Japanese encephalitis

Question 1

Japanese encephalitis - distribution

Answer 1

24 endemic countries in Asia and Pacific

68,000 cases per year

1/3rd die
33-50% have long term disability

Question 2

Japanese encephalitis - organism

Answer 2

JEV - flavivirus [arbovirus]
Culex spp associated mosquito-borne flavivirus
5 genotypes

Question 3

Japanese encephalitis - lifecycle

Answer 3

Zoonotic cycles between pigs and birds
Humans - dead end host

Question 4

Japanese encephalitis - clinical presentation

Answer 4

Asymptomatic >99%
Mainly affects children in endemic areas

Acute encephalitis/meningoencephalitis syndrome
Meningitis
Acute flaccid paralysis

Question 5

Japanese encephalitis - diagnosis

Answer 5

PCR - does not usually detect virus [only short viraemia]

Serology:
Anti-JEV IgM capture ELISA [most commonly used] - CSF or serum

Question 6

Japanese encephalitis - treatment

Answer 6

No evidence for effectiveness of any treatment

Question 7

Japanese encephalitis - vaccinations

Answer 7

4 main types available:
-Inactivated MB [mouse-brain]
-Inactivated vero cell [VC] = Ixiaro
-Live-attenuated
-Chimeric