Japanese encephalitis has infected dozens of people in many countries in recent months, amid a state of panic among people. What do you know about this deadly disease?
In India, the Assam government has announced the death of at least 63 people due to Japanese encephalitis in the last 37 days, and has set up a rapid response team for the areas on acute encephalitis syndrome and Japanese encephalitis- disease.
The latest figures show 40 human cases of Japanese encephalitis were recorded in Australia on July 19, including 5 deaths from the latest outbreak.
According to the World Health Organization, Japanese encephalitis is the leading cause of viral encephalitis in many countries of Asia with an estimated 68,000 clinical cases each year and 13,600 to 20,400 deaths.
What is Japanese encephalitis virus?
Japanese encephalitis virus (JEV), the major cause of viral encephalitis in Asia, is a virus associated with dengue fever, yellow fever and West Nile viruses and is spread by mosquitoes.
Japanese encephalitis mainly affects children, and most adults in endemic countries have natural immunity after childhood infection, but individuals of any age can be affected.
The first case of viral Japanese encephalitis (JE) was documented in Japan in 1871, with a mortality rate of approximately 30%, and permanent neurological or psychological sequelae may occur in 30% – 50% of people with encephalitis.
Twenty-four countries in the WHO South-East Asia and Western Pacific region have endemic Japanese encephalitis transmission, putting more than 3 billion people at risk.
The National Health Service in the United Kingdom has stated that the virus that causes the disease has been found in pigs and birds, is transmitted to mosquitoes when they bite infected animals, and cannot spread from person to person.
Despite its name, Japanese encephalitis is now relatively rare in Japan due to mass immunization programs.
The risk of Japanese encephalitis is highest during and immediately after rainy seasons, because mosquitoes tend to increase suddenly at this time.
There is also a risk of Japanese encephalitis in countries with a year-round tropical climate.
There are some activities that can increase the risk of infection by making you more likely to come into contact with infected mosquitoes, such as:
Living or traveling in high-risk areas for a long period of time
Visit rural areas, especially during the rainy season
Camping, cycling or working outside in rural areas
Symptoms of Japanese encephalitis
Most people infected with the Japanese encephalitis virus either have no symptoms or develop mild, short-term symptoms, which are often mistaken for the flu.
But about 1 in 250 people who get Japanese encephalitis develop more severe symptoms as the infection spreads to the brain, usually 5 to 15 days after infection.
According to the NHS website, symptoms include:
High temperature (fever).
– Inability to speak
– Jerk out of control.
Muscle weakness or paralysis
Up to 1 in 3 people who develop these more severe symptoms will die as a result of the infection, although these symptoms tend to improve slowly in those who survive.
But full recovery can take several months, and up to half of those who survive suffer permanent brain damage.
This can lead to long-term problems, such as tremors, muscle spasms, personality changes, muscle weakness, learning difficulties and paralysis of one or more limbs.
Japanese encephalitis treatment
There is no antiviral treatment for patients with Japanese encephalitis, and the treatment currently available is supportive to relieve symptoms and stabilize the patient’s condition, according to the WHO.
But safe and effective JE vaccines are available to prevent the disease, and there are currently 4 main types of vaccines: inactivated rat brain-derived vaccines, inactivated Vero cell-derived vaccines, live attenuated vaccines, and live recombinant (chimeric) vaccines.
Prevention of Japanese encephalitis
The best way to prevent Japanese encephalitis is to get vaccinated against the infection before visiting a part of the world where there is a risk of contracting it.
In addition to getting vaccinated, you should take precautions to reduce your risk of being bitten by an infected mosquito, such as:
Sleep in rooms with appropriate screens over windows and doors.
Sleep with a mosquito net moistened with an insecticide.
Use of mosquito repellent
Covered with long sleeves, trousers and stockings.
Use a high-quality insect repellent on exposed areas of the skin.