News 9 Marsh, K. (1992) Pams~tolo,~y 104, $53-S69 10 Greenwood. B,M., Marsh, K, and Snow, R.W, ( 1991 ) Parasitol. Today 7, 277 28 I II Snow, R.W. et aL (1994) Acta Trap. 57, 289-300 12 Binka,F.N et al. (1996) T~op.Med. Int. Hlth I, 147--154 13 Nevill, C.G. et al. (1996) Trap. Med. Int. Hlth I, 139-146 14 Alonso, P.L. er d. (1991) Lancet 337, 1499- 1502 15 Alonso, P.L, Molyneux. M.E. and Smith, T, (1995) Parasitol, Today I I, 197 16 Greenwood, B.M. et ,..71. (1988j Lancet ii, 1121--I 127 17 TDR News (1996) TDR News, World Health Organisauon 50, 3 18 McQ~e, A.W.R. (1968) in Uganda. Atlas of Disease Distribution. Mkerere University College, Kampala, Uganda 19 Clyde, D.F. (1967) in Malanu in Tanzania. p. 154,Oxford University Press 20 Covell, G. (1957)J. Trap. lvled. Hyg. 60, 7-16 21 Wilson. D.B. (1946) East Aft. Mad. ] 26. I-9 22 Roberts, J.M.D. (1974) in Health and Disease ~n Kenya (Vogel, L.C. et aL. eds). p. 529. East Afi-ican Library Bureau, Nairobi )-3 Melville, A.R. et al. (t945) East A/L Med.J. 22. 285 --294 24 Metselaar,D. and van Theil, P.H. (I 959) hop Geog,: Meal. I 1, 157 -161 25 Gill, G.A. (1938) The Seasonal Penod~city of Malaria and the Mechanism of the Epidemic Wave, Churchill 26 Lysenko. A.Y. and Semanshko. I.N. (1968) Medical Geography" Geography at Mulana (Lebedew, A.W., ed.), Academy of Sciences. USSR 27 Cattani. J. and Teklehaimanot, A. rl991) Report on the Meeting on the Application of Rap~d Assessment Methods to Tropical D~s- eases. Baroda, Incfla 28 January-I February 1991. TDR/SER/RAM/91.3. 28 Maguire, D.J. (1991) Pnnaples ol Geographic Information Systems. Vol. ! (Maguire. D.J.. Goodchdd,M.F.and Rhind,D.W., eds),Longman Scientific & Technical 29 le Sueur. D. et all. (1996) Towards d Spaual Rural HedI~P, In[b"matlon System. Health Sys- tems Tnust & Medical Research Council South Afi-ica. Durban Bob Snow ~sat the The Wellcome TrusdKenya Medical Research Institute Collaborative Pro- gramme, PO Box 43640, Nairobi, Kenya, and, with Kevin Marsh, at the Numeld Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital. Oxford, UK OX3 9DU. K. Marsh is ,also at 1.he Ctin~cai Research Centre, Kilifl Unit, Kenya Medical Research Institute (KEMRI), PO Box 230, Kitif~, Kenya. David le Sueur is at the National Malaria Research Programme of the Medical Research Council, Durban, PO Box 17120, South Africa. Tel: +254 2 7253981725390, Fax: +254 2 711673, e-mail: WeUtrust2@ken. healthnet.or Modelling of Potential Schistosomiasis Vaccination Programrnes M-S. Chan, B.F. Hall and D.A.P. Bundy Bethesda, USA July & September 1995 Over the course of two meetings, two months apart, discussion focused on the construction of mathematical models to predict epidemiological impacts of schistosomiasis vaccinal:ion programmes in target populations, Initially, we con- sidered structural relations of the model, including characteristics and modes of vaccine action, and then discussed appropriate parameters for these rela- tionships, Subsequently, we used the models to simulate the impacts of different vaccination programmes. The follow-up meeting focused on the discussion of clinical trial designs for potential schistosomiasis vacrines. The discussion and simulations, summarized here, provided insights relevant to the design of both preclinical and clinical schistosomiasis vaccine research, and future population-based immunization programmes ~,2 Model Structure A consensus existed among the participants (see Box I) that naturally acquired resistance to infection, vaccine- induced immunity, and immunopath- ology may all follow different pathways (known as a complementaf,-y model) and should be modelled as distinct processes. These three components will be discussed separately. Naturally acquired resistance to infec- tion. Quantitatively, the most important action of acquired in~munity was thought to be protection against further infection by acting against the establishment of adult worms (anti-establishment model), The most immunogenic parts of the life cycle were considered to be the adults and especially the eggs, The target of these responses would be the schisto- somulae. Very little is known about either the strength or the duration of immune protection. There are many additional complex- ities that may need to be taken into account when modelling the immune response. These arise largely fi'om the fact that this response is really a composite of different irnmune mecha- nisms. Naturally acquired resistance may also involve non-immunological responses. Box I. Participants at the Meetings At the workshop: Man-Suen Chan, Donald Bundy, Mark Woolhouse, Helen Guyatt (Centre for the Epidemiology of Infectious Disease, Oxford University, UK) B. Fenton Hall, StephanieJames, Mike Gottlieb, Alan Sher, Allen Cheerer, Tom Wynn (National Institutes of Health, Bethesda, USA) Mette Strand (Johns Hopkins University, Baltimore, USA) At the follow-up meeting: Robert Berquist (Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland) Nabil Galal (Schistosomiasis Research Project, Cairo, Egypt) Maged AI-Sherbiny (Egyptian Reference Diagnostic Center, Cairo, Egypt) Edgar Carvalho (Hospital Universario Prof. E. Santos, Salvador, Brazil) Carter Diggs (US Agency for International Development, Washington DC, USA) Dan Colley (Division of Parasitic Diseases, Centers for Disease Control, Atlanta, GA, USA) Taha EI-Khoby (SchistosomiasisResearch Project, Ministry of Health, Cairo, Egypt) Edward Pierce (Cornell University, Ithaca, NY, USA) Dragana Jankovic (National Institutes of Health, Bethesda, USA) Don Harn (Harvard University, USA) Barend Hans (European Commission, Brussels,Belgium) Parasitology Today, vol. 12, no. !2, 1996 cop~,-,ghto lq96. Elsev,erSoenceLtd Allnghts,eser~ed 010947~8'965i500 F~il b0,~--~-5~ ==C.C!~ ~i ~ 451