Report of the ninth session of the ecological group: Bamako, 1-4 March 1988

-a- ONCHOCERCIASIS CONTROL PROGRAI'IME IN I{EST AFRICA PROGRAT'II.IE DE LUTTE CONTRE L'ONCHOCERCOSE EN AFRIQUE DE L'OUEST EXPERT ADVISORY COI,II,IITTEE Ninth Session 0uaqadougou, 13-17 June 1988 OCP /EACI ,2 ORIGINAL: ENGLISH PAGE A B C. D. E. F. G. H. I. J. K. L. M. I NTRODUCT I ON REPORT OF THE NINTH SESSION OF THE ECOLOGICAL GROUP BAMAKO, I-4 MARCH I988 CONTENTS ADOPTION OF AGENDA ... REPORT ON VECTOR CONTROL ACTIVITIES REPORT ON HYDROBIOLOGICAL MONITORING ACTIVITIES PROGRAMME ANALYSIS OF AQUATIC MONITORING DATA INDEPENDENT ANALYSIS OF AQUATIC MONITORING DATA .. REPORT ON LITERATURE SEARCH ON ENVIRONMENTAL DISTRIBUTION AND FATE OF CARBOSULFAN RESEARCH ON NiW LARVICIDES AND FORMULATIONS WORK PROGRAMME FOR I 988-89 ARRANGEMENTS FOR THE NEXT SESSiON CLOSURE OF THE SESSION 2 3 3 9 14 l5 OTHER MATTERS l5 17 21 22 24 25 25 APPROVAL OF REPORT TABLES I AND 2 MAPS I AND 2 ANNEXES I r0 3 OCP/EAC9.2 Page 2 A. INTRODUCIION 't 2 3 The Ecological Group held its ninth session in Bamako, Mali, from I to 4 March 1988, under the cha.irmansh.ip of professor K.l.l. cummins. A list of participants'is given in Annex l. 0n behalf of the Programme D'irector;Ocp colleagues and the staff of vcU Koulouba, Dr Bernard phirippon, chief vcu, welcomed Group Members to Koulouba (Bamako). An especial]y warm welcome was extended to Dr- H.H. de Iongh,the Group's new member, who was making his first attendance at a Group Session. The .l988 Annual Meeting of Hydrobiolog'ists had been held jn Ocp Koulouba and at the ORSTOM Laboratory, Bamako, immed.iately prior to the 1988 Session of the Ecological Group and.it was noted that there had been excellent opportunities for so0e Group Members to attend both meetings. This had enabled National Hydrobiologists to have beneficial d'iscussions with some Group Members, and to profit from having the.ir own rneeting chaired by Dr c. L6v€que, to whom the programme was very grateful. It was explained to the Group that programme staff now felt in a much more optimistic s'ituation than had been the case at the time of the last session of the Group, when there had been a generally depressed atmosphere brought upon by serious technical and financ'ial problems and the prospect of having to make drastic cuts in the approved Plan of 0perations for .l987. The programme had managed to survive the serious .l987 s'ituation and its staff had learnt much about working under the influence of severe financial limitations. Early in .l988, the Programme was still fac'ing many constraints and it was to be expected that problems would contjnue to arise during the course of the year. However, the technical sjtuat.ion was currently good and staff were reassured by guarantees of continued fund i ng . OCP/EAC9.z Page 3 B. ADOPTION OF AGENDA The following agenda was adopted: - Report on vector vontrol operations - Report on hydrobiological monitoring act.ivities - Programme ana'lysis of aquatic mon.itoring data - Independent analys'is of aquat.ic monitoring data - Report on ljterature search on environmental distribution andfate of carbosulfan - Research on new larvicides and formulations - Work programme for 1988-1989: - jn the initial Programme area and Southern Extens.ion - i n the Western Extens'ion - 0ther matters - Arrangements for the next Session - Approval of Report. C. REPORT ON VECTOR CONTROL ACTIVITiES ( a ) Acti vi t'i es duri ng I 987 and earl y 1988 6. Reference was made by Chief VCU to the Report of the Eighth Session of the Ecological Group in whjch'it was explained that the spread of temephos resistance in savanna vectors, budgetary constraints and the continuing fall in the value of the US dollar, had made-it necessary to revise the operational plan for vector control in 1987. 7. The revised plan, which had been implemented, provided for: - vector control as and when required in the phase I-lv areas in order to ma'intain protection of the "core" area of the programme; _ seasonal and sel ect'i ve I arvi ci d'ing of the mai n ri vers .i n the Southern and Western Extension areas which were presumed to provide major sources of fl'ies reinvading the origina'l programme dr€d; - preparatory acti v'iti es (entomol ogi ca1 , hydrol og'ica1 , i nf rastructura'l , epi dem'io'logi ca1 , hydrobi ol ogi cal ) i n the two extensi on areas especi al Iy i n western Mali, upper Guinea and eastern senegal, at the I9g6 level of i nten s'i ty ; 5 OCP/EAC9.2 Page 4 - epidemiological research on Ivermectin, especially to determine the effects of that drug on parasite transmission. 8. In order that those qct'ivit'ies could be successful ly implemented, 'it had been essential to keep a very tight control over expenditure, especially over the h'igh-cost components of vector control operations, i.e. aircraft ff ight hours and 'insecticides. In addition, the necessity to make substantial savings had resulted 'in a 25% cut in the staffing of entomol ogi ca1 eval uat'ion teams . 9. It had also been necessary to adhere strictly and carefully to all monitoring activities (vector species'identification, determination of the dynamics of biting vector populatjons, insecticide susceptibifity testing, monitoring the intens'ity of parasite transmission, hydrobiolo- gical mon'itoring), and to 'implement the operational rotat'ion of the Programme's full arsenal of larvicjdes (5 in number), the latter activ'ity also requiring to be very carefully reviewed on a weekly basis. 10. Formulations of B.t. H-l41had increas'ingly replaced temephos as resistance to the compound had spread. However, it was very reassuring to note that'improved formulations of B.t. H-l4 had become available and that, due to sharp competition between manufacturers, the price of this product had fallen by about 40%. ll. 0ther economies had been achieved by greater optimisat'ion of treatment methods and larvicide consumption, which had been facilitated by the increased utilization of computerised aerial operat'ions and hydrological data,r The greater use of teletransmitted and computerized hydrological information had enabled vector control personnel to: - make more accurate and selective treatments, - predict changes in river discharge rates which in some cases allowed treatments to be suspended much earlier than would have been poss'i bl e f rom an analysi s of conventi onal hydrol ogi cal 'informat'ion . 12. Overall, the entomological results obtained had been some of the best recorded during the last few years. There had certainly been problems in the south-eastern and western reinvasion areas, but it was worthy of note that there had been a significant improvement jn the entomol og'ical si tuat'ion al ong the western boundary of the ori gi na1 0CP 1 Bacillus thuringiensis H-14 OCP /EAC?,2 page 5 area. At most vector catching stations, the Annual Transmission potential (ATP) had fa'llen to below 100 (the threshold of transmission acceptability). Th'is jmprovement was attributed to more extensive larviciding operations in presumed sources of rejnvasion further to the West. l3' Despite the very careful planning and implementation of vector control operations to eliminate sources of reinvasion in the Southern Extension area' those activ'ities came close to result.ing in f ai Iure. The late starting of larviciding (April 'instead of February) which had permitted a build-up of vector populations was obviously an important factor. It was also possible that larvicide appr'ications had been made far too sel ecti ve. l4' Attempts to suppress sources of reinvasion in the western part of the original Programme area had been much more successful than in I9g6 in terms of intensity of transmiss'ion. However, there had still been a significant reinvasion of Mali and for a variety of reasons it had notyet been possible to precisely identify the reinvasion sources responsjble. Movement of flies from Sierra Leone intoGuinea and poss'ibly onward into Malj was a possibility. .l5. Turning to the situatjon'in March r9gg, jt was exprained that all vector control activities were of a strictly dry season character. B.t. H-14 appl'ied to selected rivers was the only larvicide in use. Treatments had been suspended for several weeks along many rivers and further suspensions were anticipated before the onset of the Iggg wet season. (b) Review of the revis ed vector control strategy for I 988/89 .l6. Because of the savings made in I987 it was now possible to embark upon a more extens'ive plan of operations for l988/89 than had been endorsed by theJPC in December I987. Accordingly, the vector control strategy for the remaining part of ]988 and for early l9B9 had been revised and was now being implemented. 17 . The revi s'ion embraced the fol I orvi ng acti vi ti es: (i ) rout'ine Iarviciding as and when necessary in the ,,core,, area; OCP IEAC?.2 Page 6 (ii) -full vector control operations in the southern Extension (commenced February) and in the north-eastern part of the Western Extension, i.e. most of western Mali and a small part of northern Guinea (scheduled to commence.in April); (iii) -selective vector control operations in the Upper Niger and the sankarani basins of Guinea to suppress presumed sources of reinvasion (scheduled to commence in mid-March) and associated entomological studies on vector movements i (iv) -selection of catching points and of breeding sites to be kept under surveillance, the definition of f1y sampling schedules, and the implementat'ion of a system of data collection to ensure appro- pri ate coord'inati on between treatment and eval uati on act.ivi ti es ; ( v ) - 'imp1 ementat'i on of entomor ogi cal stud.i es i n Si erra Leone ( vector i denti fi catj onldi stri buti on, i nfecti on rates , breed.i ng si te productivity potential ) ; (vi) - reactivation of preparatory activ'ities in all other parts of the l'Jestern Extension area (recruitment and tra'ining of national staff , establ'ishment of operat'ional bases, procurement of equ'ipment and supplies, jnstallatjon of radio network, construction of hydro- 1og'ical stati ons ) ;(vii ) - collaborative vcU/Epl/BIS research on Ivermectin. .l8. wh'ile the Report of the 1987 session of the EAC had deplored a 3-year delay'in the implementation of the western Extens.ion, the new strategy for 1988 would enable the delay to be reduced to only I year. (c ) Anti ci pated act'iv'i ties for .I989/90 .l9. In accordance lv'ith the JPC mandate to continue with full-scale vector control operati ons, 'it lvas ant'ici pated that there'woul d be compl ete exten- sions of larviciding operations into Senegal (Senegal and Gambia river basins) and central Guinea (upper Niger and Bafing basins in l9g9),.in the Western Extension area. 20. 0n the other hand, it was expected that vector control operations in the "core" area would be progressively reduced, as Ivermectin was introduced i nto areas where there were epi demi ol og'i cal justi fi cati ons for i ts use OCP/EAC9 .2 page 7 (areas where there had been repeated larviciding shortcom'ings, where there were persistent pockets of infection and where it was necessary to suppress res'idual i nf ect'ions ) . (d) The i loso and im lementation of measures aimed at overcomin ro ems o nsec c e res S ance an u ar con s ral n s ur nq ?1. It was recalled that resistance to the organophosphates; temephos and chlorphoxim, had first appeared in the forest species S. sanctipauli (of rel ati vely 1 ow vectori al si gni fi cance ) . Level s of res'i stance had always and characterjstically been very high and pers.istent. 22. In contrast, organophosphate res'istance in savanna spec'ies had been at a much lower level of severity and had usually been much less stable/ persistent. The latter characteristic had been attributed partly to the genetic resistance mechanism, partly to gene dilut'ion in populations whjch continua'l)y receive an 'influx of susceptible fljes from untreated sources of reinvasion, and partly to less intens'ive selective pressure. 23. It was qu'ite clear that in some areas, resistance had developed spontaneously through the selection of res'istance genes with'in the popula- tion. In other areas it was deduced that resistance had either been imported through classical reinvasion movements of flies or by what is now referred to as "reverse reinvas'ion", i.e. dry season fly movements from the north-east under the influence of the Harmattan wind. Another poss'ibility was that res'istance had resulted from hybrid.isation. 24. The conclusion derived from carefully conducted experimental stud'ies of these phenomena was that, if temephos usage was discontinued at the first instance of treatment failures being observed, a serious problem coul d be avo'ided. Under such ci rcumstance the jud'ic'ious use of B. t. H-14 and other rep'lacement compounds could return the level of temephos sus- cepti bi I i ty to normal and perm'it temephos to be eff ect'ive1y rei ntroduced as an operational Iarvic'ide for short periods when'it was economicallyjustified, i.e. under wet season conditions. 25. Faced with the combined problems of resistance and budgetary cons- traints it had been necessary to introduce an extremely tight and effi- c'ient management system for larviciding operations: OCP/EAC9 .2 Page 8 - to slow down the development and spread of resistance, - to maintain satisfactory levels df'vector control once resistance had appeared and/or to rega'in normal suscepti b'i I i ty I evel s, - to minimise the risks of more toxic replacement compounds having adverse effects on aquatic non-target organisms, - to make all vector control methods and strateg'ies as cost effective as possible. 26. The Group commended the VCU on the excellence of these management measures, fully realizing the tremendous efforts that must have been made to ensure that the 'intended objectives were attained and susta'ined. It considered that the benefits which had fccrued and which cont'inued to have a significant influence on the future course of the Programme, were of significant relevance far beyond the specialized 'interests and concerns of the Group. Accordingly, further details of the current management procedures for vector control are attached hereto as Annex 2. The following stat'istics on larvicides d'ispensed during the last three years (in litres of formula- tion) also vouch for the soundness of the current management strategy: Compound I 985 I 986 I 987 Temephos B.t. H-.l4 Ch 1 orphoxi m Permethri n Carbosul fan l30,llg (35.7%) 217 ,169( 2.7%) 9,356(5e.4%) ?,967( 0.8% ) 5, 286 I 1 .4%) 94,562 ( 18.0% ) 384,58.|( s.za 17,376 (73.?%) 9,750( t.e%) .l 8,849( 3.6%) 70,882 (16.9%) 299, I 55( 7.2%) 30,055 (71 .s%) .l 0, 338( 2.5%) 8,124( t.e%) 365, 396 525,.l.l8 41 8,554 27. The figures presented above show that there was an economy of more than .|00,000 litres of larvicides in .l987, compared to the previous year, even though there had been a significant spread of temephos resistance (see Maps I and ? f or the situation 'in early lgBB), and more geograph'ically extens'ive I arvi ci di ng operati ons, especi al 1y 'i n the Western and Southern Extensi ons. Total s OCP/EAC9.2 Page 9 (e) Comment by the Ecological Group ?8. The Group very much appreciated the efforts made by the Programme w'ith a view to optimizing aerial larvic'ide treatments'in order to reduce the quant'i t'i es of I arvi ci des used . However, certai n si mul ati ons had i mp1 i ed that local'ized over-dosing rould be necessary, even though the overall quant'ity of larvic'ide appfied to a given stretch of river would be consider- ably reduced. The Group agreed that, even'in the fight of such a prediction, further tests with B.t. H-.l4 could be conducted. In the cases of temephos and chlorphoxim, the Group advised that l'imited tests could only be carried out'if a good surve'illance of the non-target fauna was assured. 0ver- dosing with permethrin and carbosulfan should not be practised for the t'ime- bei ng. D. REPORT ON HYDROBIOLOGICAL MONITORING ACTIVITIES ( a ) Annual Meet'inq of Hvdrob o1 ogi s ts 29. The .l988 Annual Meeting of Hydrobiologists (0CP, ORSTOM and National Serv'ices) responsible for aquatic monitoring throughout the Programme area, was held'in Bamako during 28 and 29 February 1988. The meet'ing which was chaired by Dr C. L6v6que was also fortunate in hav'ing the participation of two other Ecological Group Members (Drs D. Calamarj and M. Yasuno) during the second day. Partic'ipants were drawn from the OCP, from ORSIOM and from the national hydrob'iology teams of C6!e d'lvo'ire, Ghana, Guinea and Mal i . 30. Most progress reports on nati onal rnon'itori ng acti vi t'ies over the I ast year had been presented to the Programme (except for that on invertebrate sampf ing 'in Mal j ) in a tirnely fashion and in a much more standard'ized format. 0nce again, the Group acknowledged the appreciable improvement 'in the technical qua)ity and f iterary presentation of the nat'ional reports. 31. Unfortunately, due to unavoidable delays 'in the procurement of equipnrent and suppl i es , the i chthyol og'ica'l team of Mal 'i had not been abl e to commence full-scale mon'itoring operations unt'il mid-.l987. The period covered by thei r act'iv'iti es was theref ore f ar too short to enabl e them to present substanti al data. ocP /EAC9.2 Page 10 32- From the results obtained in the central part of the programme area(n. Bandama) it appeared that there had been no discernable adverse effects of carbosulfan treatments on fish fauna. Juven'ile forms of many fish species had been obseved throughout the treatment period. 33. The increase of Schilbe mystus in fish catches at different monitoring stat'ions'in the "core" area confirmed that fluctuat'ions'in abundance observed for that species were independent of larvicide applications. 34. A'lthough catches of Petrocephalus bovei had decreased sharply in recent years there was now sound evidence from some monitoring stations that popu- lations of this species were now on the increase. 35. The national hydrobiologists profited from personal contact with some Group Members to express their suggest'ions for enhancing the value of mon.i- toring activit'ies and to make some recommendations, as presented below: (i) They hoped that the Group vrould look favourably on their desire to conduct associated research, the results of wh'ich would allow thern to more ef fect'ively i nterpret mon'itori ng resul ts. Two research top.ics were highlighted as being important - studi es on the vert'ical di stri but'ion of invertebrates duri ng dri f t, the fate of these organisms in pools and the utiljzation of simple bi of j c i nd'ices, such as the Cai rn' s i ndex, other measures of di vers.ity, or the relative abundance of functional groups, - studies on the reproductive cycles of certain fish species in rela- tion to various environmental factors. (i'i ) They also wished to rece'ive jnformat.ion on the fate of B.t. H-]4 toxins and their eventuar persistence .in the environment. (tt was agreed that some Group Members would prov'ide assjstance in this matter). (iii) They also indicated their desire to study the problems of the reducti on of Tri coryth'idae whi ch was co j nc'ident wi th B. t. uti I i zati on at some monitoring stations, and, the problem of increase of some Baetidae despite their sensit'iv'ity to all chemical larvicides. (iv) They cons'idered'it desirable to try to establish a provisional model for the impact of insect'icides (according to chemical family) }cilEACe.2 Page 1 1 tak'ing into account the short-term effects observed in min'i-gutter tests and Iong-term effects recorded under riverine cond'itions. 36. The Group rev'iewed with great interest the various findings presented at the Annual Meeting of Hydrobiolog'ists, accepting many of the results wi th consi derabl e sati sfact'i on. The Group's vi ews on the recommendatj ons presented in paragraphs 35('i) to 35(iv) above, are presented later jn this report, under Section J(a). (b) Surveillance of the aquatic environment 37. One of the recommendations of the Eighth Session of the Group had been that OCP hydrobiology teams take responsib'if ity for the surveillance of aquat'ic invertebrates in the orig'inal Programme area. Accordingly, th'i s recommendati on had been i mpl emnted duri ng the f ol I ow'i ng survei I I ance session, in November .l987. It was noted that because of the great distance between the monitoring stations and OCP/HQ, it took 12-20 days each month 'in order to visit all stations. This had left the teams with little time to devote to associated laboratory work. 38. In add'it'ion, the OCP teams had been responsible for evaluating the environmental impact of certain "new" pest'ic'ides. This had greatly 'increased the volume of sampling, the numbers of days spent in the field, and, further reduced the t'ime available for Iaboratory investigat'ions. Nevertheless, all the samples collected in November and December 1987 during routine surveillances and all those obtained from stud'ies of new compounds had been processed. From the experience gained, the follovling po'ints were under I 'i ned : ('i) This system had enabled the OCP to obtain a very good knowledge of all the monitoring stations and had permitted a better follow-up of the qualitat'ive evaluat'ion of the invertebrate fauna of the rivers concerned. ('ii) It had also resulted in standardizat'ion of ident'ifications wh'ich were made by the same team, thus permitting greater comparat'ib'il'ity of the resul ts. (iii) The stations at Bamboi (Black Volta, Ghana) and GansE (Como6, C6te d' I vo'ire ) were not wel I sui ted to the col I ect'ion of invertebrates f rom OCP /EACq.2 Page 12 f rorn runni ng water, espec'ial ly at the end and at the begi nni ng of the year when there was virtually no river flow. Ifthesestations were to be retained it would be adv'isable to review the choice of the sampling period, i.e. advance it from November to September. (iv) From experience gained in recent months'it had been possible to say that the continuation of the invertebrate surveillance programme by OCp staff was possible, prov'ided that the volume of work was not increased and that the staffing level was reinforced. 39. In January and February .1987 national teams with the assistance of a consultant collected fish samples from riffles in Cote d,lvo'ire and Ghana, usi ng el ectro-fi shi ng equi pment, w'i th the fol 1 owi ng objecti ves : - to determine if riffle fish populations had been modified, by comparing the results with those obtained at the beginning of the Programme i n the same stat'ions, - to determine'if the R. Pra could serve as an untreated control river to assist in following fish population changes in other rivers wh.ich had recei ved I arv'ic'ide treatment. 40. These surveys had shown that there had been no change in the composition of the riffle fish fauna since 1975/76 and that more than lS% of the fish of the R. Pra were identical to those found in other rivers which had been under treatment. 4l. The Group was briefed on the steps be'ing taken to make large-scale maps of monitoring stat'ions and had the opportunity to examine copies of two recently completed maps; of Danangoro (R. Marahoua) and of Niaka(n. Bandama). When the Harmattan "season" came to an end, and atmospheric vis'ibility improved aerial photojraphs would be taken of other stations and then ured to make appropr.i ate maps. 42. The Group commended the OCP and national hydrobiology teams for their efforts in ensuring a thorough surve'illance of the defined monitorjng sites over the past year and strongly recommended that: ('i) Whenever possible, use be made of OCP air transport to assjst.in moving the OCP teams to and from the monitoring stations, in order to cut down travelfing time and to allow the teams more time for devoting to sampl e analysi s and other I aboratory acti vi ti es. ('ii ) (iii) OCP /EAC? ,2 Page '13 OCP gives careful consideration to the feasibility of moving the base of the OCP hydrob'iology teams from Ouagadougou to either Bamako or Bouak6. Such a move would result in 'increased effic'iency in moni- toring activities in the original Programme area, would place the teams in closer proximity to the western Extension and thus'improve liaison, and would provide for more continuous contact betrveen the teams and the sci enti f ic staff engaged i n the testi ng of new I arv'ic'ides . Every effort be made to complete the large-sca'le mapping of mon'itoring stat'ions as soon as poss'ib1e. Is it possible to extract from the large quant'ity of existing surveillance results, information wh'ich will allow us to focus surveillance on certain taxa or certain methods? (This undertak'ing would need to include the test'i ng of certa'in syntheti c i ndi ces such as the Cai rns I ndex ) . Can one, in establishing the relat'ionships between the short-term and long-term results, estabf ish pred'ictive models for the evaluation of popul ati on densi ti es and structure of popul ati ons? (c ) Questi ons concern'ing the monitorinq of lotic environments 43. The Group was presented with a working paper entitled "Questions con- cern'ing the monitoring of lotic env'ironments in the 0nchocerciasis Control Programme" prepared by ORSfOM Hydrob'iologist Dr J.M. Elouard. Extracts from the Forward and Introduct'ion of this document are presented in Annex 3, to serve as a summary of the author's objectives. 44. The Group acknowledged that th'is was a very important document, raising questions and issues whjch had to be addressed. However, 'in view of the a'imens'ions and complexities of the subjects covered, the Group considered that there was not sufficient time available for a deta'iled discussion of the document durjng the current Session. Accordingly, the Group recommended that the document be put on the agenda of the next Sess'ion. i5. After a very brief review of the document, the Group considered that :he following two questions concerning major issues, would have to be answered during the next Session: (i ) (ii) OCP/EAC9.2 Page 14 E. PROGRAMME ANALYSIS OF AQUATIC MONITORING DATA (a) Data entry and explo'itation 46. A recent developmenr had been the entry and transformation of all long-term monitoring data in the computer facility at OCp/HQ, 0uagadougou. As a result of the'implementation of th'is new system, in October 19g7, national teams were sent analysed tables of all the data which had been collected in their respective stations and sent to the Programme since the beg'i nn'ing of moni toring act.ivi ti es. 47. copies of some of the tables, which were presented to the Group compri sed: (i) For invertebrates: Tables on the mean number of indjviduals per surber and on the mean day-t'ime and night-t.ime drift indices of the different taxa per station for the d'ifferent sampling dates. The results had also been grouped according to the principal taxonomic groups. (ii) For fish: Three types of Catch Per Unit Effort (CPUE) taUte and one type of coefficient ofcondition table had been prepared: - CPUE per spec'ies and per mesh size for each sampling date, - total CPUE per species for the d.ifferent sampling dates, - total CPUE per sampling date per mesh siz'es, - Coefficient of Cond'ition for the different sampling dates and per speci es. 48. It was noted that various types of analysis could be conducted on the tabulated data and that certain modifications were now being made: - to'improve and adapt the entry programmes to changes made in the monitoring data reporting forms; - to facilitate the preparation of tables and graphs; - to 'increase the rapidity of execution and flexibi'lity of data entry and analys'i s prograrnrnes. 49. It was also noted that summary graphs of data for prev.ious years, lvith respect to requested groups of taxa, would be'in.itia1)y provided Dy the University of Salford for distribution through OCP to national hydrobiology teams. OCP /EAC? .2 Page I 5 50. The Group recommended that Ocp staff start to prepare an annual summary (data book) of monitoring data. This document should be finalized before the end of October .l988 and sent to the nat'ional hydrobiology teams to assist them in preparing their reports for the next Annual Meeting of Hydrobi o'logi sts. F. INDEPENDENT ANALYSIS OF AQUATIC MONITORING DATA 5.l. It was noted that although no independent analysis had been conducted during the past year, a contract proposal had been submitted bythe University of Salford to the Programme in accordance with a recommendation of the E'ighth sessi on of the Group. The proposal cons.iders both the ,,core,' and Western Extension areas and is'intended to establish major trends and to define the relative usefulness of the various monitoring stations. Furthermore, since the last analyses for the original Programme area were made more than two years ago, evaluations of the impact of permethrin and carbosulfan wlll be included, and it is considered likely that useful indicator species will emerge as was the case with other insecticides. 52. The Group recommended that the independent analyses 'include an eva- luation of the Cairns Index and other innovative techniques, such as an analysi s of percent aggregati on, to determ'ine thei r potent'ia1 val ue, and a study of combinations of monitoring stations and insectjcide tests to improve the concept of communi ty typi ng ( "fi nger-pri nt.i ng,') . The Group further recommended that the fjnal analyses should be made by appropriate staff of OCP and of 0RST0M. 53. The Group noted appreciatjvely that the ten-year summary of fish sampling data had already been publ'ished'in "Chemosphere" and a comparable paper on invertebrates was now ready for submjssion for publication in the same journal . Addi ti onal col I aborati ve publ i cati ons had al so been i ni - tiated and were currently in preparation. REPORT ON LITERATI'RE FAIE OF CARBOSULFAN SEARCH ON ENVIRONMENTAL DISTRIBUTION AND 54. The Group received from one of its Members a presentation on the potential environmental distribution and fate of carbosulfan, based on G OCP/EAC9 .2 Page 16 the lim'ited data available in the open literature. The conclus'ions drawn which confirm the results of a similar exercise conducted during the E'ighth Session of the Group, were that the possibjlities of delayed tox'ic effects of carbosulfan and its bio-accumulation potential, were both small. 55. Several organ'isms quickly metabolize this pesticjde which also has a great affinity for suspended sol'ids and sed'iments. Moreover, the trans'ient nature of the'insecticide suggests that the assessment of risk can be developed'in term of its short-term direct toxicity, rather than in terms of chronic toxocity. 56. The limited data available on th'is chemical in aqueous env'ironments ind'icate that there is a rapid conversion of carbosulfan to carbofuran or other metabolites, mainly by hydrolys'is and cleavage of the carbamate N-S bond of the molecule. These observations have been confirmed by other published results of studies on the degradation of carbosulfan in soils and terrestrial environments. Accordingly, a further literature search was initiated on carbofuran which is less toxic to the aquatic fauna than carbosul fan. For the carbofuran mol ecul e di ssj pat'i on patterns are rel a- t'ive1y well-defjned for neutral and alkaline waters, provided that hydrolys'is i s l'ike1y to be the domi nant degradati on process. It 'is not poss'ible to define precisely the kinetics of the process. However, available evidence limits the length of the process to an order of magnitude measurable in days. 57. Carbosulfan is not expected to accumulate to an apprec'iable extent in fish, neither from theoretical nor experimental findings. It is there' fore suggested that attention be given to investigating the ecological responses of the populations to the short-term effects of treatments, instead of studying the potential long-term effects. 58. It was to be noted that carbofuran has shown h'igh toxrcity to mammals and b'irds. However, under the conditions of field applicat'ion this molecule was not expected to produce adverse effects on warm-blooded animals due to the tendency for it to be rapidly hydrolysed into less tox'ic metabol'ites in neutral and al kal i ne water. 59. To demonstrate the procedure followed to make a preliminary hazard aSSeSSment for carbosulfan, a paper will be prepared, by a Group Member, OCP/EACg ,2 Page 1 7 assembling the existing data on environmental d'istribution and fate, exposure potential during pilot treatments, acute toxicity to African species of fish and the monitoring of field data on fish and invertebrates. 60. The Group recommended that close examinations be made of all data obtained from samples collected from rivers'in the Bandama basin wh'ich had recei ved short-term treatment w.ith carbosul fan si nce I 986. These stud'i es were considered necessary in the light of observations made on changes in al ga1 communi ti es, possi b'ly I'inked wi th a reducti on of grazi ng i nvertebrates and the results of toxic'ity tests on fish. In addition, the results of community multivariate analyses should be compared with those obtained from long-term monitoring. It was recorded that the b'io stat'istics team of the Universjty of Salford would be pleasedto assist with th'is work. H. RESEARCH ON NEl.l LARVICIDES AND FORMULATIONS 6.l. During the period under review, comparatively few new larvicides had been provided by manufqcturing firms for screenjng by OCP. This was particularly true for classical chemical coupounds. In this group only a few pyrethroid compounds and about 4 organophosphate formulations had been received and tested at the laboratory stage and in rivers. 62. 0n the other hand several B.t. n-t4 formulat'ions had been received and tested in gutters. Many of them did not show activ'ity superior to the present operational formulations or did not meet 0CP physical charac- teristics requirements. For the benefit of the Group, only those formula- t'ions which had gone through the aquatic monitoring stage of evaluation were given consideration. (a) B.t. H-.t4 63. It was reported that because of increased competition between B.t. H-14 manufacturers and in view of expected improvements in cost- effectiveness, the Programme continued to test formulat'ions of the product; especially those provided by the two ma'in manufacturers, Sandoz and Abbott. 64. Two new formulations had been tested in parallel conditions (Sandoz HPD-6000 and Abbott Vectobac 24AS) under operati onal and were both OCP/EAC9. 2 Page 18 found to be effective at a dose rate of 0.8 mg/L/10', thus permitting a 33% reduction on the dosage possible wjth formulations in current usage. However, the physical characteri st'ics of these two f ormul at'ions must be significantly improved before their operat'iona1 use can be envisaged. Accordingly, samples of new improved formulatjons will soon be field-tested and'it'is hoped that one will be found which has appropriate phys'ical properties and at the same time, allowing a further dosage reduction to 0.4-0.6 ng/L/10' for rivers hav'ing discharge rates of up to 100m3/s. (b ) Pyrethro'ids 65. The Group was 'informed that as from 1989, only the 25% Ec "pounce" permethrin from FMC would be used operationally in replacement of Talcord (from Shell) and Coopex (from I{e11come). The "Pounce" formulation was thought to be slightly less aggressive on some groups of aquatic insects, but was very similar in activity to other permethrin formula- ti ons. 66. Most of the pyrethroids that had been tested had shown more or less the same levels of efficacy and the same non-selectivity to other non-target aquat'ic f auna. Nonethel ess ef f orts were sti I I be'ing made to select one or two possible replacement compounds, should resistance develop to permethrin, even though there was a strong chance of cross- resistance across the board. 67. Therefore, cons'idering the different modes of act'ion or the mechani" involved, the l'ist of possible replacement candidates had been narrowed down to three: biphenthrin (OMS 3024) (FMC), lambdacyhalothrin (PP 32.|) (OMS 3021) tCl, and cyphenothrin (OMS 3032) Sumitomo, all belonging to the alpha cyano methylated bipheny'l alcohols group. 68. Although there is no clear-cut evidence for cross-resistance amongst the pyrethrojds, 'it appears from studies made on mosquitos that resist- ance to permethrin does not necessarily induce cross-res'istance to b'iphen- thrin, and poss'ibly also not to Iambda-cyhalothrin and cyphenothrin. However,'it had to be noted that all three of these compounds were more tox'ic to aquat'ic non-target organi sms than permethri n . 69. No further trials with these new pyrethroids have been planned for .l988. However, should resistance to permethrin be detected, the }cP /EAC9,2 Page I 9 three new pyrethro'ids would 'immediately be checked for resistance and, depending upon the results, one compound would be selected for opera- tional trial, should there be no better alternative. 70. Trough tests on other pyrethro'ids from Wellcome and Zoecon were in progress, but none had yet been tested for their toxicity to non- target organi sms. (c) 0rganophosphates: Phoxim 7'1. Since'it had been learnt that Bayer would no longer produce chlorpho- xim after I990, a replacement had been sought, and Bayer had proposed phoxim. Three formulations of phoxim had been tested: a 10% EC formu- lation and a two 50% EC formulations. The two 50% ECs had shown better activity in trough tests and had been selected for field trials. The results of the field trials were not very encouraging; the best formula- tion, at a dosage of 0.1 ng/L/ '10', was observed to have a very poor carry. 72. Further tests for a better evaluation of th'is formulation were in progress; it being kept in mind that phoxim does not sho-w cross.- resistance w'ith temephos. Furthermore, at the dosage rate of 0.1 mg/ L/.l0' its effects on non-target 'invertebrates appeared to be unacceptable; at twice that dosage environmental side effects were unacceptable. (d) 0rganophosphates: Pyraclofos (OMS 3040) 73. This compound appeared to be more attractive than phoxim and field trials were in progress. If sufficient quant'ities of the formulated material became available,an operationaltF'ial would be conducted during the I 988 wet season. 74. Tests conducted to date had not establ'ished cross-resistance of th'i s compound wi th temephos . However, f urther crossresi stance tri al s were 'in progress along the lower R. Comoe against res'istant forest larvae, and along the R. Bafing against resistant savanna larvae. (e) Insect g rowth regul ators 75. 0f several growth regulators tested in m'ini-gutters, the two juve- noids OMS 3010 (Phenoxycarb 20% EC, MAAG) and OMS 3019 (10% EC, Sum'itomo OCP /EAC9 .2 Page 20 chemical) were the only ones which had demonstrated reasonab'ly high acti v'ity aga'inst mature S. damnosum s. I . I arvae. 76. Phenoxycarb was ful'ly effecti ve ag ai nst mature S. damnosum s. I . larvae at a dosage rate of 0.1 mg/L/10'. It will be further tested against young Iarvae and smalI-scale river trials wiII eventual1y be performed. 77. 0tls-30.l9 had been tested in the field at a dosage rate of 0.1 mg/L/ 20' . The overal l eff icacy just bel ow the appl i cat'ion po'int was only 60%, increasing to 90% 3.5 km downstream. In view of these discouraging results further trials are not envisaged, it also being noted that this compound had some adverse effects on some aquatic invertebrates, e.g. chironom'ids. (f) Comments by the Ecol ogical Group 78. The Group was pleased to note the prom'ising preliminary results with some of the new formulations of B.t. H-.l4 and with the new organo- phosphate and pyrethroid compounds. In view of the great care that was always taken in testing new larvicides, the Group accepted the offer of one of its Members to conduct a literature rev'iew of the effects on non-target aquatic fauna of lambda-cyhalothrin, bipenthrin, cypenothrin and pyraclofos. 79. The Group reaffirmed 'its concurrence w'ith the Programmi's continuing policy to accord the highest priority to the development of new alter- native larvicides. The objective has been and continues to be, the se'lecti on of compounds whi ch must ef f ect'ively ki 1 1 the S'imul i um targets, while producing the Ieast effect on non-target fauna and hav'ing the I owest probab'i 1 i ty f or the devel opment of res'i stance. To thi s end, the Group advocated a strong programme for the continued testing of alternat'ive larv'icides,'including a full compliment of sc'ient'ific staff, until such time that it had been established that s'ignificant reductionsjn larviciding operations could be made possible because of the use of Ivermectin. 80. With regard to priorities for the testing of new formulations of compounds currently in use in OCP and of new compounds, the Group made the fol I owi ng recommendati ons on pri ori ti es : OCP IEACg .2 Page 2l New formulations of B.t. H-.l4; Pyracl ofos, especi al ly f i el d tri al s at hi gh di scharge rates, assuming that adequate quantities of th'is compound were made avai lable to the Prograrnme for test'ing before the onset of the I 988 wet ..uron, I ('i 'i i ) New pyrethro'ids whi ch exhi bi t the I owest probabi 1 i ty of developing cross-resistance w'ith permethrin while maintaining minimal effects on non-target fauna; ( 'i v ) I nsect growth regul ators ( rcR) . 8l . The Group also adv'ised that 'if sufficient quantities of Pyraclofos were not available by the .l988 wet season, 'it would recommend that addi- tional tests be conducted with phoxim. I . I.JORK PROGRAMME FOR 1 988-89 (a) In the jn'itial Programme area 82. The Group recommended that the monitoring of fish and invertebrates i n the i n'iti al OCP area and 'in the Southern Extensi on area be cont'inued at al I the stat'ions sel ected during i ts E'ighth Sessi on. The f actors taken i nto cons'iderat'ion i n maki ng thi s recommendati on 'incl uded: - the good background informatjon ava'ilable, extending back over l0 years, - the value of these data in terms of interpretat'ion, - the variety of river and basin types, - the necessity for OCP'to cont'inue to use permethrin and carbosulfan'in the "core" area. 83. The Group acknowledged that there were some questions about the value of data collected from mon'itoring s'ites on the Black and Wh'ite Volta rivers'in Ghana, because of construction work which could change the character of the sampling points. However, 'it was agreed that It has subsequently been learnt that the manufacturer does not yet have the formulation facil'it'ies to provide the Programme with the 2000 litres which would be required for an operational trial. Further evaluation must therefore be postponed until 1989. ('i) (ii) JOCP/EAC9 .2 Page 22 correction f actors could be 'introduced 'into the data analyses. In addi -tion, and together with the R. pru station, these stations were poten_tially valuable because they were located .ir\ or close to,areas of organo- phosphate resistance where alternative and more toxic compounds could be used. 84' The Group also recommended that the sampling interval for fish in c6te d'lvoire (Rivers Bandama, como6 and L6raba) and in Ghana (Rivers Oti and Pru) should be 2 months. Furthermore, that samp)ing for invertebrates of the Como6 (Gans6) and the Black Volta (Bamboi) should be advanced from November to september. Togo monitoring sites (Rivers 0ti and Amou) should continue to be sampled as at present. 85' Tables I and 2 give deta'ils of the monitoring stations and samp)ing frequency for studies on fish and on invertebrates, respectively. (b) In the Western Ex tension area 85' The Group recommended that additional mon'itoring sites for fish and invertebrates be selected in the western Extension area, .in Senegal andin south-eastern Guinea, and that they be monitored by national hydrobio- logical teams' once a year during the dry season. staff of Ocp and oRSToM should select these new monitoring sites taking into account their access'ibility, representativeness for fish and invertebrate fauna, flooding reg'ime and plans for treatment with larv'icides other than temephos andB't' H-.l4' The Group further recommended that two consultants, an ichthyo- I ogj st and an entomo'logi st, be 'invi ted to sampl e at the moni tori ng si tes short-listed by Ocp and ORSTOM and to propose to the Group those sites considered to be most su'itable for yearly surveillance. OTHER MATTERS (a) OCP research needs 87. The Group recognised that there were two basic research needs con- cerning hydrobiological data. 88. The first and quite clearly the most urgent was the need for new and i nnovat'ive analysi s of what 'is a tremendous data bank. Al though the hydrobiological data probably represent one of the most extensive OCP/EAC9 . Z Page 23 sets of such information on fish and invertebrate populat'ions, only m'in'imal synthetic and analyt'ica1 evaluat'ions have been made' As examples, it was important to compare all the short-term data collected from m.ini-gutter trials with the long-term monitoring data, to evaluate the sui tab.i I .ity of the short-term tests f or predi ct'ing l ong-term trends, and to make an analysis of fish and'invertebrate commun'ities according to functional feeding group. Furthermore, it was important to attempt a cl assi f i cat'ion of the regi ona'l f i sh and 'invertebrate f aunas 'in terms of their susceptibility to the larvicides used by the OCP. Such a synthesis should be used to determ'ine if laboratory and short-term (mini-gutter) information on susceptibility can be used to predict effects .in the field on fish and jnvertebrates. Another example would be the correlatjon between hydrological patterns and patterns of fish and i nvertebrate popul at'ions, i ndependent of the use of I arvi c'ides. Cl ear1y, 'if I arvi ci d'ing has had no eff ect, such correl ati ons shoul d be qu'ite good. 89. The efforts on interpret'ive analysis wh'ich have, to date, been performed largely by Dr Fa'irhurst, show considerable progress. The Group recommended most emphatically that these ana'lytica1, interpretive and synthetic efforts by Salford Un'iversity be sign'ificantly expanded and accelerated. To facilitate this most critical task, it was important that the Salford Univers'ity team had access to consultation with key members of the gCP and QRSTOM concerning the data and their interpretation 90. The second general need was to focus field research projects in such a way that they served to clarify crit'ical issues relevant to the f .i rst research need; namely i nnovati ve analys'i s of ex'i sti ng data sets and the i nterpretati on of trends and rel ati onsh'i ps w'ith'in those data sets and the 'interpretati on of trends and rel at'ionshi ps wi thi n those data sets. The major research needs f al l'ing wi thi n th'is second category which were ident'ified by the Group'in d'iscuss'ion with OCP and ORSTOM staf f and wh'ich were ei ther on-go'ing or had been proposed by nat'iona1 hydrol ogi sts, were: - reproducti ve peri ods for dom'i nant fi sh speci es, - distpibut'ion of invertebrate drift, vertical ly 'in the water column, and in settling and concentration areas in slow reaches (Pools). OCP/EACg.2 Page 24 9.l. Some small specific projects had received funding from OCP to encourage relevant independent research by National Teams. 0thers had been proposed and await a dec'is'ion concerning the ava'ilabi lity of per- sonnel and fundi ng. 92. The Group recommended that, in accordance w'ith the position adopted by the EAC, it was also important to support attempts to obtain research funds from sources outside OCP, particularly for broad-scale projects of general interest which would address problems relevant to the Programme its final years. But, more irnportantly, such projects would ensure the future use of experienced national scientists in environmental research projects critical to West Africa, after the end of the OCP. Furthermore, the Group pointed out that research fund'ing for projects which came from sources other than OCP would contribute to the inter- nat'ional recognit'ion of the Programme and would afford the opportunity to involve scientjsts not presently related to the OCP effort. 93. Finally, the Group gratefully accepted the offer of one of its Members to report to the Tenth Session on existing programmes using bivalve molluscs to monitor long-term biological effects of env'ironmental i mpacts . (b) Ivermect'in 94. Dr Fa'irhurst gave the Group a brief report on the effects of Avermectins on the decomposition of faecal matter. Because of both the scarcity and conflicting nature of the literature encountered so far, the Group recommended that Dr Fa'irhurst be asked to extend his search for literature on this subject K. ARRANGEMENTS FOR THE NEXT SESSION ( a ) Cha'irman 95. The Group announced that Dr L6v6que would be the Chairman for the Group's Tenth Session (.l989). Dr L6v6qrrewould also represent the Group at l9B8 meetings of the Expert Advisory Committee and the Joint Programme Commi ttee. ?cP /EACg .2 Page 25 (b ) Date and pl ace of Tenth Sess'ion 96. It was agreed that the Tenth Session would be held either during the week commending 20 February or l3 March .l989, depending upon the avail- abiljty of Members. Preferences should be communicated to the Programme Director as soon as Members have had an opportunity to review their exi sting engagements f or I 989. 97. A decision on the venue of the Tenth Sess'ion would be taken when more deta'ils became available on opportunities for Members to v'isit field act'i- vities. 98. The Group reconmended that a Hydrobiology Workshop be held in .l989, immediately prior to the Tenth Session of the Ecolog'ica1 Group. L. APPROVAL OF REPORT 99. The draft report was reviewed before the end of the Sess'ion and the fi nal i zed versi on approved by the Cha'i rman. M. CLOSURE OF THE SESSION (a) Address by the Proqramme Director Dr E. M. Samba I00. The Director expressed how very much he had appreciated having the opportunity to participate in this session of the Ecological Group. He underl'ined the importance of the Group to the Programme and thanked the Group for its excellent collaborat'ion, for its understandjng of Programme requirements and problems, and for the high level of its sc'ientific dis- cussions and 'inputs 'into the Programme. The Programme was very gratefui to the Group for its efforts in tailoring environmental monitoring activities to meet Programme requ'irements during the last two years. It was also very obvious that with the encouragement of the Group and'in col I aborati on wi th the 0CP Hydrobi ol ogi st, nati onal hydrobi ol ogy teams had iipprec'iably improved the qual i ty of thei r mon'itori ng acti v'iti es and of thei r reporti ng. l0l. In presenting an overv'iew of the status of the Programme in .l987 and at the present time, the Director endorsed the remarks made by Chief, OCP /EAC9.2 Page 26 Vector Control, during h'is welcoming address to the Group. Turn'ing to the present and'immed'iate future the D'irector re'iterated that the Programme was continu'ing 'its pof icy of strict f inancial control in order to retain donor confidence and to allow Programme actjvities to be both expanded and accelerated. In addition, the most encouraging results had been obtained from trials with the qicrofilaricide, Ivermect'in, and there were now good'indications that this drug could soon be used on a large scal e, paral I ei wi th vector control . .l02. At the end of h'is presentat'ion the Di rector expressed hi s si ncerest thanks to Professor K. l.l. Cummins, the retiring Chairman, for the excellent way in which he had led the Group during the last three years. He also took the opportun'ity to congratulate and welcome the Chairman-elect, Dr C. L6v6'que. (b) Address by the Cha'irman, Prof. K. t,J. Cumm'ins .l03. The sess'ion was closed by the Chairman during the afternoon of 4 March I 988. 104. In his closing remarks, the Cha'irman noted with great regret that the ORSTOM Laboratory in Bamako would be closed down in 1988. He reminded the Group of the very important contributions made by ORSTOM personnel to the Programme and recalled that the Group had benefited most s'ignificantly from its contact with ORSTOM staff. it was particularly stressed that ORSTOM hydrob'iologists had always provided valuable ins'ight into such matters as sampling strategies, the inter- pretation of msnitoring data, and specific environmental tests of I arvi c'i des .l05. The Cha'irman expressed his gratitude to the French-speaking part'i- cipants for their very serious efforts with the English language which had enabl ed the Sessi on to be conducted i n Engf i sh, thus avo'iding the expense of having to provide simultaneous interrrrerar1on faciliries. .l06. Finally, the Chairman thanked Mr B. Nango, Mrs M. Coul'ibaly and Miss Nignan for providing valuable administrative and secretarial support. TABLE I : FISH !,|0NIT0RING STATI0NS RETAINED AND THEIR SAHPLING FREQUENCY, 1988/89 Country/ri ver /stati on IgP Reference IC6te d'Ivoire Bandama - Ni aka Comoe - Gans6 Leraba - pont Routier Ghana Oti - Sabari Pru - Asubende Gui nea Sankarani - l,landi ana Dion - Baranama l,laI i Baoul6 - l,li ssi ra Coastal Guinea/Sierra Leone I 7 6 5 4 l3 1Z Sampl ing frequency Every 2 months Every 2 months Every 2 months Every 2 months Every 2 months Every 2 months Every 2 months Every 2 months To be established after selection of sites. I I I'laps I and 2. (\ I R ( \ I I -/' -(- R R ( I I I t\ I R B FA R R \,, OODIENNE B EYLA o o BOUAKE ro MAP I,: MONITORING STATIONS IN THE WESTERN BOBO-DIOULASSO o CIV I I R KAN 4R 3 L I I t R 7 \ 9 R 5ct I R N toa MAI AMAKO ) I I 2 o I r l\ K TA GU I R ) t t. I I o MAN Y TEMEPHOS RESISTANCE IN S AVANNA VE CTORS I , , I LIB I t\ \ \ I ( o In loo ABIDJAN 200 &,&tff:rry- oPERATTONAL AREA, 1988/ 99 *"J TABLE 2: INVERTEBRATE I'IONIT0RING STATIONS RETAINED AND THEIR SA!.|PLING FREQUENCY, 1988/89 !lap Reference 8 9 l0 II l4 ICoun /ri ver/stati on C6te d'Ivoire Como€ - Gans6 Bandama - Niaka l,larahou6 - Danangoro l,larahou6 - Entomokro Ghana Black Volta - Bamboi Gui nea Ni andan - Sassambaya l,lal i Bakoye - Kokofata Togo Amou-Amou-Oblo Coastal Guinea/Sierra Leone 7 Sampling frequency Once a month, September to January Every 2 weeks, l{ovember to January Once a month, February to Apri I Every 2 weeks, November to January Once a month, February to Apri I To be established after selection of sites. 3 2 (i ) (ii ) (i ) (ii ) Once a month, September to January (i) Every 2 weeks, November to January(ii) Once a month, February to April Once a month, June to December I Maps I and 2. ) ) ) ) f I I\ I I NIG KARA3t I I BFA -fz- --' \ I I R o B EN .) K ANDI \.\\--/ \ a TAMALE I GHA R R R t---- OUAGAOOUGOU o R I I I I t? KOUPA o NIE I I I I \ I I t4 \ \ I I I I t.T )( j KUMASI \ \ I TEMEPHOS RESISTANCE IN SAVANNA VECTORS R COTONOU LOME ACCRA 200 lm o too ln ,{ MAP 2: MONITORING STATIONS IN THE EASTERN oPERATTONAL AREA, t988 /89 t*i -{ l I I I I I I I I I o 9 ANNEX I LIST OF PARTICIPANTS l,lembers Professor D. calamari, Institute of Agricultural Entomology, Faculty of Agriculture, university of Hilan, via celoria 2, zol33 Milan, Italy. Professor K.l{. Curmins (Chairman), Appalachian Environmental Laboratory, University of l,laryland, Frostburg, l.lD Zl53Z, USA. Dr H. De Iongh. Haskoning, Berg_en Dalseweg 81, 6500 AD Nijmegen, Netherlands. Dr c. L6v6que Di recteur de Recherches, l,luseum Nati onal d,Hi stoi re Naturelle, Laboratoire d'Ichtyologie, 43 rue cuyier, 75005 paris, France. Dr l'l- Yasuno, Chief of Aquatic Ecology, National Institute for Environ- mental Studies, 0nogawa, Tsukuba, 305 Japan 0ther arti ci ts Dr J-l'l- Elouard, Charg6 de Recherches, Laboratoire d'Hydrobiologie, SRSTOM,B-P. 2528, Bamako, l,lali. Dr C.P- Fairhurst, Department of Biological Sciences, University of Salford, Salford l.l5 4t{l, England. Dr D- Paugy, Charg6 de Recherches, Laboratoire d'Hydrobiologie, gRSTgl,l, B.P. 2528, Bamako, Mali. 0bserver Dr Margaret A. I'lilzbach, Assistant professor, Appalachian Environmental Laboratory, university of Maryland, Frcstburg, l,lD 21532, USA. -?- Secretari at Dr D. Baldry (Secretary), VCU, B.P. 549, Ouagadougou, Burkina Faso. Dr J, Grunewald, VCU/0CP, B.P. 2279, Bamako, Mali. Dr P. GuiIIet, VCU/0CP, B.P. 2279, Bamako, MaIi. l.lr l.l.H. Ocran, VCU/OCP, B.P. 1474, Bouak6, C6te d,Ivoire. Dr B. Philippor, Chief VCU/OCP, B.P. 2279, Bamako, tlali. Dr E.l,l. Samba, Director 0CP, B.P. 549, Ouagadougou, Burkina Faso. Dr A. Sek6t6li, VCU/0CP, B.P. 2279, Bamako, tlali. l,lr L. Yar€ogo, VCU/OCP, B.P. 549, Ouagadougou, Burkina Faso. ( ANNEX 2 MEASURES BEING TAKEN BY OCP/VCU TO IMPROVE THE MANAGEMENT OF VECTOR CONIROL OPERATIONS 1. To slow down the development of teme phos resi stance During the dry season 8.t. H-.l4 is used throughout the Programme area. with the most recent operEEonal formu'lations, B.t. H-l4 is more cost-effective than temephos for treating rivers with ffischarge rates below ?5n3/s. At higher discharge rates temephos is more cosi-effective, and it is used as long as possible while susceptibility levels remain unchanged. The practi ce of mak'i ng sel ect'ive I arvi ci de treatments aga'inst susceptible savanna species which were breeding together with res'istant non-vector spec'ies has been discontinued. At very high river d'ischarges (more than 300m3/s) permethrin can be used for short periods of time because: - it is more cost-effective than temephos, - vectors resistant to temephos have increased susceptibilityto permethrin. 2. To mai nta'in ood levels of vector control once resistance has eve op Once resistance to temephos has developed, chlorphox.im is the replacement larvicide of choice, prov'ided river discharge rates are between 25 and 60-70m3/s. Above the latter level, it ii replacedby permethrin and/or carbosulfan. Because of the wide use of pyrethroids in agriculture, per- methrin is not used for treatjng rivers flowing through cotton-growing areas. In view of the rapid development of pyrethroid resistance in other insects,OCP never uses permethrin for more than 6 consecutive treatment cycles. Carbosulfan is a costly 'larvic'ide, and, a full evaluation of its environmental impact has not yet been completed. Accordingly, carbosulfan is only used in areas where'it is not poss'ible to usepermethrin for the treatment of rivers w'ith moderate wet season discharge rates. In other situations carbosulfan is used in alterna-tion with permethrin and/or chlorphoxim when'it is not possible to useB.t. H-.l4 for long periods of time. 3. To minimize the s'ide-effects of larvic.ide treatments For 6-8 months Lf tn. year most of the Programme area i s under treatment with B.t. H-.l4. The use of other compounds as replacements for temephos always confined to the main stretches of rivers; headwaters and 'ls smal I tributaries are-llrlY,, treated with B.t. H_.l4. 2 i!:li:g l,$J:l iI..r.f s i ;;; =;,^:ui.afrir,' il : r1i* l'lo; i, iliilll.;.Xn.nto be -;.;; i ;; ;.;xiJ';3x:ir,r;:,':ruJi3*j,*,i;l i* ili.Hr :r, retc he s durins ,.rf;;lt;ioF.,jif,'IT:ij:.are suspended as orten as possibre, especiar, The maximum used of teletransmitted hydrolo gical data now al II arvi ci de dosages to be calculated ve ry'accur.ate]y, th us avoiding over_d osing. ows The programme has .inwork whi cn cJr"enirv rii iii.r"iSuiffSr..::;:;ilnsmi ssi on. hydrol osi ca t n ;::1, :i, ; ::.;;:;1,;.. ii; ;. i;,:fft :; ;[sff Ei], *:::jl' i.#m.lij J,'., with these facirities, river d.ischarge rates can be measuredat anv time, o:fTitiiri-iJJJili; griJg."jir:rll,i.rrr^dyrins the course ori"ffi;tl;li,'l8JE;,ri:;jil;;;;, a compute. -,0a. r or di scharse preci si on ' The optimar use of teretransmitted hydro.rogicar data resurts :i:il:d';;i:il'i,'i,:ll:i;l;:iry, -ili.ii"JJ,ia' itnerwi se he ,p .induce resi st-which is both cosry .,;-;;;;.ri:iii iEii;,.i1.i,;; i;a,i*,mi:;,1;;s"-ffi ri;ffi i:; n ix;.i;1 ;ii;$rjii i'#ri iFilii:;; I i:: il t#;i;. s "; it ; ;,,ttoods arrive, ind .i-;;;'h;i'git or the wet season. Finally'. the .application of-very precise dosages results in more:l:iiJ';;.il;'l;;,;l gii:; l;';,', ur i o*',I.1'i..q,.,t - suspenii on,, espe 4 To im rove cost -effect i veness andtom inimize the side-effects ofarvi c n opera ons 4.1. B reater accur ofa I 'ied dos s a better use of la rvi ci de4.2 of ,arvi.,5'lS'il.:ffild,f.;l:,il:J:nJ::J-;;Slliili! ilf,i:il:i.:[0.:i.actionof larvicides in,water, ,,ri.-rr.action-or"i..ri.ides on btai[rtv Iarvae,etc). As a resu]l.t I ;r;;";";;1.: tglutiorinip,between ;i;;;. j,tr.r,u.s.ilor]s:"cide carrv .u, no*'bJ"estabr i;;;;";;.'rh. rir. i;;;i.;d.. cu'enry A^-__ gorputer models are no ) !og,ases ana pSints^of appl icati rw under developr:.1! for determining optimal .tribution of 'oriclriy #5;;;;; ':u! dccordins to rjy... aisir,i.g;, "th. dir_was succe,sr,iii t.,i.o ;;;;,.,i iij"iriirdi:1.:l;;,:ffi.jJ.:S.;lll Fi:1,;;ti;l':ili,::ll;ii:;-in"ii."!uintiti.i oi"ri,ii.ide appried anJ the costi TRACEX ANNEX 3 FROM "QUESTIONS CONCERNING THE MONITORING OF LOTIC ENVIRONMENTS THE ONCHOCERCIASIS CONTROL PROGRAMME" BY DR J. M. ELOUARD The Onchocerciasis control Programme has evolved greatly since its begi nn'ing. Th'i s evol ut'ion concerns not only the i nsecti ci des employed and the Iogistics for the'ir application but also knowledge of the vectors. It follows from this that the present strategyfor the spraying of the d'ifferent insecticides is very far fr6mthat used at the start of the Programme. The same applies to the monitoring of the watercourses. The achjeve- ments are many from the viewpoint not only of methodology and taxonomy of the 'insects but also of biologica'l knowledge of the environments. The monitoring has, of course, been adjusted every year to new Ocp strategies. It has been a matter of adjustments or improvements. However, with the passing of t'ime and the ach'ievements, there shouldbe a more in-depth review of the mpnitoring in order, on the onehand, to highlight its positive aspects and, on the other hand, make up for shortcomings. This very general quest'ionnaire is therefore a reflection paper being oiltftbuted to all those involved in monitoring (national teams, ORSTOM, 0cP, Egological Group). The objective is that they would answer if not all then at least the part concerning theirfield of competence. A synthesis of the different views-and trends could then be prepared in a form that has nct yet been established. TS IN Foreword (i ) (ii ) (iii ) ('iv) Introduct'ion (i) (ii ) After l3 years of biological monitoring of the watercourses treated with antisimuliid insect'icides within ihe framework of the Oncho- cerciasis Control Programme, a review of the results obtained seemsto us to be necessary. This appears to be all the more essentjal s'ince, on the one hand, the river treatment strategy has evorved in 13 years and, on the other hand, OcP'is extending its act'ivities to new areas wh'ich must be monitored. It wi1l, perhaps, become necessaryto reformulate the objectives and reflect on possible changes to be made as regards the future. strategy, network and methods for the moni tori ng. The author had tried to formulise the problems of monitoring in ageneral framework wh'ich we would like to be qu'ite broad. Many of !he1e problems have been studiect sometimes eipric'itly but oft6nimpl'icitly by OcP. The point here is to estabrish wirat an ideal monitoring is, f ist the problems and d'ifficulties and then examinethe solut'ions which have been or are to be adopted in regard to the ecological monitoring of the rivers treated with antisimutiiainsect'icides by 0CP. The I i st of questi ons i s open s'ince the author does not cl a'im to have compiled all the problems related to an jdeal monitoring. we hope, therefore, that others will contribute to making it complete. (iii)