The unacknowledged impact of chronic schistosomiasis

Abstract

To summarize new knowledge on the range of disease due to chronic schistosomiasis and examine the debilitating burden of both light and heavy infection; to outline goals of disease prevention, including current age-targeted strategies and more extended programmes aimed at preventing transmission. A systematic search of 2004-2007 papers via PUBMED and related databases using 'schistosom' and disability- or treatment-related subject headings. Reports were independently reviewed for inclusion. Sixty-eight papers met review objectives. These suggest new evidence for a causative link between schistosome infection, antiparasite inflammation, and risk for anaemia, growth stunting and undernutrition in affected populations, as well as exacerbation of co-infections and impairment of cognitive development and work capacity. Formal quality-of-life assessment defines a significant 9.5-24% disability with the most aggressive schistosome species, Schistosoma japonicum. Schistosomiasis represents a serious but under-recognized disease burden for many developing countries. Infection (and not intensity of infection) should be considered the defining feature of morbidity formation. Links between infection and long-term disabilities reduce the chances of combating rural poverty. Changes in our appreciation of schistosomiasis-related disease burden means it is no longer appropriate to leave infected persons untreated, and newer approaches to control should focus on preventing transmission.