The Japanese Encephalitis (JE) virus must be spread through the bite of an infected mosquito and is never transmitted directly from human to human. Japanese Encephalitis is found throughout rural areas from India across southern Asia and into Japan. The virus lives in many types of livestock and jungle animals so it is never eliminated from these areas. Occasionally, outbreaks occur in or around urban areas. Once infected the virus is able to invade the brain and cause serious damage. Symptoms usually appear 6-8 days after being bitten. The symptoms of Japanese Encephalitis are fever, seizures, neck stiffness, changes in consciousness or coma. About 1 in 4 people with Japanese Encephalitis dies. Up to half of everyone who recover from the disease typically suffer some sort of permanent brain damage.
Virtually all health authorities recommend vaccination against Japanese Encephalitis for persons 17 years of age or older who are traveling into JE risk areas. The vaccine is given as 2 shots separated by 28 days and a third shot at 12 months for travelers who continue to be exposed beyond 1 year. However, the risk of infection can vary greatly depending upon the time spent and type of travel a person is engaged in. Persons traveling to an area with Japanese Encephalitis disease should seek a consultation from a travel medicine clinic. A travel medicine clinic is more complete than a visit to your Family Doctor or Health Department unless they specialize in this area.
The Japanese Encephalitis vaccine is not required by any country at this time. This means that a person is permitted to enter the county whether or not they have received vaccination against Japanese Encephalitis. However, healthcare authorities may recommend certain vaccines to travelers for their protection. The likelihood of catching a disease while traveling, and the severity of the disease, clearly outweighs any risk from the vaccination.
JE vaccine is not a live vaccine and can be given with other vaccines. All vaccines, or any medical treatment, typically carries some amount of risk such as: allergy to the medication or adverse side effect. The CDC Vaccine Information Statement for JE vaccine currently reads:
• pain or tenderness where the shot was given (about 1 person in 4)
• redness or swelling where the shot was given (about 1 person in 20)
• headache, muscle aches (about 1 person in 5)
Moderate or Severe Problems
Studies of this vaccine have shown severe reactions to be very rare. Like all vaccines, it will continue to be monitored for serious problems.
Pregnant women are advised not to travel into JE infected areas, the risk posed by vaccination is currently unknown.
The best way to prevent Japanese Encephalitis is to avoid a mosquito bite
Table – Risk for Japanese encephalitis, by country1 CDC.GOV
COUNTRY AFFECTED AREAS HIGH SEASON COMMENTS Australia Outer Torres Strait islands Outer Torres Strait islands 1 human case reported from north Queensland mainland Bangladesh Little data, probably widespread Unknown; most human cases reported May–October 1 outbreak of human disease reported from Tangail District in 1977; sentinel surveillance has recently identified human cases in Chittagong, Dhaka, Khulna, Rajshahi and Sylhet Divisons; highest incidence reported from Rajshahi Division Bhutan No data No data Brunei No data; presumed to be endemic countrywide Unknown; presumed year-round transmission Burma (Myanmar) Limited data; presumed to be endemic countrywide Unknown; most human cases reported from May–October Outbreaks of human disease documented in Shan State; antibodies documented in animals and humans in other areas Cambodia Presumed to be endemic countrywide Year round with peaks reported May–October Sentinel surveillance has identified human cases in at least 14 provinces, including Phnom Penh, Takeo, Kampong Cham, Battambang, Svay Rieng, and Siem Reap China Human cases reported from all provinces except Xizang (Tibet), Xinjiang, and Qinghai; not considered endemic in Hong Kong and Macau, but rare cases reported from the New Territories Most human cases reported June–October Highest rates reported from Chongqing, Guizhou, Shaanxi, Sichuan, and Yunnan provinces; vaccine not routinely recommended for travel limited to Beijing or other major cities India Human cases reported from all states except Dadra, Daman, Diu, Gujarat, Himachal Pradesh, Jammu, Kashmir, Lakshadweep, Meghalaya, Nagar Haveli, Punjab, Rajasthan, and Sikkim Most human cases reported May–October, especially in northern India; the season may be extended or year-round in some areas, especially in southern India Highest rates of human disease reported from the states of Andhra Pradesh, Assam, Bihar, Goa, Haryana, Karnataka, Kerala, Tamil Nadu, Uttar Pradesh, and West Bengal Indonesia Presumed to be endemic countrywide Human cases reported year-round; peak season varies by island Sentinel surveillance has identified human cases in Bali, Kalimantan, Java, Nusa Tenggara, Papua, and Sumatra Japan Rare sporadic human cases on all islands except Hokkaido; enzootic activity ongoing Most human cases reported July–October Large number of human cases reported until JE vaccination program introduced in late 1960s; most recent small outbreak reported from Chugoku district in 2002; enzootic transmission without human cases observed on Hokkaido; vaccine not routinely recommended for travel limited to Tokyo or other major cities Korea, North No data No data Korea, South Rare sporadic cases countrywide; enzootic activity ongoing Most human cases reported May–October Large number of human cases reported until routine JE vaccination program introduced in mid-1980s; highest rates of disease were reported from the southern provinces; last major outbreak reported in 1982; vaccine not routinely recommended for travel limited to Seoul or other major cities Laos Limited data; presumed to be endemic countrywide Year round, with peak June–September Sentinel surveillance has identified human cases in north, central, and southern Laos Malaysia Endemic in Sarawak; sporadic cases reported from all other states; occasional outbreaks reported Year-round transmission; peak October–December in Sarawak Most human cases from reported from Sarawak; vaccine not routinely recommended for travel limited to Kuala Lumpur or other major cities Mongolia Not considered endemic Nepal Endemic in southern lowlands (Terai); cases also reported from hill and mountain districts, including the Kathmandu valley Most human cases reported June–October Highest rates of human disease reported from western Terai districts, including Banke, Bardiya, Dang, and Kailali; vaccine not routinely recommended for those trekking in high-altitude areas or spending short periods in Kathmandu or Pokhara en route to such trekking routes Pakistan Limted data; human cases reported from around Karachi Unknown Papua New Guinea Limited data; probably widespread Unknown Sporadic human cases reported from Western Province; serologic evidence of disease from Gulf and Southen Highland Provinces; a case of JE was reported from near Port Moresby in 2004 Philippines Limited data; presumed to be endemic on all islands Unknown; probably year-round Outbreaks reported in Nueva Ecija and Manila; sporadic human cases reported form other areas of Luzon and the Visayas Russia Rare human cases reported from the Far Eastern maritime areas south of Khabarovsk Most human cases reported July–September Singapore Rare sporadic human cases reported Year-round transmission Vaccine not routinely recommended Sri Lanka Endemic countrywide except in mountainous areas Year-round with variable peaks based on monsoon rains Highest rates of human disease reported from Anuradhapura, Gampaha, Kurunegala, Polonnaruwa, and Puttalam districts Taiwan Rare sporadic human cases islandwide Most human cases reported May–October Large number of human cases reported until routine JE vaccination introduced in 1968; vaccine not routinely recommended for travel limited to Taipei or other major cities Thailand Endemic countrywide; seasonal epidemics in the northern provinces Year-round with seasonal peaks May–October, especially in the north Highest rates of human disease reported from the Chiang Mai Valley; sporadic human cases reported from Bangkok suburbs Timor-Leste Limited data; sporadic human cases reported No data Vietnam Endemic countrywide; seasonal epidemics in the northern provinces Year-round with seasonal peaks May–October, especially in the north Highest rates of disease in the northern provinces around Hanoi and northwestern and northeastern provinces bordering China Western Pacific Islands Outbreaks of human disease reported in Guam in 1947–1948 and Saipan in 1990 Unknown; most human cases reported October–March Enzootic cycle might not be sustainable; outbreaks may follow introductions of virus
The Vaccine Center and Travel Medicine Clinic has ALL the recommended and/or required vaccines needed for your travel:
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