U
- Ultraviolet light
- A shortwave solar irradiation likely to cause mutations in cells and ultimately skin cancer.
- Undulant fever
- One of several common names applied to the disease brucillosis.
- Unicellular
- An organism that has only one cell, for example, bacteria.
- Urechis caupo
- A free-living burrowing marine worm that lives in tidal mudflats.
- Urethra
- The tubular passage through which urine is discharged from the bladder to the exterior of the body.
- Urethritis
- An inflammation of the urethra caused by various bacterial sources, especially Neisseria gonorrhoeae (in gonorrhea) or of non-gonococcal or non-specific origins, as well as Chlamydia trachomatis and Mycoplasma hominis. Symptoms include the inflammation that produces painful urination. Infection usually results through sexual contact with an infected person.
- UTI's (urinary tract infections)
- Infections of the urinary tract caused by numerous pathogens including Shigella, Campylobacter, E. coli, and Salmonella, infecting mainly the bladder and urethra.
