Schistosomiasis: its significance in a changing human ecology

Schistosomiasis is a man-made disease. Evaluation of the current status of schistosomiasis requires knowledge of the intensity of infection, a measure now dependent on quantitative egg counts and applied to data only on a limited scale. The determinants of intensity of infection are as yet ill-defined. Morbidity and mortality associated with schistosomiasis are difficult to assess in indigenous populations saddled with a multiplicity of diseases. However, the problem of schistosomiasis and its deleterious consequences will rapidly worsen as an expanding population creates new aquatic habitats favorable for the snail intermediate hosts and as people have increased contact with infected water. Moreover, the number of children is increasing fastest in the developing regions of the world. Children and young adolescents are the age groups primarily responsible for the transmission of schistosomiasis. We are in an era when a predominantly young population will increasingly contaminate a finite environment.