Health education in control of fluke infections

Human trematode infections are largely confined to the tropical and oriental countries. Especially schistosomiasis, clonorchiasis, paragonimiasis, heterophydiasis and fasciolopsiasis are great public health problems in certain countries. The control of clonorchiasis, paragonimiasis and intestinal fluke infections theoretically is very simple, as the infection is transmitted to man mostly by eating fish and crabs serving as intermediate hosts and harbouring metacercariae. It is different with schistosomiasis where, by contact with contaminated water, man gets infected with cercarial larvae penetrating the intact skin. Therefore, prophylactic measures are far more difficult to apply successfully. Thus, except in schistosomiasis, the most practical method of preventing human trematode infections is to avoid eating raw, freshly pickled or imperfectly cooked fresh-water fish, crayfish or crabs, etc. It is, however, exceedingly difficult to enforce such simple measures in face of century old traditions, to which relatively primitive populations cling with great tenacity. Therefore, in areas where the consumption of raw fish or crabs is customary, insistent and persistent educational propaganda stressing the importance of thoroughly cooking all fresh-water fish or crabs appears to be the most effective means of preventing such diseases. Such educational efforts should be directed primarily toward school children because they are less entrenched in their food habits. Thus, the educational process could involve various levels to successively change knowledge, attitudes, behaviour, habits and customs of their lives. However, this could better be accomplished by supporting health education by successful chemotherapy.