the savanna belt of Africa. 3. STRATEGY AND TACTICS TO BE APPLIED IN IIIE NIGERIAN ONCHOCERCIASIS CONTROL CA},IPAIGN 3.1 Strategy The Representative of Nigeria at the fourth session of the Joint Coordinating Comittee declared: 'rOnchocerciasis is one of the comunicable diseases to be controlled in the current five years development plan of Nigeria. Ttre programe of onchocerciasis control is requested by the Federal Republic of Nigeria for the whole country with intensive operations in the severely affecEed areastt. The Federal Goverrment has also decided that the highest priority had to be given to the Protection of the Federal Capital Territory (ECT) (map 4) and should the caryaign be planned and iqlemented in phases, the phase I area should necessarily include this territory. 3. 1. 1 Phase I In his report, Crosskey (L978,loc. cit.) states about, whaE he describes as the rnid- northern zone (rnap 3): "Ttris is tt"-Iilffi and most corylex of the endemi-c zones heredistinguished. Perennial, or at almost continuous, breeding occurs in the major riverg of the western part of the zone, especially the Kaduna and Garara and their affluents. A very large number of breeding sites have been discovered during superficial prospection of mrny other Parts of the zone that are Ehought to be pertoanent (rrap 1)". It also appears from our present knowledge of the distribution of onchocerciasis in Nigeria, that this area is, as most of the other onchocerciasis foci in Africa, not isolated and , thus, subjected Eo periodic reinvasions as ldas shown by the control caryaign carried out in the Abuja area (see above). Ihus, the strategy on which OCP is based will have to be adopted the extenE of flight of the female vector of the savanna cytospecies trakes it necessary to treat fairly large areas; the longevity of the parasite in roan (15 to 20 years) and the lack of therapeutic Eeans of control make it necessary to pursue an entomological control campaign over a very long period. Llmits of the phase I area (map 4) In order to reduce to a minimuu the reinvasion phenomenon in this non-isolated zone, thelimits of the phase I area will have to be designed as follows: in the north the limit of the phase I area will have to correspond to the northern llolt of distribution of the disease and lts vectors in the nld-northern region of Nlgerla; the southern lioit will correspond to the border, if any, between: the savanna and forest types of onchocerciasis; the savanna and forest species of the S. damnosL@ complex; the western and eastern limits wilt have to be far enough frm the FCT in order to include the entirety of the breeding rivers situated at a distance corpatible with the reinvasion of this territory and surrounding zones. t ! vBcf78.6 Page 6 Ihe surface of this phase I area can be estitrated at 2OO OOO km2 concept of thettoinimal surfacettwhich, in accordance to our Present envisaged in any onchocerciasis control campaign dealing with savanna . It corresponds to the tactics, has to be cytospecies of the S. damnosrm couplex. 3.L,2 Phase II (map 4) The delimitation of the phase II area is much easier to define - northward, the limit of the phase II area will correspond to the northern limit of distribution of the disease and its vectors; southward, the limit will correspond to the border, if any, betvreen the savanna and forest types of the disease and its vectors; the eastern limit will correspond to the western limit of the phase I area; Ehe western limit will correspond to the eastern border of the OCP in Benin (present phase III easc area and southern extension). 3.1.3 Phases III and IV (map 4) AlI the foci located, in Nigeria, eastward of the phase I area will have to be included in Ehe Control Caryaign. A provision has been made for two successive phases but further studies may lead Eo the conclusi.on that the operation, in this zorte, could be irylemented in one phase only. 3.2 Relations with the OCP Despite its conE.iguity with the OCP, this prograrune cannot, for the following reasons, be envisaged as an extension of this first project: - with the southern exEensions implemented or planned in Ivory Coast, Ghana, Togo and Benin, the OCP has already reached its maximum possible size as far as circulati-on of data, technical and administrative instructions, personnel, etc. is concerned; - the OCP has already reached iEs rnaintenance phase, phase III areas having been under treaEment for already two years. However, it can be expected that the experience gained in the OCP could be transferred to the Nigerian Programne (training, meEhods and techniques, exPertise, exchange of data, etc.), 3.3 Tactics The structures of the OCP, the methods and techniques used in this progranrne could be adapted to the Nigerian Progranme as Ehey have proven to be valid especially as concerns: - direction and technical units; - methods of treatment (aerial applications); - insecticide selection and efficacy; - methods and structures of evaluation; - enEomology: sectors, sub-sectors, radio-corrnunications, etc. ; - epidemiol-ogy: simple and detailed evaluation; - hydrobiology. i a vBcfl8.6 Page 7 4. PIAN OF ACTION FOR IITE PRXLIMII{ARY PHASE In order to design a precise plan of the Control Caryaign, further studies will have to be organj.zed and irylerented. These studies will be concentrated in the phase I area and progressively exEended to phases II, III and IV areas. 4.L Studies to be carried out ( i) Entomology: - delimitation of Ehe boundaries (3.1.1) between: (a) forest and savanna cytospecies of the S. damnosum coryIex. Ttrese sEudies will fix the southern limit of the Nigerian Control Caryaign, especially souEhward of the phase I area; (b) phase I and phase II; (c) phase I and phases III and IV areas. The northern boundary of the Progranme will have to be determined. The results obtained will determine the limits of the phase I area in which the follovring activities will then be concenErated: - location of the breeding siEes of S. damnosun at the different seasons - study of the vectors populationsr dynamics; - study of the transmission dynaoics; - estirnation of the susceptibility leve1 of S damnosum to Teoephos and alternative insec ticide s. (ii) Epidemiology: - delimitation of the phase I boundaries (see (i)), especially in the south and south-rrest; - assessment of the leve1 of endemicity and of the severity of the disease in selected villages of the phase I areal - collection of existing data in the remaining areas. (iii) Hydrology: - collection of existing data (structure of the present hydrological network, quality of deta alreedy avallable) ; - planification for lrryroveoent of the number of sEatlons and quality of data. (iv) Hydrobiology: - collection of basic data in the different basinsl - selection of monitoring points. (v) Socioeconomi.cs: - collection and analysis of existing data. The analysis will concern.existing and planned development programes with their actual relation with onchocerciasis. { t wcf78.6 Page 8 4.2 Training Ttre training of the necessary personnel (Annexes 2 and 3) will have to be planned and undertaken as.soon as possible. Ttris training could be provided by the following instj.tutions: - University of Jos (Regional Centre for training of medical entooologists): entomology; - University of Ife: hYdrobiologY; - Ahoadu Bel1o University, Guinness Eye Clinic: ophthalmology; - the OCP: entomology, parasitology, ophthalmology, aerial operations, administration, general mrnagement. 4.3 Structures of the P.ogt.,r-"l Itre following structures, based on the experience gained in the OCP, are proposed (see Annex 2). (i) Headquarters: The office of the Programtne Director, the headquarters of the Vector Control Unit, the Epidemiological Unit, the Economic DevelopoenE Unit, the Adminislrative Services will be based at l(aduna. (ii) Entomological secEors and sub-sectors: The entomological secEors and sub-sectors will be located throughout the Prograrme area: - phase I area: two sectors and eight sub-sectors (see map 4) will be located as follows: - Dlinna sector - ltinna, Kafanchan, Keffi, Abuja sub-sectors; - Lokoja sector - Lokoja, Bugana, Abaji, Pategi sub-sectors; phase II area: E\do secEors and seven sub-sectors are anticipated (north and souEh); - phase III area: two sectors and eight sub-sectors (south-west, norttFeast); - phase IV area: one sector and four sub-sectors. Ihe locations of sectors and sub-sectors of phases II, III, IV areas will be precised during the preliminary studies period. (iii) Aerial operations bases: I\^ro bases will be necessary. Their locat.ion will be defined during the preliminary studies period. 4.4 Time-tab1e The foIlor^ring time-table is proposed: Year 1 SelecLion, training and recruitment of the Prograume Director' Selection, training and recruitment of headquarters and phase I personnel. 1 The present report does not show the necessary suPer-structure which will have to be , organized by the Nigerian Government, for Ehe direction of the Prograrme. Year 2 Year 3 vBcf7}.6 page 9 Settlement of the headquarters. Settlerrent of the two sectors and eight sub-sectors of the phase I area, Ordering and purchase of equipment (cars, laboratory and field equipmenE, radio, etc.). Organization of relations with collaboraEing institutions. Starting of the preliminary studies in the phase I area. Selection, training and recruitnent of phase II personnel. Settlement of two sect.ors and eight sub-sectors in the phase II area. Coryletion of the preliminary sEudies in the phase I area. Starting of the preliminary studies in the phase II area. Selection, training and recruitoent of phase III (possibly IV) personnel. Settlement of two sectors (possibly 3) and eight (12) sub-seccors in rhe phase III(possibly IV) area(s). Plan of operation for the phase I area. Preparation of the conErol caryaign in the phase I area. Starting of the phase I operations. Cornpletion of the preliminary studies in the phase II area. Starting of the preliminary studies in the phase III (possibly IV) area(s). Year 4 4.5 Proposed support from ins titutions outside the Prosrame (see Annex 2) The following institutions are expected to provide support to the Programe during thedifferent phases (prelininary studies, control caryaign). 4.5.1 Niserian Institutions - NIIR: Research (entooology, parasitology) Collection of data (epidemiology) - TTD: Aerial operations expertise - Ahnadu Bel1o University: Training (ophthalmology) - Jos University: Training (entomology) Research (entomology) - Ife University: Hydrobiology Hydrology - Ibadan University (NISER): Socioeconomics - Water boards: Hydrology t I vBcf78 6 page 10 4.5.2 tJorld Health Organization - WHO, Vector Biology and Control Research Unit (IGduna). Although this unit r^ri11 conEinue its studies on the bio-ecology of vectors (i.e. malaria) its staff has been trained and a specialist in cytotaxonomy has been recruited in order to provide the best possible scientific and technical suPPort to the Progranme: - cytotaxonomy (distribuEion of the different cytosp ecies of the S. damnosum cornp Iex ) ; 4 - insecticide trials (including susceptibility tests); - distribution of breeding sites; - vectors populations dynamics; - transmission dynamics. - wuofxttfEsD,/ool (xaduna). This unit could provide support in the field of ophtha Imology. - OCP (see 4.2: Training). 6 Requirelents Annexes 3 and 4 show the respective requirements for: 4.6.L Personnel (Annex 3) necessary in headquarters and for phase I for the two mein techni- cal units (VCU and EPI). Personnel of the DirecEorrs office and staff required for the economic development and administrative units (whose structure will be decided upon by Ehe Nigerian Government) will be in addition to the VCU and EPI staff. As more sectors and sub- secEors are incorporated in the prograume (phases II, III and IV) additional staff will be required as shourn in columns 3 and 4 (sector) or columns 5 to 12 (sub-sector) of Annex 3' Apart from the Chief of the Unit, phases II, III and IV operaEions. the staff requirement for EPI will be doubled for 4.6.2 Equipment (Annex 4) necessary for the direction and the administrat.ive and Eechnical uniEs for headqr:arters and for phase I. As more sectors and sub-sectors are incorporated in the programe (phases 11, IIl and IV) additional equipment will be required as shown in columns 3 and 4 (sector) or columns 5 to 12(sub-sector) of Annex 4. FifEeen Ehousand litres of Temephos (Simulium formulation) have already been purchased and will be used for experimental treatments carried out in the phase I area during the first three-year period. vBcf7}.6 Page 11 ANNEX 1 REFERENCES Aust,en, E. E. (1909) IllustraEions of African blood-sucking flies other than mosquitoes and tsetse-f1ies, British Museuo, London, xv + 22L pp. Bradley, A. K. (L972) The effect of disease on rural economy, social structure and seEElement; A case study of onchocerciasis in Ehe Hawal va1ley, Nigeria. Unpublished mimeographed documenE wHo/oNcHo/7z.93, 11 pp. EffecEs of onchocerciasi.s on settlement in the middle Hawal valley, r. Soc. trop. Med. Hyg. , 70, 225-229 Budden, F. H. (1955) Incidence of human infection with onchocerciasis in different conmunities in relation to the incidence and type of the ocular lesions, Br. J. Ophthal., 39, 32L-332 Budden, F. trop. H. (1956) The epidemiology of onchocerciasis in Northern Nigeria, Trans. r. Soc. Med. Hyg. , 50, 366-378 Budden, F. H. (1957) NaEural history of onchocerci.asis, Br. J. Ophthal. , 4L, 214-227 Budden, F. Trans H. (1963a) ComparaEive study of ocular onchocerciasis in savannah and rain forest, r. Soc. trop. Med. Hyg. , 57, 64-70 Bradley, A. K. Nigeria, (L97 6) Trans. (1963b) The incidence of microfilariae in the eye and of ocular lesions to the age and sex of persons living in conrmunities where onchocerciasis Trans. R. Soc . trop. Med. Hye ., 57, 7L-75 Budden, F. H. relation endemic, Crosskey, R. med. J. w. (1954a)(n.s.), 8, 1n IS Onchocerciasis in the Galma valley area, Northern Nigeria, W. Afr. 75-79 Crosskey, R. W. (1954b) InfecEion of Simulium damnosr.m with Onchocerca volvulus during the wet season in Northern Nigeria, Ann. trop. Med. Parasit. , 48, L52-L5g Crosskey, R. t'I. (1955) Observations on the bionomics of adult Simullum damnosuo Theobald(Diptera, Simuliidae) in Northern Nigeria, Ann. troD. Med. Par 49, L42-L53 Crosskey, R. W. (1956) The distribution of Simulirn damnosum Theobald in Northern N igeria, Trans. r. Soc. trop. Med. Hve ., 50, 379-392 as it. Crosskey, R. W. (1957a) Man-bit.ing behaviour and infection with developing filariae, in Simulium bovis de Meillon in Northern Nigeria, Ann. troD . Med. Parasit. , II, 8o-86 Crosskey, R. W. (1957b) Further observaEions on infection of Sinuliuo daronosr-u with Onchocerca volvulus in Northern N igeria, Tre4s. r. Soc. trop. Med. Hyg. ,51,541-548 Crosskey, R. W. (1958a) The body weight in unfed Simuliua dnmnosum Theobald , and its relationto the time of biting, the fat-body and age, Ann. trop Med. Parasit. , 52, L49-L57 Crosskey, R. W. (1958b) First results in the control of Simulir.rm dannosum Theobald (Diptera; Simuliidae) in Northern Nigeria, lql 1. ent. Res., g, ll5-735 Crosskey, R. W. (1960) Distribution records of the black-flies (Diprera: Sirnuliidae) ofNigeria and the Southern Cameroons, with a key for their identification in the pupal s tage, Jl I"I Afr Sci. Ass. , 6, 27-45 I vBcf78.6 Page 12 Annex 1 Crosskey, R. W. engorgement Crosskey, R. Nature, Crosskey, R. W. & Crosskey, I"1. under t\renty years of age @!!. , 53, lO-24 in an endemic area in NorEhern Nigeria, Ann. trop. Med. (tg'Z) Observations on the upt.ake of human blood by Simuliurm damnosum: the time and size of the blood-meaI, Ann. trop. 4q4. tglg!]!., 56, 141-148 W. & Crosskey, M. E. (1958) Filarial infection in Simulium griseiqglle Becker, Lond. , lL1., 713 E. (1959) A quantitative survey of onchocerciasis in persons I Da' . B. (1963a) Further distribution records of the black-flies (Diptera: Simuliidae) 1ge ria with notes on the occurrence of Simulium damnosurr Theo. in abnormal situations, Afr. Sci. Ass. , 7, L34-L37 Davies, J. B. (1963b) An assessment of Ehe insecticidal control of Simulium damnosum Theobald in Abuja Emirate, Northern Nigeria, from 1955 to 1960. I. The effect prevalence of onchocerciasis in the human populati-on, Ann. trop. l,led. Parasit., ,J fN 1W vtes o J 161-181 Davies, J. B. (1965) An assessment of the insecEicidal control of Simulir.rm damnosum Theobald in Abuja Emirate, Northern Nigeria, from 1955 to 1960. II. The effect on the incidence of Onchocerca larvae in Ehe vector, Ann. trop. Med. Parasit.,59r 43-46 Davi-es, J. B. (1966) A reporE on the Simulium Control Scheme at Abuja, Northern Nigeria and its effect on the prevalence of onchocerciasis in the area. Unpublished mimeographed document wHo/oNcHo/66.54 Rev. l (arn/oucrr/l1 Rev. l), 29 pp. Davies, J. B. (1968) The !imql:Lum Control Scheme at Abuja, Northern Nigeria, and its effect on the prevalence of onchocerciasis in the area, Bull. Wld Hlth Or ., 39, L87-2o7 Davies, J. B., Crosskey, R. W., Johnston, M. R. L. & Crosskey, M. E. (1962) The control of Simuliuu damnosum at Abuja, Northern Nigeria, 1955-60, Bull. Wld Hlth Or .r 27, 491-510 Duke, B. O. L. (1968) Studies on factors influencing the transmission of onchocerciasis. IV. The biting cycles, infecEive biting density and transmission potential ofttforesttr Simulium damnosum, Ann. trop. Med. Parasit., 62, 95-106 Dyce Sharp, N. A. (L926) A contribuEion to Ehe study some observations on its prevalence in Nigeria, 373-388 of Onchocerca volvulus Leuckart, Trans. r. Soc. trop. Med. Hyg., Grenier, P., Mouchet, J Rageau, J. & Adao, J. P. (1961) Simulies de la R6publique du PaEh. exot., 54, 1131-1143Cameroun, BuI1. Soc. Ikejiani, O. (1959) A laboratory epidemiological study of cerEai-n infectious diseases in Nigeria, W. Afr. med. J. (n.s.), 8,37-42 on the 57, wi Eh 19, IvBcf78.6 Page 13 Annex 1 Lewis, D Ann Observations on Simulium damnosum Theobald at Lokoj in Northern Nigeria, Parasit , 52, 216-23L Nnochiri, E. (1964) Studies on the epidemiology of onchocerciasis in Ehe Ibadan area of western Nigeria, W. Afr. med. J. (n.s.), 13, 139-15O Nwokolo, C. (1950) Studies in onchocerciasis (A review of 1OO cases from Enugu District of Eastern Nigeria), Trans. r. Soc. trop. Med. Hyg , 43, 493-5OL J. ( 19s8) trop. Med. Philippon, B., S6chan, Y. & Bernadou, J. (1969) Map showing damnosum in West Africa (situation in October 1968). wnoftlrcno/6g.73, 5 + viii pp. t Parsons, A. C. (1909) Filaria volvulus Leuckart, iEs distribution, structure and pathological ef fecrs, p"...itoGilI65'II359-368. fini" paper has been wrongly dated by mosE authors as 1908. IE appears in Ehe journal part nominally_for December 1908 but not issued unEil 11 March 1909 as stated on the original coverJ Rodger, F. C. (L973) The Simulium Control prevalence of ocular onchocerciasis, the distribution of Simulium Unpublished mimeographed document Scheme at Abuja, North Nigeria, and its effect on the Trans. r. Soc. trop. Med. Hye. , 67, 225-237 Ann. trop. Med. Parasit. Simpson, J. Bul1. J. (lgLZ) Entomological research in British West Africa. II. Northern Nigeria, ent Res. , 2, 3oL-356 Vajime, C. G. & Dunbar, R. W. (1975) Chromosomal identification of eight species of the subge nus Edwardsellum near and includi ng Simulium (Edwardsellum) damnosum Theobald(Diptera: Simuliidae), Tropenmed. Parasit., 26, 111-138 Wa1sh, J. F. (1968)'rFifty years of applied entomology in Nigeriarr. The Simuliidae and'their control with special reference to the Kainji control scheme. pp 1O1-106 in Fifty years Ctptre4 lllgqqlgsy iB \ip1ia , pt II (being the Proceedings of a conference of Ehe Entomological Society of Nigeria held at the Nigerian Institute for Trypanosomiasis Research, Kaduna, 25-28 March 1968) Walsh, J. F. (1970) The control of Simulium damnosum in Ehe river Niger and its tributaries in relation to the Kainji Lake Research Project, covering the period 1961 to 1969. Unpublished mimeographed documerLE PD/7O.4, 33 pp. ttl,lya ,, G. B. (1971) Onchocerciasis in Ibarapa, Western State, Nigeria, 65, 513-523 vBc/78.6 Page 14 ANNEX 2 I a e o o o o dlIdl o al 6HI zlr I €l x!l M6l o ol d al o Ll €dl x ul Egl , o I oo x o a d ! o at <HIEl I I udoo ooEEoo >{trcpl o o .:lvv olLl M!ol c o >l .iL .rl trddl .i o =l 6 6l!oal? dolll rr I s o o E dt a o s ti 6F H I m.Oa oo .i.c .t() av o .e:, ( ! d € q o o -d .rU!ko60oi looldo Iltt cHHz @ HAHfiaq> OiOoz&A0{H zd<oHO&4UFJOJHoz.) o o o € E ; >lN!l u o .;l E d ol o o Hl 6.i ol 6 ! >l o o 'il L L cl .d i =l > xI rtOl dvql Hl r FH zD J a oHE zooH tr !.i > 4O .do o 6o q o oqo I oq '1 00{ o ri@ dltt zoH ts frH @HzH Eo o o!6000tr o.n oO dr o o 6 0d! tr ad o.i 5 ! t o E o 8Jo HEH &E d.J O o oiioq Orq EOO laa!d6 ! H trqd6 0q o ao 6 ri H H H H o cltt tul ou ! .doo s.r o! o o.i .i r oqd oiq 5 600JUq G.i OOEqa !ooqHl!kdq o I ad oq .d ol o a o d! ol O 6l riio3t rtul rrrr d H o H c H o GI E E & (9 o c tu o d c !l o ol6 olq olq a@l d ! lu o H6lO Hl u H '-i Hl o H olo I d ll 6 ol o oOl d ol aJlo (l N 6ttE ral rQ .AdO sd.iOio o.i ( O! . u a Eqd o!q o !< d JJJ@ ! o o oq 6 E I d o EOH oUO r6 rtu ! dd !4!oo4dE .rvo O! o!d o.iEmuooc !i6q E^ oO ..i o E ao , oo6 ora itl H o o o 4 E ou>OH o N6 IQ z() H tu =4U rloc E{zoo @H 6 soE HuoEozo z &a Hz a H Ec5 Er o5d tsq Hq oe dtu h 5ocsooAl 6.duOl .d!ool c E o .t o .ild&ot!xoO[rE@ d € dV ololxlool o aladl o -\6 UIJ '-ll dzl .c Nc) .36 o Elaq qr x k 6 i , El o0 or O c dq A Er O Et u € ''.;H q dr -J Er o i ! !H Y kr O iit O d D ot o 6 oor E o o o -- pl !r t.i or q 6 c;a(, -Cl rr o k tsr -e c 6 o 'iAZ \ r.d G Qr o o .) o uE: H (Jl €r o r r 6 i o ! .d.;@HEl Orddt.;6>,!g!Q < >l Er @ E 6i o !j o i A o44 _l @r F cr ! o >, c OOO Ol'ir o. or ouLiae6FA iEl dr u o .it a x, o H dtu { !l 3r o . ur O o o A ij ltFl 6t O.r .it Eg !r !r > v !r o r r r IF O . @t 5t c3O r Ht I <t O vRcf78.6 Page 15 ANNEX 3 I G o FT rdHJoorinNiioooioNooroo.+N6 I Q Jh N J!j$ d-E NN $r Nts o6 \<a N ,;6 *l N o !Z ! o o o NN (!t (! 6!z o o @ NN !6 o, o!\<a NN 6 cc E o o q N l! oJ o FI ! ou o oo rd dJ .crr\tHdNd Xo u: 3E rJ d; -tdi-tirNr o! roE!dHo6 :E5 v Jrrioodd6NrditrtdN.gdtnrNN< o c c o ok oA Io.oo Hg9U o! .A>r X -o Hv!\ d I o!k!.d(u d 00d o 6.d u.HE O d.r ! x o !5A Oq @ r.d-t oHH.d d a-\ &q E o o o xo o od! odo.d M d .d @ d c-\ c H cq.c @, 'dll d 01, o o ! d o . o !! > ! o .d.c k c! H o o.d d 6 .E Ad O 6 ri o s 5 0()OA{(JFlz(,=O()= Hq ts: o >! 6 od .do AAH()o!a, E OH>r O Xu ! o'd pu go a>H duuQc9o{-E6uo@o.l l!dk-\!o .d.rErHr€.@'d soo! 6n o c o-\! .d o Io o c.d x o.6 0 0 0 6 h oiidoro6.do@usOO!'r6 6!Cgkd-'\ dE E o E O ! O d O ii€ Ooo.d-E,.dq!!.>.HHop ! u o olt 6 o o o.d E o 6 6o cc ao6d!oo6k€d50 > aH<FFrCo>E<A<o()E ) o o H o 6 ad F ou Fd q d o :l a ts Hz Fl H(J o tsl H E Ha z F.to&Fz O coHUH il h oHilH dHc JE z2oa& tsIA N @ 6 o HOEom o.i ,t6oocao(!otdi .ro THo! ooE .do 2r) (! o F oosr6 0\taaa ooNdJr i O NI J oo o \:f,.+6o N il IANdNNNJO60 0N O{.r J! *H .+ HB' *{ I-, odoo @ .io o? x{ -\Y -t ov a o q { a(! .E o a6 g o o $ uq, o, \_<q A$ 6t c E ! o o @ i -t d I o >f ! o ! o o @ H( o h o H6 o .p, o a ooNro rN-t-tr ooN i o Ni a o 8 o N lNdr N NiO4\t Oh I idNiNNN <.d il i sa Jd i EEu=OYo:: lb Hr,'9[ *a d o aa aC ftl d o o oko 6u6 a doo! >,d ool !!l o oal o u ol a!l^ dlo d6do o cl 'i ! .dln d!.o .rrlE dhlv E oco o .dd c -d .d .toE .4o(,o o . oEd d oCEEU .io o .ctro so.i c c x .6 >.i .i H od o.U u O Ho6 ddfo00r o o u co a .r.i.il .iuaoauc aodq o6 !xE 6 6 5 ! ,HAOOOOh 6d o .9)l | .6NlO o . . Clo lio olo^ ovv .ilorlO O ^ o dt60 0 ! sl-\€oulr O O ! olvoo d ,al6r!6Clo-\Oo u 'ilo.r 6 E c Eld 6 0 0 dlE oo ti < oI ol! co .t .i o!eo o d ul o 6 E^ trlo E o \t olo H k Eto o o oo I o do L N ! cil u .il ao o d'r! o alo.io!!d!i6 o 6 ! o 6 ! d v olo o q oor ts , Io o r .t 5 0 0 0 El!!a!oaoEdiOoOqav6!ol .d! o o 6 n o .iJEoodo ()h hl !oc, .do o^ ^ o E ^! o d f a! 5lui 6 > o .J ulul@! tll o , >lclr 6 o 6 d vloloou 660 q, I61 6 ! O 6 .9 ulal d o r o r o @ dl .dl:d ro v.H H, olslvv o @ g o o 6ld o50 No dol 4coE ! L o d .dlle E e a o d o d alitd6{5uikJ66laJdqd5qiololrr!9orol .rl9 ! u 6 (, 0 a o .ltl.d.d ! t d c o o 3lold d o b o ..{ o .i 6l z,lqoO r(,oA= '.Il 50!o o .ro.d dk 6t.J6l i(r! q v600td > o or.iekad ! p 6rC, € O^q ,a I @ Qda o aa o o od.i! o d E No! r o d E.iv.i EE H O o €tr1 uo I >r c .J I >|v ts H Ool! O A! ! od .d!l H o E , r @ o.d 'Edl O 'd O O, E 6()l.f L) k FI E @ d N vrcfta.o page 16 ANNEX 4 @ o N Hz E]EaH 5 H I H q #a az @dE Fd4 =d a tsI z() H g 4 lfo&Hz o @ H a so&Eoofo4 sd tsI(, Hz N vBcf78 .6 MAP 'l PaEe L7 The geographical distribution of known breeding sites of Simulium damnosum s. l. in the river systems of Nigeria. (From data available to 1977). Rivers that normally flow only in the wet season are shown with broken lines. See text for further explanation of the symbols used. The dotted line around the Jos Plateau represents the 1000 metre contour. Ouery marks indicate improspected rivers in which breeding is expected to be found or near known onchocerciasis foci. J \ "g l. t I i,:-. .b.; t a 'q "'f". ) a l, ',1 E ".i.. ,., '1. t q' \'% - 't.- \.1. "o ",b ,r.io. -_ r x I II oIt\) N o a.t .= oLO -1' .:o 6:oL -eE c o: -Uoto9lo.=c-! =-ocSoI5;c oJ; .gta'E!cfqr=iEUSjEt llol.o eUI z E *r*r, \. vBcf78.6 Page 18 MAP 2 The geographical distribution of breeding sites, and of capture sites of adult females other than at known breeding sites, of Simulium damnosum s. L in Nigeria in relation to simplified basic geology. (From data available to 1977). Sedimentary/alluvial areas unshaded and contrasted with precambrian basement complex that has not been inundated by the sea. 100 km Sedimentaries ^ Adult f lies f ound man-biting at sites other than known brecding sites o Natural breeding sites O Man-made breeding sitesPrecambrnn (volcanics rncluded) wHo 7EE46 JD '!.. 'a ia ''.. i ,11 od6 a , ( wcf7}.6 Page 19 MAP 3 The geographical distribution of human onchocerciasis in Nigeria, with an approximate indication of prevalences and outlines of the major endemic zones (From data available to 19771 F.C.T. : Federal Capital Territory. ?,w 100 km o 0nchocerciasis not found (Budden, 1956) o Low prevalcnces . Moderate prcvalcnccs O High prevalcnces (with serious onchocercal blindncs) '......"' 0utlines of main endamic zoncs State boundaries tyHo 7E84E ( I t 1 t t i t I I \ BORNO NIGER T I F. C.T. o o o o a o oBAUCH I o a ,v 95. i_ / 7 o o 1u o oo a o a a Orl 3 1 19(. / KAOUNA ..i aa C- i) a I a o , -6i ..q KAilO -PLATEAU ..., d o o 'd-r-OO(OoO ? ) I )2 o o o o soKoro I /r 1 .!o \ ol o) -9,p 4 ,, .tf GOIIGOLA XWARA 5 o I t OGUN a a ONDO a 9 ^', ? )t_ a BENDEL a t ,Q- ) _t ( a o o t' RIVERS o -r IMO I -l a a! .t ANAMBRA i cRoss r RIVER BENUE a o wcf78.6 Page 20 MAP 4 DISTRIBUTION OF PRELIMINARY STUDIES AND CONTROL AREAS o4.t .u a N o t a , \ ) o(, o EE €8:6=- =88EEioc= -uJg, ffist a q, G Eo olt I i \.-' E l ot Or -Yl _31 ., 'r.;ir- \ l I I o a F O) ,(o ,lg e 6 El.EI =l o't \ o, (o Ie ) '-\., a, rE CL E ii \i -t'9J"- i-- c. llJ 9 z Nqte