Japanese encephalitis virus is harboured by pigs and birds and transmitted to humans through the bite of infected Culex mosquitoes; however, no human to human transmission occurs. These mosquitoes breed in rice paddies and feed outside in the hours around dusk, so the virus may be found in both cities and rural areas.
Encephalitis has taken 102 lives in north Bengal in the past month and about the same number of people have died so far in West Bengal. Recent reports from Vietnam and Hong Kong say the risk has increased this year, thought to be connected to climate change and increased rainfall.
Twenty-four countries in the WHO South-East Asia and Western Pacific regions have endemic JE transmission, exposing more than 3 billion people to risks of infection.
There are 30-68,000 cases reported annually with 10-15,000 deaths per annum. In Asia the normal Incubation period of the disease is five to 15 days with an Illness that usually lasts around 10-14 days. Convalescence may be up to four to six weeks.
Various symptoms are associated with the disease such as fever, headache, convulsions, encephalitis, meningitis, cranial nerve paralysis, and may progress to brain damage and death.
All travellers to Asia should be aware of the risks and consequences of Japanese encephalitis and should take great care not to be bitten, by use of insect repellents containing 40% DEET (diethyltolumide) or picaradin and mosquito nets.
Clothing spray containing EX4 is useful too as it helps prevents all mosquito borne diseases. Vaccination should be considered for repeated visits to, or prolonged stays in endemic regions, especially if staying in rural areas and for short stays in rural areas during outbreaks - often during the rainy season when the mosquitoes are most active
The vaccine consists of two doses which should be given about 28 days apart and then boosted at 12 -24 months.
For more information and your own personal consultation tailored to meet your needs contact us at The Travel Clinic Ltd, Cambridge and Ipswich.
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