Marr, J. D. M.

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116 Environmental Conservationside-effects of Abate on the aquatic fauna (see Hamon etal., 1974, for review), and this is currently receiving atten-tion from WHO and also from ecologists, chemists, andtoxicologists, from various institutes in Europe, Africa,and North America. Rivers in the area sprayed are beingmonitored to detect any changes in the fauna that mightbe caused through insecticidal usage. Furthermore, inves-tigations are being vigorously pursued in various scientificinstitutes throughout the world to try and develop alter-native control methods for black-flies, such as biologicalcontrol with pathogens and parasites. Unfortunately,however, there are no practical alternative methods thatcan at present be substituted for insecticidal control.I hope to have shown that onchocerciasis is a moreserious disease in West Africa than was acknowledged byDr Asibey, and that the authorities involved in the VoltaBasin project are fully aware of the possible environmentaleffects associated with the eradication of river blindness.I am not arguing as to whether this project should havebeen initiated in West Africa when it was, as much dependson medical and non-medical priorities and whether avail-able technology is considered sufficient to ensure success.However, as it was decided to undertake the project therewas (and still is) no alternative but to use insecticides.*MICHAEL W. SERVICE, Senior LecturerDepartment of Medical EntomologyLiverpool School of Tropical MedicinePembroke PlaceLiverpool, England* See also the WHO rejoinder published below.—Ed.ReferencesANDERSON, J., FULSANG, H., HAMILTON, P. J. S. & MARSHALL,T. F. d'E. C. (1974). Studies on onchocerciasis in the UnitedCameroon Republic. II, Comparison of onchocerciasis inrain-forest and Sudan savanna. Trans. R. Soc. Trop. Med.Hyg., 68(3), pp. 209-21.ASIBEY, E.O.A. (1975). Black-fly and the environment. Envi-ronmental Conservation, 2(1), pp. 25-8.BUCK, A. A. (1974). Global problem of onchocerciasis and itseconomic impact. Pp. 3-10 in Research and Control ofOnchocerciasis in the Western Hemisphere. Pan. Am. HlthOrg., Sci. Publ., No. 298, 154 pp.DUKE, B. O. L. (1974). Clinical manifestations and geographicdifferences. Pp. 25-9 in Research and Control of Oncho-cerciasis in the Western Hemisphere. Pan. Am. Hlth Org.,Sci. Publ., No. 298, 154 pp.DUKE, B. O. L., LEWIS, D. J. & MOORE, P. J. (1966). Oncho-cerca-Simulium complexes. 1, Transmission of forest andSudan-savanna strains of Onchocerca volvulus from Came-roon, by Simulium damnosum from various West African bio-climatic zones, Ann. Trop. Med. Parasit., 60(3), pp. 318-36.GANLEY, J. B. & BILES, J. E. (1973). Prevalence of Onchocer-ciasis: Visual Impairment and Blindness in Six Villages inthe Upper Region of Ghana. World Health Organizationdocument, PD/73.2, 38 pp. (mimeogr.).HAMON, J., QUELENNEC, G., VILLARS, R., MARR, J. D. M.,STILES, A. R., GRATZ, N. G., PARKER, J. D. & ARATA, A. A.(1974). Onchocerciasis vectors in the Western Hemisphere.B, Vector control aspects. Pp. 69-84 in Research andControl of Onchocerciasis in the Western Hemisphere. Pan.Am. Hlth Org., Sci. Publ., No. 298, 154 pp.Black-fly and the EnvironmentReference is made to the article under the above titleby Dr Emmanuel O. A. Asibey which appeared in Volume 2No. 1 of Environmental Conservation (being the Spring issueof 1975). Although a preliminary draft of this article wassent to the World Health Organization (WHO) and receivedextensive comments of a technical nature already in Decem-ber 1974, its actual publication was not known until it wasrecently brought to our attention by a member of ourScientific and Technical Advisory Committee. In thepublished article there was little reference to these com-ments, which clarified the raison d'etre of the WHO Oncho-cerciasis Control Programme and, therefore, it seemsinappropriate that acknowledgment be made in it to seniorofficials of the Organization.We appreciate Dr Asibey's concern (as Chief Game andWildlife Officer of Ghana) regarding the environment, butfeel it necessary to emphasize that this particular Pro-gramme, which is being carried out by WHO at the requestof seven countries in the Volta River Basin area, is thesubject of environmental monitoring which is perhapsgreater than that associated with any former vector-controlprogramme anywhere in the world.It should be noted that, on environmental grounds,WHO did not utilize DDT as a larvicide, although thischemical has been employed for many years in black-flycontrol in the project area by the governments concerned.In this respect, it may be pointed out that a great varietyof residual insecticides have been used for some time in thearea to control agricultural pests. The selection of Abateas the insecticide of choice was made following the screeningof approximately 1,000 compounds, and was chosen on thebasis of its relatively specific effect on black-fly (Simuliumspp.) larvae.An independent Ecological Panel has approved an aqua-tic monitoring programme which was drawn up with theassistance of hydrobiological experts from around theworld, to determine if, or to what extent, environmentalchanges are being produced by the application of insecticidefor black-fly control. This Panel reviews twice a year theresults obtained. Members of the Ecological Panel havevisited the Onchocerciasis Control Programme area andthere have been no reports of any adverse environmentaleffects to date. The Institute of Aquatic Biology of theRepublic of Ghana, and the ORSTOM HydrobiologicalUnit stationed in Bouake in Ivory Coast, are engaged full-time in this monitoring programme.We do not consider it appropriate to comment specifi-cally on a number of points mentioned in the article byDr Asibey. However, it should be clearly understood thatthere is as yet no drug which can be used as a prophylactic,and the drugs available to treat those suffering from oncho-cerciasis are not recommended by experts in this field formass treatment because of their toxicity and other side-effects. Furthermore, when a suitable drug is developed,chemotherapeutic measures will be undertaken concomi-tantly with black-fly control.*J. D. M. MARR, Entomologist!BiologistOnchocerciasis Control ProgrammeWorld Health OrganizationAvenue Appia1211 Geneva 27Switzerland.* See also Dr Michael W. Service's comments in his 'Black-fliesand the Environment: A Reply to Dr Asibey' published onpp. 115-6 of this issue. Dr Asibey, having seen both these com-munications engendered by his original paper, reserves the rightto reply in due course.—Ed.https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900018142Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:59:08, subject to the Cambridge Core terms of use, available at

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