Deadly "brain-eating" amoebas have been in the news lately, as a number of people have died this year from being infected with them through contaminated water. From Yahoo News:
The third case, in Louisiana, was more unusual. It was a young man whose death in June was traced to the tap water he used in a device called a neti pot. It's a small teapot-shaped container used to rinse out the nose and sinuses with salt water to relieve allergies, colds and sinus trouble.
Health officials later found the amoeba in the home's water system. The problem was confined to the house; it wasn't found in city water samples, said Dr. Raoult Ratard, Louisiana's state epidemiologist.
The young man, who was only identified as in his 20s and from southeast Louisiana, had not been swimming nor been in contact with surface water, Ratard added.
He said only sterile, distilled, or boiled water should be used in neti pots.