Updated: 2007
Occupational HIV Exposure
Exposure to HIV as a result of work (job). Exposure may include accidental exposure to HIV-infected blood following a needlestick injury or cut from a surgical instrument. OI
See
Opportunistic Infection. Oncology
The branch of medicine that studies cancers or other tumors. Opportunistic Infection
An illness caused by various organisms, some of which usually do not cause disease in persons with normal immune systems. Persons living with advanced HIV infection suffer opportunistic infections of the lungs, brain, eyes, and other organs. Opportunistic infections common in persons diagnosed with AIDS include Pneumocystis jiroveci pneumonia; Kaposi sarcoma; Cryptosporidiosis; histoplasmosis; other parasitic, viral, and fungal infections; and some types of cancer. Opt In
In HIV testing, a procedure whereby an individual is counseled about HIV and is given the option of accepting or rejecting an HIV test. They "opt in" when they agree to have the tested done. Opt Out
In HIV testing, a procedure whereby an individual is counseled about HIV and is only given the option of refusing an HIV test. If they refuse the test they have "opted out" of HIV testing. Studies have shown that more individuals agree to HIV testing when an opt out approach is used. OPV
Oral polio vaccine. Oral Fluid Test
A test using oral mucosal fluid. To differentiate this fluid from saliva, an absorbent material is left in the mouth for several minutes. In an HIV-infected person, oral mucosal fluid is likely to contain HIV antibodies. Oral Hairy Leukoplakia (OHL)
A whitish lesion that appears on the side of the tongue and inside the cheeks. The lesion appears raised, with a ribbed or hairy surface. OHL occurs mainly in persons with declining immunity and may be caused by Epstein-Barr virus infection. OHL was not observed before the HIV epidemic. Oral Sex
A type of sexual intercourse in which the partner's genitals are stimulated by mouth and tongue. Oropharyngeal
Relating to the division of the pharynx between the soft palate and the epiglottis. The pharynx is a tube that connects the mouth and nasal passages with the esophagus, the connection to the stomach. The epiglottis is a thin, valvelike structure that covers the glottis, the opening of the upper part of the larynx (the part of the throat containing the vocal cords), during swallowing. Oropharynx
The area beginning at the lips and extending to the back of the mouth. Otitis
Inflammation of the ear, which may be marked by pain, fever, abnormalities of hearing, hearing loss, tinnitus, and vertigo. Otitis Media
Infection and inflammation of the middle ear space and eardrum. OVC
Orphans and vulnerable children. Oxytocin
A peptide hormone from the hypothalamus that induces smooth muscle contraction in the uterus and mammary glands. | 
