Definition
Japanese Encephalitis is a tropical disease that occurs mainly in East and Southeast Asia. It is caused by the Japanese Encephalitis virus, which is transmitted to humans by a mosquito bite. In most cases an infection proceeds without serious symptoms.
In severe cases, however, an inflammation of the brain (encephalitis) can develop with loss of consciousness, paralysis and epileptic seizures. A causal therapy is not available. A vaccination against the disease is possible.
Causes of Japanese Encephalitis
Japanese Encephalitis is a tropical disease caused by viruses. The Japanese encephalitis virus belongs to the same group as the virus that causes yellow fever. A mosquito bite can infect a person with it.
The disease is a zoonosis. These are diseases that can be transmitted from vertebrates to humans. The mosquito acts as a disease carrier.
Intermediate hosts for infection in humans are usually domestic animals such as pigs or horses. The disease is widespread in Asia. The risk of infection is particularly high in rural areas; at the end of the rainy season.
Diagnosis of Japanese Encephalitis
Clinically, Japanese Encephalitis presents itself with the typical symptoms of encephalitis: loss of consciousness, paralysis and epileptic seizures. Blood tests show an increased number of white blood cells (leukocytosis). Antibodies against the virus can sometimes also be detected.
It is also possible to examine cerebrospinal fluid (liquor); in this case, an increased number of inflammatory cells can be seen in normal sugar concentrations. This is a typical finding for an inflammation caused by viruses. Using a special examination method (PCR), the virus can also be detected directly in the cerebrospinal fluid.
Associated symptoms of Japanese Encephalitis
In most patients, the disease causes no or only discreet symptoms such as fatigue, headache and slight fever; most likely comparable to a flu-like infection. In severe cases, however, an inflammation of the brain (encephalitis) may develop. This stage is characterized by sudden onset of high fever, chills, headache and aching limbs.
Neurological symptoms appear shortly afterwards. These are usually severe disturbances of consciousness up to coma. Paralysis, speech disorders or epileptic seizures can also occur.
