An “isolated” case of Japanese encephalitis, a zoonotic viral disease, has been reported in Delhi. Health officials have said there is no cause for concern and public health measures are being followed as per the guidelines of the National Center for Vector Borne Disease Control (NCVBDC).

A Delhi Municipal Corporation order on November 27 said a 72-year-old man from west Delhi was admitted to the All India Institute of Medical Sciences (AIIMS) on November 3 due to 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 15 November.

What is Japanese Encephalitis?

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

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

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

The disease has a very high mortality 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 in 24 states and union territories in 2024, of which 925 were from Assam alone.

The central government has included two doses of Japanese encephalitis vaccine in the universal immunization schedule since 2013.

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

Signs and symptoms

According to the NCVBDC, the symptoms of Japanese encephalitis (JE) virus infection are similar to those of other forms of viral encephalitis.

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

It can be challenging to differentiate JE from other viral encephalitis cases based on symptoms alone.

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) may be given to reduce fever and relieve headache or body ache. Adequate hydration is essential, especially if the patient has high fever, vomiting, or diarrhea.

Intravenous fluids may be given if necessary.

(With inputs from PTI)