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Seminar Presentation:

Epidemiology of Japanese Encephalitis

Presenter: Dr Sandhya Rani J

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Outbreak in Gorakpur 2005

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Outbreak of encephalitis in Jalpaiguri district. So far 47 patients have died of JE , 36

patients admitted in hospital.

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Current outbreak 22/7/14

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Introduction History of JE Problem statement List of endemic areas and Outbreaks in last 5 yrs. Epidemiological traid Clinical features, Differential Diagnosis Treatment and Preventive Measures Article on a case in Bellary Situation Analysis in Karnataka References

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Content

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Japanese encephalitis is a viral disease that

infects animals and humans. It is transmitted by mosquitoes In humans causes inflammation of the

membranes around the brain The first time severe epidemics occurred in

Japan Since then it occurred annually and gradually

spread towards S E Asia07-08-2014

Introduction

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Global Picture

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1870’s: “Summer encephalitis” epidemics

1924: Great epidemic outbreak in Japan

1935: Virus first isolated from a fatal human encephalitis case

1938: Virus isolated from Culex tritaeniorhynchus

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History of JE

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1940-1978: Disease spread with epidemics in

China, Korea and India

1955: Disease was first time recognised in India

1972: Outbreaks reported in UP, Assam, West Bengal

1983-1987: Vaccine available in U.S. on investigational basis

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2005: Outbreak in Ghorakpur , UP

2006: Government of India introduced vaccine in UIP schedule in highly endemic states.

2009: National Program for prevention and control of JE

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Type A / Type B JE

Type A Japanese Encephalitis

Encephalitis lethargica

Von Economos disease

Unknown etiology

Type B Japanese Encephalitis

Vector borne disease Viral infection of CNS

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JE virus causes at least 50 000 cases of clinical

disease each year(children < 10 years) Results in 10 000 deaths ,15 000 neuro-

psychiatric sequelae Outbreaks of JE have occurred in several

previously non-endemic areas It is a preventable disease and no specific

antiviral treatment

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Why JE is important for Public Health Experts?

WHO biologicals, http://www.who.int/biologicals/areas/vaccines/jap_encephalitis/en/

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First case was reported in 1955 Outbreaks have been reported from different

parts of the country. 15 states have reported JE incidence Annual incidence ranged between 1714 and

6594 and deaths between 367 and 1665

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Extent of problem in India

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Endemic areas in India

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NVBDCP, updated on 13/3/14

Karnataka

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Time

Agent

Host Environment

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Epidemiological Triad

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Agent: ARBOVIRUSES

Viruses of vertebrates transmitted by hematophagus insect vectors

Special characteristic: Ability to multiply in arthropods

More numerous in tropical than in temperate zones

Flavivirus

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Vector Transmission

Most common type of Mosquito:Culex vishnui group

Culex tritaeniorhynchus

Culex vishnui Culex pseudovishnui

Culex

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Irrigated rice fields Shallow ditches Pools of water

Primarily outdoor resting in vegetation Flight range : 1-3 kms

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Breeding places

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Natural reservoir of infection

Amplifier Hosts

Accidental Host

Dead end Host

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Hosts

Pond heron

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Specific vectors for different geographical and

ecological areas Immune status of various population groups Increased Rainfall Piggeries within 4-5 kms from human

dwellings

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Environment

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Increase in susceptible population High density of Culex mosquitoes Presence of amplifying hosts such as pigs,

water birds etc. Paddy cultivation

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Factors favouring outbreak

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Pathogenesis

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Incubation Period - 5 to 15 days

Only 1 in 300 infections develop into encephalitis.

Prodromal stage: Fever, headache and malaise.

Acute encephalitic stage: Fever, focal CNS signs, convulsion altered sensorium progressing to coma.

Late stage and sequelae: Temperature & ESR normal level, neurological signs become stationary

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Clinical Features

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Suspected case:

Probable Cases:

Laboratory-Confirmed case:

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Case Classification

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Presence of lgM antibody in serum and/ CSF Four fold difference in lgG antibody titre in

paired sera Antigen detection by immunofluroscence Nucleic acid detection by PCR Virus isolation from brain tissue

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Lab investigations

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Meningitis Febrile Convulsions Rey’s Syndrome Rabies Cerebral Malaria Toxic Encephalopathy

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Differential Diagnosis

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There is no specific anti-viral medicine

available against JE virus. Managed symptomatically. In the acute phase maintaining fluid and

electrolyte balance and control of convulsions, if present.

Maintenance of airway is crucial

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Treatment

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Position of the patient

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Reducing the vector density and in taking

personal protection against mosquito Reduction in mosquito breeding sites Piggeries and cattle may be kept away (4-5

kms) from human dwellings Vaccination of all children in endemic areas

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Preventive and control measures

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Outdoor habit of the vector Scattered distribution of cases spread over

relatively large areas Role of different reservoir hosts Specific vectors for different geographical and

ecological areas Immune status of various population groups is

not known making it difficult to delineate vulnerable population groups

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Challenges faced in Prevention and control JE

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JE vaccination campaign was launched during

2006 During 2009-2010 an amount of Rs.2.90

crores was allocated to the JE endemic states Guidelines were developed on AES/JE case

management and on prevention and control 2009

AES/JE treatment facilities at Gorakhpur, Rs.5.88 crores has been released NRHM.

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THE STEPS TAKEN BY GOVT. OF INDIA PREVENTION CONTROL

OF AES/JE

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Two day state level workshop on AES/JE

surveillance and case management

One day orientation training courses for clinicians handling AES/JE cases

In UP, West Bengal, Tamil nadu, Assam, Delhi

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Capacity building by Gov of India

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Types Used in UIP ? Production site ? Central Research Institute,

Kasauli Dosage: Route of administration: Schedule Adverse events Contraindications

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JE vaccine

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Objective: to study epidemiological factors

influencing JE Study design: case series Cases reporting to VIMS, 82 subjects Conclusion: Illiteracy, low socio economic

status and living in unhygienic conditions near rice fields contributed to the high incidence of J.E. in and around Bellary.

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Article on Bellary epidemic 2004-

2005

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Objective: to assess coverage of children in

target age group by JE vaccination In Mandya district the evaluation showed 92%

coverage In Koppal district the evaluation showed 70%

coverage, among the selected sample Only 19.85% of the heads of household had

the knowledge of JE

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A coverage evaluation survey of JE vaccination in two districts, Karnataka.

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It was the longest and most severe epidemic in 3

decades Caused 5,737 cases in 7 districts of eastern Uttar

Pradesh 1,344 persons died Studied viral RNA sequencing1. Abundance of rice fields2. A bowl-shaped landscape allow water to collect in

pools. Heavy rains which caused ideal breeding conditions for mosquitoes

3. High temperature and relative humidity provided a suitable environment for JEV transmission.

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Japanese Encephalitis

Outbreak, India, 2005

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History of JE Endemic areas Epidemiological factors Role of Gov of India JE vaccine

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Lessons learnt

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Operational Guidelines National Programme for Prevention &

Control of JE/AES (NPPCJA) Directorate General of Health Services (Ministry of Health & Family Welfare) National Vector Borne Disease Control Programme, 22-Sham Nath Marg, Delhi- 110054

Details of AES/JE Cases and Deaths from 2008-2014 Directorate of National Vector Borne Disease Control Programme- Delhi.

Guidelines clinical management of acute encephalitis syndrome including japanese encephalitisGOVERNMENT OF INDIA Directorate of National Vector Borne Disease Control Programme 22, Shamnath Marg, Delhi-110054 Directorate General of Health Services, Ministry of Health & Family Welfare AUGUST 2009

WHO biologicals, http://www.who.int/biologicals/areas/vaccines/jap_encephalitis/en/

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References

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Parida MM, Dash PK, Tripathi NK, Ambuj, Santhosh SR,

Saxena P, et al. Japanese encephalitis outbreak, India, 2005. Emerg Infect Dis [serial on the Internet]. 2006 Sep [date cited]. http://dx.doi.org/10.3201/eid1209.060200

Anuradha SK .Epidemiological aspects of japanese encephalitis in bellary, karnataka, India 2010Int J Biol Med Res. 2011; 2(3): 691-695

Kumar KR1, Basha R, Harish BR, Sanjay TV, Vinay M, Prabhu S, Babu R. A coverage evaluation survey of JE vaccination in two districts of Karnataka. J Commun Dis. 2010 Sep;42(3):179-84.

Japanese encephalitis, NVBDCP website07-08-2014

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