National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Encephalitis, Japanese is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Related Disorders List
Information on the following diseases can be found in the Related Disorders section of this report:
- Murray Valley Encephalitis
- Saint Louis Encephalitis
- West Nile Encephalitis
Japanese Encephalitis is a severe inflammation of the brain caused by the Japanese B Encephalitis Virus that is transmitted by the bite of infected mosquitoes in certain areas of the world, particularly Asia. This disorder most commonly affects children and tends to be more actively spread during the summer. Symptoms include high fever, headaches, weakness, nausea, vomiting, paralysis, personality changes, and coma, possibly leading to neurological damage or death.
Japanese Encephalitis is a rare viral disorder characterized by high fever, headaches, weakness, nausea, vomiting, mental deterioration, personality changes, psychoses, impaired speech, spastic rigidity, and paralysis of the face or extremities.
In adults, paralysis may occur on both sides of the body without altered sensation. The duration of symptoms can vary widely and convalescence may be prolonged. Some affected individuals may experience swelling and small areas of bleeding within the brain. Wasting away (atrophy) of brain and nerve cells may also occur. The immune system is also weakened by the virus, potentially making affected individuals vulnerable to more serious infections.
Japanese Encephalitis is caused by the Japanese B Encephalitis Virus, an arbovirus (mediated via insect bites), and transmitted through the bite of infected mosquitoes. Symptoms occur as the virus directly invades the central nervous system causing selective infection, destruction of nerve cells, and weakening of the immune system.
Japanese Encephalitis occurs in approximately 20,000 people each year. The disorder erupts in the form of epidemics usually during the summer months in India, Bangladesh, the eastern part of Russia, China, Korea, Nepal, Burma, Viet Nam, and northern Thailand. In tropical areas of southeast Asia, southern India, southern Thailand, and Sri Lanka, the disease is present year-round and causes sporadic outbreaks. During the tropical rainy season, the illness can be transmitted in epidemic proportions.
Japanese Encephalitis is the leading cause of viral encephalitis in Asia, with approximately 30,000-50,000 cases being reported. Fewer than one case per year is reported among U.S. citizens and military personnel traveling to, or living in, Asia.
Symptoms of the following disorders can be similar to those of Japanese Encephalitis. Comparisons may be useful for a differential diagnosis:
Murray Valley Encephalitis is also known as Australian X Disease and is characterized by severe brain inflammation. The virus which causes this disorder is related to the Japanese B virus and is transmitted from mosquitoes to birds to other mosquitoes. Cases among children tend to be most severe. The first noticeable symptoms may be headache, fever, a general feeling of discomfort, drowsiness and/or convulsions, and a stiff neck. Extensive brain damage may result.
Saint Louis Encephalitis is characterized by less severe inflammation of the brain and the sheath surrounding the brain and spinal cord. Group B Arbovirus causes this type of Encephalitis in sporadic outbreaks in urban areas of Missouri, Arizona, Colorado, Nevada, Texas, Indiana, Illinois, Kentucky, Florida, New Jersey, Pennsylvania, and the Ohio Valley. This disorder tends to be more prevalent during midsummer to early fall. High fever, headache, nausea, vomiting, tiredness, dizziness, neck stiffness, irritability, confusion, and speech problems may occur.
West Nile Encephalitis is also known as West Nile Fever and is characterized by severe headaches, high fever, enlargement of the lymph nodes, and inflammation of the sheath surrounding the brain and spinal cord. Inflammation of the spinal cord may also occur. Symptoms of this disorder may last only a few weeks, but it may cause permanent neurological damage.
In Asian nations, vaccinations are available that prevent Japanese Encephalitis. American travelers to areas at risk can obtain the vaccination in the United States. High risk areas include India, Bangladesh, the eastern part of Russia, China, Korea, Nepal, Burma, Viet Nam, northern Thailand, tropical areas of southeast Asia, southern India, southern Thailand, and Sri Lanka.
Short-term travelers to Asian urban centers are at low risk to contract this disorder. The mosquitoes which transmit the virus appear in the greatest numbers in rural areas where standing water may be common and are most active at dawn, dusk, and on overcast days. Precautions against mosquito bites such as sleeping in screened quarters under mosquito netting, wearing clothing that adequately covers the skin, and using insect repellents on exposed skin are also advised. Repellents containing over thirty percent active ingredient N,N-diethyl-meta-toluamide ("deet") are recommended.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
For information about clinical trials sponsored by private sources, contact:
Thoene JG., ed. Physicians' Guide to Rare Diseases. Montvale, NJ: Dowden Publishing Company Inc; 1995:545-46.
Fauci AS, et al., eds. Harrison's Principles of Internal Medicine, 14th Ed. New York, NY: McGraw-Hill, Inc; 1998:1138 .
Bennett JC, Plum F., eds. Cecil Textbook of Medicine. 20th ed. Philadelphia, PA: W.B. Saunders Co; 1996:1813-14.
Mandell GL, et al., eds. Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases. 4th ed. New York, NY: Churchill Livingstone Inc; 1995:1466-67.
Thompson, RF, et al., Travel vaccines. Infect Dis Clin North Am. 1999;13:149-67.
Sabchareon A, et al., Japanese encephalitis. Ann Trop Paediatr. 1998;18 Suppl:S67-71.
Abe T, et al., Japanes encephalitis. J Magn Reson Imaging. 1998;8:755-61.
Nakashima A, et al., A case of Japanese encephalitis: CT and MRI findings in acute and
convalescent stages. Radiat Med. 1999;17:369-71.
Cuzzubbo AJ, et al., Evaluation of a new commercially available immunoglobulin M capture enzyme-linked immunosorbent. J Clin Microbiol. 1999;37:3738-41.
Defraites RF, et al., Japanese encephalitis vaccine (inactivated, BIKEN) in U.S. soldiers: immunogenicity and safety of vaccine administered in two dosing regimens. Am J Trop Med Hyg. 1999;61:288-93.
Khang G, et al., Preparation and characterization of Japanese encephalitis virus vaccine loaded poly(L-lactide-co-glycide) microspheres for oral immunization. Biomed Mater Eng. 1999;9:49-59.
Robert-Thomson L, Japanese encephalitis. Aust Fam Physician. 1999;28:480.
Transverse Myelitis Association
1787 Sutter Parkway
Powell, OH 43065-8806
Centers for Disease Control and Prevention
1600 Clifton Road NE
Atlanta, GA 30333
NIH/National Institute of Allergy and Infectious Diseases
NIAID Office of Communications and Government Relations
5601 Fishers Lane, MSC 9806
Bethesda, MD 20892-9806
World Health Organization (WHO)
Avenue Appia 20
Geneva 27, 1211
18 North Broadway #404
Tarrytown, NY 10591
North Yorkshire, YO17 7DT
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
For a Complete Report
This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email firstname.lastname@example.org
Last Updated: 4/7/2009
Copyright 1987, 1989, 1993, 2000, 2009 National Organization for Rare Disorders, Inc.
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.