A new study states that viral infection in the nose can lead to infection in the middle ear.
More than 85 percent of children below the age of 3 are affected by middle ear infection.
Researchers at the Wake Forest Baptist Medical Center did an animal study and found that the flu virus inflamed the nasal tissue and drastically increased both the number of bacteria and their tendency to travel through the Eustachian tube and infect the middle ear. The team had simultaneously infected the nose with a flu virus and a bacterium that is one of the leading causes of ear infections in children. The bacterium used in the animal study is also found in the noses of children in two phases - one relatively invasive while the other relatively benign.
"Every individual has bacteria in the nose that most of the time doesn't cause problems," study lead author and professor of microbiology and immunology at Wake Forest Baptist W. Edward Swords said in a press release. "However, under certain conditions those bacteria can migrate to the middle ear and cause an ear infection, and now we have a better understanding of how and why that happens."
According to Swords, the findings indicate that a flu infection modifies the response of the immune system to this particular bacterium. This in turn enables even the type that has previously been considered benign to infect the middle ear.
The research was sponsored by NIH Institute of Deafness and Other Communication Diseases grant and AstraZeneca.
The study is published in the journal Infection and Immunity.
