![](https://webarchive.library.unt.edu/eot2008/20090514051338im_/http://www.cancer.gov/images/spacer.gif) |
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![](https://webarchive.library.unt.edu/eot2008/20090514051338im_/http://www.cancer.gov/images/spacer.gif)
| An infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems. |
Previous Definitions: | ophthalmologist, ophthalmoscope, opiate, opioid, opioid growth factor | Next Definitions: | oprelvekin, OPT-80, optic chiasm, optic chiasma, optic nerve |
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![](https://webarchive.library.unt.edu/eot2008/20090514051338im_/http://www.cancer.gov/images/spacer.gif) |