Japanese encephalitis is a viral disease spread by mosquitoes that infects the brain. It is caused by the Japanese encephalitis virus, which is related to dengue, yellow fever, and West Nile viruses. The virus exists in a transmission cycle between mosquitoes, pigs, and water birds. Humans can be infected when bitten by an infected mosquito, with symptoms including headache, fever, and seizures. There are five genotypes of the virus found globally. The disease occurs principally in rural agricultural areas where mosquitoes breed near pigs, birds, and humans. There is no treatment for the disease, so prevention focuses on mosquito control and vaccination in at-risk areas.

1. JAPANESE ENCEPHALITIS
symptoms, causes & preventions
ADITYA DAS
MSc. 2nd Sem,Dept. of EBWS
Cotton College State University, Panbazar

2. WHAT IS JAPANESE ENCEPHALITIS???
• Japanese encephalitis virus (JEV) -arthropod-borne zoonotic viral disease .
• Japanese encephalitis (JE) is an infection of the brain caused by the Japanese
encephalitis virus.
• The JE virus is a flavivirus related to dengue, yellow fever and West Nile
viruses.
• The virus exists in a transmission cycle between mosquitoes, pigs and/or
water birds. Humans get infected when bitten by an infected mosquito.
• The disease is predominantly found in rural and periurban settings.
• In these cases symptoms may include headache, vomiting, fever, confusion,
and seizures. This occurs about 5 to 15 days after infection.
• JEV is generally spread by mosquitoes, specifically hosts by the Culex
tritaeniorhynchus mosquito and other Culex spp.

3. Few Lines on JEV
• The first outbreak of encephalitis attributed to JEV was reported in Japan in 1871.
• JEV is a virus from the family Flaviviridae, part of the Japanese encephalitis
serocomplex of 9 genetically and antigenically related viruses, some which are
particularly severe in horses, and four known to infect humans.
• It has been noted that Japanese encephalitis infects the lumen of the
endoplasmic reticulum (ER) and rapidly accumulates substantial amounts of viral
proteins.
• Globally, it is responsible for approximately 68,000 clinical cases every year.
• Based on the envelope gene, there are five genotypes (I–V).
• GENOTYPE I = GD is Australia, Northcambodia,India,Japan,China,Thailand
• GENOTYPE II =GD is Malaysia, N.Australia, S.Thailand
• GENOTYPE III =GD is widely distributed in Asia
• GENOTYPE IV = GD is from Indonesia from 1980-1981
• GENOTYPE V = GD is from only Singapore strain from 1951
• The G-I and G-III genotypes are present mostly in temperate epidemic areas,
whereas G-II and G-IV are reported in tropical endemic region.
(GD = global distribution)

4. GEOGRAPHICAL DISTRIBUTION OF JEV

5. TRANSMISSIONof JEV
• The disease principally occurs in rural agricultural areas where
vector mosquitoes breed in the close proximity with pigs, wading
birds and ducks.
• The increase in JEV activity in newer areas has been attributed to
the increase in human population, rice fields and pig farming.
• Moreover, ardeid birds are considered responsible for the long-
distance propagation of JEV and act as a reservoir for the disease.
• Domestic pigs serve as key virus-amplifying host as they develop
high viral as well as and long-lasting natural infection with JEV and
facilitate transmission to humans living in their close proximity.
• Transmission is principally associated with the rainy season in
Southeast Asia, however, can happen throughout the year in
tropical regions.

6. LIFE CYCLEOF JEV

7. HOW DO THEY EFFECT ACTUALLY
• Entry through mosquito bite, the virus infects Langerhans's
dendritic cells in the skin and is carried to nearest draining
lymph nodes initiating a immune response.
• It spreads to secondary lymphoid organs before entering the
blood circulation through the efferent lymphatic system
• During the ensuing transient, peripheral organs such as kidney,
liver and spleen are known to be infected.
• After which the neuro-tropic flavivirus spreads to the CNS.
• The virus effectively affects the brain neurons but not
completely destroying the cells in brain.

8. SYMPTOMS
• sudden onset of headache
• high fever
• Seizures
• Disorientation
• 30%–50% of people with encephalitis
develops permanent neurologic issues.
• Coma
• Death in some cases.

9. GLOBALSCENARIO
• The first outbreak of encephalitis attributed to JEV was reported in
Japan in 1871.
• Major epidemics have been reported about every ten years.
• In temperate regions, transmission is highest during the summer and
early fall, between roughly May and September.
• In some tropical areas, transmission might occur at any time of the year,
depending partly on agricultural practices.
• Postulated explanations are bird migration, certain irrigation projects,
animal smuggling, and global warming.
• Development of rice plantations is theoretically foreseeable in other
regions (Pakistan, Afghanistan, Nile Valley, Madagascar, and Oriental
Africa), creating a favourable environment for further vector
proliferation.

10. DISEASE INCIDENCE IN INDIA
• In India, JE is a leading pediatric health issue and epidemics have been
reported from many regions since 1955.
• A major outbreak occurred in the Bankura district of the state of West
Bengal in 1973, Since then, the virus was found active almost in every
part of India and outbreaks have been reported regularly.
• The most affected states comprise of Andhra Pradesh, Assam, Bihar,
Haryana, Karnataka, Kerala, Maharashtra, Manipur, Tamil Nadu, Orissa,
Uttar Pradesh and West Bengal.

11. Conditions of India
• The three southern states of Tamil Nadu (TN), Andhra Pradesh,
Karnataka were reported in higher incidence.
• JE is emerging as a public health problem in Kerala.
• In India, the fist human case was reported from North Arcot
district of Tamil Nadu in 1955.
• The first epidemic of JE was reported in 1978 in Uttar Pradesh.
• In India, while 24 states are endemic for JE, Uttar Pradesh
contributed more than 75% of cases during the recent past.
• A total of 5,737 cases from 7 districts of eastern UP were
reported of which 1,344 persons succumbed to the disease.

12. CASE REPORTSfrom INDIA
• The first recognition of JE based on serological surveys was in
1955, in Tamil Nadu, India.
• A major outbreak resulting in a 42.6% fatality rate was reported in
the Bankura District of West Bengal in 1973.
• In Uttar Pradesh, the first major JE epidemic occurred in
Gorakhpur in 1978, with 1,002 cases and 297 deaths reported.
• Uttar Pradesh faced a devastating outbreak of JE, mostly confined
to Gorakhpur, with 6,061 cases and 1,500 deaths occurred in 2006.
• Approximately 597,542,000 people in India live in JE-endemic
regions, and 1,500 to 4,000 cases are reported every year.
• In India, the state of Karnataka experiences two epidemics each
year, with a severe form from April to July and a milder one from
September to December along with the rest of India.

13.  C, cases; D, deaths; P, provisionally acute encephalitis syndrome cases
Sl. No.
Affected
States/U
Ts
2004 2005 2006 2007 2008 2009(P) 2010(P)
C/D C/D C/D C/D C/D C/D C/D
1
Andhra
Pradesh
7/3 34/0 11/0 22/0 6/0 14/0 132/1
2 Assam 235/64 145/52 392/119 424/133 319/99 462/92 274/59
3 Bihar 85/28 192/64 21/3 336/164 203/45 325/95 19/0
4 Delhi 17/0 6/0 1/0 0/0 0/0 0/0
5 Goa 0/0 4/0 0/0 27/0 39/0 66/3 23/0
6 Haryana 37/27 46/39 2/1 32/18 13/3 12/10 0/0
7
Karnatak
a
181/6 122/10 73/3 32/1 3/0 246/8
8 Kerala 9/1 1/0 3/3 2/0 2/0 3/0 19/5
9
Maharas
htra
22/0 510 1/0 0/0 24/0 1/0 0/0
10 Manipur 0/0 1/0 0/0 65/0 4/0 6/0 111/5
11
Nagalan
d
0/0 0/0 0/0 7/0 0/0 9/2 11/6
12 Punjab 0/0 1/0 0/0 0/0 0/0 0/0
13
Uttrakha
nd
0/0 0/0 0/0 0/0 12/0 0/0

14. CASE SCENARIOS from ASSAM
• The number of cases of Japanese encephalitis (JE) is on the rise in Assam with as
many as 26 of the 27 districts in the state being affected by it.
• According to figures given by the state government, 2,071 cases of AES and 347
deaths caused by AES have been reported between May and September 17
2015. Out of these, 744 cases and 160 deaths were caused by JE.
• Earlier, we had only 13 such centres for 27 districts in the state. Now, we have
one for each district.
• Initially, cases were mostly reported in the upper Assam districts of Lakhimpur,
Dhemaji, Golaghat, Sivasagar, Dibrugarh, Tinsukia and Jorhat.
• Explaining agricultural patterns as one of the causes, Talukdar said, “The culex
mosquito breeds on water in agricultural land. Now, with multiple cropping,
there is water in the field for several months of the year, and this gives more
time and space to the mosquito to breed.

15. PREVENTION
• As it is said there is not a proper treatment for JEV till now.
• Protect yourself and your family from mosquito bites, use insect
repellent.
• Keep your surroundings clean and dry.
• Different kinds of vaccines (inactivated, attenuated and chimeric) are
available and used in several Asiatic countries.
• consider staying indoors during dawn and dusk hours.
• Inactivated vaccine is available under restrictive regulations for adults
with potential risk of exposure.
• Keep distance from the degraded water filled areas, as mosquitoes breed
there the most.
• Use vaccines if you are more regular to the rural areas while travelling.

16. SOME CLIPS FROM AROUND THE GLOBE

17. THANK YOU