WORLD HEALTH ORGANISATION MON D~ALE ORGANIZATION DE LA SANTE Uganda 17 AFR/Oncho/8 Rev.l ~~. : ·~:·~ . WHO/Oncho/30.65 Rev.l . .. ·.. ENGLISH ONLY (Conclusions et recom­ mandations en fran9ais) ONCHOCERCIASIS AND.ITS CONTROL IN UGANDA by . 1. 2 M. J. Colbourne and R. W. Crosskey WHO Consultants .. CONI'ENTS 1. Introduction • • • • • • . 3 ,. 2. General description of Uganda . 4 Onchocerciasis distribution • . 6 Uganda- and Africa as· a~ whole • •. • • • • • • • • • • • . c... 6 Broad pictUre of onchocerciasis in U~anda . 6 Onchocer~iasis foci in Uganda •.•••••• . 8 3.3.1 The main proven foci • • • • • • • • • • • • • • • • 8 ~.,.2 Lfttle known ahd suspected foci · • • • • • • • • • • 10 3.3.3 Known vector areas without known disease • • • • • • 11 3.3.4 . Negative· areas • • • • • • • • • • • • . 11 4. Onchocerciasis· s\lrvey ·and control to date in Uganda . 11 4.1 · Vector· Contr.ol Division ·(vCD) •••• . 11 4.1.1 Constitution and.functions •• . .. 11 4.1.2 Work of the Division to date • . 12 4.2 Clinical work . 16 4.3 Other work •• . 18 5. Importance of onchocerciasis to Uganda . 18 1 Department of Social Medicine, University of Singapore. 2 Conunonweal th Inst;itute of Entomology, London. AFR/Oncho/8 WHO/Oncho/30. 65 page 2 ~ 6. Discussion of special problems in Uganda . • • • . 22 6.-1" The border problem • . 22 6.2 Non-anthropophily of vectors • . ' . 22 6.3 Place of drug treatment . 24 6.4 Eradication by attrition • . • • • . 24 6.5 Do-it-yourself dosing . • • • • • • • • 26 Conclusions and recommendations . Conclusions and recommendations . Z7 7.1.1 Main conclusions • • • • • • • • • • • • • • . 27 7.1.2 Additional technical conclusions •••••• . 29 7.1.3 Conclusions on priorities . 30 7.2 Phasing of control and its integration into a communicable disease service . 31 Conclusions et recommandations (en fran9ais) • . 33 7.1 Conclusions et recommandations ••• . - . 33 7.1.1 Principales conclusions • • • • • • • • • • • • • • • • • 33 . 7 .1.2 Conclusions techniques supplementaires • • • • • • • • • • 35 7.1.3 Conclusions rel.a~ives aux priorites ••••••••••• 36 8. Acknowledgements • ·• • • • • • ·• • . • • . .. References . .• . ~· . .. .. 39 Ann,ex 1. .. I.t1ne~ar'Y, • • • • • . • • • • • • • • • • • • • • • • • • • 42 Annex 2. Detailed review of main onchocerciasis foci • • • • • • • • • 45 Annex 3. Historical resume of work to date. .. 76 Annex 4. List of personal entomological findings ••••••••.•.•••• 8o Map. Approxim~te known distribution_of onchocerciasis in Uganda ::. AFR /Oncho/8 WHO/Oncho/30.65 page 3 ··r-·· \.' . .. ; ;- .·. ,._ 1. INTRODUCTION ..; ! :.,_. The writers visited Uganda from 9 October until 14·Noverriber 1964, and the terms of reference were "to make a preliminary assessment of the onchocerc-iasis problem in that country and to advise on control methods with a view to establishing priorities for the initiation of control campaigns in the various foci". This assignment required investigation into every aspect of past and present work on onchocerciasis and its Simulium vectors·, ~d this report is iri part a' digest of all · that is known of the disease in Uganda and of the control work that has already been carried out. The conclusions presented in this report (Section 7) derive from the · threetypes of available infoma.tion: firstly from,consultation and discussion with every­ one interested in or in any,~ .way. ·concerned with onchocerciasis and its control (officials of the Ministry of Health, personnel of the Vector Control Division, senior and district medical officers responsible for regions and districts where the disease occurs, d!strict health inspectors, medical assistants, staff of mission hospitals and speciali~ts at _the ~kerere University College); secondly fx-om c;locumenta.ry info~tion including departmental files, published scient~fic papers and semi-published documents '; • · ..1· • •. .·· • • . • . • ·' -··.· such a~ WHO. 7eports; and thirdl;y: from the writers'- extensive study tour .of all the .main ~reas . .. : onchocerciasis in. the country.. .,, . '. Three and a half weeks.rwere spent in the field; all the'tnain onchocerciasis areas being visited: by a single· long•.circuit safari (full d~tails of the itinerary are given in Annex 1). This tour- of.· the foci ·was paJ7ticularly valuable in demonstrating the different types of environment in which the disease occurs, the varied topography influencing the prospects for control, and ~e diverse ways in which onchocerciasis and • • : !'• ·.'' . .'.. • .·• Simulium can impinge on the economic well-peing of Uganda. While on safari in the ----- ·.. - . ~ , .. - . : . various foci, collectiol)S were made of vector. Simulium and these are enumerated in Annex 4. '. ~~-------~ Attention should be drawn to a few points concerning the report. It was considered undesirable to burden the body of the report with too' much detail about the main onchocerciasis foci, and therefore most •of·. the factual data on these foci has been ·placed in Annex 2, where it is readily available for• the· more specialist reader. AFR /Oncho/8 WHO/Oncho/30.65 page 4 The Vector Control Division figures frequently in the report, and to avoid repetition of the name in full the abbreviation VCD has been adopted. Throughout the report, following a practice of the VCD, the name Murchison Nile has been used for that stretch of the River Nile between Lake Kyoga and Lake Albert, and the Murchison Nile Focus is used for that onchocerciasis area centred upon it; however, it should be pointed out that on maps both the stretches of the Nile from Lake Victoria to Lake Kyoga and that from Lake Kyoga to Lake Albert are called the Victoria Nile. Since there are foci on both stretches it is far the _most convenient for the purposes rJf this report to distinguish the Kyoga-;~1 bt:rt s t.retch by the name Murchison Nile. The very greatest co-operation and courtesy was received from all concerned with this visit to Uganda, and the writers have pleasure in acknowledging this more fully in Section 8. 2. GENERAL DESCRIPl'ION OF UGANDA Most of Uganda lies between 3000 and 4500 feet aboye sea-level and forms part of the ancient landmass of Africa which has not been overlain by the sea, but the periphery of the country consists in part of mountain massifs which rise far above the flat or undulating hinterland. In the east on the Kenya border Mount Elgon attains more than 14 000 feet, and the Ruwenzori on the western (Congo) border rises to nearly 17 000 feet with perpetual glaciers; in the south-west the irregular highlands of Kigezi are in part over 8ooo feet arid the extinct volcanoes of Mufumbiro (forming the frontier with Rwanda) reach over 13 000 feet. Uganda is land-locked (bordered to the south-east by Lake Victoria) and its rivers are ~ithout direct outlet to the sea, feeding almost entirely to the Nile wbich bisects the central·table-land of Uganda in a meandering course from Lake Victoria to the Sudan border in the ·extreme north of the country. The Nile within Uganda is in three parts; a first stretch frOm Jinja to the swampy Lake Kyoga in the south central part of the country, a second stretch from Lake Kyoga to Lake Albert, and a third stretch from the northern outlet of Lake Albert to the Sudan "bend" at Nirnule. The first two stretches AFR:/Oncho/8 WHO/Oncho/30 .• 65 page 5 (Victoria Nile and Murchison Nile) flow over precarnbrian basement and are largely rocky with rapids.and falls: the third stre~ch (Albert Nile) is broad and smooth, flowing over sedimentaries. The western boundary of Uganda with the Congo lies to a larg~ extent along .watersheds, that part of the boundary in We~t Nile District lying on the • 4. ' •• divide betweeQ headwaters of the Congo and:Nile rivers; on~y in a few places do rive~s . ' - -··· originating o~ts~de.en.ter Uganda territory.. On the other hand virtually all the waters of Uganda.leave it by the Nile. Most -of Uganda, being densely populated by African standards,' is heavily cultivated (principally with banana, cassava, cereals, sugar, coffee, tea and cotton) and the natural .vegetation has been correspondingly reduced. Large stands (some 60oo square miles altogether) of undisturbed tropical forest still exist, mainly as follows: in crescentic bands on the slopes of Mount Elgon and Ruwenzori; Budongo, Siba and Bugoma Forests (Bunyoro District); Kibale Forest (Toro District); Kalinzu Forest (Ankole District); and the Maramagambo and impenetrable forests (Kigezi District). In other areas where there is no cultivation the natural vegetation consists of open savannah woodland or. 'rolli.ll8: grassland With only scatt~red trees ~ The rain(all i~ between 35 and 70 inches a year in almost all qf Uganda, eJ(ceeding •. : ~ ;. •. .'. ~ 70 in.ch~ only on ,Mo~:t El.gon and in parts of Kige~i. The rainfall distribution is · •. • • • ~ •- ~ I • .. ,." • • . sea~ons seas.qnal.;. ,.· .. but. .the dry . ... ·:. are much less severe than in the. savannahs of West Africa • The rainfall and relief is such.that almost all the rivers and streams .flow throughout ·' ~ · , • '· ., . t : •.• 'i . ; 1. ' • ·•- _ ·-· ~ •. ·· • • tll,e year; ~ost watercours,e,~;·:~-~.;;, Sl'rift,, . rocky and turbulent where theY. traverse the uplands or x:un down from,"l!r~ mountain massifs, but many.of them degeqe,rate into papyrus-choked swamps on reaching the base plains. The area of Uganda is 93 000 square miles, but the land surface only 80 000 square miles; almost all the land area is inhabited except for the two National Parks. The population 'is no~ about 6 500, ..-ooo .Md the me~~ populatio~ density appr~imately 80 to the ; ,, square mile. Distribution ~fpopulation is irregular and density is lo~est (0?59 per square mile) in the north-east and west-central parts of the country; in the south-east . ' against Lake Victoria and northwards to Mount Elgon, in southern Kigezi District, parts AFH /Oncho/8 WHO/Oncho/30.65 page.6 of the Ruwenzori and West Nile District many areas have more than 300 or 400 inhabitants per square mile.