Sadun's major research thrust was on the human immunologic reaction to parasitic diseases, or more precisely, host-parasite immunological interactions.

His areas of expertise are evolutionary genetics, host-parasite interactions and social evolution.

His research in community ecology has been in two broad areas: the role of disturbance in structuring natural communities and the ecology of host-parasite interactions.

In addition the modes of selection can differ between the various loci involved in host-parasite interactions.

In its original form, the model does not allow for stable host-parasite interactions.

Its anti-predator adaptations, host-parasite interactions, sensory physiology, reproductive physiology and endocrinology have also been much studied.

In host-parasite interactions, the parasite organisms benefits at the expense of the host organisms.

Costs are also present in digital host-parasite interactions: performing more or more complex tasks implies larger genomes and hence slower reproduction.

"Shared control of epidemiological traits in a coevolutionary model of host-parasite interactions".

His work constitutes a major contribution to modern theory of host-parasite interaction in plant populations.