Visceral leishmaniasis: a model for infection-induced cachexia.

Parasitic infections and malnutrition coexist in many tropical and subtropical areas. Studies of Leishmania donovani and of experimentally infected Syrian hamsters have provided important insights into the complex interrelationships between malnutrition and this parasitic disease. Malnutrition, which adversely affects cell-mediated immunity, is associated with the development of visceral leishmaniasis (kala-azar) in children living in endemic areas. In turn, L. donovani can cause wasting as well as hepatosplenomegaly, fever, and anemia. Syrian hamsters infected with L. donovani develop a disease that is comparable to that of humans with kala-azar. Weight loss in infected hamsters is associated with splenic macrophage secretion of potentially catabolic cytokines as measured by the D10.G4.1 assay for interleukin-1 and the L929 cytotoxicity assay for tumor necrosis factor/cachectin. Although decreased food intake contributes to wasting in infected hamsters, studies of skeletal muscle function indicate that it is not the sole factor. Leishmania donovani-infected hamsters have also been used to study drugs with the potential to prevent or reverse cachexia.