JAPANESE ENCEPHALITIS Community Health Nursing

Communicable Diseases

1. JAPANESE ENCEPHALITIS

2. INTRODUCTION Japanese encephalitis (JE)is the most important cause of viral encephalitis in Asia. Recent literature maintains that there are nearly 68,000 clinical cases of JE occur each year,with up to 20,400 deaths globally . (Bulletin of WHO ,October 2011). And again among survivors 20-30% suffer with permanent intellectual, behavioural, or neurological problems such as paralysis, recurrent seizures or the inability to speak. The disease is predominantly found in rural and peri-urban areas, where people live in closely with vertebrates.

3. DEFINITION Japanese encephalitis is a virus spread by the infected mosquitoes . Its more common in rural and agricultural areas.

4. EPIDEMIOLOGICAL TRIAD

5. * CAUSATIVE AGENT -It is caused by a group of B arbovirus(flavi virus). -The virus causing Japanese encephalitis is transmitted to man by mosquitoes belonging to the culex ritaeniorhynchus and culex vishnui groups, which breed particularly in flooded rice fields. -These culicines are normally zoophilic ,ie,they prefer to take blood meals from animals.

6. * HOST - All ages and both sexes are affected . -The most affected group is children below the age of 15 years. - Pigs are amplifying hosts: the virus reproduces in pigs and infects mosquitoes while taking blood meals, but does not cause disease.

7. - The natural maintenance reservoir : birds of the family Ardeidae(herons and egrets).Although they do not demonstrate clinical disease, they do generate high viraemias up on infection. -Humans are considered a dead -end host.

8. * ENVIRONMENT - prilmarily the JE virus transmission occurs in rural agricultural areas ,often associated with rice production and flooding irrigation. - In some areas of Asia,this conditions can occur near urban centers. -In temperate areas of Asia, JE virus transmission shows seasonal trend. Human disease usually peaks in the summer and fall. -In the subtropics and tropics ,transmission can occur constantly, often with a peak during the rainy season.

9. TRANSMISSION JE virus is transmitted to humans through the bite of infected culex species mosquitoes, particularly culex triaeniorhynchus.

10. INCUBATION PERIOD An average incubation period is 6-8 days , may range between 4-15days.

11. CLINICAL FEATURES - The prodromal period may last for many days and is characterized by fever , headache, nausea, diarrhea, vomiting and myalgia. -Mental status may be altered ranging from mild confusion to overt coma. Seizures are common among infected especially in children. -headache and meningismus are found among adults.

12. - Tremor or other involuntary movements may be present . - A syndrome of Acute Flaccid Paralysis (AFP). - Fever disappear by the second week, and choreoathetosis or extrapyramidal symptoms may develop.

13. LABORATORY DIAGNOSIS Serum or cerebrospinal fluid (CSF) is tested to find specific IgM antibodies of JE virus. IgM antibodies are usually detectable 3-8 days after onset of illness and continuous for 30-90 days.

14. DETECTION OF ANTIBODIES FROM SERUM Antibodies are detected from serum by Hemagluttination Inhibition Test(HIT), Complement Fixation Test (CFT),Neutralization Test(NT) and immune diffusion.

15. 2. DETECTION OF ANTIGEN FROM CSF Antigen detection tests are; -Immuno Flu orescent Assay (IFA) - Reverse Passive Haemagglutination Test (RPHA).

16. PREVENTION AND CONTROL Early diagnosis is based on recognizing the clinical symptoms and ref erring the patient to hospital. Community should be educated about this. People can suspect JE and seek hospital care based on: ●Fever, loss of consciousness or altered behaviour for 1 hour to 4 days. ●Symptoms like abnormal movements and posture,squint, fits and paralysis.

17. While shifting the patient to hospital: ● Maintain calm,quiet , dark environment. ● Do not fiddle the patient much. ● Facilitate clearance of secretions nose and mouth by turning the head to one side.

18. VACCINATION Inactivated JE vaccine - JENVAC The Vero cell - derived purified inactivated JE vaccine JENVAC was introduced by India in October, 2013. Earlier the vaccine was imported from China. Mass vaccination compaigns JENVAC can be administered as a single dose during epidemics. As a part of the National Immunization Programme in endemic regions - JENVAC is given in 2 doses as a routine immunization .

19. ●Inactivated , Vero cell derived, alum - adjuvanted vaccine (SA 14 - 14-2 strain).Primary immunization consists of two intramuscular doses, 4 weeks apart, booster is recommended after 1year. First dose at 9 months is recommended by IAP. ●Inactivated Vero cell-derived vaccines (Beijing-1 strain). Primary immunization, three doses at a days 0,7 and 28 or two doses given preferably 4 weeks apart (0.25 mL for children <3years, 0.5 mL for all other ages).First booster is given at 12-14 months after primary immunization and after that every 3 years.

20. SURVEILLANCE The component of JE surveillance consists of three major areas; •Clinical surveillance through early diagnosis and management of JE patients at primary health centers . •Vector surveillance in risk areas of JE to assess the vector behaviour and strengthen the system accordingly. •Sero- surveillance to monitor JE specific antibodies in sentinel animals or birds as well to recognize high risk areas.

21. VECTOR CONTROL INTERVENTION STRATEGIES ■ Alternate wet and dry irrigation (AWDI) As recognized ,flooded rice fields have been the ideal breeding place for several mosquito species including those that transmit JE. The alternate wetting and drying of paddy fields, helps in interfering with the development of the mosquito from larvae and pupae to adult which in turn helps as a technique to control the mosquito of JE.

22. BIOLOGICAL CONTROL STRATEGIES Natural fishes like Gambusia affinis, Tilapia spp, Poeciliareticulata or cyprinidae, killfish, nematodes and crustaceans are used in biological control. CHEMICAL CONTROL Deltamethrin,organophosphates and carbamates are used to control vectors.

23. HEALTH EDUCATION ■Educate community on cause,spread , prevention and management of JE. ■Involve community members to keep the surroundings clean. ■Engage community in the activities like filling pools ,draining of accumulated water weekly,lowering water levels in rice fields etc that would cut down the mosquito breeding places.

24. PERSONAL PROTECTIVE MEASURES ●Wear full sleeved clothes . ●Use of mosquito coils. burn neem leaves around the house. ●Avoid water stagnation.

25. ●Avoid sleeping outdoors. ●insecticide treated mosquito nets. ●Apply repellents to avoid mosquito bites. ●eliminate pig farming.

26. MANAGEMENT ●There is no specific treatment available . Most often hospitalized patients are managed with feeding ,airway management, and anticonvulsants for seizure control. ●in rare cases ,relapses occur months after the recovery. These patient's may require long term care and rehabilitation. ●In case of increased intracranial pressure manitol is used.

27. CONCLUSION Japanese encephalitis is a disease with high mortality and leaves behind a cripping disability. It can be prevented by the effective use of vaccine as well by vector control and environmental modification.

28. THANKYOU