Japanese encephalitis (JE) is a mosquito-borne viral infection that causes encephalitis. It is the leading cause of viral encephalitis in Asia, affecting over 24 countries. In India, JE was first identified in 1955 and is now endemic in 18 states, especially Assam, Bihar, Haryana, Uttar Pradesh, Karnataka, West Bengal and Tamil Nadu. JE has three stages: prodromal, acute encephalitic, and late stages. Diagnosis is based on detecting IgM antibodies in CSF or blood within 7 days of onset. There is no specific treatment, only symptomatic treatment and preventive measures. The best prevention is vaccination of at-risk populations, along with vector

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2.  Japanese encephalitis (JE) is a mosquito-borne
encephalitis caused by a group B arbovirus
(Flavi-virus) and transmitted by culicine
(culex) mosquitoes.

3.  JE is the leading cause of viral encephalitis in Asia and
occurs in almost 24 Asian and Western Pacific countries. In
India JE was first identified in1955 in Tamil Nadu. Presently
it has been reported from different parts of the country. The
disease is endemic in 18 states. Assam, Bihar, Haryana,
Uttar Pradesh, Karnataka, West Bengal and Tamil Nadu are
most affected states.

4.  Mostly cases of JE are asymptomatic. Based on sign
and symptoms JE has three stages-
Prodromal stage.
Acute encephalitic stage. and
Late stage

5.  Onset of prodromal stage is characterized by-
 fever,
 headache,
 gastrointestinal disturbances,
 lethargy and malaise.
 This stage lasts for one to six days

6.  In this stage sign and symptoms related to
encephalitis starts such as-
 High fever,
 Nuchal rigidity,
 convulsions
 difficulty of speech.

7.  Ocular palsies,
 hemiplegia,
 quadriplegia,
 coarse tremors,
 altered sensorium,
 patient may enter into coma.

8.  This stage begins when active inflammation comes to an end.
The temperature touch to normal. Neurological signs become
stationary or tend to improve.
 Convalescence may be prolonged and residual neurological
deficits may stay for some time.
 The case fatality rate varies between 20-40 per cent. The
average period between the onset of illness and death is about
9 days

9. diagnosis of JE is mainly based on serology
using IgM-capture-ELISA which detects
specific IgM in the cerebrospinal fluid or in
the blood of almost all patients within 7
days of onset of disease.

10.  There is no specific treatment for JE. Only
symptomatic treatment is provided along with
rest and adequate fluid. Antipyretic and pain
killers are given to provide symptomatic relief.
Attention is given for preventive measures.

11.  (a) VACCINATION : Vaccination of population at risk is best method
of prevention of JE . Currently, the two primary doses of JE vaccines
are given at 9 and 16 months of age. Recommended primary dose is
0.5 ml subcutaneously and site is left upper arm.

12.  Booster doses are given after 1 year and subsequently
at 3-yearly intervals until the age of 10-15 years.
The vaccine is given subcutaneously in doses of 0.5
ml for children under 3 years and one ml for
children more than 3 years of age. Protective
immunity develops in about one month time after the
second dose.

13.  (b) VECTOR CONTROL: The vector mosquitoes of JE
are widely scattered and not easily amenable to
control. An effective way to deal with them is to
resort to aerial or ground fogging with ultra-low-
volume (ULV) insecticides (e.g., malathion,
fenitrothion). All the villages reporting cases should
be brought under indoor residual spray.

14.  The spraying should cover the vegetation
around the houses, breeding sites and animal
shelters in the affected villages. Uninfected
villages falling within 2 to 3 km radius of the
infected villages should also receive spraying as
a preventive measure.

15.  Other measures to prevent JE includes prevention of
mosquito bite by using mosquito repellants sticks,
mosquito nets, mosquito repellant creams and
removing breeding places of mosquitoes. Imparting
health education regarding prevention of JE also
prevents the disease in general public.

16. By – SURESH KUMAR ( Nursing Tutor )