Doctors in India are advising tourists to seek appropriate vaccination against Japanese encephalitis before visiting the country.
To date, in the Indian state of Uttar Pradesh, more than 300 people have so far died of the disease, and nearly 400 others have been admitted to various government hospitals.
According to reports, the disease has already spread to several districts along the Nepal border and in northern Bihar state, and the affected areas include several Buddhist pilgrimage sites.
Kushinagar in Uttar Pradesh, where at least 54 people have died, is one of the five worst affected districts.
Each year thousands of foreigners arrive in Kushinagar from Nepal via Sonauli, and although many visit for only for a short period, some stay in Kushinagar for a month or longer.
Professor K.P. Kushwaha of Gorakhpur Medical College is advising all tourists who plan to stay for more than 15 days in an affected area, to seek vaccination before they arrive.
Professor Kushwaha said the infection was caused only after prolonged contact with mosquitoes.
Dr T. N. Dhole of the Sanjay Gandhi post graduate medical institute in Lucknow, has called on all embassies to issue health advisories to foreign tourists.
Normally the main tourist season for Buddhist pilgrims begins in October, but some from Sri Lanka, China, Thailand and Japan have already arrived in region.
The affected areas also include the Buddhist pilgrimage sites of Shravasti, Kapilvastu, Lumbini and Kushinagar.