Viruses are the most common cause of meningitis in adults and a cause of substantial long-term ill health, a study has found.

The study conducted by researchers at the University of Liverpool's Institute of Infection and Global Health studied the diagnosis and treatment of more than 1000 patients with suspected meningitis. Diagnosis of meningitis is often delayed due to unnecessary brain scans being performed before lumbar puncture which is the essential investigation to determine the cause of the illness.

Cases of bacterial meningitis - the life-threatening form of the disease have significantly reduced over the last few decades following the introduction of vaccines against some of the most common types, and the study found that viral meningitis now accounts for the majority of cases.

A delay in diagnosis means that antibiotics are often inappropriately used in patients with viral meningitis, resulting in a longer than necessary stay in a hospital. Dr Mike Griffiths, senior investigator of the study, said, "Diagnosing a specific cause of meningitis quickly is key to getting patients on the right antibiotics if needed, or avoiding unnecessary antibiotics in those with viral meningitis."

"Meningitis can strike without warning and the bacterial form of the disease can kill in hours. Many survivors have long-term, disabling after effects as serious as brain damage and deafness," said Vinny Smith, Chief Executive at MRF. The full findings are present in the Journal- the Lancet Infectious Diseases.