The opposite could be unhealthy, sick, ill, or afflicted.
I suppose the opposite would be a healthy and safe animal. If it has to be one word, perhaps "healthy."
The opposite of sick is healthy.
uncritical
healthy
healthy, well
healed, healthy
The opposite of pestilence would simply be living a long and healthy life.
Gentle, healthy, harmless, nonpoisonous, or lifegiving. Those words are the opposite of poisonous.
healthy
unhealthy, diseased , sick
the answer to that is very simple it is ill
ILL ?