Report to the Scientific and Technical Advisory Committee on a visit to the Onchocerciasis Control Programme in the Volta River Basin Area: 19-29 January 1976

@ ONCHOCERCIASI S CONTROL PROGRAMME IN THE VOLTA RIVER BASIN AREA SCIEI.ITIFIC AND TECHNTCAL ADVISORY COMMITTEE Third Meeti ns Geneva, 2 to 4 March 1976 Agenda item 4 ocP/srAca.6 ORIGINAL: ENGLISH RESTRICTED Report to the Sc ient i fic and Technical Advisory Committee on a visit to the Onchocerc iasis Control Programne in the Volta River Basin Area 19-29 January by Dr Letitia E. 1976 Obeng United Nations Environment Programme, Nairobi, Kenya I I United Nations Environment Programme - Programme des Nations Unies pour I'environnement' I DR LETITIA E. OBENG MEMBER. STAC/OCP REPORT ON A FIELD STUDY TOUR OF THE ONCHOCERCIASIS CONTROL PROGRAIVIME AREA L9-29 January l-916 The trip was undertaken with Dr C. Gibson, Member. STAC. Tour Progfetnme. 19 -fenrrArv 197 6 , Ou adougou. Uooer Volta. ' We visited the Headquarters of the OCP in the afternoon and had briefing on the programme from Dr Zeigler and his staff. 20 Januarv : Trip from Ou adougou to Tamale in Ghana: On the way we stopped at the Nagbangare barr age which is on a tributary of the White Volta and an active breeding site in the rainy season. The Red Volta was drv and represented bv a stagnant pool. The White Volta was low but actively breeding Simulium. We collected samples. We visited the laboratory at Bolga-tanga. We stopped at the Sector headquarters of Tamale and we joined the Epidemiological Team for the nigh t at Janga Village. 21 January We returned to Tamale and visited Naweni treatment site on the White Volta. 22 January We went to the Village Sugu north of Tamale where we met the Epidemiological team again. 23 January We left by helicopter for Bobo- aulasso . We stopped at Daboya treatment site where the breeding site was of stones piled on the dorvnstream site of a long bridge. r colrected few larvae United Nations Environment Programme - Programme des Nations Unies pour I'environnement. -2- and pupae of Simulium and egg masses which were abundant. We followed the Whice Volca and the Mol e river out of Ghana and afE.er sEopping at Ehe Chache breeding site on the Black Volta flew along the course, notinB the breeding siEes, co Bobo-Dioulasso, Upper VoLta. 24 January we met. Dr Le Berre and his scaff and had a briefing from t,hem. 2t5 Jqlgary_: The morning was sPent. at the Bobo office where rde sat in Ehe meeE,ing of sub-secEor heads reportlng on Eheir fry catches for the previous week. In che afEernoon we saw a demonsEraEion of aerlal spraying by a helicopEer and a fixed wing plane, on Ehe Samandeni near Bobo. 27 .Ianuarv: We went Eo Ehe Slkasso st.atlon in Mali. On t.he way we sEopped at, a site Banfulaque where the Black Vo1ta flows over and chrough huge rocks and gorges.- I collecced some Slmulium larvae. At breeding sit.e near Lanviera on the Plandl?- chere were larvae of Simulium spp. We flew over a number of breedtng sites on the river. On t.he return journey we stopped aE. Ehe il9IHO Damrr where as an experimenE, a number of different slopes for spillwap had been consErucEed over a river. The surface of che spillways r^rere coat,ed wiEh larvae and pupae of Simulium. 28 Jaquary_i iouqk€, I\rary leeE! We vlsited Ehe O.R.S.T.O.M. laboraEory. I was very much impressed by Ehe work of t,his team. AE both Janga and Sugu the co-operaEion of the villagers was a credlt to the social and prbllc relatlons of che SecEion. EssenEially the survey progrzulEre lncludes reglstraEion (by familfes); examinaEion for head and body nodules; skin blospy and microscopic examinaEioni preparation of blood samples; acuicy and vision EesE. AE Janga vlllage 229 persons were examined. 68 blind men rePorted to Ehe Team. t Epidemioloeical Evaluacion Section United Nations Environment Programme - Programme des Nations Unies pour I'environnement. -3- IE seems Eo me that the number of project staff lnvolved in this work is not collunensurate wit,h the magnitude of the work. I was rather surprised Eo noEe thac there are no ?rlocalrr (meaning persons from the progranune area) counEerPart staff and no parEicipation by rrlocalil medical and scientific persons aE. Ehe professional level. The E.echnical side however was very ably manned by "locaIil peopLe. In spite of the difficulcy in recruiEing ?rlocalrt medical professionals, iE would seem desirable chac some way is found to involve the illocalrrpeople. It woul'i be a pit.y not. to ensure through local parciclpacion, the conEinuity of a Prograflme of such imporEance which is expected t,o last so long. Perhaps Ehen, with more sEaff, additional methods like che urine r.esE. which I undetstood in hyperendemic areas E.ends Eo be more senstive chan che skin Eest may be undert.aken. There ls also an opporEune pot.encial in the survey work of Ehe E,eamrto collecE and prepare material for educat,lon of nurses and ot.her workers in this fleld. Although it. may not be part of t.he responstbiliE.ies of che Progrartme, trith addition Eo prefesslonal staff perhaps, folLowing rhe identification of head nodules some could be removed. I uriderscand Ehis may minimise che risk of blindness ln chlldren. Let, me sEress t.hat I am aware chat these suggesEions may not be irunediaEely written in t,he Eerms of the prograrrune buE Ehey may contribuEe in some uray to lts final success. Treatment ODerat,ion The spraying Eeam certalnly is good at it,s work of dropping rhe chemical. The weekly t,reatment ensures continos: suppreslon of the simulium larvae. BuE at Periods when eggs are most abundant in the aquatlc phase, as it was ac Daboya, EreaEment. of the fuII beneflt oay noE be realised. VecEor Evalu tion Studies Enthusiastic work is belng done in this very important, seccion of che prograflrme. Surveillance 1s maincalned and larval sEages diligencly sought afcer t,he aerial treatment.. Fly boys paCiently catch unsuspecting flies aE breeding slt.es. Because of che known long flighE range of the fly, I should like ro suggesr rhac fly boys c,ry t.o obEain some informaE.lon of blting in villages, rice fields and oEher working places. Sugu village is quite close to a White Volta breeding sice all people examlned by the epidemiology EeEIm, young and old, were posiEive. How many United Nations Environment Programme - Programme des Nations Unies pour I'environnement, -4- are biEcen whlle in E.he village ? AE. Janga where the villagers are ei:her rice farmers or fishermen, infection is high. Do che rice farmers get bitten while in che field ? rn pract.ice, such a sampling may be difficult bur ir could also provide furcher informarion on rhe fLy fIight par.Eern. May I recorrnend also that a corresponding survey and stmpling of Larval stages of$damnosum is undertaken even lf only on a limited scale. If properly done, there could be a means of correlating the larval breeding cycle vrith the resulEs of rhe fl-y boys catches and vice versa. one advant,age would be thac iE may confirm, through field work, lf indeed wiEhln the t,reatmenE area and under existing conditions at breeding sites, conElnuous oviposiE.ion of !. damnosum does occur. IE is generally accepted that Ehere is no reliable mechod for sampling larvae quanEitatively but thac should noE be a barrier E.o obtalning the information. rf there is conEinorrs oviposition, how does it relaEe co the developrnenE and maEuraEion rat.e of t,he Larvae and their population discrlbution ? How may this be related to hand treatment of locallsed areas which r understood supplements the aerial spraying ? rf. t.Ly boys catch uninfecred flies, would they have come from the breeding site which E.hey'man or from elsewhere ? The information collected could provlde guidance. The reason for introducing this aspecE inEo t,he prograrune r betieve was so as to be informed of the effecE of the chemical formulacions used in the conErol of S. damnosum on non-EargeE organisms, waEerr mudr eEc. and on the quality of the water entering the Volta Lake. From whar I gat,hered although smpling is being done on Ehe oti and Black Volca which will provlde baseline dat.a, on ghe whiEe volta in the Phase r area, however, the sampling progratune is noE relaced reaily Eo the traaEment Prografirlle. The inEerval which lapses bet.ween sampling and Ereatment is quite long and from a cursory glance aE, Ehe range and population disEribuEion of the fauna so far recordedrt.here may not be a reliable refLection of the effect of the treatment. on the organisms. It was easy to find botEom dwellers on stones ln created areas. This is to be expected since the chemicals riay pass fasE. especiatly at. breeding sit.es. t United Nations Environment Programme - Programme des Nations Unies pour I'environnement. a -5- The pelagic surface dwellers are likely to be more affecced and removed. BuE. with Ehe passage of time and che normal drift, che t.reaE,ed area may become rapidly recoloni sed. The monitorlng prograrune ls intended to provide guidance. If ic is undertaken ouE of context wit,h the overall progranme, as lt seems Eo be now, it. may noE serve much purpose and may {'ven be misleading. There is liccle doubt that against desEroying S. damnosum in order Eo prevenr, blindness, desEruct.ion of other fauna and conEamlnat,ion would be a price Eo pay. But. if it is intendec'Eo study the effecc then it would be desirable to forge some co-ordlnation of this section worEh the ot.hers. Research It uras very refreshing to visit che Bouake Laboratory where programnes are betng undertaken on g. .$@i]g cyEocypes, larvar sampling, adult sampling, testlng of larval sampllngl adult sanpling, E.esting of larvlacldes, standardlsation of larviacides.evaluaEion and biological control wlth merolthids. The results which are emerglng should herp to fill some of che gaps inourlnfor.mation. Ocher cootrent It is always dangerous Eo draw some conclusions. At the flrst meetlng of the STAC, the matter of considering in ghe near fuEure, the provlston of laboratory facllitles for undertaking sanrple analysls, establishlng fly colonles, eEc., wLthln the OCP area was raised. The tour has conflrmed for me EhaE on a long-Eerm basis, Ehls ls essentlal and should be given serlous attenEion so that whacever tralning may be requlred is initiaced. r raise a[so the matter of considering habitat, modlficat.ion of breeding sires, where feasible, as an additlonal element to the present, conErol prografttre. An aerial vlew confirms Ehe locallsed dist.ribucion of acEive breeding sit,es (during the season of my vislE). some of the breeding sit.es are man-made and usualry consist of stones and rocks plled ln the stream-bed buE moveable. The movlng I"ater encounEering Ehe obsE.ruct.ion cascades over the sEones to provlde breedlng sit'es. In ocher insEances Erailing vegetatlon which provlde sultable habirats for Larvae and ovlposition may be removed. I I a United Nations Environment Programme - Programme des Nations Unies pour I'environnement. -6- HabiEac modificat.ion Eends co be a dlfficult. operation buE iE is not impossible. I saw, one breeding site for example which is a chain of rocks and sEones in raEher shallow water and may be easily cleared. Wit,h marginal veget,ation destroyed and the banks suitably modified t,he area may become unsuitable for Simulium breeding. Finally, it. is Possible t.o encourage National CoffitritEees to be concerned with Ehe EreaEmenE of breeding areas outside Ehe treatmenE area buE from which flies re-infesE EreaEed areas ? And can they get t,he scienEific and medical conrnuniEies in eheir counEries interested ln Ehe Progranme ? Acknowledqement I should like co record sincere thanks for Ehe recepEion given us and che kind hospitality of che officers of che Progranrme. The trip was really worthwhile. I I it I