What is Japanese Encephalitis (JE)?
Japanese encephalitis is a viral infection caused by the Japanese encephalitis virus (JEV). There are more than 70,000 cases of JE reported worldwide annually and up to 35% of patients fully recover. However, in more severe cases, it can result in brain swelling (encephalitis), which can be fatal (up to 30% of cases) or lead to long-term cognitive neurological and/or physical disabilities. There is currently no specific treatment available for JE.
How is Japanese Encephalitis Transmitted and Where In The World Are Risk Areas?
Japanese encephalitis is spread through the bite of an infected mosquito, particularly the Culex species. These mosquitoes are typically present in rural parts of Asia and the Pacific Islands. However, the risk for transmission may shift as boundaries between rural regions and urban areas are blurred. Traditionally the risk of infection is higher for those who spend extended periods outdoors or in areas with high mosquito populations. The threat can sometimes be unpredictable with cases being reported in travellers visiting for short time periods, with little to no rural exposure and outside the established transmission season.
Symptoms of Japanese Encephalitis
The majority of infections in humans are asymptomatic. For those who develop symptoms they can range from mild flu-like symptoms to severe neurological manifestations. In more severe cases, the disease can cause:
High fever
Headache
Seizures
Confusion or changes in mental status
Muscle weakness or paralysis
Coma
Up to 50% of survivors may suffer from long-term disabilities including cognitive, neurological and physical disabilities.
Who is at Risk of Japanese Encephalitis?
While Japanese encephalitis is primarily a concern for residents and travelers in endemic regions, certain individuals are at higher risk for contracting the virus. These groups include:
Travelers to endemic areas: Those who are planning to visit rural or agricultural areas in Asia or the Pacific Islands, particularly for longer periods, are at a higher risk of exposure.
People living in or working in areas with high mosquito activity: People who work outdoors, particularly in farming or agricultural settings, are more likely to encounter infected mosquitoes.
Children and elderly individuals: These groups may have weaker immune systems, making them more susceptible to severe illness if infected with JE.
Vaccination Against Japanese Encephalitis in Canada
While Japanese encephalitis is not a common concern in Canada, vaccination is recommended for those traveling to areas where the disease is prevalent (Asia and Australia).
In Canada, IXIARO® is the vaccine against JE. It is indicated for those 2 months of age and older and is a two-dose series, with the second dose given 28 days after the first, ensuring immunization is completed one week prior to departure. There is a rapid schedule available for those aged 18-65 years of age, with the two doses administered 7 days apart, continuing to ensure that the two dose series is completed one week prior to departure.
IXIARO® offers protection for about one year, and a booster dose may be recommended which provides protection for an additional 10 years, especially for those at continuous risk for acquiring JE (ie. those residing in endemic areas).
Conclusion
For travellers heading to regions where Japanese Encephalitis is endemic it is an unpredictable threat. It can potentially be fatal and there is no specific treatment available. Although many infections are asymptomatic, up to 50% of survivors suffer from enduring disabilities. The JE vaccine, IXIARO®, combined with other preventive measures like insect repellent and protective clothing, can significantly reduce the risk of contracting the virus.
If you are planning a trip to an area where Japanese encephalitis is a concern, we at Virtual Wellness Voyage would be happy to discuss appropriate vaccination and preventive measures to ensure a safe and healthy journey. Please see the link below to book a consultation:
If you'd like to further read about pre-travel health, consider reading the blog posts below:
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