Japanese Encephalitis(JE), a life threatening disease

What is Japanese Encephalitis(JE):

Japanese encephalitis virus (JEV) is the most important cause of viral encephalitis in entire Asia. It is a mosquito-borne flavi virus, and it belongs to the same genus as dengue, yellow fever and West Nile viruses. The first case of Japanese encephalitis viral disease (JE) was documented in 1871 in Japan.

Why we afraid of:

World Health Organisation report from 24 South-East Asia and Western Pacific countries have endemic JEV transmission, exposing more than 3 billion people to risks of infection. As per data of World Health Organisation it has 68,000 clinical cases every year. In India JE cases are currently being reported from Assam, Bihar, and Arunachal Pradesh.

What is the cause:

Japanese encephalitis (JE) virus, a flavivirus, is closely related to West Nile and St. Louis encephalitis viruses. JE virus is transmitted to humans through the bite of infected Culex species mosquitoes, particularly “Culex tritaeniorhynchus”. Humans, once infected, do not develop sufficient viraemia to infect feeding mosquitoes. The virus exists in a transmission cycle between mosquitoes, pigs and/or water birds (enzootic cycle). The disease is predominantly found in rural and per urban settings, where humans live in closer proximity to these vertebrate hosts.

#What_are_the_symtoms:

Most JEV infections are mild (fever and headache) or without apparent symptoms, but approximately 1 in 250 infections results in severe clinical illness. The incubation period is between 4-14 days. In children, gastrointestinal pain and vomiting may be the dominant initial symptoms. Severe disease is characterized by rapid onset of high fever, headache, neck stiffness, disorientation, coma, seizures, spastic paralysis and ultimately death. The case-fatality rate can be as high as 30% among those with disease symptoms. Of those who survive, 20%–30% suffer permanent intellectual, behavioural or neurological squeal such as paralysis, recurrent seizures or the inability to speak.

What is the cure:

There is no treatment or cure for Japanese encephalitis. Once a person has the disease, treatment can only relieve the symptoms. Antibiotics are not effective against viruses, and effective anti-viral drugs are available. Prevention is the best form of treatment for Japanese encephalitis. However Safe and effective vaccines are available to prevent JE. WHO recommends that JE vaccination be integrated into national immunization schedules in all areas where JE disease is recognized as a public health issue. There are 4 main types of JE vaccines currently in use: inactivated mouse brain-derived vaccines, inactivated Vero cell-derived vaccines, live attenuated vaccines, and live recombinant (chimeric) vaccines.

Over the past years, the live attenuated SA14-14-2 vaccine manufactured in China has become the most widely used vaccine in endemic countries, and it was prequalified by WHO in October 2013. Cell-culture based inactivated vaccines and the live recombinant vaccine based on the yellow fever vaccine strain have also been licensed and WHO-prequalified. 

#What_are_the_immediate_measures_to_prevent:

1. Use a repellent containing 20%-30% DEET or 20% Picaridin on exposed skin. Re-apply according to manufacturer's directions.

2. Wear neutral-coloured (beige, light grey) clothing. If possible, wear long-sleeved, light-weight garments.

3. If available, pre-soak or spray outer layer clothing and gear with permethrin.

4. Get rid of water containers around dwellings and ensure that door and window screens work properly.

5. Apply sunscreen first followed by the repellent (preferably 20 minutes later).

6. Follow insect bite prevention measures.