What is encephalitis?
Encephalitis is an inflammation of the brain, usually caused by a direct viral infection or a hypersensitivity reaction to a virus or foreign protein. Brain inflammation caused by a bacterial infection is sometimes called cerebritis. When both the brain and spinal cord are involved, the disorder is called encephalomyelitis. An inflammation of the brain's covering, or
meninges, is called meningitis.
Victims are usually exposed to viruses resulting in encephalitis by insect bites or food and drink. The most frequently encountered agents are arboviruses (carried by mosquitoes or ticks) and enteroviruses (coxsackievirus, poliovirus and echovirus). Some of the less frequent agents are measles, rabies, mumps, varicella and herpes simplex viruses. Of the many different viruses that can cause encephalitis, enteroviruses (particularly coxsackievirus and echovirus) are the most common cause in the United States. Encephalitis also can be caused by the herpes simplex virus, which also causes cold sores and genital herpes. This type of encephalitis is less common but tends to be more severe. The mumps and measles viruses also can produce encephalitis. All of these viruses are transmitted directly from one person to another.
Other viruses that cause encephalitis are spread by animals. Equine viruses (which also are found in horses) and arboviruses are transmitted from animals to humans by the bites of insects, typically mosquitoes. The West Nile virus, one of the arboviruses, is widespread in Africa, Central Europe, the Middle East and Asia. Since 1999, it has become increasingly common in the United States. West Nile virus does not cause encephalitis in most humans who are infected, but when it does, the symptoms can be severe.
More information on encephalitis
What is encephalitis? - Encephalitis is an inflammation of the brain, caused by a direct viral infection or a hypersensitivity reaction to a virus or foreign protein.
What causes encephalitis? - The cause of encephalitis varies depending on the season, the area of the country, and the exposure of the child. Viruses are the leading cause of encephalitis.
What're the symptoms of encephalitis? - The symptoms of encephalitis vary depending on the cause of the encephalitis. Patients with encephalitis suffer from fever, headache, vomiting, confusion.
How is encephalitis diagnosed? - Diagnosis of encephalitis includes careful questioning to determine possible exposure to viral sources. Tests which can help confirm the diagnosis.
What's the treatment for encephalitis? - Choice of treatment for encephalitis will depend on the cause. Bacterial encephalitis is treated with antibiotics. Viral encephalitis is usually treated with antiviral drugs.
Can encephalitis be prevented? - Encephalitis may be prevented by avoiding the infection. Vaccines are available against some viruses, including polio, herpes B, Japanese encephalitis.
What is Japanese encephalitis? - Japanese encephalitis is a viral disease that infects animals and humans. Japanese encephalitis is a leading cause of viral encephalitis in Asia.
What causes Japanese encephalitis? - Japanese encephalitis (JE) is a disease caused by a flavivirus that affects the membranes around the brain.
What're the symptoms of Japanese encephalitis? - Japanese encephalitis begins with fever, severe headache, nausea, and vomiting. The patient will develop a stiff and painful neck.
How is Japanese encephalitis diagnosed? - The diagnosis of Japanese encephalitis is made primarily on the basis of the patient's symptoms and the knowledge of illnesses endemic to a particular geographic region.
What's the treatment for Japanese encephalitis? - There are no treatments available to stop or slow the progression of Japanese encephalitis. Only the symptoms of each patient can be treated.
What's herpes encephalitis? - Herpes encephalitis is inflammation of the brain. Herpes simplex infection is a relatively common cause of meningo-encephalitis.