Minimal requirements for planning control projects.

Abstract

The different life cycles of trematodes causing the snail-transmitted infections, the complex interactions of the numerous groups of variables representing the five major areas of the epidemiology - human prevalence, incidence and intensity rates, parasite strains, intermediate hosts, ecological backgrounds and human behavioural factors - all combine to render control projects both area and parasite specific. Control must never be equated with eradication which is the complete and permanent cessation of transmission - and rarely, if ever, achievable. In medical and epidemiological terms, control means reduction of morbidity and mortality. Minimum requirements common to efficient planning for any control projects are: a community awareness of the problem; a community expression for the need of control; pathological, statistical and socio-economic evidence of morbidity/mortality produced and the associated economic loss to area, region or country, medical interest and governmental commitment to action as a priority in health policies; appropriate, simple, yet adequate diagnostic technology; appropriate control tools, which, for this group of infections, will rely heavily on population-based chemotherapy; a cadre of trained technicians, field workers and health educators; a programme for training trainers; a delivery system which can be used as an entry point to other health improvements, e.g. sanitation, nutrition, family planning; baseline demographic and epidemiologic information, a pre-tested system of data recording, collection, reduction and analysis; and, finally, funding support. These factors will be discussed.