Japanese encephalitis

Head | Allergy & Immunology | Japanese encephalitis (Disease)


Description

Japanese encephalitis is a type of viral brain infection that is spread through mosquito bites. It’s common in rural areas throughout Southeast Asia, the Pacific islands and the Far East.

Most people who are infected by the Japanese encephalitis virus do not develop any symptoms, or they get only mild, flu-like symptoms.

However, around one person in 250 infected by the virus has serious and severe symptoms. Fever, headache and malaise are other non-specific symptoms of this disease which may last for a period of between 1 and 6 days. Signs which develop during the acute encephalitic stage include neck rigidity, cachexia, hemiparesis, convulsions and a raised body temperature between 38 and 41 degrees Celsius. Mental retardation developed from this disease usually leads to coma. Mortality of this disease varies but is generally much higher in children

Causes and Risk factors

Japanese encephalitis is caused by a flavivirus. This type of virus can affect both animals and humans. The virus is found in pigs and birds, and is passed to mosquitoes that bite the infected animals. It’s more common in rural areas where there are pig farms and rice fields. It cannot be spread from human to human.

The virus can cause swelling inside the brain (encephalitis), leading to increased pressure in the brain. This can cause permanent brain damage. Around one in three cases of encephalitis is fatal.

Diagnosis and Treatment

The virus can be identified in blood or cerebrospinal fluid (CSF). A blood test to identify the antibody (IgM) against the virus can also be performed.

There is no specific treatment. Patients should drink plenty of fluids, take acetaminophen, a non-steroidal anti-inflammatory (ibuprofen) or aspirin for their fever. Children should not take aspirin because of the risk of Reyes syndrome. Immediate treatment should be sought for persistent vomiting, severe headache, confusion seizures, weakness, or other serious symptoms. Some patients may require hospital admission. ...