Related concepts:

Meningoencephalitis, Viral encephalitis, West Nile encephalitis

Introduction to encephalitis:

West Nile virus frightens many parents because it can cause a type of infection called encephalitis.

What is encephalitis?

Meningitis is primarily an inflammation of the lining of the brain and spinal cord, and sometimes of the brain itself. Encephalitis is primarily an inflammation of the brain.

Most of the time, the inflammation is caused by viral infections. West Nile virus rapidly spread across the United States at the turn of the 21st century as a cause of encephalitis, but enteroviruses are far and away the most common cause. Arboviruses and herpes are also common. West Nile virus is an arbovirus.

Measles, mumps, chickenpox, rubella, CMV, EBV, and rabies are other noteworthy causes. For example, before vaccination, mumps encephalitis was a common cause of deafness.

Most children with viral encephalitis recover completely with no complications, but sometimes the results are devastating. Some viruses, such as herpes, tend to cause more severe illness than others.

Who gets encephalitis?

Anyone can get encephalitis. It tends to be more common in the summer and fall. Some types are found in those who are bitten by infected mosquitoes or other insects. Some types are found in those who get infected stool particles in their mouths. Some types are found in those who just spend time in the same room as someone infected with the virus.

What are the symptoms of encephalitis?

The symptoms of encephalitis can vary quite a bit, from those of a very mild illness to coma or sudden death. A severe headache is usually the central symptom. Often there is sensitivity to light. There may be a fever, vomiting, fatigue, and/or irritability. With some viruses there is a characteristic rash. Neck pain, back pain, and leg pain are common.

In some, there are severe seizures, hallucinations, and loss of bowel or bladder control. Even these children may recover completely with no lasting problems.

Is encephalitis contagious?

Some types of encephalitis, such as that caused by West Nile virus, do not spread easily from person to person, although they can be spread by transfusion or organ transplant. Other encephalitis viruses, such as measles, spread very easily among unvaccinated people.

How long does encephalitis last?

These infections may be brief or prolonged.