Japanese encephalitis is a dangerous disease, because the initial clinical symptoms of the disease are easily confused with other diseases.

Transmission of Japanese encephalitis

Japanese encephalitis is an extremely dangerous disease and summer is the time when it is most likely to become an epidemic. The main infected subjects are children under 15 years old, especially those from 5 to 7 years old.

There are more than 30 species of mosquitoes that transmit Japanese encephalitis virus, especially Culex Tritaeniorhynchus. C. Tritaeniorhynchus often breeds in rice fields, swamps and other shallow water bodies. These mosquitoes bite in the evening and at night.

The risk of Japanese encephalitis virus infection is highest in rural, agricultural areas. Some cases of Japanese encephalitis are sometimes reported from urban areas.

Symptoms of Japanese encephalitis at each stage

After the Japanese encephalitis virus enters the body, the patient’s brain and central nervous system will show many lesions. In particular, many unwanted symptoms can occur at each stage as follows:

• Incubation period

After the Japanese encephalitis virus enters the body, the patient will experience an incubation period of 5 to 14 days. At this stage, there are usually no symptoms.

• Onset stage

After the incubation period, the encephalitis virus will begin to attack the brain’s blood vessels, causing cerebral edema. Symptoms will begin to appear suddenly, such as a high fever above 39 degrees Celsius. In addition, the patient also feels headache, nausea or vomiting.

During the first 1 to 2 days of the disease, people with Japanese encephalitis may experience typical symptoms such as stiff neck, loss of consciousness, increased muscle tone or impaired eye movement… In particular, young children with this disease often have symptoms that are easily confused with food poisoning such as abdominal pain, vomiting and loose stools.

Japanese encephalitis is an extremely dangerous disease.

• Full-blown stage

This is the stage where extremely dangerous symptoms of encephalitis appear. These are brain damage in general and localized nerve damage in particular, such as paralysis of limbs, facial paralysis or strabismus. The condition does not improve but becomes increasingly worse. The patient will become delirious and gradually fall into a deep coma.

In addition, the patient also has many symptoms of the autonomic nervous system such as excessive sweating, rapid pulse, high blood pressure and breathing disorders. In particular, the mortality rate of people with Japanese encephalitis is very high if not treated promptly, especially for children.

• Remission stage

After about 7 to 8 days, if there is no secondary infection, the patient’s body temperature will gradually decrease and there will no longer be a high fever. In addition, brain syndromes as well as neurological disorders will improve significantly if treated promptly and properly.

However, this encephalitis will leave neurological sequelae such as paralysis of limbs or nerves. This greatly affects the quality of life and health of the patient. Moreover, dangerous complications are also inevitable.

Prognosis of Japanese encephalitis

There is currently no specific treatment for Japanese encephalitis and currently only supportive treatment is provided. Therefore, when patients have Japanese encephalitis, the mortality rate is high and will leave neurological sequelae later.

The mortality rate in hospitalized patients with encephalitis is about 20 – 30%, often occurring after a period of prolonged coma. Among survivors, neurological sequelae occur in at least 30 – 50%.

The most common sequelae include:

• Psychiatric problems and recurrent seizures.
• Severe cognitive or language impairment.
• Difficulties in learning and interacting with the social environment when returning to life before the disease.

How to prevent Japanese encephalitis

The virus is transmitted mainly by Culex mosquitoes. Therefore, people need to do the following to prevent the disease:

• Children should not play near livestock pens.
• Wash hands regularly with soap, eat cooked food, and drink boiled water.
• Sleep under mosquito nets both day and night to prevent mosquito bites.
• Keep the environment and barns clean so that mosquitoes have no place to rest.
• Isolate well and limit contact with sick people, wear masks when caring for sick people.
• Personal protective measures to prevent mosquito bites are very important, as this will reduce the risk of disease. Vaccination against Japanese encephalitis is the best proactive measure to prevent the disease.

According to statistics and research, children between the ages of 2 and 6 are at the highest risk of contracting Japanese encephalitis. For best prevention, children should receive a booster shot every 3 years until they are 15 years old.