Encephalitis Bvirus

马

姝

叶

翔

吕卓珍

吕钊鹏

孙晓君

李

艳

姜

蓉

姜振宇

夏文君

秦伟栋

黄俊霞

Biological properties

Also called Japanese encephalitis virus (flavivirus )+ssRNACapsid: Icosahedral symmetry EnvelopedThree kinds of structural proteins

E the glycoprotein on the surface of envelope

M inner surface of the envelope C the protein of the capsid

Antigenicity stability

Picture of Encephalitis B virus

The course of infection the bite of an infected mosquito

Proliferation in the endothelium of capillary and the regional lymph node

Little into the blood caused the first viraemia

Proliferation in the mono macrophage of the spleen and livera secondary viraemia

some cases the virus crosses the blood brain barrier

Encephalitis

Abortive infection

EpidemiologySource of infection and reservior host  

The major source is domestic animal 、 poultry

pig→mosquito→pig Proliferation in mosquito and trans

mit to its eggs.The virus lives in the mosquito for ever.

Vector Culex tritaeniorhynchus( 三带喙库蚊 ) 、

aedes 、 anopheles

Susceptible people

The children under 10 years old is easy to be Infected

Life time long immune to the virus

The Piglet

Characteristics of epidemiology

EB only distributes in Asia.

80 ～ 90% case all focus on July ,August, September.

South china June ～ July ， north china July ～ August, nor

theast August ～ September ， all identical to the density curve of mo

squitoes.

Highly disperse.

Epidemic Region

Encephalitis B

Clinical ManifestationLight type

38 ～ 39 , always consciousness ℃ 嗜睡 commonly no twitch,no evident stimulation to meninx ,reco

very within a week.

Medium type 40 or so hard to conscious such as light coma ,sometimes ℃

twitch ,last 10days or so . Severe type above 40℃ ， coma ， persistently twitch ,may cause fail

ure of respiratory ,manifestation of different extent of mental disorder and paralysis during recovery.

Break-out type high fever ever super high fever, deep coma and r

epeated strongly twitch,may die due to centrally respiratory failure during very short time ,even survivals often have severe sequelae.

coma

above 40℃ ， coma ， persistently twitch ,may cause failure of respiratory ,manifestation of different extent of mental disorder and paralysis during recovery.

twitch

paralysis

Immunity

IgM presents 5~7 days later after infection

IgG hemagglutination inhibition antibody

Neutralization antibody

complement fixation antibody （ no protection ）Stable immunity ， latent infection also can get the immunity

Microbiological detection

Test for cerebrospinal fluid(CSF) PCR 100% specific

Isolation and Identification Necropsy or viral culture using Vero, LLCMK2

and PS cells

Serology test Source of false positive :heterologous flavi

viral antibody

ELISA Test specific IgM Ab in serum or cereb

rospinal fluid

Hemagglutination inhibition test detect IgM antibodes and IgG antibo

dies

Neutralizing test Early stage:IgM later stage:IgG

Complement binding test

Treatment

No specific treatment Interferon-alpha A Mortality

less than 10%

Report

Prevention

Kill mosquitoes

Inoculation of vaccine

live attenuated vaccines

Cell culture-derived inactivated vaccine (primary hamster kidney cell )

children 6 months----10 years

old in epidemic region.