JAPANESE ENCEPHALITIS

February 2010

What is Japanese Encephalitis?

Japanese encephalitis (JE) is a virus which causes swelling of the brain, and possible long-term nerve and brain damage. It is spread to humans by the bite of an infected mosquito and can be prevented with a vaccine.

 

 

 

 

Symptoms

• Can take between 5 to 15 days to appear. It is common for many people to show no symptoms
• In more severe cases
  • usually include sudden onset of fever, headaches, and gastrointestinal symptoms;
  • can also include neck stiffness, disorientation, mental or behavioural changes, generalized weakness, paralysis, coma, seizures, or convulsions and may lead to death.

Transmission

• Japanese encephalitis is spread through the bite of an infected Culex mosquito.
• Mosquitoes that carry Japanese encephalitis bite mainly during the evening and night (dusk to dawn).

Where is Japanese Encephalitis a concern?

• Japanese Encephalitis occurs in almost all Asian countries and occasionally in limited areas of northern Australia and Eastern Russia;
  • It is primarily a threat in rural agricultural areas, particularly in areas where there is widespread irrigation, and in rice-growing areas.
  • In temperate regions such as China, Japan, and Korea, transmission is sporadic with seasonal activity (July to September);
  • In subtropical areas of South-East Asia, (i.e.: Indonesia, Malaysia, Singapore, Thailand, Vietnam, etc.) transmission can occur year-round
• A map of countries and risk areas for Japanese encephalitis is available on the website of the World Health Organization

Recommendations for Travellers

1. Protect yourself from mosquito bites
   1. Cover up: Wear light-coloured, long-sleeved, tucked-in shirts, long pants, shoes (not sandals), and a hat
   2. Use insect repellent on exposed skin
      • Of the insect repellents registered in Canada, those containing DEET are the most effective
      • Use as directed by the manufacturer
      • Do not apply to cuts, abrasions or irritated skin
      • Do not spray directly on the face
      • Wash hands after application, to avoid contact with lips and eyes
      • When using sunscreen: do not use insect repellent and sunscreen combination products
      • If application of sunscreen and repellent with DEET is required, apply the sunscreen first and let it soak into the skin for about 20 minutes, then apply repellent with DEET
      •  After returning indoors, wash off repellent.
   3. sleep under a bed net, preferably treated with insecticide:
      • Ensure the net is intact (no tears or large holes)
      • Tuck it under the mattress
      • Ensure it is not touching you (or you still may be bitten through the net)
   4. Consider your accommodations: Stay in a well-screened or completely enclosed air-conditioned room
   5. Apply a permethrin insecticide to tents and clothing and other travel gear for greater protection:
      
      • Permethrin-treated clothing is effective for up to 2 weeks or 6 washings
      • Although permethrin is not available in Canada, travel health clinics can advise you how to purchase permethrin and pre-treated gear before or during your trip
      • This could be considered for playpens, crib, or strollers to protect babies under six months of age
        
        More information on precautions to take to avoid mosquito bites while travelling…
2. Consider getting vaccinated:
   • Most travellers to countries where Japanese Encephalitis occurs are at low risk; however those who may be at high risk should consult a health care provider to discuss the benefits of getting vaccinated.
   • It is recommended that the following travellers consider getting vaccinated:
     • those spending one month or more in a rural area where JE is present
     • those spending less than one month in a rural area, but spending a large amount of time outdoors, particularly at night.
3. Monitor your health:
   • If you experience symptoms similar to Japanese encephalitis when you are travelling, or after you return from travelling to an area where Japanese encephalitis is found, see a health care professional immediately.

Don't Forget …

1. Consult a doctor, nurse, or health care provider, or visit a travel health clinic at least six weeks before you travel.
2. What to do if you get sick when you are travelling.
3. What to do if you get sick when you return to Canada.
4. Know what vaccines you need and when to get them.

Other Related Information

• Public Health Agency of Canada (PHAC) – Vaccine-Preventable Diseases: Japanese Encephalitis
• Committee to Advise on Tropical Medicine and Travel (CATMAT) – Statement on Protection against Japanese Encephalitis
• CATMAT – Statement on Personal Protective Measures to Prevent Arthropod Bites
• World Health Organization (WHO) – Water-Related Diseases: Japanese Encephalitis
• WHO – Japanese Encephalitis (JE) Vaccines