Travel Health Advisory
Update: October 20, 2005
The Public Health Agency of Canada (PHAC) is monitoring outbreaks of Japanese encephalitis (JE) in India and Nepal.
India
As of October 14, 2005, the state of Uttar Pradesh has reported 4.679 suspected cases, including 1.016 deaths, of Japanese encephalitis (JE), since the outbreak first began in July. Of the total suspect cases reported, 352 cases and 84 deaths are from the adjoining state of Bihar.
Nepal
As of September 27, 2005, Nepal has reported a total of 1.879 cases, including 298 deaths, of Japanese encephalitis. Of these, 1.636 cases and 262 deaths have occurred in the western, mid-western and far-western regions of Nepal, which borders the state of Uttar Pradesh in India.
Source: WHO
Japanese encephalitis, a flavivirus, is a mosquito-borne viral disease that is primarily transmitted to humans through the bite of an infected mosquito. Wild and domesticated animals, such as pigs and birds, are the principal hosts for JE virus. The majority of infections are mild with little or no symptoms. In cases where severe infection occurs and illness develops, approximately 30% of cases are fatal and between 33% to 50% of survivors are left with permanent psychologic and neurologic effects. In Asia, more than 50,000 cases of JE are reported annually. Children under the age of ten years and the elderly are most at risk.
Mosquitoes that commonly transmit JE are most heavily concentrated in rural, rice growing areas and feed most actively in the late afternoon and early evening. Transmission may occur year-round, but epidemics usually begin during the rainy season when mosquito populations are at their highest levels. In the temperate regions of China, Japan, Korea, and the eastern areas of the Russian Federation, transmission tends to be between May and September. In sub-tropical and tropical areas, transmission periods are extended and vary with the rainy season. Agricultural irrigation is also an important factor, as flooded rice fields are excellent breeding grounds for mosquitoes.
JE is endemic in parts of China, India, Korea, Japan, the South East Russian Federation, Islands in the Torres strait Australia, Nepal, Thailand, Vietnam, Cambodia, Lao PDR, the Philippines, Taiwan, Indonesia, Malaysia, and Sri Lanka. Large outbreaks are known to occur in India and Nepal.
The incubation period for JE ranges from 5 to 15 days and presents with a range of symptoms depending on the severity of infection. Minor infections may only result in fever and headache, while the symptoms associated with sever infections include quick onset, headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions (especially in infants) and spastic paralysis. Acute encephalitis; can progress to paralysis, seizures, coma and death.
Although there is no cure or treatment, an inactivated vaccine is available for use in Canada to protect against the development of symptomatic disease.
Recommendations:
Canadians traveling to the states of Uttar Pradesh and Bihar in India
and/or to Western Nepal are advised to obtain an individual risk assessment
with a travel medicine physician or their family physician four to six
weeks prior to their departure, to determine both the risk of exposure
to and the need for vaccination against JE, as determined by their travel
itinerary and medical history.
Furthermore, the personal insect protective
measures that follow are very effective at preventing arthropod-borne
diseases and are recommended for all travellers to JE endemic and/or
epidemic areas.
stay in well-screened or completely enclosed, air-conditioned accommodation;
sleep under insecticide-treated bed nets;
wear clothing that reduces the amount of exposed skin; wear long-sleeved shirts (tightly weaved material, sleeves down, buttoned/zipped up, tucked into pants) and long pants (tucked into socks or footwear);
light-coloured clothing may be less attractive to some mosquitoes and make mosquitoes more noticeable;
use DEET-based products as repellents on exposed skin. The higher the concentration of DEET in the repellent formulation, the longer the duration of protection. However, this relation reaches a plateau at about 30% to 35%. DEET formulations that are "extended duration" (ED), such as polymers, are generally considered to provide longer protection times, and may be associated with less DEET absorption. Formulations over 30% are not currently available in Canada, although they are available internationally, including in the United States. It should be noted, however, that products sold outside Canada have not been evaluated by Health Canada's Pest Management Regulatory Agency (PMRA). Most repellents containing "natural" products are effective for shorter durations than DEET and for this reason are not considered the preferred products for protecting against mosquito bites.
Note: Regulatory agencies in western nations may differ regarding the recommended maximum concentration and application rates of DEET, especially for children. The Committee to Advise on Tropical Medicine and Travel (CATMAT) is satisfied that, for travel outside of Canada where the risk of mosquito-borne diseases (malaria, JE, dengue) outweighs the risk of any important adverse reaction to DEET, the threshold for use of DEET should be low.
CATMAT recommends that concentrations of DEET up to 35% can be used by any age group.
For children, alternative personal protective measures, such as mosquito nets treated with insecticide, should be the first line of defence, especially for infants less than 6 months of age. Portable mosquito nets, including self-standing nets, placed over a car seat, a crib, playpen, or stroller help protect against mosquitoes. However, as a complement to the other methods of protection, the judicious use of DEET should be considered for children of any age. Recent medical literature from Canada suggests that DEET does not pose a significant or substantial extra risk to infants and children.
DEET/sunscreen combination products are not generally recommended, because DEET can decrease the efficacy of sunscreens. As well, sunscreens should be used liberally and often while DEET should be used sparingly and only as often as required. If application of both is necessary, the Canadian Dermatology Association recommends that the sunscreen be applied first and allowed to penetrate the skin for 20 minutes, prior to applying DEET.
Travellers are reminded that JE occurs in many areas in the regions
of east, southeast and middle south Asia, the far eastern Russian Federation,
and some of the Pacific islands and that outbreaks of JE in these areas,
are not uncommon.
As a reminder...
The Public Health Agency of Canada routinely recommends that Canadian international travellers consult their personal physician or a travel clinic prior to international travel, regardless of destination, for an individual risk assessment to determine their individual health risks and their need for vaccination, preventative medication, and personal protective measures.
The Public Health Agency of Canada recommends, as well, that travellers who become sick or feel unwell on their return to Canada should seek a medical assessment with their personal physician. Travellers should inform their physician, without being asked, that they have been travelling or living outside of Canada, and where they have been.
Additional Information
The Public Health Agency of Canada's Committee to Advise on Tropical Medicine and Travel Statement on Japanese Encephalitis Vaccine provides comprehensive information on Japanese encephalitis, including information on immunization and geographic regions where transmission is a risk; it can be accessed through the following link: Canada Communicable Disease Report
Update:
October 20, 2005
[Information for Travellers]
[Information for Travel Medicine Professionals]
