  We consider a three-level food chain in which an epidemics affects the
intermediate population. Two models are presented, respectively either allowing
for unlimited food supply for the bottom prey, or instead assuming for it a
logistic growth. Counterintuitive results related to the paradox of enrichment
are obtained, showing that by providing large amounts of food to the bottom
prey, the top predator and the disease in suitable situations can be
eradicated.
