Presentation made by Md. Kabiul Akhter Ali, VBD Consultant, Uttar Dinajpur, West Bengal

1. MD.KABIUL AKHTER ALI
Vector Borne Disease Consultant
NVBDCP, NRHM
District Heath & Family Welfare Samiti
Uttar Dinajpur

2. Overview
Economic impact
History
Epidemiology
Transmission
Clinical Signs
Diagnosis and Treatment
Disease in Humans
Prevention and Control
Actions to Take/Program mode

3. Japanese Encephalitis
Flaviviridae
Flavivirus
The name is derived from
the Latin ‘flavus’
Flavus means “yellow”
 Refers to yellow fever virus
Enveloped
Single stranded RNA virus
Morphology not well defined

4. History
 1870s: Japan
 “Summer encephalitis” epidemics
1924: Great epidemic in Japan
 6,125 human cases; 3,797 deaths
1935: Virus first isolated
 From a fatal human encephalitis case
1938: Isolated from Culex tritaeniorhynchus
1952: First evidence of J E
1955:First case in India
1958:First viral isolation in India
1973:First outbreak inBankura/Burdwan
1978:widespread occurance/monitoring NMEP
Initiation of immunisation –killed mouse brain vaccine

5. Economic Impact
Animals
Porcine
 High mortality in piglets
Equine
 Up to 5% mortality rate
Humans
 Cost for immunization and medical treatment

6. Geographic Distribution
Endemic in temperate and
tropical regions of Asia
Reduced prevalence in Korea Japan
Japan China
Has not occurred in U.S. India Philippine
s
Indonesia

7. Morbidity/Mortality
Swine
High mortality in piglets
Death rare in adult pigs
Equine
Morbidity: 2%, during an outbreak
Mortality: 5%
Humans
Mortality: 5-40%
Serious neurologic sequelae: 45-70%

8. Transmission
Vector-borne disease
Enzootic cycle
Mosquitoes: Culex species
 Culex vishnuii/pseudovishnui/tritinorinchus
 Paddy fields
Reservoir/Amplifying hosts
 Pigs, bats
 Ardeid (wading) birds
 Possibly reptiles and amphibians
Incidental hosts
 Horses, humans,(dead end)

10. Global Problem
Leading cause of viral encephalitis
3 billion live in endemic areas
50000 cases reported annually
10-15 thousand deaths annually
INDIA-33o million live in endemic areas in 15
states/ut
135 districts are affected

11. Clinical Signs: Swine
Incubation period not known
Exposure early in pregnancy more harmful
Birth of stillborn or mummified fetuses
Piglets: Neurological signs, death
Boars: Infertility, swollen testicles

12. Post Mortem Lesions
Horses
Non-specific
Nonsuppurative
meningoencephalitis
Swine
Fetuses
 Mummified and dark in appearance
 Hydrocephalus
 Cerebellar hypoplasia
 Spinal hypomyelinogenesis

13. Differential Diagnosis
Equine
 Other viral encephalitides, Hendra, rabies,
neurotoxins, toxic encephalitis
Swine
Myxovirus-parainfluenza 1, coronavirus, Menangle
virus, porcine parvovirus

14. Sampling
Before collecting or sending any samples, the proper
authorities should be contacted
Samples should only be sent under secure conditions
and to authorized laboratories to prevent the spread
of the disease

15. Diagnosis
Clinical
Horses: Fever and CNS disease
Swine: High number of stillborn piglets
Laboratory Tests
Definitive: Viral isolation
 Blood, spinal cord, brain, CSF
Rise in titer
 Neutralization, HI, IF, CF, ELISA
 Cross reactivity of Flaviviruses

16. Treatment
No effective treatment
Supportive care

17. Clinical Signs-Humans
Incubation period: 5 to 15 days
Most asymptomatic or mild signs
Children < 15 years and Elderly
At highest risk for severe disease
 Elderly: High case fatality rate (30%)
 For every case 200-1000 undetected/asymptomatic cases
 Disease clinical perspective divided into
mild/moderate/severe/asymptomatic cases

18. Clinical Signs: Severe
Acute encephalitis
Headache, high fever, stiff neck, stupor
Severe encephalitis
Paralysis, seizures, convulsions, coma, and death
Neuropsychiatric sequelae
45-70% of survivors
In utero infection possible
Abortion of fetus

19. Post Mortem Lesions
Pan-encephalitis
Infected neurons scattered
throughout CNS
Occasional microscopic
necrotic foci
Thalamus generally severely
affected

20. Diagnosis and Treatment
Clinical
Laboratory Tests
Tentative diagnosis
 Antibody titer: HI, IFA, CF, ELISA
 JE-specific IgM in serum or CSF
Definitive diagnosis
 Virus isolation: CSF sample, brain
No specific treatment
Supportive care

21. Public Health Significance
Strengthening of surveillance
Capacity building for diagnosis/case management to
reduce fatality
Clinical laboratory support/adequacy of medicines in
hospitals
Vector surveillance strengthening
Focused IEC for early reporting
Increasing indigenous capacity of vaccine production

22. Disinfection
Biosafety Level 3 precautions
Chemical
Ethanol, glutaraldehyde, formaldehyde
Sodium hypochlorite (bleach)
Iodine, phenols, iodophors
Physical
Deactivation at 133oF (for 30 minutes)
Sensitive to ultraviolet light and gamma radiation

23. Prevention
Vector control
 Eliminate mosquito breeding areas
 Adult and larvae control( chemical larvicides, Biolarvicides,
larvivorous fish)
 Environmental management
Vaccination
 Equine and swine
 Humans
Personal protective measures
 Avoid prime mosquito hours/IVM
 Space spray-Fogging with pyrethrum/malathion
 Use of repellants /ITN/curtains

24. Prevention(Program mode)
Strengthening JE surveillance- identifying /setting of
50 sentinel sites
12 Apex Referral laboratories(Diagnosis)
Guidelines for AES/JE surveillance
VBD Control Surveillance Unit at BRD Medical
College Gorakhpur
Sub office ROHFW Lucknow at Gorakhpur
NIV Pune unit at BRD Medical College
Gorakhpur(funded by GOI/ICMR)

25. Vaccination
Live attenuated vaccine
Used in equine and swine
Successful for reducing incidence
Inactivated vaccine (JE-VAX)/SA 14-14-2 Chinese-
Single dose IM(Children 1-15 years)
 Used for human beings
 2006-11 districts in 4 states(Assam,Karnataka,WB &UP)
 2007 – Expanded to 27 districts in 9 states
 2008- 23 districts in 9 states covered
 Left out and new cohorts covered in routine immunisation

26. THANK YOU