Japanese Encephalitis

What is Japanese Encephalitis ?
Japanese encephalitis - originally know as the Japanese B encephalitis. Is a mosquito-borne arbovirus infection, with seasonal distribution. It is regional inparts of China, India, Republic of Korea, Japan, Russia Federation, island in the Torres Strait of Australia, Nepal, Thailand, Vietnam, Cambodia, Laos, Philippines, Taiwan, Indonesia, Malaysia and Sri Lanka. Japanese encephalitis virus belongs to the Flaviviridae family, genus Flavivirus. Large outbreaks of Japanese Encephalitis in India and Nepal shows the continuing expansion of the continuing expansion of the geographic range of Japanese encephalitis in recent years.external image 211212-211213-233802-1555254.jpg

What is the cause of Japanese Encephalitis ?
The virus causing Japanese encephalitis is transmitted by mosquitoes belonging to the Culex tritaeniorhunchus and Culex vishnui group, they breed particularly in flooded rice fields. the virus circulates in ardeid birds (herons and egrets). Pigs are amplifying hosts, virus reproduces in pigs and infects mosquitoes that take blood meals, but does not cause disease. The virus spill over into human population when infected mosquitos populations build up rapidly and the human biting rate increases.
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Transmit cycle of Japanese encephalitis

What are the symptom of Japanese Encephalitis ?
Japanese encephalitis has an incubation period of 5 to 15 days, it is characterized by a flu-like illness with sudden onset of fever, chills, headache, tiredness, nausea and vomiting. Vast majority of infections are asymptomatic. Only 1 of 250 infections develop into encephalitis. Symptoms which develop during the acute encephalitic include neck rigidity, cachexia, hemiparesis, convulsions and a raised body temperature between 38 and 41 degrees Celsius.

Can it be cured ?
Nowadays, there are no treatments available to stop or slow the progress of Japanese encephalitis. Antibiotics are not valid against it. Only the symptoms of each patient can be treated. Fluid are given to decrease dehydration and medication are given to decrease fever and pain. Medications are available to attempt to decrease brain swelling. Patient in a coma may need mechanical assistance with breathing. People develop into encephalitis have a 50% death rate.

  1. World Health Organization, WHO. (2010). Water-related diseases, Japanese encephalitis. Retrieved from http://www.who.int/water_sanitation_health/diseases/encephalitis/en/
  2. Department of Health, HKSAR. (2006, June 6). Disease surveillance. Retrieved from www.dh.gov.hk/english/pub_rec/pub_rec_ar/pdf/0405/ch01.05.pdf - 2008-06-06
  3. Western Pacific Region, World Health Organization. (2010). Encephalitis, japanese. Retrieved from http://www.wpro.who.int/health_topics/encephalitis_japanese/
BY: Aran Au 9.5