Encephalitis is an acute inflammation of the brain that can be caused by viruses, complications from other illnesses like measles or HIV, or unknown causes. Common symptoms include fever, headache, nausea, vomiting, seizures and neurological deficits. Diagnosis involves brain imaging, spinal fluid analysis, and testing for specific viruses. Treatment focuses on relieving symptoms and preventing complications while the body's immune system fights the infection. Japanese encephalitis virus is a leading cause of viral encephalitis in Asia, spread through mosquito bites. It can cause mild flu-like illness or severe disease with brain damage and death. Prevention emphasizes mosquito control and use of effective JE vaccines in at-risk areas.

1. Encephalitis

2. Encephalitis
Encephalitis Definition: -
It is an acute inflammation of the brain, is a serious and sometimes fatal disease
Aetiology and risk factors: -
•Viruses, cytomegalovirus ,Seasons -Rainy
•certain geographic area- forestry,Ticks and mosquitoes to transmission
•Epstein Barr encephalitis, Japanese encephalitis. La crosse encephalitis,
St Louis encephalitis.West Nile encephalitis, western esquire
encephalitis.Non epidemic encephalitis
•Complication of measles, Chickenpox , Mumps , HIV (Secondary
infection).

3. Clinical manifestations (Acute & subacute)
• Fever
• headache
• nausea
• Vomiting
• hemiparesis
• tremors
• Seizures
• Cranial
• Nerve palsies
• personality changes
• memory impairment
• amnesia & dysphasia.

4. Diagnostic Evaluations: -
-Brain imaging techniques to identify the cerebral lesions, location and affected
area of infection etc. –CT, MRI, PET, PCR
-Blood Screening for presence of infection and the specific microorganism(organ
cells & tissues studies will help before organ donation)
CSF findings of lymphocytic or neutrophilic pleocytosis, elevated protein.
Prevention:-
Mosquito control-
• Cleaning rain gutters
• removing old tires
• Draining bird bath
• Removing water where mosquitoes can breed

5. Management:-
•Acyclovir (Zovirax), Vidarabine - decrease the viral multiplication, length and
severity of disease, and also reduces the spread if mouth to other parts of body.It is
beneficial to start antiviral agents before the onset of complications
Japanese encephalitis
Japanese encephalitis virus JEV is the most important cause of viral encephalitis in
Asia. It is a mosquito-borne flavivirus, and belongs to the same genus as dengue,
yellow fever and West Nile viruses. The first case of Japanese encephalitis viral
disease (JE) was documented in 1871 in Japan.
Clinical Manifestations:
•Mild (fever and headache)
•Without apparent symptoms.
•The incubation period is between 4-14 days. In children
•Gastrointestinal pain and vomiting.

6. •Severe disease is characterized by rapid onset of high fever, headache, neck
stiffness, disorientation, coma, seizures, spastic paralysis and ultimately death.
•The case-fatality rate can be as high as 30% among those with disease symptoms.
•Of those who survive, 20%–30% suffer permanent intellectual, behavioural or
neurological sequelae such as paralysis, recurrent seizures or the inability to speak.
•Initial symptoms are usually nonspecific and might include fever, rigors, headache,
vomiting, and diarrhoea.
•Mental status changes
•Generalized weakness,
•Focal neurologic deficits (e.g., hemiplegia, tetraplegia, or cranial nerve palsies),
and movement disorders might occur over the next few days
•Seizures are common, especially among children

7. •A distinctive clinical presentation of JE is a parkinsonian syndrome resulting from
extrapyramidal involvement, with mask-like facies, tremor, cogwheel rigidity, and
choreoathetoid movements .
•Acute flaccid paralysis, with clinical and pathological features similar to
poliomyelitis, also has been associated with JE virus infection .
•Status epilepticus
•Brain hypoxia,
•Increased intracranial pressure,
•Brainstem herniation,
•Aspiration pneumonia are the most common complications associated with poor
outcome and death
Transmission
•24 countries in the WHO South-East Asia and Western Pacific regions have JEV
transmission risk, which includes more than 3 billion people.

8. •JEV is transmitted to humans through bites from infected mosquitoes of the Culex
species (mainly Culex tritaeniorhynchus).
•Humans, once infected, do not develop sufficient viraemia to infect feeding
mosquitoes. The virus exists in a transmission cycle between mosquitoes, pigs
and/or water birds (enzootic cycle). The disease is predominantly found in rural
and periurban settings, where humans live in closer proximity to these vertebrate
hosts.
•In most temperate areas of Asia, JEV is transmitted mainly during the warm
season, when large epidemics can occur. In the tropics and subtropics, transmission
can occur year-round but often intensifies during the rainy season and pre-harvest
period in rice-cultivating regions.

9. Diagnostic evaluations :-
JEV-specific IgM antibody in a single sample of cerebrospinal fluid (CSF) or serum,
using an IgM-capture ELISA
Management
There is no antiviral treatment for patients with JE. Treatment is supportive to
relieve symptoms and stabilize the patient.

10. Prevention and control
•Safe and effective JE vaccines are available to prevent disease.
•There are 4 main types of JE vaccines currently in use: inactivated mouse brain-derived vaccines,
inactivated Vero cell-derived vaccines, live attenuated vaccines, and live recombinant (chimeric) vaccines.
•Over the past years, the live attenuated SA14-14-2 vaccine manufactured in China has become the most
widely used vaccine in endemic countries, and it was prequalified by WHO in October 2013.
•Cell-culture based inactivated vaccines and the live recombinant vaccine based on the yellow fever
vaccine strain have also been licensed and WHO-prequalified. In November 2013, Gavi opened a funding
window to support JE vaccination campaigns in eligible countries.
•To reduce the risk for JE, all travellers to Japanese encephalitis-endemic areas should take precautions to
avoid mosquito bites.
•Personal preventive measures include the use of mosquito repellents, long-sleeved clothes, coils and
vaporizers. Travellers spending extensive time in JE endemic areas are recommended to get vaccinated
before travel.

11. Thank You