U. S. Department of Health, Education, and Welfare, Public Health Service, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Parasitic Diseases, Bethesda, Maryland
Several factors may be involved in the pathogenesis of hepato-splenic schistosomiasis mansoni, but their relative importance has not been convincingly demonstrated. It has been postulated that malnutrition, toxic products of worms, dead worms, eggs produced by the worms or any combination of these factors may be the cause of this disease. Studies of this problem in the past have been hampered by the lack of a suitable experimental animal. Recently, the occurrence in mice of a syndrome resembling hepato-splenic schistosomiasis in humans has been reported. With the development of this syndrome in mice used as a criterion of significant disease, the effect of each of the above factors was studied. On the basis of the results obtained it is felt that eggs are the prime factor in the development of hepato-splenic schistosomiasis in the mouse, that toxins produced by the worms or an allergic reaction to their presence may be a contributing factor in the early stages, and that dead worms and malnutrition are probably only of ancillary importance.