First case of Japanese Encephalitis confirmed in Delhi: What is this viral disease?

Delhi has reported the first case of Japanese Encephalitis in 13 years. The disease, spread by Culex mosquitoes, has a high fatality rate.

In Short

• A case of Japanese Encephalitis has been reported in Delhi
• Japanese Encephalitis is a zoonotic viral disease
• Its vaccine is covered in the Universal Immunisation Programme since 2013

Delhi has reported an "isolated" case of Japanese Encephalitis, a zoonotic viral disease. Health officials have said that there's no reason for alarm and public health measures are being followed, as per guidelines by the National Centre for Vector Borne Diseases Control (NCVBDC).

A Municipal Corporation of Delhi order on November 27 stated that a 72-year-old man from West Delhi was admitted to the All India Institute of Medical Sciences (AIIMS) on November 3 with chest pain.

The patient, who had diabetes, coronary artery disease, weakness in both legs, and bowel and bladder incontinence, tested positive for Japanese Encephalitis on November 6 after a blood sample was taken. He was discharged on November 15.

WHAT IS JAPANESE ENCEPHALITIS?

Japanese Encephalitis (JE) is a zoonotic viral disease which is caused by JE virus.

The virus spreads to humans through the Vishnui group of Culex mosquitoes, which act as vectors between animals, birds (especially those in the Ardeidae family, such as cattle egrets and pond herons), and pigs.

It can cause a fever of varying severity, often impacting the central nervous system. This may lead to severe complications, seizures, and even death, in critical cases.

The disease has a high case fatality rate, and survivors often experience long-term neurological complications to varying degrees.

According to data from the Integrated Disease Surveillance Programme, 1,548 cases of Japanese Encephalitis were reported across 24 states and Union Territories in 2024, with 925 of them from Assam alone.

The central government has included two doses of the Japanese Encephalitis vaccine in the Universal Immunisation Programme since 2013.

For adults, the vaccine has been introduced in high-burden states.

SIGNS AND SYMPTOMS

As per NCVBDC, the Japanese Encephalitis (JE) virus infection shares symptoms with other forms of viral encephalitis.

It often causes a fever and neurological issues, such as headaches, meningitis, or encephalitis. Common symptoms include fever, headache, stupor, disorientation, coma, tremors, paralysis, hypertonia, loss of coordination, and signs of meningitis.

Differentiating JE from other viral encephalitis cases based on symptoms alone can be challenging.

WHAT IS THE TREATMENT?

Currently, there is no specific antiviral treatment for Japanese encephalitis that directly targets the virus. However, supportive care is given to manage the symptoms.

Acetaminophen (paracetamol) could be given to reduce fever and relieve headache or body aches. Adequate hydration is essential, especially if the patient has high fever, vomiting, or diarrhoea.

Intravenous fluids may be administered, if necessary.

(With inputs from PTI)