The presence of fluid in the middle ear accompanied by signs and symptoms of local or systemic infection. In the U.S. 12,000,000 cases of otitis media are estimated to occur each year. More than 90% of children experience at least one episode by age 2 years. Because infants and children have short, horizontal eustachian tubes, they are at risk for obstructions of the middle ear, allowing fluid to accumulate and bacteria to proliferate in the fluid, resulting in inflammation and infection.