Epidemiology of Common Tropical GI Diseases

With the exception of tropical sprue, the diseases reviewed in this chapter are caused by protozoan and helminth parasites. Some of these infections (echinococcosis, fascioliasis, leishmaniasis, schistosomiasis, and soil-transmitted helminthiasis) are included in the World Health Organization's list of Neglected Tropical Diseases. A large proportion of the world's population is symptomatic and an even larger proportion is infected. However, case numbers and their distribution within populations are only estimates. Determinants of disease are largely inferred by implication from the complex life cycle of the causative organisms, rather than from surveys or observational studies. Accurate epidemiology is hampered by diagnostic techniques that may be insensitive but require technical expertise. While the infections discussed have gastrointestinal manifestations many of these diseases have severe complications in other body systems.