CompDiseaseEventImmunity is a comp class that allows an animal to not be affected by the animal disease event. If they get animal flu or animal plague through a different means, this will NOT heal them, though, for that use CompDiseaseImmunity

It is a comp class, so you just add it in XML in the <comps> tag. For example, this allows the constructs in Vanilla Psycasts Expanded to avoid animal diseases

<comps>
	<li Class="AnimalBehaviours.CompProperties_DiseaseEventImmunity">			
	</li>
</comps>