Encephalitis simply means inflammation of the brain. The condition is most often caused by a virus, though it can also be caused by a bacteria or fungus. The viral disease can be primary, which means it directly attacks the brain, or it can be secondary. This means that the viral infection began somewhere else in the body and spread to the brain.
Information. Encephalitis affects about 1 in 200,000 people every year, and most of its victims are very young, elderly or have compromised immune systems. These include people with HIV or who are taking drugs to suppress their immune systems. People are also more likely to get the disease if they live in areas where mosquitoes and ticks that harbor the viruses are common. Because these creatures proliferate in warm weather, encephalitis is more common in the summer. The statistics on encephalitis are estimates because some people have such mild symptoms that they do not seek medical treatment. Most cases of encephalitis are mild, and the person makes a full recovery without going to the doctor. In cases where the patient does seek medical help, a diagnosis can be made through a lumbar puncture, an electroencephalogram that measures the activity of the patient’s brain or an MRI or CT scan of the person’s head.