MD.KABIUL AKHTER ALI Vector Borne Disease Consultant

NVBDCP, NRHMDistrict Heath & Family Welfare Samiti

Uttar Dinajpur

OverviewEconomic impactHistoryEpidemiologyTransmissionClinical SignsDiagnosis and TreatmentDisease in HumansPrevention and ControlActions to Take/Program mode

Japanese EncephalitisFlaviviridae

FlavivirusThe name is derived from

the Latin ‘flavus’ Flavus means “yellow”

Refers to yellow fever virus

EnvelopedSingle stranded RNA virusMorphology not well defined

History1870s: Japan

“Summer encephalitis” epidemics1924: Great epidemic in Japan

6,125 human cases; 3,797 deaths1935: Virus first isolated

From a fatal human encephalitis case1938: Isolated from Culex tritaeniorhynchus1952: First evidence of J E1955:First case in India1958:First viral isolation in India1973:First outbreak inBankura/Burdwan1978:widespread occurance/monitoring NMEPInitiation of immunisation –killed mouse brain vaccine

Economic ImpactAnimals

Porcine High mortality in piglets

Equine Up to 5% mortality rate

Humans Cost for immunization and medical treatment

Geographic DistributionEndemic in temperate

and tropical regions of Asia

Reduced prevalence in Japan

Has not occurred in U.S.

Japan

China

Korea

Indonesia

India

Philippines

Morbidity/MortalitySwine

High mortality in pigletsDeath rare in adult pigs

EquineMorbidity: 2%, during an outbreakMortality: 5%

HumansMortality: 5-40%Serious neurologic sequelae: 45-70%

TransmissionVector-borne diseaseEnzootic 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)

Global ProblemLeading cause of viral encephalitis3 billion live in endemic areas50000 cases reported annually10-15 thousand deaths annuallyINDIA-33o million live in endemic areas in

15 states/ut135 districts are affected

Clinical Signs: SwineIncubation period not knownExposure early in pregnancy more

harmful Birth of stillborn or mummified fetuses Piglets: Neurological signs, deathBoars: Infertility, swollen testicles

Post Mortem LesionsHorses

Non-specificNonsuppurative

meningoencephalitisSwine

Fetuses Mummified and dark in appearance Hydrocephalus Cerebellar hypoplasia Spinal hypomyelinogenesis

Differential DiagnosisEquine

Other viral encephalitides, Hendra, rabies, neurotoxins, toxic encephalitis

SwineMyxovirus-parainfluenza 1, coronavirus,

Menangle virus, porcine parvovirus

SamplingBefore 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

DiagnosisClinical

Horses: Fever and CNS disease Swine: High number of stillborn piglets

Laboratory TestsDefinitive: Viral isolation

Blood, spinal cord, brain, CSFRise in titer

Neutralization, HI, IF, CF, ELISA Cross reactivity of Flaviviruses

Treatment No effective treatmentSupportive care

Clinical Signs-Humans

Incubation period: 5 to 15 daysMost asymptomatic or mild signsChildren < 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

Clinical Signs: SevereAcute encephalitis

Headache, high fever, stiff neck, stuporSevere encephalitis

Paralysis, seizures, convulsions, coma, and death

Neuropsychiatric sequelae45-70% of survivors

In utero infection possibleAbortion of fetus

Post Mortem LesionsPan-encephalitisInfected neurons

scattered throughout CNS

Occasional microscopic necrotic foci

Thalamus generally severely affected

Diagnosis and TreatmentClinicalLaboratory 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 treatmentSupportive care

Public Health SignificanceStrengthening of surveillanceCapacity building for diagnosis/case

management to reduce fatalityClinical laboratory support/adequacy of

medicines in hospitalsVector surveillance strengtheningFocused IEC for early reportingIncreasing indigenous capacity of vaccine

production

DisinfectionBiosafety Level 3 precautionsChemical

Ethanol, glutaraldehyde, formaldehydeSodium hypochlorite (bleach)Iodine, phenols, iodophors

PhysicalDeactivation at 133oF (for 30 minutes)Sensitive to ultraviolet light and gamma

radiation

PreventionVector control

Eliminate mosquito breeding areasAdult and larvae control( chemical larvicides,

Biolarvicides, larvivorous fish)Environmental management

VaccinationEquine and swineHumans

Personal protective measuresAvoid prime mosquito hours/IVMSpace spray-Fogging with pyrethrum/malathionUse of repellants /ITN/curtains

Prevention(Program mode)Strengthening JE surveillance- identifying

/setting of 50 sentinel sites12 Apex Referral laboratories(Diagnosis)Guidelines for AES/JE surveillanceVBD Control Surveillance Unit at BRD

Medical College GorakhpurSub office ROHFW Lucknow at GorakhpurNIV Pune unit at BRD Medical College

Gorakhpur(funded by GOI/ICMR)

VaccinationLive attenuated vaccine

Used in equine and swineSuccessful 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

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