Viral Infection in the Nose can Trigger Infection in Middle Ear

A team of researchers has stated that infection in the middle ear can be caused by a viral infection in the nose.

Nearly 85 percent of children under the age of 3 years experience an infection in the middle ear. This common and painful infection is also known as otitis media or glue ear and occurs in the region behind the eardrum. In a latest study, researchers at the Wake Forest Baptists Medical Center, found that this middle ear infection can be triggered by a viral infection in the nose and not just by a bacterial infection.

To prove the hypothesis, the researchers conducted an experiment in which they instantaneously infected the nose with a flu virus and a bacterium that is known to be the leading cause of ear infections in children. 

They observed that the flu virus caused inflammation in the nasal tissue and dramatically elevated not just the number of the bacteria, but also their tendency to travel through the Eustachian tube and cause an infection in the middle ear.

"Every individual has bacteria in the nose that most of the time doesn't cause problems," said the study's lead author, W. Edward Swords, Ph.D., professor of microbiology and immunology at Wake Forest Baptist. "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."

In the animal study, the researchers used the bacterium called Streptococcus pneumonia. This bacterium is known to exist in the nose of the children in two phases in which one is relatively invasive and the other is relatively benign.

The invasive phase was seen more often in the infected ears of the children. But this study shows that the flu virus boosts the bacterial growth and ear infection, irrespective of which phase of the bacterium is present in the nose.

"These findings suggest that a flu infection modifies the response of the immune system to this particular bacterium, enabling even the type that has previously been considered benign to infect the middle ear," Swords said.

The finding was documented in the American Society for Microbiology's journal Infection and Immunity.