JAPANESEENCEPHALITIS

SUBASH KUMAR PATRANEWSHREE ROUT3RD SEMESTERS.C.B. MEDICAL COLLEGECUTTACK

DR BIMOCH PROJNA PATYASSOCIATE PROFESSOR, DEPT. OF MICROBIOLOGYS.C.B. MEDICAL COLLEGECUTTACK

INTRODUCTION Japanese Encephalitis is an arboviral infection

of horses, pigs, birds and humans caused by mosquito borne Japanese Encephalitis Virus(JEV) Why the

name ARBO ???ARTHROPOD

BORNE

HISTORY 1871: 1st case of JE 1924: Great epidemic in Japan -6125 human cases, 3797 deaths 1930’s: JE vaccines first became available 1935: Virus first isolated -From a fatal human encephalitis case 1938: Virus first isolated from mosquito

GEOGRAPHICAL DISTRIBUTION

IndiaBangladeshPhilippinesPakistanChina

JapanSri LankaThailandVietnam

Republic of Korea

DISTRIBUTION IN INDIA Mainly in the rural

agricultural areas where flooding irrigation is practised

Transmission is usually during rainy season but can also occur all round the year in tropical areas

Highest incidence in states of:Uttar PradeshAssamBihar

ETIOLOGY

ABOUT THE VIRUS Caused by Arbo Virus CLASS

B Genus: Flavivirus Genome: ss RNA Mol. Weight: 3x106 Dalton Virion: spherical, lipoprotein

enveloped particles40-50nm in diameter3 structural and 7 non

structural proteins

RESISTANCE Temperature: Destroyed by

heating above 56oC for 30 minutes

pH: Inactivated in acidic environment pH 1-3

Survival: sensitive to UV light and gamma irradiation

TRANSMISSION

HOSTS AND VECTORS

Amplifying host: Pig Reservoir host: Ardeid birds (heron, erget) Incidental host: Human, horse, donkey Vector: Mosquito (Culex tritaeniorhynchus)

AMPLIFYING HOSTAn amplifying host is a host in which the level of pathogen can become high enough that a vector that feeds on it will probably become infectious.

PIGS

RESERVOIR HOSTA reservoir host can harbour a pathogen indefinitely with no ill effects

HERON ERGET

INCIDENTAL HOST

An incidental host is an intermediate host that generally does not allow transmission of the virus, thereby preventing the parasite from completing its development

They are also known as dead-end host.

HORSE HUMAN

VECTOR

• Culex tritaeniorhynchus is the chief mosquito vector for JE

• Wide host range• Oviposit in flooded fields• Active during twilight• Other species (ades,

anopheles, mansonia)

CULEX

ENVIRONMENT Flooded fields Fish ponds Rice paddy Ditches

I am so sick

PATHOGENESIS

Manifestation of various neuronal symptoms

Virus proliferates and damages the neuronal tissue

Virus is transported to brain via blood

After multiplication in R.E. system, viremia ensues

Virus enters the body through the bite of mosquito

CLINICAL FEATURESProdermal stage

Acute encephalitic stage

Late stage

Sequale

PRODERMAL STAGE Lasts for 1-6 days Fever, Rigor Headache GI problems Lethargy Malaise

ACUTE ENCEPHALITIC STAGE Convulsions Altered sensorium,

unconsciousness, coma Tremor Abnormal movement of

limbs Mask like face Stiff neck Muscular rigidity

LATE STAGE

Mental impairment Increased deep tendon

reflex Epilepsy Speech impairment Behaviour abnormalities

PATHOLOGICAL FEATURES Perivascular chronic

inflammation Microglial nodules Neuronophagia Neutrophilic

inflammatory filtrate

Bilateral Thalamic Hemorrhage

DIAGNOSIS AND TREATMENT

DIAGNOSIS History Brain tissue analysis CSF analysis: moderately

increased CSF protein Serological tests: JE specific IgM

TREATMENT No antiviral drug for JE

has been found yet Only supportive

treatment:Suction-oxygenIV fluids and mannitolAnti convulsionInj. Paracetamol

JENVAC JENVAC ® is a purified inactivated JE

vaccine Prepared at National Institute of

Virology, Pune 2 doses of 0.5 ml at 28 days interval Booster dose after 1 year

PREVENTION AND CONTROL

Sanitary prophylaxis

Medical prophylaxis

Agricultural practices

Animal reservoir

Vector control

SANITARY PROPHYLAXIS Housing of animals

indoors in screened stabling During JE outbreaks During peak vector

activity Aerial or ground

fogging with ULV insecticides

MEDICAL PROPHYLAXIS

Vaccination of humans, horses and pigs

Available under UIP in 112 endemic districts of India

Travellers are needed to take proper vaccination before visiting the south east Asian countries

AGRICULTURAL PRACTICES

Adopt water management practices of paddy cultivation by having a dry day in a week this will: Conserve water Reduce larval population Increase rice grain yield Reduce emission of methane

Using neem products as fertilizers.

ANIMAL RESERVOIR

Japanese encephalitis was controlled in Japan by vaccinating the pig population

All pig rearing practices must be undertaken away from human habitations

This kind of practice of pig husbandry must be promoted (bank loans)

VECTOR CONTROL Eliminate mosquito

breeding areas Adult and larva control:

ULV insecticides and PPM Cover all water containers,

wells, water storage tanks Use mosquito nets, coil

incenses mosquito repellents

Japanese EncephalitisIn ODISHA

CASE SENARIO IN ODISHA

Most affected district : Malkangiri 1st JE death – 8th Sept 2016 Death toll reached more than 130

Now Odisha has been added to the list of JE high burden state [23rd Nov 2016]

CAUSE

More faith in tantriks than doctors Low availability of doctor

No. of doctors Entire district District HQPresent 23 11Required 115 45

23

Entire District

11

District HQ

EXPERTS SPEAK… Dr John Jacob, CMC Vellore

suspected Cassia Occidentalis beans (bana chakunda) to be culprit

Case similar to Saharanpur, UP case of 2007 (81 deaths)

Vaccination drive started from 5 Dec 2016

REFERENCES