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
healed, healthy
healthy, well
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.
unhealthy, diseased , sick
healthy
ILL ?
the answer to that is very simple it is ill