Encephalitis: All About The Monster

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New Delhi:As the death of children in BRD Medical College Hospital Gorakhpur rocked the country, a need for a comprehensive analysis of the disease is essentially required.

According to a research group in the area of human molecular virology and immunology at Institute of Medical Sciences, Banaras Hindu University, led by the head of the Molecular Biology Unit, Dr. Sunit Kumar Singh; emphasizes that most of the JE virus infections area symptomatic with less than 1% of the population developing the disease. JE virus infection primarily occurs in children less than 15 years old, but it has also been reported in adults.

JE virus transmission starts with infected mosquito bite. The patient's central nervous system is affected. It can be caused due to bacterial or viral infections of the brain, injection of toxic substances or increased complications of an infectious disease. In India, Japanese encephalitis has claimed many lives.

What exactly is Japanese encephalitis?

Japanese encephalitis is caused by a flavivirus, which can affect both humans and animals. The virus is passed from animals to humans through the bite of an infected mosquito. Pigs and wading birds are the main carriers of the Japanese encephalitis virus. 
 

JE Symptoms:

Most JEV infections that usually take 5-15 days to develop include fever, headache, vomiting, confusion, neck stiffness, disorientation and difficulty in moving whereas Symptoms that develop later include swelling around the brain, coma, seizures, spastic paralysis and ultimately death.

JE History:

Japanese encephalitis virus JEV is the most important cause of viral encephalitis in Asia. It is a mosquito-borne flavivirus, and belongs to the same genus as dengue, yellow fever and West Nile viruses.

The disease is predominantly found in rural and periurban settings, where humans live in closer proximity to these vertebrate hosts. In mosttemperate areas of Asia, JEV is transmitted mainly during the warm season, when large epidemics can occur. In the tropics and subtropics, transmission can occur year-round but often intensifies during the rainy season and pre-harvest period in rice-cultivating regions.

The first case of Japanese encephalitis viral disease (JE) was documented in 1871 in Japan. The annual incidence of clinical disease varies both across and within endemic countries, ranging from 1 to 10 per 1, 00, 000 population or higher during outbreaks.

A literature review estimates nearly 68 000 clinical cases of JE globally each year, with approximately 13 600 to 20 400 deaths. It primarily affects children but individuals of any age may be affected.

JE viral activity has been widespread in India. The first evidence of presence of JE virus dates back to 1952. Its Outbreaks have been reported from different parts of the country. During recent past (1998-2004), 15 states and Union Territories have reported JE incidence ranged between 1714 and 6594 and deaths between 367 and 1665 in total.

Japanese Encephalitis Treatment and Vaccination: Intensive supportive therapy is indicated as there is no specific therapy for this disease. On the other hand, Inactivated Mouse Brain-Derived JE Vaccine is available against JE in India; manufactured at Central Research Institute, Kasauli, and Himachal Pradesh.

It is a mouse brain killed vaccine and 3 doses are required to produce primary immunization. Two doses are administered sub-cutaneously within a gap of 7-14 days followed by third dose any time after one month and before one year of the second dose. A booster is required after 3 years.

The Vaccine is prepared by subjecting the mouse brain infected with Nakayama strain of JE virus to a sequence of protamine sulphate treatment, formalin inactivation, ultrafilteration and ammonium sulfateprecipitation. The purified product is without myclin basic protean and supplied in a freeze dried form.

“Japanese encephalitis is a vector borne disease and several species of mosquitoes are capable of transmitting JE virus whose transmission intensifies in the rainy season, during which vector population’s increase,” said Dr. Yashveer from Gurgaon.

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Therefore, to prevent mosquito bites:

• Cover exposed skin by wearing long-sleeved shirts, long pants, and hats.
• Use an appropriate insect repellent as directed.
• Higher percentages of active ingredient provide longer protection.
• Stay and sleep in screened or air conditioned rooms.
• Use a bed net if the area where you are sleeping is exposed to the outdoors.

And, if you are bitten by mosquitoes:

• Avoid scratching mosquito bites.
• Apply hydrocortisone cream or calamine lotion to reduce itching.
• Do not take pain relievers that contain aspirin and ibuprofen (Advil), it may lead to a greater tendency to bleed.
• Get lots of rest, and drink plenty of liquids.
• Avoid spreading the disease by preventing more mosquito bites.

JE is one kind of encephalitis which falls under a spectrum of diseases called Acute Encephalitis Syndrome (AES). Doctors in endemic regions in U.P. have found cases with similar symptoms but without the virus, leading to some debate over the cause of the disease. While public health experts have found a difference in case definitions across Eastern districts of U.P., this is something Indian scientific community is still trying to understand.

While Gorakhpur has a considerable burden of disease, many precautionary measures are being taken in the affected areas. The government has also appealed people to be aware and take the precautions.

But, it took 63 deaths for the Union health minister to announce a research facility for Japanese Encephalitis in Gorakhpur but what the minister forgot to mention is that the proposal has been pending since 2014.

References:

http://nvbdcp.gov.in
wwwnc.cdc.gov
http://www.who.int
http://timesofindia.indiatimes.com
http://www.oneindia.com

 

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