It is the nature of living organisms to compete with one another. It is the nature of leopards to catch and eat gazelles, it is the nature of some bacteria and viruses to reproduce within the bodies of more complex creatures that it kills them. Other bacteria and viruses are beneficial to their hosts. But we do not have a need to praise beneficial gut bacteria, nor do we have a need to curse malignant bacteria. The wise thing to do is to AVOID malignant bacteria an anything else that we see can cause us to sicken and die,
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By responsible, I am referring to causation, not guilt. It is silly to believe that a bacteria can be blamed for disease and death.
All organisms have the primary goal of reproducing themselves. And that can benefit a host organism or harm or even kill a host organism. But there is no guilt or malfeasance involved.
If God is in fact the creator of all that exists in the Universe, then God is responsible for creating dangerous natural environments as well as disease.
Death is part of a natural process. All living creatures die, none is immortal. Of course, a truly omnipotent God would by definition be capable of creating a much more long lived human, but not one that cannot die, because the nature of the Universe is that every component of the Universe is subject to change, and eventually change results in death.