What is Life

As medical technology gets better our techniques for eliminating disease gets better.  Pathogens such as bacteria or fungi are not as deadly as they were in the past.  As we fight other pathogens such as viruses or prions the definition of living is brought into question.  How does one kill something that is not living?  Viruses, infectious strands of DNA or RNA, and prions, infectious proteins, do not follow the typical parameters for a living organism.  They ca not reproduce on their own and they do not have a typical cell structure with a metabolic cycle.  They are just chemicals that react with our bodies in negative ways.  If these pathogens are considered living then dead cells  should be considered living too.