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Name: Katie
Status: Student
Grade:  6-8
Location: MD
Country: United States
Date: January 2006

Can the good bacteria in us reproduce into bad bacteria? Or, can it be a host to a harmful to humans virus?

Any type of bacteria can be a problem and cause disease.


Any bacteria can become harmful if the host's immune system is damaged or weak. Sometimes good bacteria pick up genes from other bacteria through the process of conjugation. If these genes are for functions that are harmful they can become "bad".


I don't know of a mechanism by which symbiotic bacteria could mutate to become harmful to their host. Bacteria cannot be the host for human viruses. Human viruses can only multiply in human or certain other animal cells. The only viruses that can multiply in bacterial cells are called bacteriophage and they are harmless to humans because they can't infect human cells.

Ron Baker, Ph.D.

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