Upload
hilary-horn
View
219
Download
0
Tags:
Embed Size (px)
Citation preview
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.
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.
SYMPTOMS
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
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