JAPANESE ENCEPHALITIS

VIROLOGY PRESENTATION

GROUP MEMBERS:

SYEDA KANWAL FATIMA

NIMRAH GHOURI

CONTENTS Introduction Epidemiology Causes Symptoms Life cycle and replication Transmission Diagnosis Treatment and prevention References

INTRODUCTION viral disease Infects animals and humans A mosquito-borne flavivirus JE is mainly a problem in rural farming areas. Occurs more commonly in the rainy season. Affect the CNS and cause severe complications

and death.

TAXONOMY Group: Group IV ((+)ssRNA) Family: Flaviviridae Genus: Flavivirus Species: Japanese encephalitis virus

EPIDEMIOLOGY JE is endemic throughout most of Asia and parts of the

Western Pacific region. Within the JE-endemic region, there are two typical

patterns of transmission:

In areas with temperate climates, most cases occur over a period of several months when the weather is warmest, usually after the monsoons begin or associated with heavy rainfall.

In areas with tropical climates, there is year-round transmission.

7

Distribution of Japanese encephalitis in Asia

Different patterns of age distribution of cases

Distribution of encephalitis cases by age group Andhra Pradesh, India, 2000

6

136

201

00

50

100

150

200

250

Under 1 yr 2 to 5 yrs 6 to 15 yrs 16+ yrs

Num

ber

of C

ases

Death and disability from JE

Up to 30% of all patients with JE die.

For those that survive the illness, 30% to 75% cases are left with disability.

Disability is both physical and cognitive.

Photo credit: Julie Jacobson

EVOLUTION

originated from its ancestral virus in the mid 1500s in the Indonesia-Malaysia region

evolved there into different genotypes and spread across Asia.

CAUSES AND SYMPTOMS

caused by an arbovirus (arthropod-borne virus) Arboviruses are a large group of viruses that are

spread by certain invertebrate animals (arthropods)

most commonly, blood-sucking insects. Like most arboviruses, JE is spread by infected

mosquitoes..

Most infected people develop mild Japanese encephalitis symptoms or no symptoms at all.

In people who develop a more severe disease, Japanese encephalitis usually starts as a flu-like illness, with:

Fever Chills Tiredness Headache Nausea Vomiting. Confusion and agitation can also occur in

the early stage.

AFTER TWO DAYS:

Suffer the effects of swelling in the brain

Prob. With balancing and coordination Tremors Paralysis Seizure Lapses in consciousness Mask like appearance of the face

• if the patient survives the illness, the fever will decrease by about 7 days. And symptoms will begin to improve

• coma and death occur in 7-14 days • Or patient who recover have permanent

disability due to brain damage.

SYMPT

OMS

JAPANESE ENCEPHALITIS VIRUS:

STRUCTURE

Animal hostBirdsMosquito vectors

Breeding places of mosquitoes Irrigated rice fieldsShallow ditches.Pools and standing water.

Animal host Pigs are a major source of reservoir of JE virus. Infected pigs do not show any overt symptoms of illness and can transmit the virus to human beings through mosquito bites. The pigs are considered as “Amplifiers” of the virus.

Birds Pond herons, cattle egrets, poultry ducks ardeid birds appear to be involved in the

natural history of JE virus.

Mosquito vectors C. Vishnui, C. pseudovishnui, C.

tritaeneorhynchus, C. gelidus are the known vectors of JE virus.

HOST

LIFE CYCLE

REPL

ICAT

ION

TRANSMISSION

There is no man to man transmission. Man is only an accidental and dead end host.

Children below the age 15 are often victims of the disease

DIAGNOSIS JE is diagnosed by

detection of antibodies in serum and CSF (cerebrospinal fluid) by IgM capture ELISA

Viral antigen can also be shown in tissues by indirect fluorescent antibody staining

TREATMENT No treatment Fluids are given to decrease dehydration Medication to decrease fever and pain Medication to decrease brain swelling

PREVENTION Personal protective

measures and mosquito elimination are the most important

Control mosquito population with insecticides

Avoid contact with mosquitoes

REFERENCES japanese-encephalitis-epidemiology-diagnosis-

treatment-and-prevention.htm#H3 www.who.int/water_sanitation_health/

diseases/encephalitis/ emedicine.medscape.com/article/233802-

overview www.nhs.uk/conditions/japanese-encephalitis www.cdc.gov/ncidod/dvbid/jencephalitis