Transcript EPIDEMIOLOGY OF JAPANESE ENCEPHALITIS AND CONTROL MEASURES Dr.I.Selvaraj, I.R.M.S B.SC., M.B.B.S., ( M. D COMMUNITY MEDICINE )., D.P.H., D.I.H., P.G.C.H & FW (NIHFW, NEW DELHI) Sr.D.M.O.

EPIDEMIOLOGY OF
JAPANESE ENCEPHALITIS
AND CONTROL MEASURES
Dr.I.Selvaraj, I.R.M.S
B.SC., M.B.B.S., ( M. D COMMUNITY MEDICINE )., D.P.H.,
D.I.H., P.G.C.H & FW (NIHFW, NEW DELHI)
Sr.D.M.O (ON STUDY LEAVE)
INDIAN RAILWAY MEDICAL SERVICE
Seen in picture is a man rushing his child to
a hospital in Ghorakpur, Uttar Pradesh.)
Doctors look at a child who is being treated for Japanese
Encephalitis at a hospital in Lucknow, India, Thursday,
Sept. 8, 2005. The death toll from an outbreak of Japanese
Encephalitis in northern India has reached nearly 600, as
another 53 people died overnight.
•Japanese Encephalitis is a viral zoonotic disease of Public
health importance, because of its epidemic potential and
high case mortality rate.
•It is a mosquito borne zoonotic disease.
•The virus infects mainly animals through migrating
birds. Pig is the amplifier host. Man is affected incidentally.
•J.E. is primarily a disease of rural,semi urban, agricultural
areas where vector mosquitoes proliferate in close
association with pigs and other animal reservoirs.
•Man to man transmission is not possible.
•The detection of cases are difficult due to the disease appare
and in apparent nature.
•Once the human is infected with the disease it leads to
death in most of the cases.
•If survive the patient will be with severed physical and
neurological complications.
Japanese Encephalitis is a mosquito-borne
viral infection that occurs chiefly in three
areas: (1) China and Korea, (2) the Indian
sub-continent consisting of India, parts of
Bangladesh, southern Nepal, and Sri Lanka,
and (3) the southeast Asian countries of
Burma, Thailand, Cambodia, Laos,
Vietnam, Malaysia, Indonesia and the
Philippines. Japanese Encephalitis also may
occur with a lower frequency in Japan,
Taiwan, Singapore, Hong Kong, and eastern
Russia.
•The virus was isolated for the first time in the world
from a post-mortem human brain in Japan in 1933
•JE was clinically diagnosed for the first time in India
in 1955 at Vellore, erstwhile North Arcot district of
Tamil Nadu.
•Approximately 3 billion people and 60% of the
world's population live in endemic region
•50,000 cases with 10,000 deaths were notified
annually from a wide geographic range.
•In India there was a rise of JE incidence in 1980s and
has dropped significantly and maintained till 1995
•. The major outbreaks coincided with the heavy
rainfall and or floods.
•In India, JE is considered mainly as a pediatric
problem.
JE OUTBREAK INDIA
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Nagpur (1954-1955)
North Arcot , Madras (1955)
Agra,U.P- 1958
W.Bengal – 1973
TN, KA,WB,AP,Bihar,Assam,&U.P-1977-1979
Goa, Kerala, Haryana (samuel et.al.2000) .
1145 cases of Japanese encephalitis have been
reported from 14 districts of Uttar Pradesh
Province, India from 29 July to 30 August 2005.
About one-fourth of these (n=296) have died. 90
cases from the adjoining districts of Bihar have also
been admitted to the hospitals in Uttar Pradesh.
Children romp in a rice
field near Rakshwapar
village in the northern
Indian state of Uttar
Pradesh, a bowl-shaped
breeding ground for
mosquitos that spread
Japanese encephalitis.
This year has been
exceptionally rainy, leaving
mosquito-friendly pools of
water everywhere. At least
850 people, mostly
children, have already died
from the incurable disease.
AREA OF HIGH OCCURRENCE
IN INDIA
• The three southern states of Tamil Nadu
(TN), Andra Pradesh, Karnataka were
reporting higher incidence.
• JE is emerging as a public health
problem in Kerala
• In a few villages of Cuddalore district of
Tamil Nadu, a known JE-endemic area
(Chidambaram, Virudhachalam,
Thittakudi)
TAMILNADU
• In the early 80s cases were reported from
Tamilnadu in the following revenue
districts Tiruvannamalai, Dharmapuri,
Namakkal, Trichirapalli, Dindigul, Theni,
Madurai,Virdhunagar, Tirinelveli, and
Tuticorin.
• However for the past 5 years sporadic cases
are reported from Villupuram,
Cuddalore,and Perambalur districts only.
Incidence of Japanese Encephalitis - Tamil Nadu
YEAR
CASES
DEATH
1995
115
57
1996
111
53
1997
89
42
1998
25
14
1999
14
05
2000
116
17
2001
119
18
2002
126
28
2003
163
36
2004
82
09
• The viruses responsible for these diseases are
classified as arbovirus and these diseases are
collectively called as arbovirus encephalitis.
• JEV is related to St. Louis encephalitis virus,
Murray Valley virus and West Nile virus.
• The virus is antigenically related to several
other flaviviruses including dengue virus.
• JE virus is a member of the family
Flaviviridae.
• I t is a single stranded RNA virus.
• It has three proteins
• A) envelope protein
• B) core protein
Culex mosquito biting human.
FEMALECULEX QUINQUEFASCIATUS
Image: Culex mosquito laying eggs.
(Photograph by Richard G. Weber)
VECTORS
• JEV can be transmitted by mosquitoes in the genera Culex
• major vectors for JEV transmission in India belong to Culex
vishnui subgroup which comprises of Cx. pseudovishnui colles.
• Though JEV has been isolated from 16 species of mosquitoes, the
majority of the isolations are from Cx. vishnui complex, which
breed extensively in rice eco system.
• The disease occurrence coincide with the rainy season
• The predominant mosquito species involved in JEV transmission
breed in rice fields and water surfaces.
• The birds (egrets, pond herons, paddy birds) which a have role in
JEV transmission have close link with rice fields and water.
• . Among the vertebrate hosts, though the cattle populations do not
circulate the virus (dead end), they support the mosquito species
by providing blood meal to them.
• . Establishment of pig forms for economical reasons are related to
human activities in the country side.
• Building reservoirs and canals for agricultural purposes may
harbor potentials for JEV transmission.
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Cx. tritaeniorhynchus -TN, KA, KL
Cx. vishnui
- TN, KA, WB
Cx. Pseudovishnui
- KA, GOA
Cx. bitaeniorhynchus - KA, WB
Cx. epidesmus
- WB
Cx. fuscocephala
- TN, KA
Cx. gelidus
- TN, KA
Cx. quinquefasciatus - KA
Cx. whitmorei
- TN,KA, AP, WB
An. barbirostris - WB
An. paeditaeniatus - KA
An. Subpictus TN, KA, KL
Ma. annulifera - KL, ASSAM
Ma. indiana - KL
Ma. uniformis - KA, KL
• Man is an incidental and dead-end host.
• Man-to-man transmission does not occur in
nature.
• Cattle also act as dead-end host in the transmission
cycle.
• From Ardeid birds, JE infection is transmitted by
mosquitoes to pigs/ducklings.
• The pigs/ducklings serve as amplifying hosts since
thevirus multiplies in them.
. Man or cattle get infected either from birds or
pigs/ducklings through mosquito bite.
. Ardeid bird–mosquito–Ardeid bird and
pig/duckling–mosquito–pig/duckling cycle exist in
• Transmission is usually seasonal
• In temperate zones of China, Japan, Korea
and northern areas of Southeast Asia,
Japanese encephalitis is transmitted during
summer and early autumn -- May to
September.
• In north India and Nepal transmission occurs
from June to November
• In south India and Sri Lanka epidemics are
found from September to January.
• The vast majority of JE infections are in apparent
• only 1 in 250 infections results symptomatic illness
• Most infected persons develop mild symptoms or no
symptoms at all.
• Symptoms soon after exposure appear 6-8 days after the
bite of an infected mosquito.
• The incubation period is about 5-15 days.
• Extrinsic incubation period in vector mosquitoes is 9-12
days.
• Approximately 25-30% of cases are fatal, some with a
fulminate course lasting a few days and others run a more
protracted course in coma.
• . About 30% of those who survive may have sequelae.
• Young children (under 10 years) are more likely to die, and
if they survive, they are likely to have residual neurological
disability and principal sequelae
JE disease manifestations can be divided
into three stages.
•A Prodromal Stage
•An Acute encephalitic Stage
•and a late stage
Prodromal Stage : is characterised by
•Fever
•Rigors
•Headache
•Nausea
•and Vomiting
The Prodromal stage usually lasts for 1 to
6 days. It can be as short as less than 24
hours or as long as 14 days
An Acute Encephalitic Stage:
Begins by the third to fifth day. The symptoms
include:
•Convulsions
•Altered sensorium, unconsciousness, coma
•Mask like face
•Stiff Neck
•Muscular Rigidity
•Tremors in fingers, tongue, eyelids and eyes.
•Abnormal movements of limbs
•Speech impairment
A Late Stage:
Characterised by
•the persistance of signs of CNS
injury such as,
•Mental impairment.
•Increased deep Tendon reflexes
•Paresis either of the upper or lower
motor neuron type.
•speech impairment
•Epilepsy, Abnormal movements,
Behaviour abnormalities.
Differential Diagnosis
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Cerebral Malaria
Meningitis
Febrile Convulsions
Rey’s Syndrome
Rabies
Toxic Encephalopathy
LABORATORY INVESTIGATION
• Peripheral blood picture shows moderate peripheral
leucocytosis with neurophilia and mild anemia.
• CSF: (cerbro spinal fluid) analysis: Neutrophils may
predominate in early CSF samples but a lymphocytic pleocytosis
is typical.
• CSF protein is moderately elevated in about 50% of cases.
• Serological tests: These are to detect antibodies to viral
antigens, which include the plaque reduction virus
neutralization test, hemagglutination inhibition, and
complement fixation. . A significant rise in titer should be seen
with paired samples from the acute and convalescent stages.
• The virus is isolated from CSF by inoculating into 2-4 day old
mice and the virus is identified by haemagglutination inhibition.
Japanese encephalitis virus may also be identified by infection of
cell cultures (chicken embryo or hamster kidney cells, or the
mosquito cell line C3/36) and by IFA.
DIAGNOSTIC FACILITIES: TAMILNADU
• Sera are collected from the J.E. cases and
sent to Virology department, Madurai
Medical college (or) King Institute, Guindy,
Chennai (or) Institute of Vector Control
and Zoonoses, Hosur for
Laboratory diagnosis of J.E. case.
• Vector mosquitoes collected from the field
are sent to CRME, Madurai and Institute
of Vector control and Zoonoses, Hosur for
PCR analysis for detection of virus.
JE CASE CLASSIFICATION, NICD,
NEW DELHI
• SUSPECT: A CASE THAT IS
COMPATIBLE WITH THE CLINICAL
DESCRIPTION
• PROBABLE: A SUSPECT CASE WITH
PRESUMPTIVE LABORATORY
RESULTS
• CONFIRMED: A SUSPECTED CASE
THAT IS LABORATORY CONFIRMED
JE CONTROL STRATEGY
• Early Case Detection and Treatment
• Vector Control
A)REDUCTION OF BREEDING SOURCE
FOR LARVAE
B) REDUCTION IN MAN-MOSQUITO
CONTACT
C) CONTROL OF ADULT MOSQUITOES
. Prevention
A) JE VACCINATION
Reduction of Breeding Source
for Larvae
• They are water management system with
intermittent irrigation system
• incorporation of neem products in rice fields
• The water management is nothing but a
strategy of alternate drying and wetting
water management system in the rice fields.
• This can be implemented only with the coordination of the farmers.
• Introduction of composite fish culture for
mosquito control in rice fields have been
evaluated and proved to be successful.
PIG CONTROL
• segregation
• slaughtering,
• and vaccination
MOSQUITO CONTROL
• spraying,
• draining mosquito habitats,
• or using bednets
JE VACCINE
•INACTIVATED MOUSE BRAIN VACCINE
•It is expensive vaccine, complicated dosing schedule, side effect of this
vaccine.
•Inactivated Mouse brain vaccine
•3-5 US dollars/dose
•9 – 15 US dollars/per child
•The ‘mouse brain vaccine’ manufactured by killing populations of
mice was being manufactured by Central Research Institute, Kasauli.
•LIVE ATTENUATED VACCINE
•SA 14 - 14-2 (Chinese live attenuated vaccine at affordable cost, safe,
effective).
•This vaccine was developed in China and has been used there since 1988.
•it has been licensed and used in South Korea and Nepal and licensed in Sri
Lanka.
•It also appears feasible that a single dose of vaccine will provide life-long
NEW DELHI, DECEMBER 31: The worst of encephalitis
is over but India has finally identified a potential
provider for bulk vaccines — China.
The health ministry has sent a letter of intent to China
and plans to procure five to eight 8 million doses in
2006. The order, sources in the Health Ministry said,
would be placed in a few days. China is the only
country in the world which produces ‘tissue culture
vaccines’ for the disease. Both WHO and PATH, a US-based
non-profit organisation, have assured the Centre it is “safe and
effective”, the official said.
Once the vaccines are procured, the Ministry plans
to immunise all children in the 19 high-risk districts in
Uttar Pradesh, where the disease has been reported
since 1952. ‘‘Procuring vaccine was necessary to
prevent deaths of children in the country,’’ said
P.K.Hota, Secretary in the Health Ministry. Ref:In 2006,
India’s JE vaccines to come from China
Posted online: Sunday, January 01, 2006 at 0127
hours IST
OTHER NEW VACCINE
• A live, attenuated “chimeric” vaccine which uses a
yellow fever vaccine virus strain as its backbone
(ChimeriVax-JE, manufactured by Acambis).
• Clinical trials also are underway for a JE vaccine
candidate manufactured by Intercell. Following a
successful Phase II study in the United States,
Intercell initiated Phase III trials in September 2005
to test the vaccine’s safety and immunogenicity in
nearly 5,000 adult subjects throughout the United
States, Europe, and other countries. This vaccine is
inactivated but does not require mouse brains for
production.
RESEARCH PROJECT:
TAMILNADU
In collaboration with the public health
department, the CRME, Madurai is
undertaking the impregnated curtains
trials at Sirimangalam and Nallur
Primary Health Centres in Cuddalaore
district for control of J.E. vectors.
REFERENCE
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http://www.path.org/projects/JE_in_depth.php
http://www.pon.nic.in/vcrc/jemanag.html
K.PARK
LECTURE NOTES ON MALARIA CONTROL AND OTHER
VECTOR BORNE DISEASES, HOSUR
• MANSON’S TROPICAL DISEASES
• JAPANESE ENCEPHALITIS GLOBALLY AND IN INDIAINDIAN JOURNAL OF PUBLIC HEALTH VOL.XXXXVIII
No.2APRIL-JUNE 2004
• Japanese encephalitis in India: An overview
Kabilan Lalitha, Rajendran R, Arunachalam N, Ramesh S,
Srinivasan S, Philip Samuel P, Dash AP
Centre for Research in Medical Entomology, Madurai, India
Year : 2004 | Volume : 71 | Issue : 7 | Page : 609-615