Report of the seventeenth session of the ecological group: Lomé 31 January-2 February 1996

WORLD HEALTH ORGANIZATION ORGAMSATION MONDIALE DE LA SANTE ONCHOCERCIASIS CONTROL PROGRAMME IN WEST AFRICA PRoGRAMME DE LUTTE CONTRE L',ONCHOCERCOSE EN AFRIQLJE DE L',OUEST EXPERT ADVISORY COMMITTEE Seventeenth session Oragadoug6u. 1G14 June 1996 Annex 1 Annex 2 Annex 4 Annex 5 ocP/EACl7.1 ORIGINAL:FRENCH REPORT OF THE SEVENTEENTH SESSION OF THE ECOLOGICAL GROUP Lom6. 31 January-2 February 1996 TABLE OF CONTENTS Page SI'MMARYOFRECOMMENDATIONS... ......2 A. INTRODUCTION 3 B. ADOPTION OF THE AGENDA 5 C. REPORT ON THE VECTOR CONTROL ACTTVITIES . . . 5 D. OPERATIONAL RESEARCH AND NEW LARVICIDE FORMULATIONS . . . . . . . 6 E. RESULTS OF THE SURVEILLANCE ON AQUATIC EI.TVIRONMENT 8 F. WORK PROGRAMME FOR 1996/1997 . 12 G. CONSIDERATION ON AQUATTC EIWIRONMENT MONITORING IN THE PRESENTANDFUTUREOCPCONTEXT ...... 13 H. FOLLOW-IJP OF THE RECOMMENDATIONS OF THE SIXTEENTH SESSIONOFTHEECOLOGICALGROIJP ...... 14 I. , ARRANGEMENTS FOR THE NEXT SESSION 14 J. READINGANDAPPROVALOFRECOMMENDATIONS .,.... 14 K. CLOSURE OF THE SESSION 14 Annex 3 Operational organization of the aquatic environment monitoring List of participants List of documents Origin and evolution of the Ecological Group's mandate Main stages of the introduction of operational larvicides, l5 l6 t7 18 19 20 and methods and techniques of environmental risk assessment . . . . . . Annex 6 Work Programme for 1996 SUMMARY OF RECOMMENDATIONS The surnmary of the Ecological Group's recommendations is presented below: Recommendations to OCP Publication of the results of the study on the impact of Vectron (etofenprox) on the non tafget aquatic fauna @ara. 37). Delivery in 1996 of the necessary means for the prepamtion of reports on the 20 years aqrutic monitori4g and budgeting in 1997 of adequate funds for the publication of a consolidltcd doqrme,lrt on the results of the monitoring @ara. 65). Renewal of the 1987 recommendation to cease aquatic monitoriqg on the Mono river ud suspension of spot snrdies on the Ou6m€ river @ara. 61). Participation of the hydrobiolgy teams in the Maroua (Cameroon) seminar on environmeotrl impact studies (para. 63c). Recommendations to the hydrobioloeists 1. 2. 3. 4. 5. 6. Special attention to be paid to certain species of fish such as P. bovei and C. aufttfrs(para. 52). Consolidation of the environmental impact studies carried out in the different countries in 1995 and continuation of the routine monitoring of the selected stations listed in annetr 6(para.62b). Preparation of reports on the 20 years of aquatic monitoring, to be presented to the *[t meeting of the Ecological Group, following the work plans established during fte hydrobiologists meeting (para. 62d and 65). 7. Recommendations to the Committee of Soonsoring Asencies (CSA) 8. The Ecological Group felt that it was its duty to draw OCP and CSA attention m environmental issues likely to reach great magnitude in the years to come if a number of appropriate principles and recommendations are not established for the utilization of tte oncho-freed valleys wirhin the framework of an integrated environmental numagernent atd a sustainable development prospect. Three major issues of concern will emerge: - quantitative management of water resour@s (dams, irrigation) and its consequences on thc aquatic environment in terms of water quality; - public health issues linked to the evolution of both aquatic and land environments; - management and preservation of the habitats and of aquatic living resources keeping io mind that fishing activities for instance provide 200 000 tons of fish per year in the OCP arsa, the equivalent of about a 200 million dollar market value. Consequently, the Frological Group recommended that CSA should initiate specific studics to address these issues in the perspective of a sustainable development of the valleys. -3- A. INTRODUCTION 1. Thc Ecological Group held its seventeenth session from 31 january to 2 February 1996 in Lom6, Togo, under the chairmarrship of Professor D. Calamari. The three new members (Professor D. Colman, Professor V.H. Resh, and Mr F.H. Toornstra) were absent for reasons beyond their control and had asked to be excused. The lists of participants and of working documents are appended hereto as annexes I and 2 respectively. Opening session 2. The opening session ceremony was presided over by Dr K. Agbekou who, in the absence of the WHO Representative in Togo, on behalf of WHO/AFRO, welcomed the members of the Ecological Group and other participants from the different Participating Countries in the Prograrnme. He excused the WHO Representative who had had to depart for previously scheduled mission. He then indicrted that he was convinced that the results of the discussions would be fruitful considering the habitual scientific rigor demonstrated by the Group. He wished full success to the meeting and declared qen the seventeenth session of the Ecological Group. 3. On behalf of the Programme Director, Dr K.Y. Dadzie and on his own behalf, Dr J.M. Hougard, Chief Vector Control Unit (VCU), also welcomed the members of the Ecological Group and extended to them the Programme's best wishes for the new year. He thanked the WHO Representative for accepting to chair the opening ceremony of this seventeenth session of the Ecologicatr Group. He regretted the absence, for various reasons, of the new members of the Ecological Group, but indicated that he remained confident in the quality of the discussions and the adequacy of the deliberations. 4. Chief VCU then provided the Ecological Group with general information on the Programme. He commented on the regular VCU meetings which had taken place over the past 12 months: IRU and AREM meetings in May 1995 in Bouak6 (Cdte d'Ivoire); annual meeting of Eastern zone in October 1995 at Kara (Togo); annual meeting of the Western zone in November 1995 in Bamako (Mali). Four other meetings with VCU direct involvement were held in Ouagadougou (Operational Research and Strategies in March 1995 and Expert Advisory Committee in June 1995), in Cotonou @rainstorming session in October 1995) and in Washington (Joint Prograrrme Committee in December 1995). 5. With regard to the outcome of these moetings, Chief VCU higtrlighted the following salient points: - the pertinent conclusions of the Cotonou worlshop on actions to be undertaken in the coming years; - the design of a new technique for the identification of adult blacldlies by DNA probe (heteroduplex) which would allow a better understanding of the transmissionprocess under natural conditions; - the renewal of the Abbott contract for B.t. H-14 procurement over a period of three years starting on I January 1995, and that of the aerial contract awarded to the Evergreen Company (EHI) for three years starting on I January 1996; - the restructuring of the various units due to budgetary constraints and current evolution of the Programme. A coordinator position for the Director's office was created and the DEVO, EPI and BIS units were merged into one unit called PET (Planning, Evaluation and Transfer). As regards VCU, there was no restructuring as such but rather the closing down of some sub-s@tors essentially due to the definitive and progressive cessation of -4- larvicide treaunent in the various river basins. This, among other things, was materiatt2ed by the reconversion of the Barnako sub-sector into an Operational Base startingr on I January 1996, and the closing down of other sub-sectors (Kandi and Tamale by 31 December 1995) following the definitive cessation of aerial treatnrent of the Niger rlter tributaries in Benin, and of the White Volta in Ghana. 6. Finally, he informed participants of the departure in December 1995 of Dr C. Back (AREM Coordinator), of Mr J.M. Trudel (CAM) and of their respective replacement by Dr Y. Bis6an(currently Assistant to the CAT of the Western zone) and Mr Donald Miller previous Administrative and Financial Director of WHO/AFRO in Brazzaville (Congo). 7. In an introductory statement, Professor Calamari, chairman of the Ecological Grqry, welcomed Mr G. Ciparisse from FAO/Rome, Officer in charge of issues relating to the developffit of oncho-freed zones and rqrresentative of the Committee of Sponsoring Agencies (CSA) at &e Ecological Group meeting. Joint meeting between the Ecological Group and hglrobiologists 8. During the opening of the day of exchange of views between the national hydrobiologi*c, those of OCP, and members of the Ecological Group on 31 January 1996, Professor D. Calamti, the session's chairman, welcomed Dr C. IlvEque, a member of the Ecological Group, and gree6d the presence of Mrs A. Reenberg, an observer guest expert at this meeting of the Ecological Grorp. 9. He then made a presentation on the operational organization of the aquatic monitoring of watercourses under larvicide treatment, the origin and evolution of the Ecological Group's mand$c and lastly, the main phases of the introduction of the various operational larvicides as well as fu methods and techniques of environmental risks assessment (annexes 3, 4 and 5). The evolution of tlrc different strategies for larvicide evaluation was thus discussed as well as ttrat of acute toxicity tost methods and techniques, the medium term impact study of larvicides and risks evaluation. Thc presentation, which was highly appreciated by participants, was mainly aimed at briefing tlp hydrobiologists and new participants on the activities and attributions of the Ecological Group. 10. The Ecological Group pointed out that this evolution of the various strategies of larvicidc evaluation was to be closely related not only to the evolution of scientific knoweldge but also to Oc necessity of evaluating the long term impact of the used insecticides on an aquatic environment whioh is subject to other sources of aggression. ll. After the exchange of information between the members of the Ecological Group and tto hydrobiologists on issues concerning the Group's new mandate and the monitoring results, t& hydrobiologists thanked the Ecological Group for the efforts made to improve their knowledge ad the Programme for having given them the oppornrnity to spend a few days in Ouagadougou in ordor to further improve their knowledge. 12. The Ecological Group, for its part, congratulated the Programme for the attention it had always paid to the hydrobiologists. Field visit 13. The two members of the Ecological Group, the guest expert and part of the OCP staff who participated in the Ecological Group's meeting visited the hydroelectric dam of Nangbeto on the Mon6 River (Togo) on 3 February 1996. The environmental changes which resulted from the construction of this structure of great importance for Benin and Togo, the problems encountered as well as tlr beneficial aspects of the darn were discussed with the staff of the electric power station run by tbc Communaut6 Electrique du B6nin (CEB). Members of both parties showed a real interest in thie -5- exchange of views. The Deputy Director of the station (Dr Tchato Alloula) expressed the wish to maintain contact with the members of the Ecological Group with a view to benefiting from their expertise in the management of such an infrastructure. B. ADOPTION OF THE AGEI{DA 14. The agenda, as presented in the list of contents of this report, was adopted. C. REP'ORT ON VECTOR COI\TROL ACIWITIES 15. The Chief of the Vector Control Unit (VCU) indicated that larviciding was carried out successfully in 1995. With the chiefs of Administrative and Technical Services (CATs) of the Programme's t$/o operational zones, he reviewed the unit's activities since the last meeting of the Eoological Group. 16. The seven operational insecticides were used in rotation in the different river basins under trealurent, taking into account the discharge, the specific qualities of each larvicide, the blacKly susc€ptibility level and cost-effectiveness. 17. Lrviciding had been definitively stopped in the following rivers: - the Black Volta upstream of its confluence with the Fako, its tributaries Bin6da, Guim6b6 and Kohodio ; - the White Volta (below VB 900), the Mole and the Kulpawn; - the lower Daka; - the Alibori and the Sota; - the Sewa/Bagbe; - the Baoul6; - the Bago6 (with the exception of the lknk6laba). No further definitive cessation of larvicide treatment was scheduled for 1996. 18. In a few rare zones of the original area, vector control had experienced some difficulties in reaching its objectives. These difficulties were to be linked either to the inadequacy of the entomological evaluation network, to seasonal recolonization by exogenous blacldlies, or to the savannization of some border zones suspected of being the sources of exogenous infective blacldlies or infectod human populations. In these zones named "trouble spots" (basins of the Kank6laba, KulpawnAvlol6, Dienkoa, Kara/I(6ran/Mo, Sota/alibori ard the Bui area), three types of action were proposed: - continuation of larvicide treatrnent in the zones where this strategy is likely to give good results; - intensification of ivermectin distribution in other cases; - further research in order to get a clearer epidemiological picture of onchocerciasis in the border zones and decide on the appropriate actions to be undertaken. L9. Rainfall and watercourse discharges in the eastern zone had been higher to the east (Togo/Benin) than to the west in 1995. Nevertheless, the seven available insecticides were used in the area eccording to the rotation system set up by VCU and following the guidelines established by the Ecological Group. The treatrnent concerned a total of 8 695 km of river but the maximum length covered in a week (7,155 lan) was recorded during week 36 whereas the minimum covered (675 km) was recorded during week 12. -6- 20. In the western zone, hydrological pattems were comparable to those of 1994. As inr{he eastern zone, the standard rotation system for insecticide use was respected as well as the Ecolo$cal Group's guidelines concerning the use of carbosulfan and permethrin. However, contrary to tibat happened in the eastern zone, larviciding over the minimal length of river (2000 knr) occurred al lhe height of the spate (week 39) whereas the maxirnal length of river treated was recorded dufhg week 8. 21. Overall, the entomological results recorded through the larviciding coverage were satisfadcy in the whole Progranrme area. Considering the Annual Transmission Potential (ATP) calculated br all S. datmoszrz species which were infected by Onchocerca volwhts, only ten points had an ATp of more than 100 infective larvae/person/year. 22. In the southern extension zone, six points had an ATP of more than 100 whereas in the western extension zone, only Pont-Loutou had more than 100. 23. Considering the transmission of O. volvulus by savanna species of S. dannoszrz alone, fuir points had an ATP of more than 100. Three of these poin6 @ont Dytanrba, Titira and Tapounde)iare located on the border of the Programme's original area still under larvicide treafinent. Moreover, r&e internal technical meeting of March 1995 recommended the assimilation of the Kara/Kdran and Mo basins to the southern extension zone insofar as they were subject to reinvasion until the settiug rp of the southern extension zone in 1988. 24. The Ecological Group congratulated the Programme on the excellent entomological resnlts recorded and on the compliance with its guidelines for the use of those larvicides least selective on non target aquatic fauna. D. OPERATIONAL RESEARCH ArrID NEw LARYICIDE FORMIILATIONS 25. Operational research activities in VCU essentially centred on: - the study of the biogeography of Simuliumdarwtoswncomplex species in order to monilor their seasonal dynamics in the basins controlled by OCP; - the determination of the vectorial capaclty of each of these species as well as their degre of involvement in the transmission of savanna and forest O. volvuhts strains; - the determination of larval population suscsptibility level to the operational insecticides and the fine tuning of the methodology aimed at testing the efficiency of B.t. H-14 in ordpr to improve the formulation of this product. These activities were being caried out through the application of various new techniques: Vector indentification 26. Cytotaxonomy remained the reference technique for the identification of members of the S. danwtoswn complex. Insofar as it was used only with larvae, operational needs in terms of Simulium populations monitoring had ld to the selection of micromorphological and morphonretric features enabling the identification of adult females. As a result, over the entire OCP entomologiod evaluation network, the savanna blacKlies had been reliably separated from the forest group among which S. yalrcnse was identified. If necessary, the savanna species (5. sirbarutm and S. damnosm s.s.) as well S. squmoswn could also be identified. 27. Various other techniques were being implemented for more detailed and more reliabh identification of female S. datwpswn s./. More specifically, this refers to enzymatic techniEpr (electrophoresis) and heteroduplex analysis based on the use of mitochondrial DNA probes. It mtrl -7 - be pointed out that this latter technique was very recent and applicable to all development stages of the vector (from egg to adult). It now allowed the identification of most species of the S. dantnosurn complex. Parasite identification 28. For many years, O. ochengi larvae had been taken into account in the calculation of the Annual Transmission Potential. This parameter was then overestimated, particularly in the areas where O. ochengi was naturally predominant (northern part of OCP Western extension zone) as well as in areas where O. volvuhts had practically been eliminated (OCP original area). The recent use by OCP of DNA probes allowing the separation of O. volvuhu from O. ochengi had considerably contributpd to the improvement of the quallty of the entomological evaluation data, particularly those related to the transmission of O. volvuhu whose savanna and forest species can be identified by specie-specific DNA probes. Susceptibility monitoring 29. Monitoring of blacKly larvae susceptibility to insecticides is essential for the sucoess of the insecticide rotation strategy applied by OCP. The strategy mainly aims at maximizing the use of temephoo for logistical, economic and ecological reasons. Resistance to temephos being the most frequently observed, it mobilizes most of the surveillance teams efforts. In the eastern zone, the resistance focus of southern COte d'Ivoire (lower Comoe, lower Bandama) is still active. However, the resistance levels have greatly decreased in 1995. 30. trndeed, the resistance tests carried out in April 1996 in the lower Como€ indicated an SmgA LCrrr for S. sanaipauli populations while in January 1994 it was still at lOomg/l (i.e. 250 times the normal 0.4mg/l threshold level). This clear improvement was attributable to the selective effect of permethrin, combined with that of etofenprox (Vectron) during the flood-subsidence period. The treatnerls had also resulted in a strong reduction of S. sanaipauli populations compared to S. darnnoswn and ,S. sirbanum, which now showed a near normal susceptibility. 31. In the western zone, the resistance focus on the main Sassandra was still active and relatd to the pnesence of S. damnosum s.s. during the rainy season. The second resista:nce focus located on the Niger in Bamako was in clear regression compared to 1994 and the latest results indicated a normal susceptibility level among the S. sirbanum populations tested. It was probable however, that resistance levels would rapidly increase if temephos were reintroduced at large scale. B.r. H-14 quality control 32. In accordance with the protocol developed by IRU in collaboration with Abbott Co., the quality, efficiency and stability of Vectobac 12AS batches were systernatically checked. The evaluation of the new formulations of the product was also being carried out. The main objective of funrre rcsearch on insecticides would be the implementation of the new biotests protocol in order to improve the preciseness of the evaluation of B.t. H-14 operational and experimental formulations. The formulations of B.t. H-14 produced from recombinant strains recently supplied by the Pasteur Insitute and Roussel-UCLAF would be in priority order. The quality control of the operational chemical insecticitles could also benefit from the improvement of the biotests methods. The second IRU priority research activity, in collaboration with the aerial operations bases, would consist in continuing to inprove the management and planning tools of larvicide treatrnents. Finally Vectron which was recently included in the group of operational insecticides would be the subject of research aimed at maximizing its integration into the insecticides rotation strategy. I LC: lethal concentration -8- 33. The Ecological Group noted the efforts being made by VCU to control rqsistance and irnprovs the forrrulation of B.t. H-14. The Group recommended that efforts should be continued fi thb direction. As regards vector identification techniques through DNA probes, the Ecological Group pondered over a probable reconsideration of previously held views. Medium-term effects of Vectron on non-target aquatic fauna 34. In the short term, Vectron presented a toxicity on the entomocenoses that was comparable lo that of pyraclofos and therefore inferior to that of perrrethrin. Its impact on shrimps (Cariditu sp,) was almost five times less than that of permethrin. As regards fishes, Vectron was 100 times tere toxic than permethrin on Oreochronis niloticus and about 20 times less toxic onTttqia zillii. 35. The mid-term effects were evaluated on the Bagb6 at Ngolodougou. Six consecutive cycloe of Vectron were applied from the end of november 1995 to the beginning of January 1996 I discharges between 18 to 35 m3/s. Ttre total density of the fauna presented an upward trend due b x high abundance of Chironomidae, Philopotamidae and Hydroptilidae. Ttre Hydropsychidae were not affected. only the Baetidae, Tanypodinae and Pyralidae were slightly affected. 36. The effects of the treatments on the drift were shortlasting (24 hours maximum). Indico measured six days after treatment were fairly stable, showing a fairly rapid return to the originfl siuation. 37. Overall, no particular environmental changes were observed as cornpared to the existiqg situation just before the six cycles of Vectron. Similar results were observed on other watercourser where Vectron was used. 38. The Ecological Group's conclusion was that the impact of Vectron on non-target fauna wa6 cornparable to that of pyraclofos. It therefore confirmed the authorization given to the Programm for an operational use of Vectron and recommended &e publication of the results of this larvicidg impact study on non-target aquatic fauna. However, the hydrobiologists were to continue data collection on the medium to longer term effects of the product on non-target aquatic fauna. B. AQUATTC MONTTORTNG RESULTS General remarks 39. The Monitoring activities were carried out according to the time table and frequencicf established in 1995 by the Ecological Group. Most of the collected data was centralized at tho Programme's headquarters where the entries on computer were made and the diagrams and tablo produced for the annual r€ports of the national teams. 40. In accordance with the recommendations of the Ecological Group, the national tearns werc asked to undertake environmental impact studies on a selected watercourse in each country. They therefore participated, in Ouagadougou, in discussions on the conduct of such studies and on datt numagement. Moreover, spot studies were conducted on watercourses which were no longer urdef surveillance in the eastern zone and which were treated with carbosulfan and permethrin. Fish monitoring 41. In Ghana, the hydrological conditions were more favorable in 1994t95 since the spate peah as well as its extent were clearly more important than during the previous ye:trs. On the Oti, tho catches were fairly poor with small-mesh nets, but good with medium and largemesh nets. On thc Pru, the catches were increasing compared to those recorded in previous years. Finally, the CPUT on the Black Volta remained fairly low. The poor recruitment observed on the Oti and the Black -9- Volta would have to be carefully monitored during the next carrpaigns. Also worthy of noting was the disappearance in the catches, of Petrocephalus bovei, a species previously abundant- The coefficient of condition and size frequency distribution of the fishes remained at the same levels as those that had been observed in previous years. 42. In Guinea, whatever the size of the meshes, a decrease in catches was observed at Mandiana since the beginning of the monitoring and conversely, a notable increase at Boussoul6 and Baranama. However, the medium and small-mesh nes appeared to be more efficient. For the next campaigns, the abundance of C. auratus would have to be particularly monitored infosar as current catches of this species have decreased in all the stations. This synchronous decrease which had already been observed among other species (,S. mysrzs for instance) and in other zones, was certainly due to natural causes, but its evolution had to be monitored nonetheless. 1995 had been also marked by a global increase in species richness. Similarly, the coefficient of condition values for most species was excellent. However, a decrease in the coefficient of condition of M. mmto and I/. forstalii, concomitant with the decreare of their catches at Mandiana, had to be noted. 43. The continuation of research on the reproduction cycles of the various species made possible the classification of most of the species found in the zone into three distinct categories. The first comprises the species which reproduce once a year at a specific period, generally at the beginning of the spate. The second corresponds to the species whose egg-laying period stretches over a good portion of the year. Finally, the third category includes all the species whose egg-laying cycle stretches sver the entire year. This basic information is important for the analysis of insecticide impact on the recruifrnent of the juveniles. M. Three sites were to be sampled regularly in Sierra Leone. However, because of the social umest, only the Rokel was sampled according to the timetable established in 1995. As a general rule, the catches per unit effiort vary from year to year. During the current years, catches with small-mesh nets are more abundant than those with medium and large-mesh nets. This meant that a priori the recruitnent seemed to be good. No disappearance of any species was observed. Besides, though some variations were noted during the year, the global species richness remained roughly the same. All of the most commonly captured species exhibited a coefficient of condition similar to that observed in previous ycars. 45. In C6te d'Ivoire, even though the monitored watercourses were no longer under larvicide treafinent, catches still remained at low value levels, particularly on the kraba. This global reduction was basically attributable to the significant decrease in abundance of generally abundantly captured species such as Characidae, Chrysichthys and Marcusenius. However, species richness remained practically unchanged in each of the watercourses concerned. No disappearance of any species was therefore noted. Moreover, the trend of the coefficient of condition and size frequency distribution did not show any significant change as compared with the sinration in the previous yea$. 46. On the whole, the basic parameters of the ichthyological populations structure show variable but quite acceptable values. ln some cases, a decrease in the catches of small size species (or juvenile individuals) was observed; in other mses, the decrease concerned the CPUE, of fishes caught with large-mesh nets. These variations appeared to be influenced by many factors not directly attributable or linked to OCP vector control activities. Monitoring of the entomofauna 47. Discussions were continued on the drift trends of watercourses insofar as data had been collected before the Ecological Group's decision to cease routine drift sampling. 48. In Ghana, an upward trend of the drift index on the two watercourses monitored (Oti and pru) was observed since 1992/1993, The influence of the Kompienga dam on the Koulpeogo (a tributary -10- of the Oti) could be at the origin of the observed phenomenon on the Oti. It should be rmd furthermore that this watercourse had no longer been under treaftnent since 1992. As for &e saxicolous fauna, some density fluctuations were noted in relation to the importance of the vegetaffon cover (Tristicha) on the rocks. 49. On the Maraoud in C6te d'Ivoire, the densities of the saxicolous fauna were better than thme of the two previous years. However, fluctuations were observed in the densities or drift indices whhh could not always be related to the toxicity level of the larvicides used. The impact of indusfial pollutants on the Sassandra , combined with the effect of some of the poorly selective larvicides rned by the Programme continued to maintain low levels of faunal density at Bac S6mien. On watercoumes which were no longer under larviciding (White Bandama and l/raba) an irnprovement of the frequency of appearance of some taxa in the night drift had been observed. The densities of the saxicolous fauna were also increasing. 50. In Guinea, the Milo and the Niandan showed a downward trend in the densities of non-trrget insects even if some organisms such as the Hydropsychidae showed stable densities on the Milo or were more abundant on the Niandan compared to the pre-larviciding period. The decreases mafnly concerned the Baetidae and Tricorythidae. 51. Despite the circumstancial c€ssation of anti-blackfly larvicide spraying in Sierra leone, trm- target Diptera were becoming the most important group whereas in some watercourses such as the Kaba, the Ephemeroptera and Trichoptera were dominant before and even at the beginniqg of treatnent. Among the Diptera, the Chironomidae (ubiquitous organisms having a relatively low susceptibility and a fairly short life cycle) were the most important group. This situation was basicdly linked to the impact of ichtyotoxins and that of the ongoing human activities near the monitoring stations. 52. Although the abundance of the ichthyological fauna in watercourses not strongly exposod to the influence of human activities remained within acceptable limits, the Ecological Group expre*rcd its concern about the rarefaction or the near-total disappearance of some species such as Petrocepffius bovei in C6te d'Ivoire and Chrysiclttys ailratus in Guinea. It recommended that particular atteilbn be paid to these species in the years to come. As regards non-target aquatic insects, the chaqes observed in the relative abundance of taxa did not seem to be prejudicial to the energetic baltnce between the different guilds and were therefore considered to be acceptable. Research studies, however, should be continued for a better appraisal of the situation. Environmental impact studies 53. Upon the recommendation of the Ecological Group, the national teams had collected data on the factors likely to have an impact on the results of the aquatic monitoring of the selectd stations in four countries of the Programme area (C6te d'Ivoire, Ghana, Guinea and Sierra l-eone). 54. In COte d'Ivoire, the S6mien area on the Sassandra was experiencing an intensification of activities of all sorts (agriculture, stock breeding, industry, woodland clearing, etc. . .). Concomita0tly, a decrease in the density of aquatic organisms was being observed, as well as frequent pollutior of the watercourse by waste from the Boroutou sugar factory. 55. In Ghana, very few activities were undertaken on the Pru in the Asubende area. Those mted were not harmful to the aquatic environment. The potential source of pollution was the Prografrne with the use of antiblacldly larvicides. The monitoring results did not show any particular impact on the aquatic fauna. 56. The situation at Boussoul6, on the Milo, in Guinea, was close to that on the Pru but the presence of a diamond factory was noted, a factory which had developed initiatives to improvc the - lt - tnmsparency of the water whieh was rejected into the Milo. Monitoring data, however, indicated a disruption in the invertebrate fauna without any harm to the fishes. 57. As for the situation at Musaia, on the Mongo, in Sierra Leone, the fauna was poor, even in the abserrce of larvicide treafrnents. In addition to the use of ichthyotoxins by the populations, the presenoe of Musaia and of agricultural activities upstream were noted. Deforestation and important movements of human populations and livestock were also noted by the tearn. 58. The data of the first phase of the impact studies were considered encouraging by the Ecological Group. They made it possible to distinguish two types of situations: a fauna with little disruption in the absence of important human activities (as in the cases of the Pru and the Milo), and a fairly affected fauna on the way to disruption under the influence of human pressure (resettlement in the valleys and industrialization in C0te d'Ivoire on the Sassandra, mainly agriculnual activities in Sierra lrone on the Mongo). The Ecological Group recognized, however, that environmental inrpact strrdies required an interdiscrplinary approach involving different specialiss and could not, therefore, be efficiently and adequately carried out by the hydrobiologists alone. Thus while asking the hydrobiologists to consolidate the studies undertaken in 1995, the Ecological Group expressed the wish that the Programme and CSA consider the possibility of granting a complementary technical support for a successful continuation of the work. Spot monitoring of the Mono and the Ou6m6 59. The Mono and the Ou6m6 having been off monitoring since 1987 while being treated with poorly selective insecticides such as permethrin and carbosulfan, the Ecological Group recommended a spot nnnitoring during the flood-subsidence period in order to assess the faunal situation seven years after the beginning of treatments on these watercourses. 60. The results showed a relative increase in the CPUQ in all stations visited as compared to the pre-treatment period. The richness in species and coefficient of condition values of the main species did not seem to have been affected by the Programme's larvicide treafinents. 61. As regards invertebrates, the available fragmentary pre-treatment period data could not make possible a reliable comparison of the situations. Nevertheless, the results for 1995 showed an impact of the Nangbeto dam on the day drift of the organisms at T6t6tou on the Mono. At B6t6rou and M'B6t6koukou on the Ou6m6, the faunal densities were low, pointing to a direct impact of the fishing, bathing, laundry etc... activities carried out in the vicinity of these sampling stations. 62. The impact of antiblackfly spraying was therefore considered by the Ecological Group to be within acceptable limis insofar as the results presented herein (which were the conclusions drawn from different impact studies) did not show any major disruptions of the environment. The changes induced by the construction of the Nangb6to dam upstream of T6t6tou led the Ecological Group to recommcnd that the aquatic monitoring of the Mono be stopped. Moreover, spot studies on the Oudm6 would not be carried out this year. The Ecological Grouo's responses to the h)rdrobiolosist's recornmendations 63. The Ecological Group congratulated all the hydrobiologists on the quality of the data collected and analyses made. The Group encouraged them to persevere in that direction. It then considered the recommendations made by the hydrobiologists and made the following suggestions: (a) The joint meeting day should be maintained in order to allow the exchange of information between the hydrobiologists and members of the Ecological Group to be continued. On this occasion, some scientific presentations could be made by members of the Group on topics directly related to the monitoring progralnme. -12- O) The work programme proposed by the hydrobiologists for 19961L997 was examino{, by the Ecological Group which made some changes in the list of the entomofau4 monitoring stations (see Annex 6). Furthermore, the Group recommended t consolidation of the environmental impact studies initiated in 1995 on the following watercourses and sites: - Pru, at Asubende (Ghana) - Sassandra, at Bac s6mien (C6te d'Ivoire) - Milo, at Boussoule (Guinea) - Mongo, at Musaia (Sierra Leone) (c) The participation of the hydrobiologists in the Maroua (Cameroon) seminar on environmental impact studies should be facilitated by the Programme. (d) The work session proposed by the hydrobiologists for the production of I consolidated document on the resulm of 20 years' monitoring was endorsed by tb Ecological Group. It recommended, however, that each team take stock of tht situation on its own before the different groups (invertebrate biologists an{ ichthyologists) meet separately in Ouagadougou. For these meetings, the Programril should schedule a training of the hydrobiologists in data analysis, particularly it multifactorial analysis. F. WORK PROGRAMME FOR 1996/19Yl U. The Ecological Group reviewed the work prograrnme proposed by the hydrobiologists, of which a part was the subject of recommendations made above. It was the Group's view that thp environmental impact studies carried out by the national tearns in 1995 should be consolidated. Tbc reports produced this year would have to be reviewed and complemented by a more detaile{ description of the environment around the sampling stations. Complementary biological data would have to be collected on the Sassandra and the Mongo at sites which are not under the direct influenoc of human pressure. 65. With regard to the routine monitoring of watercourses, the Group made some changes in ttE work prograulme proposed by the hydrobiologists. Routine monitoring would be given leet impoaance and the spot studies undertaken in 1995 with a view to appraising the level of recolonization of watercourses no longer under larviciding, as well as evaluating the ecologicd situation of watercourses that had no longer been monitored since 1987 would not be repeated (sec Annex 6). 66. Another matter of concern to the Ecological Group was the valorisation of the aquatig monitoring results. Indeed, if the results of the use of Abate had been published, the Ecological Grorry recognized that much remained to be done as far as the impact of larvicide rotation was concerned. It therefore endorsed and supported the action plans established by the hydrobiologists for tb exploitation of the monitoring data and recommended that the necessary means be delivered in ordetr to make possible the preparation of two consolidated reports (one on ichthyofauna and one oo invertebrates) which should be made available for the eighteenth session of the Group. At the outcom of this phase, the Ecological Group called for the publication of a consolidated document with thc participation of renowned specialists. It therefore recommended that the Programme make provisiou in the 1997 budget for the production of such a document which would entrance the Programme'r work in the field of aquatic environment monitoring. _13_ G. CONSIDERATTONS ON AQUATIC ETWIRONMENT MONITORTNG WITIm{ OCP'S PRESEI\IT AI{D FUTT'RE ACTTVITIES 67. The preliminary results of the impact studies carrid out by the national hydrobiology teams ard the prograrnme of work discussed above led the Ecological Group to engage in a more general consideration on aquatic monitoring within the present and future context of the Onchocerciasis Control Programme. The Group felt that it received a mandate for its competency to be extended to the different aspects of the utilization and development of the oncho-freed valleys which were likely to have an impact on the evolution of aquatic environment. 68. Strc.h broadening of the Group's competency was in direct line with the observations made in previous years acrording to which anthropic influences were becoming more and more important in the evolution of the fauna in the monitoring stations. 69. The Ecological Group then considered it its duty to draw OCP's and CSA's attention on those environmental issues which were likely to reach great magnitude in the years to come if a certain rrurfier of principles and recommendations were not set for a sound utilization of the valleys within the framework of an integrated management of the environment and the perspective of a sustainable development. 70. Three major concerru; were likely to emerge: - the quantitative numagement of water resources (dams, irrigation) and its consequences on the aquatic environment in terrrs of water qudr$; - public health issues linked to the evolution of the aquatic and terrestrial environment; - the management and preservation of the habitats and living aquatic resourcrs, given that fishing, for instance, provides up to 200 000 tons of fish every yeiu in OCP area, which represents a market value of about 200 million dollars. 71. Consequently, the Ecological Group recommended that CSA initiate specific studies to address these issuos in the perspective of a sustainable development of these valleys. 72. Moreover, considering the current results of the monitoring, the Ecological Group anticipated that over the period L998-2W2 (OCP's Phasing-out period) aquatic monitoring would be more oriented toward the search for refuge zones, toward recolonization potentials and return to original conditions by some taxa which had been subject to the strong pressures of the insecticides (Baetidae, Tricorythidae, etc...) and toward more specific issues such as the rarefaction of some Mormyridae spocies. 73. Impacts other than those of antiblacldly larvicides (agriculture, stock breeding, industries, the various human pressures) would become more prevalent, thus reducing the part played by the Programme in the observed effects on the aquatic environment and consequently the role of VCU in environmental surveillance. The Ecological Group, therefore, held the view that the Sponsoring Agencies should take the necessary measures so that the institutions involved in issues of sustainable developmont would be given a more important share in the responsability of this type of evaluation. The hydrobiologists, however, would continue to play the major role in that part of the evaluation dealing with the aquatic environment. -14- H. FOLLOW.UP OF TIIE RECOMMEITDATIONS OT TIIE STXTEET{TII SESSION OFTIIE ECOLOGICAL GROTJP 74. The Ecological Group expressed satisfaction at the implementation of almost all its recommendations. However, the Group would like the scientific valorization of the data on the rcn- target a$utic fauna monitoring to be continued. I. ARRANGEIVIETTITS FOR TIIE NEIM MEETING 75. The next meeting of the Ecological Group would be held on 30 and 31 January lgryt in Accra (Ghana), preceded by that of the hydrobiologists on 27 and 28 January 1997. Ajoint meetiag(Ecological Group/hydrobiologists) would take place on 29 January and a field visit would bi organized on lst rnd, if necessary, on 2 February. J. READING AT{D APPROVAL OT RECOMMEhIDATIONS 76. The summary of the main recommendations was read and approved by the participants in&e seventeenth session of the Ecological Group. The draft report which was also read will be submi&tl to the chainnan of the Group and to Dr C. LEveque for approval before its finalization for presentation to the Expert Advisory Committee. K. CLOST'RE OT TIIE SESSION 77. The Chairman of the Ecological Group thrnked the OCP staff and the WHO Representadon in Togo for the perfect organization and for the attention paid to himself and to the other participaffi. Furthermore, he congtatulated the secretariat and all the participants for their positive contributlms to the success of this seventeenth session of the Ecological Group. - t5 - ANNF:X I LIST OF PARTICIPAN'TS Members Pr. D. Crlamari, University of Milan, 3rd Faculty of Science, L,aboratory of Ecology, Via Ravasi 2,2llOO Varese, Italy, Fax 00 39-332-2811308 Dr. C. I-rlvdque, D6l6gu6 Permanent i I'Environnement, ORSTOM, 213 rue La Fayette,75480 Paris C6dex 10, France, Fax (33.1) 48 03 75 26 Dr Franke H. Toornstra, AlDEnvironment, Donker CurtiusstraatT-523, l05l JL Amsterdam, The Netherlands, Tel. + 31.20.6868121168 Other participants (Observers) Mr. G. Ciparisse, I-and and Settlement Officer, Viale delle Terme di Caracalla, 00100 Rome, Italy Tel. (396) 5225 3&5, Fax : (396) 5225 3t52 Dr. D. Faugy, D6partement Eaux Continentales, ORSTOM, 213 rue I-a Fayette, 75480fulg, France Tdl. (33 1) 48 03 75 32, Fax : (33 l) 40 35 37 18 Dr Anette Reenberg, Instirute of Geography, Oster Voldgade 10, DK-1350 Copenhagen K, Denmark Tel. +45 35322562, Fax *45 35 32 25Or Secretariat Dr. H. Agoua, VCU/OCP, B.P. 36 Kara, Togo Dr. L.K.B. Akpoboua, VCU/OCP, 8.P.2279 Bamako, Mali Dr. Y. Bissan, VCU/OCP, 8.P.2279 Bamako, Mali Dr. J.-M. Hougard, VCU/OCP, B.P. 549 Ouasadouqou, Burkina Faso Mr. E.J. Senghor, INF/OCP, B.P. 549 Ouasadousou, Burkina Faso Mr. J.M. Tapsoba, VCU/OCP, B.P. 549 Ouaqadousou, Burkina Faso Dr. L. Yam6ogo, VCU/OCP, B.P. 549 Ouaqadousou, Burkina Faso -16- ANNEX 2 LIST OF DOCUMENTS OCP/VCU/HYBIO/96.1 Monitoring of the aquatic environment in Guinea (Summary repon- 1985-1995) - Fish fauna. By Moussa Elimane Diop. OCP/VCU/HYBIO/96.2 Invertebrate biology in Guinea. Summary of annual report (199{- 1995). By Fanfod6 Kond6 and K6l6tigui Nab6. OCP/VCU/HYBIO/96.3 Monitoring of invertebrate fauna of Sierra Leoneans' rivers (annual report) - Summary by Daniel Tholley OCP/VCU/HYBIO/96.4 Summary of the annual report on the ichthyological monitoring of water courses treated with antiblackfly larvicides by the Onchocerciasis Control Programme in Sierra Leone. By Zac Bah OCP/VCU/HYBIO/96.5 Monitoring of the non-target aquatic entomofauna of treated and untreated watercourses in C6te d'lvoire and Burkina Faso (Summary). By OCP Aquatic Environmental Monitoring Division OCP/VCU/HYBIO/96.6 Summary of the annual report of ichthyological monitoring of treated watercourses in COte d'lvoire. By Traor€ Kassoum OCP/VCU/HYBIO/96.7 OCP Fish monitoring in Ghana (Summary). By E.K. Abban. F.Y. Amevenku, H.R. Dankwa OCP/VCU/HYBIO/96.8 InvertebratemonitoringreportofGhana(Summary). By J. Samman - I7 - AT.INF.X 3 A()tJA'l'l(' ENVIRONMEN'l' MONt'l'OlllN(; Sl'lttJ('l'tjRtrs lvl'tl1: O('l' EXPERT ADVISORY COMMITTEE ONCHO PROGRAMME (DIR) INDEPENOENT INSTITUTIONS TEAMS & CONSULTANTS HYDROBIOLOGICAL EVALUATION DIVISION /VCU NATIONAL TEAMS OF AQUATIC MONITORING rar '' -l- a a: - 18 - ANNEX 4 frE- o-(Dcooo 8E Eo Eqc- =!t EEco fr(,l3E€i8 Otot 3 0't ; s=Bt8P EE 8EYE(, .= c o.-= E; E6E <.ts-= E.9 ? E 68fi =r gEx ot - oE .c u,J 3- p p -r(z I EdFrrl:: (U EHET gbzSo F, =3HEE-=.,Q?uJ olt u.l =.. s I uJ eP 3 Efi2lD/,2=c =FEE H€EE ='Bt tHEE; 95E E E.=oEb =de 9ttq.a f;igs o bU E=E a.e 6O: () -zal)&98E6E FRP E6:o'- .8gE c> il gEEF&bfi -c Eb35r€EH 3E EHE qE:5E Q= t 9.grJ XOcul LIJoo ' bg Eri* 6.9E,E oF r >rxoz(r<[L (L Ui7\) <o 59 o() ul -6 tFo orh .ct= EEe u gEEo'5 s .E;OE .eE$;> F*Ez EE g E #,86 E '62 E q, e9 ae EEH E6ooo(L oE E8(o toocolo(l,N9u E8 - crcb8q c cI889 i6 90$3;E 'EF !so' c. €uib- ' FO<{' 2gIe:o inF E,[! o-x u, t.l- o(L fo E,o Fz uJoz u, o-tlloz z ILo zotr :)tFaz oo t()(n(r) q O) o, O) @ O) t\6q, (o @ or o @ o) ro t'- o, q r- o, fo or Oo -o9E6: E$ U- r'- CD x.g;P E"g6E - l9 - ANNEX 5 Fz tlJ u.t <,, U' trloo + UJ cl, Y @ E tJS: t'if ' :4i,H o,J E,F oJg LL n U ooJ oo =oF ll:ll Itll ttll |.)o O! s o) o) c, o,o o(It or f.- .(' o, r{l @(n N ao O) .('(D oc, o) () t-g) g F- O) ru = =fl ood o. IIJ F z U'F v, ul EIxoF Fz tutr uJ TL Eo ulIF C]z (r, ruo 6 Fo ul U'z J zo F tr IU o- o lut ll. o z. o tro =o otF = -g -po_o !2 =t>3 d,e === o -I Eg#(' 0E (i t t ll F oz & oL z. o m rSrE5;€58 EEE Ex?+t i6Oo c 5et6E *o 9.7g=o cE* -orF: E-e rOlx- o .c 1= .ri = -20 - AI{NEX 6 WORK PROGRAMME FOR 1996 ta a T 1 Country/Site/River Sampling period/fr equency lnvertebrates Fish January to April, Nov.-Dec January to June then Nov.-Dcc C6te d'Ivoire Danangoro/IVlaraoue Entomokoro/lvlaraoue Niaka/White Bandama Ganse/Comoe Border bridge/laaba Ghana Sabari/Oti AsubendelPru Guinea Sassarnbaya/Niandan Baranarna/Dion Tere/Dion Boussoule/Milo Mandiana/Sankarani Sierra Leone Musaia/Mongo Outamba-park/Kaba Malganlora/Seli Matotaka/Jong Bumbuna/Seli once/monttr once/month once in dry season once/month once/month once/month once/month once/month once/month once/month once every 2 months ir rl once every 2 months onoe every 2 months once every 2 months once every 2 months once every 2 months once/year once every 2 months I i ti N.B.: Day and night drift (once/year)