Acute encephalitis

1. ACUTE ENCEPHALITIS: INDIAN
SCENARIO
 Dr.Suresh kumar

2. INTRODUCTION
 Acute encephalitis is a group of similar neurologic manifestation caused by
several different viruses, bacteria, fungus, parasites, spirochetes ,
chemicals/toxins.
 WHO introduced the term AES(Acute Encephalitis Syndrome) in order to
get more number of cases.

3.  DEFINTION
 ETIOLOGY
 EPIDEMIOLOGY
 CLINICAL FEATURES
 DIAGNOSIS
 MANAGEMENT
 PREVENTION AND CONTROL

4. DEFINITION
 Encephalitis : Acute, diffuse, inflammatory process affecting brain
parenchyma – Most commonly viral
 Encephalopathy : Clinical syndrome of altered mental status, manifesting
as reduced consciousness or altered behaviour – Many causes, incl. viral
encephalitis
 Acute Encephalitis Syndrome : Defined as a person of any age, at any
time of year with the acute onset of fever and a change in mental
status(confusion, disorientation, coma, or inability to talk) and/ or new
onset of seizures ( excluding simple febrile sz.)

5.  AES is a spectrum of diseases with equal contribution of JE and non JE
etiology.
 Till date, Japanese encephalitis is the leading cause of AES all over India,
both in pediatric and adult population.

7. EPIDEMIOLOGY OF JE
 Agent
 Geographical Distribution
 Hosts
 Transmission
 Morbidity and Mortality

8.  Definition: JE is an inapparent to acute arboviral infection of horses, pigs
and humans. It’s a zoonotic disease i.e. infecting mainly animals and
incidentally man.

9. AGENT
 Flavivirus related to St. Louis encephalitis
 Most important cause of arboviral encephalitis worldwide, with over
45,000 cases reported annually
 Transmitted by culex mosquito, which breeds in rice fields
 Mosquitoes become infected by feeding on domestic pigs and wild birds
infected with Japanese encephalitis virus. Infected mosquitoes transmit
virus to humans and animals during the feeding process.

10. History of Japanese Encephalitis
 1800s – recognized in Japan
 1924 – Japan epidemic. 6125 cases, 3797 deaths
 1935 – virus isolated in brain of Japanese patient who died of encephalitis
 1938 – virus isolated from Culex mosquitoes in Japan
 Today – extremely prevalent in South East Asia. 30,000-50,000 cases
reported each year.

11. FOUR GENOTYPES OF JE
 Genotype 3 is mostly found in panindia
 Genotype 1 is found in UP and west Bengal
 Genotypes 2 and 4 rarely found in India
 The JE virus is mainly isolated in ardied birds (cattle egrets and pond
herons) – natural reservoirs
 The JE virus multiply in the body of some animals particularly pigs –
amplifying host

13. NATURAL RESERVOIRS

14. Mosquito Vectors
 C. Tritaeniorhynchus
 C. Vishnui
 C. Gelidus
 Anopheles

16. PATHOGENESIS
Virus enters the body through the bite of the insect vector – mosquito
After multiplication in local and regional lymph nodes,viremia of varying
duration ensues
Virus is transported to target organ (brain) via blood
Virus proliferate and damage the neuronal tissue, thereby elicits nervous
manifestations

17. CLINICAL FEATURES
 Incubation Period - 5 to 15 days
 Only 1 in 300 to 1 in 1000 infections develop into encephalitis, rest
asymptomatic
 Course of disease- 3 stages
 Prodromal stage
 Acute encephalitic stage
 Late stage and sequelae

18. PRODROMAL STAGE
 Fever
 Headache
 Nausea,Vomiting
 Diarrhea
 Myalgia
 Lasts for 1 to 5 days

20. ACUTE ENCEPHALITIS STAGE
 Fever
 Irritability
 Altered behaviour
 Convulsions
 Coma
 Signs of increased intracranial tension

21. LATE STAGE
 Aphasis or Dysarthria
 Ocular palsies
 Pyrimidal and extra pyramidal signs in the form of hemiplegia,
quadriplegia, dystonia , choreoathetosis and coarse tremors.

23. SEQUELAE
 Full recovery
 Recovery with residual complications
 Death

24. Morbidity/Mortality
 Swine
– High mortality in piglets – Death rare in adult pigs
 Equine
– Morbidity: 2%, during an outbreak – Mortality: 5%
 Humans
– Mortality: 5-35% – Serious neurologic sequelae: 33-50%

25.  30-50% of the people that survive the infection develop paralysis, brain
damage, or other serious permanent sequelae
 Average period between the onset of illness & death is about 9 days
 In utero infection possible: Abortion of fetus

26. DIFFERENTIATION OF JE AND NON JE,
AES
 Acute fever with altered sensorium persisting for more than 2 hours with
focal seizures of any part of body, suggestive of encephalitis
 Rash with fever excludes encephalitis
 AES with symmetrical neurological signs likely to be cerebral malaria

27. DIAGNOSIS OF AES
 Imaging
 EEG
 CSF fluid analysis

28. IMAGING

29. HSV ENCEPHALITIS

30. JE

31. JE

32. EEG
 EEG usually shows abnormal spikes in acute encephalitis.
 Spikes in temporal lobe region suggestive of HSV Encephalitis

33. CSF STUDY
 High CSF pressure
 Increased WBC count ( usually < 250/cu mm ;predominantly lymphocytes)
 Elevated protein concentration (usually < 150 mg/dl)
 Normal glucose concentration
 Specific diagnostic tests – PCR tests for viruses, culture for bacteria, fungi
and mycobacteria, serology for arboviruses.

34. SEROLOGY
 Detection of virus specific IgM antibody – provide definitive diagnosis
 IgM antibody is present only for 1 to 3 months and hence denote acute
encephalitis

35. TREATMENT OF AES
 A broad spectrum antibiotic such as ceftriaxone – can be stopped when
investigations does not reveal bacterial meningitis
 Acyclovir must be started in all cases of sporadic viral encephalitis – should
be stopped when an alternate diagnosis has been made or HSV PCR is
negative

37. PREVENTION AND CONTROL OF AES
 Surveillance for cases of AES
 Vector control
 Reduction in man vector contact
 Vaccination

38. JE VACCINATION – TWO TYPES
 Inacivated vaccine derived from vero cell prepared from an Indian strain of
JE virus (JENVAC)
 Very safe and effective
 2 doses given 1 month apart

39.  The recently introduced Chinese live attenuated SA 14 14 2 JE vaccine
 Now available in routine immunization in children under universal
immunization program in 181 endemic districts of India since 2011
 NVBDCP has identified 20 hyperendemic districts in assam, UP and west
Bengal for introduction of adult JE vaccination (>15 to 65 yrs)
 Till now, 8 districts have been covered by adult vaccination programme
 In 3rd july 2014, the GOI had announced the introduction the single dose
of JE vaccine for adults in endemic districts

40. RECENT TRENDS OF AES IN INDIA
 In recent years, investigations into large outbreaks of AES have been
negative for JEV
 Instead outbreaks were found to be due to a rhabdovirus (Chandipura
virus) or water borne entero viruses
 Factor might account for Entero viruses replacing JEV as the major cause of
AES is JE vaccination campaigns launched in endemic districts

41.  A multisector approach involving health, water resources, sanitation and
rural development departments is needed for designing and implementing
novel preventive strategies that would focus on containment of water
borne entero viruses and vectors for chandipura virus
 We also need to move from JE surveillance to surveillance for the entire
spectrum of AES

42. THANK YOU