A new study shows that while childhood ear infections are generally considered bacterial diseases, they are often the result of both bacteria and viruses, leading to complications in treatment.

Finnish researchers used lab tests to identify the pathogen that caused ear infections, known clinically as acute otitis media, in 79 young children. They found bacteria in 92 per cent of the cases, viruses in 70 per cent, and both bacteria and viruses in 66 per cent.

"This is actually logical since acute otitis media is virtually always connected to viral respiratory infection," said Dr. Aino Ruohola of Finland's Turku University Hospital, lead author of the study.

She says her team's findings have implications for treatment.

Antibiotics are effective against the bacteria that cause ear infections but have no effect on the viruses. That means standard treatment for ear infections — antibiotics — is at best partially effective in most cases.

"Based on this and previous research, it is possible that viruses cause a considerable proportion of clinical treatment failures. Thus, in these cases a new antibiotic is not necessarily the best choice although bacteria resistant to common antibiotics are wide-spread," Ruohola said in a news release.

According to the study, published in the Dec. 15 edition of Clinical Infectious Diseases, the good news is that many children recover on their own without antibiotic treatment.