There is no evidence that corpses cause or spread disease following a natural disaster. There would have to be more direct circumstances for potential damage from corpses.
The risk associated with epidemics is correlated to the population displaced and affected by infrastructure.
The most commun post-natural disaster diseases are related to water contamination and crowding. While corpses could potential contaminate water, because the population is displaced the corpses likely won't contaminate the new water source, but the overcrowded displaced population will. Some of such disease include Hepatitis A and E, Leptospirosis, and measles. Meninginitis and Acute Respiratory Infections can also develop if vaccinations are not prevelant there.