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 • Japanese encephalitis is a viral disease that infects animals and humans • Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is the most important cause of viral encephalitis in Asia based on its frequency and severity.
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.
EVOLUTION • The virus appears to have originated from its ancestral virus in the mid 1500s in the Indonesia-Malaysia region and evolved there into five different genotypes and spread across Asia. • The mean evolutionary rate has been estimated to be 4.35×10(-4) nucleotides substitutions per site per year
CAUSES AND SYMPTOMS • Japanese encephalitis is caused by an arbovirus. • Arbovirus is short for 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, Japanese encephalitis 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
JAPANESE ENCEPHALITIS VIRUS: STRUCTURE
HOST • 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. Animal host Birds Mosquito vectors Breeding places of mosquitoes Irrigated rice fields Shallow ditches. Pools and standing water.
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 • Japanese Encephalitis 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 • Three dose of vaccines • Where disease is endemic travelers can also receive the vaccine • 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